2024 |
Melchers RE, 'Corrosion at the Steel Medium Interface', Corrosion and Materials Degradation, 5 52-72 [C1]
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2024 |
Richardson PJ, Melchers RE, 'Short- to medium-term corrosion of mild steel in highly calcareous seawaters: effects of calcium carbonate concentration, coupon orientation and nutrient addition', CORROSION, (2024) [C1]
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2024 |
Chaves IA, Petersen R, Melchers RE, Jeffrey R, 'Corrosion of the interior steel surfaces of offshore monopiles', SHIPS AND OFFSHORE STRUCTURES, 19 125-133 (2024) [C1]
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Nova |
2024 |
Melchers RE, 'Trends in Longer-Term Corrosion Loss of Magnesium Alloys', Crystals, 14 172-172
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2023 |
Laleh M, Huo Y, Melchers RE, Tan MY, 'Electrode array probe designed for visualising and monitoring multiple localised corrosion processes and mechanisms simultaneously occurring on marine structures', npj Materials Degradation, 7 [C1]
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Nova |
2023 |
Melchers RE, Humphrey H, 'Concrete Alkali Aggregate-Reactivity-Induced Steel Reinforcement Corrosion', Corrosion and Materials Degradation, 4 428-444 [C1]
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Nova |
2023 |
Petersen RB, Melchers RE, 'Development of Pitting Corrosion for Mild Steel Exposed to Particulate Media and Natural and Nutrient-Dosed Seawaters', CORROSION, 79 121-131 (2023) [C1]
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Nova |
2023 |
Melchers RE, Richardson PJ, 'Carbonation, Neutralization, and Reinforcement Corrosion for Concrete in Long-Term Atmospheric Exposures', Corrosion, 79 395-404 (2023) [C1]
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Nova |
2023 |
Melchers RE, Tan MY, 'Long-term corrosion of abandoned offshore steel infrastructure', Corrosion Engineering Science and Technology, 58 712-722 (2023) [C1]
A common practice in the offshore oil and gas (O&G) industry is to leave abandoned decommissioned pipelines and other steel infrastructure on the seafloor. Decisions about lon... [more]
A common practice in the offshore oil and gas (O&G) industry is to leave abandoned decommissioned pipelines and other steel infrastructure on the seafloor. Decisions about long-term environmental and other impacts and about the possibility of recovery require estimates of the likely long-term rate of deterioration, including corrosion loss and pit depth. These are considered as functions of time and environmental conditions including seawater temperature, dissolved oxygen concentration, salinity, seawater velocity, water pollution, microbiological activity, water depth, calcareous deposition and the effect of burial, all interpreted using established physico-chemical behaviour relevant for long-term exposures. Data for exposures up to some 600 years in seawaters are reviewed. Remaining research gaps and future perspectives of marine corrosion control are briefly discussed. Specific attention is given, by way of an example, to the influence on long-term durability of protective coatings and remnant cathodic protection, both areas in which further research is required.
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Nova |
2023 |
Petersen RB, Melchers RE, 'Pitting Corrosion of Mild Steel in Long-Term Contact with Particulate Media in Seawater', Corrosion, 79 1040-1051 (2023) [C1]
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Nova |
2023 |
Melchers RE, 'Mechanisms in Long-Term Marine Corrosion of Steel Reinforcement in Concretes', Corrosion, 79 380-387 (2023) [C1]
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Nova |
2023 |
Melchers RE, 'Internal corrosion of seabed parked steel oil and gas pipelines', Ocean Engineering, 276 (2023) [C1]
Seabed ¿parking¿ of steel pipelines is a common practice in the oil and gas industry. For ¿wet parking¿ severe internal corrosion, often at the 6 o'clock position, remains an... [more]
Seabed ¿parking¿ of steel pipelines is a common practice in the oil and gas industry. For ¿wet parking¿ severe internal corrosion, often at the 6 o'clock position, remains an issue, despite the use of corrosion inhibitors and biocides ostensibly to control microbiologically influenced corrosion. Biocides may have undesirable environmental consequences if eventually or accidently released. Recent findings for internal corrosion inside water injection pipelines are reviewed as these have implications for managing the internal corrosion of parked pipelines. After initial oxygen controlled corrosion longer term corrosion can occur under anaerobic conditions. This has implications for corrosion during periods of stagnant conditions and for corrosion under deposits of rusts and other debris. Microbiologically influenced corrosion can increase internal corrosion but only if the nutrients necessary for bacterial metabolism are available. Acceptably low levels of corrosion can be achieved inside ¿wet¿ parked pipelines with the use of seawater with low concentrations of particulate matter and low concentrations of microbiologically-critical nutrients.
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Nova |
2022 |
Chaves IA, Melchers RE, Nascimento BJD, Philips J, Masia M, 'Effects of inter-cavity corrosion on metallic wall ties in masonry structures', AIMS Materials Science, 9 311-324 (2022) [C1]
An important structural component for cavity brick and masonry-veneer construction are wall ties. Typically, they are galvanized steel, sufficiently strong to provide continuity f... [more]
An important structural component for cavity brick and masonry-veneer construction are wall ties. Typically, they are galvanized steel, sufficiently strong to provide continuity for transmission of direct and shear forces. However, field observations show they are prone to long-term corrosion and this can have serious structural implications under extreme events such as earthquakes. Opportunistic observations show corrosion occurs largely to the internal masonry interface zone even though conventional Code requirements specify corrosion testing for the whole tie. To throw light on the issue electrochemical test for 2 grades of galvanized ties and 316 stainless steels combined with three different mortar compositions are reported. Most severe corrosion occurred at the masonry interface and sometimes within the masonry itself. Structural capacity tests showed galvanized ties performed better than stainless steel ties in lieu of stainless steel R4 class ties presenting significantly greater relative losses of yield strength, ultimate tensile strength and elongation structural capacity compared to R2 low galvanized and R3 heavy galvanized tie classes.
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Nova |
2022 |
Bobby Kannan M, Rahuma M, Khakbaz H, Melchers R, 'Antipsychotic drug waste: A potential corrosion inhibitor for mild steel in the oil and gas industry', Waste Management, 145 38-47 (2022) [C1]
In this study, the corrosion inhibition efficiency of thioridazine hydrochloride (TH), an antipsychotic drug, on mild steel (commonly used pipeline material in the oil and gas ind... [more]
In this study, the corrosion inhibition efficiency of thioridazine hydrochloride (TH), an antipsychotic drug, on mild steel (commonly used pipeline material in the oil and gas industry) in 1 M hydrochloric acid (HCl) was evaluated using electrochemical techniques and weight loss method. Electrochemical impedance spectroscopy (EIS) results suggest that TH significantly enhances the polarization resistance (Rp) of mild steel. Similarly, potentiodynamic polarization results showed that the corrosion current density (icorr) of mild steel decreased significantly with addition of TH. To understand the long-term effect of TH, mild steel was tested for 7 days in 100 ppm TH containing electrolyte. EIS results showed that the Rp did not change significantly after 24 h exposure as compared to 2 h exposure; whereas the Rp increased by 28% after 7-day exposure. Weight loss measurements revealed that the inhibition efficiency of TH is remarkably high (98.8%) after 7-day exposure. The adsorption free energy calculation suggests that at the initial stage (1-day) of mild steel exposure, TH was physically adsorbed onto the surface. However, at a later stage (7- day) the binding of TH was chemical, and hence the corrosion protection increased with increase in the exposure period. As compared to the wide range of corrosion inhibitors reported in the literature, TH has shown to be highly effective for mild steel. Thus, it can be suggested that TH drug waste is a potential corrosion inhibitor for mild steel pipelines in the oil and gas industry.
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Nova |
2022 |
Melchers RE, Jeffrey R, 'The Transition from Short- to Long-Term Marine Corrosion of Carbon Steels: 2. Parameterization and Modeling', CORROSION, 78 427-436 (2022) [C1]
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Nova |
2022 |
Kee Paik EBJ, 'A pioneer of corrosion science', Ships and Offshore Structures, 17 1-6 (2022)
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2022 |
Melchers RE, 'Corrosion of Steels and Irons Immersed in Natural Seawater for up to 600 Y', CORROSION, 78 87-95 (2022) [C1]
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Nova |
2022 |
Melchers RE, Jeffrey R, 'The Transition from Short- to Long-Term Marine Corrosion of Carbon Steels: 1. Experimental Observations', Corrosion, 78 415-426 (2022) [C1]
This paper is concerned with developing an understanding of the transition between modes 1 and 2 of the bi-modal characteristic often observed for corrosion (mass) loss of many di... [more]
This paper is concerned with developing an understanding of the transition between modes 1 and 2 of the bi-modal characteristic often observed for corrosion (mass) loss of many different alloys and in a variety of longer-term (years) exposure conditions. Corrosion losses and pit depth and size for carbon steels (0.01 wt%, 0.04 wt%, and 0.06 wt% C) immersed continuously in sheltered 20°C (av.) seawater, 30°C (constant) seawater, and 70°C (constant) distilled water environments are reported with observations at 14 d and 28 d intervals over 1.4 y. The data allow clear demonstration of bi-modal behavior and variability in mass loss much less than typical for unprotected environments. All cases showed significant development of pit depths and pit areas particularly later in mode 1, through the transition phase and into mode 2. Using established observations of pitting mechanisms, the development of pitting is interpreted as facilitating the reduction in pH at the corrosion interface that permits the cathodic reaction to change from oxygen reduction in mode 1 to hydrogen evolution in mode 2, consistent with longer-term predominantly anaerobic corrosion in the later part of the bi-modal model. The observations also shed some light on the relationship between pitting corrosion and what is conventionally referred to as uniform corrosion.
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Nova |
2021 |
Melchers RE, 'New insights from probabilistic modelling of corrosion in structural reliability analysis', Structural Safety, 88 (2021) [C1]
Infrastructure intended to contain or exclude fluids or gasses, or reinforced with glass or other fibres may be subject to failure caused by pitting corrosion of the containment s... [more]
Infrastructure intended to contain or exclude fluids or gasses, or reinforced with glass or other fibres may be subject to failure caused by pitting corrosion of the containment system or of the reinforcement. To assess the reliability of the infrastructure then requires probabilistic models for the deterioration processes involved. Typically the critical deterioration is through localized pitting and in particular the most extreme pit depth as this governs containment capability and also fibre strength. The ¿arch-typical¿ distribution for representing maximum pit depth is the Gumbel extreme value distribution, for which complying data plot linearly on a so-called Gumbel plot. However, there is increasing evidence that large, homogeneous datasets show significant deviations from linearity. This is demonstrated for steel plates continuously immersed in seawater, for the interior corrosion of water injection pipelines and for crude oil production pipelines. Further examples are given for the maximum pit depth on stainless steel rollers in the papermaking industry and for localized corrosion of glass fibre reinforcement in concrete structures. In each case the non-linear trends obtained permit a re-interpretation of, and new insights for, the underlying physico-chemical-material mechanisms. The results are important for accurate representation of deterioration processes and for best-practice structural reliability analyses.
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Nova |
2021 |
Melchers RE, 'Long-term corrosion of steels in deep, cold, low oxygen sea waters', Corrosion Engineering Science and Technology, 56 736-741 (2021) [C1]
Corrosion of steels in deep, cold, low oxygen sea waters over many decades often is attributed to microbiologically influenced corrosion (MIC). Herein it is argued that the availa... [more]
Corrosion of steels in deep, cold, low oxygen sea waters over many decades often is attributed to microbiologically influenced corrosion (MIC). Herein it is argued that the available evidence does not support this proposition since (a) the few available in-situ deep sea field observations are consistent with long-term corrosion under abiotic conditions and (b) independent environmental studies indicate dissolved inorganic nitrogen, a necessary nutrient for MIC, is likely negligible or very low in deep sea waters. On that basis it is proposed that the rusticles observed on some shipwrecks, such as the Titanic, largely are the result of formation of ferrous hydroxides from ferrous ions released, very slowly, from the oxidation of magnetite rusts to maghemite. Direct evidence for this proposition is not available in-situ but is consistent with field observations and laboratory results.
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Nova |
2021 |
Melchers RE, Howlett CM, 'Reinforcement corrosion of the Phoenix caissons after 75 years of marine exposure', Proceedings of the Institution of Civil Engineers: Maritime Engineering, 174 19-30 (2021) [C1]
The reinforced concrete (RC) caissons, code-named Phoenix, still visible off the coast of Arromanches, France, have been exposed to marine immersion, tidal, splash and atmospheric... [more]
The reinforced concrete (RC) caissons, code-named Phoenix, still visible off the coast of Arromanches, France, have been exposed to marine immersion, tidal, splash and atmospheric conditions since 1944. Little evidence of corrosion of the steel reinforcement was observed during inspections in 2011, 2015 and 2019, although there was much structural damage. Archival material from the Second World War reveals the caissons were designed to low safety margins, without consideration of durability and constructed at a very fast rate mostly with unskilled labour, minimal material usage, without additives and no restrictions on adding water to aid concrete workability. Analysis of data that has recently become available indicates the concretes had a high cement content and were made with calcareous aggregates. It is concluded that these factors contributed to the high strength, low permeability and high remaining alkalinity of the concretes and hence to the very low evidence of reinforcement corrosion. When interpreted using recent experimental observations, these observations have implications for the design of new RC structures in marine exposures and for the prediction of the remaining life of older marine-exposed RC structures.
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Nova |
2021 |
Melchers RE, 'Long-Term Immersion Corrosion of Irons and Steel in Seawaters with Calcareous Deposition', CORROSION, 77 524-537 (2021) [C1]
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Nova |
2021 |
Jeffrey R, Melchers RE, 'Atmospheric and immersion corrosion of steel alloyed with aluminium', Corrosion Engineering Science and Technology, 56 162-170 (2021) [C1]
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Nova |
2021 |
Chaves IA, Melchers RE, Sterjovski Z, Rosen J, 'Long-term marine immersion corrosion of welded ABS grade steels', CORROSION ENGINEERING SCIENCE AND TECHNOLOGY, 57 195-203 (2021) [C1]
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Nova |
2021 |
Bretreger D, Yeo I-Y, Melchers R, 'Terrain wetness indices derived from LiDAR to inform soil moisture and corrosion potential for underground infrastructure', SCIENCE OF THE TOTAL ENVIRONMENT, 756 (2021) [C1]
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Nova |
2021 |
Melchers RE, Ahammed M, 'Estimating the long-term reliability of steel and cast iron pipelines subject to pitting corrosion', Sustainability (Switzerland), 13 (2021) [C1]
Water-injection, oil production and water-supply pipelines are prone to pitting corrosion that may have a serious effect on their longer-term serviceability and sustainability. Ty... [more]
Water-injection, oil production and water-supply pipelines are prone to pitting corrosion that may have a serious effect on their longer-term serviceability and sustainability. Typically, ob-served pit-depth data are handled for a reliability analysis using an extreme value distribution such as Gumbel. Available data do not always fit such monomodal probability distributions well, partic-ularly in the most extreme pit-depth region, irrespective of the type of pipeline. Examples of this are presented, the reasons for this phenomenon are discussed and a rationale is presented for the oth-erwise entirely empirical use of the ¿domain of attraction¿ in extreme value applications. This per-mits a more rational estimation of the probability of pipe-wall perforation, which is necessary for asset management and for system-sustainability decisions.
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Nova |
2021 |
Melchers RE, Chaves IA, 'Durable Steel-Reinforced Concrete Structures for Marine Environments', SUSTAINABILITY, 13 (2021) [C1]
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Nova |
2021 |
Melchers RE, 'Reconstructing the Detailed Proportions of Archaeological Iron Anchors', Journal of Maritime Archaeology, 16 477-492 (2021) [C1]
Wrought iron anchors recovered from archaeological sites invariably show signs of considerable corrosion loss. This affects cross-sectional dimensions and in turn particularly the... [more]
Wrought iron anchors recovered from archaeological sites invariably show signs of considerable corrosion loss. This affects cross-sectional dimensions and in turn particularly the bending and shear strength of anchor arms and lower part of the shanks and also the original potential holding power of the anchor. To assist in estimating such loss of strength, herein the amount of corrosion loss for long-term exposures is used to obtain estimates of the critical original cross-sectional sizes for some 40 calcareous encrusted anchors recovered from archaeological sites. From these, the ratio of critical size to arm span of anchors is estimated. This ratio is then considered as an indicator of the historical development of anchors, from the early Roman period to the mid-1800s. The results are compared to the (narrow) range of the proportions of Old Plan Admiralty Long-Shank anchors as derived from the dimensions for 6 sheet anchors published in the literature. The results permit estimation of the original critical dimensions of iron anchors after they have corroded for a specific period of time under calcareous conditions and known average temperature.
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Nova |
2021 |
Melchers RE, 'Experience-Based Physico-Chemical Models for Long-Term Reinforcement Corrosion', Corrosion and Materials Degradation, 2 100-119 (2021) [C1]
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Nova |
2020 |
Melchers RE, Chaves IA, 'Durability of reinforced concrete bridges in marine environments', Structure and Infrastructure Engineering, 16 169-180 (2020) [C1]
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Nova |
2020 |
Melchers RE, 'Modelling durability of reinforced concrete structures', CORROSION ENGINEERING SCIENCE AND TECHNOLOGY, 55 171-181 (2020) [C1]
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Nova |
2020 |
Melchers RE, 'Nonlinear trending of corrosion of high nickel alloys in extended marine and atmospheric exposures', Corrosion Reviews, 38 515-528 (2020) [C1]
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Nova |
2020 |
Mokhtari M, Melchers RE, 'Reliability of the conventional approach for stress/fatigue analysis of pitting corroded pipelines Development of a safer approach', Structural Safety, 85 (2020) [C1]
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Nova |
2020 |
Liang M, Melchers R, 'Two years pitting corrosion of AA5005-H34 aluminium alloy immersed in natural seawater: data interpretation', CORROSION ENGINEERING SCIENCE AND TECHNOLOGY, 56 129-136 (2020) [C1]
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Nova |
2020 |
Petersen RB, Wells T, Melchers RE, 'Development of long-term localised corrosion of cast iron pipes in backfill soils based on time of wetness', Corrosion Engineering Science and Technology, 55 550-561 (2020) [C1]
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Nova |
2020 |
Melchers RE, 'Models for Prediction of Long-Term Corrosion of Cast Iron Water Mains', Corrosion, 76 441-450 (2020) [C1]
Corrosion of cast iron pipes buried in wet soils has long been associated with severe localized effects often attributed to microbiological influences and also with the chemical a... [more]
Corrosion of cast iron pipes buried in wet soils has long been associated with severe localized effects often attributed to microbiological influences and also with the chemical and physical properties of the soils. Despite more than 70 y of research effort, correlations have remained poor. Recently, the reasons for this have been elucidated, as reviewed briefly herein. Also, interpretation of data from actual cast iron pipes buried in a variety of soils for up to 129 y shows that two critical factors governing depth of local corrosion penetration are the type of soil and the compaction of that soil around the pipe. The latter influences the size of wet air-voids in the soil at the pipe surface. These cause differential aeration and associated severe localized corrosion. The other critical factor is the time of wetness of the soil/metal interface. This is related both to atmospheric precipitation (e.g., rain) and to soil permeability as governed by compaction. Microbiological corrosion has no influence unless essential nutrients continue to be available. These new views on an old subject permit the development of corrosion penetration models for longer-term corrosion.
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Nova |
2020 |
Melchers RE, Chaves IA, 'Reinforcement corrosion in marine concretes-2. Long-term effects', ACI Materials Journal, 117 217-228 (2020) [C1]
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Nova |
2020 |
Bretreger D, Yeo I-Y, Melchers R, 'LiDAR derived terrain wetness indices to infer soil moisture above underground pipelines', International Journal on Smart Sensing and Intelligent Systems, 13 1-7 (2020) [C1]
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Nova |
2020 |
Liang M, Melchers R, 'Two years pitting corrosion of AA5005-H34 aluminium alloy immersed in natural seawater: morphology characterisation', Corrosion Engineering Science and Technology, 55 696-707 (2020) [C1]
Pitting corrosion of aluminium alloy AA5005-H34 immersed in natural sea water for up to 2 years is presented, together with new interpretations of the development of the pitting p... [more]
Pitting corrosion of aluminium alloy AA5005-H34 immersed in natural sea water for up to 2 years is presented, together with new interpretations of the development of the pitting process over extended exposure periods. Trenching initiated at surface-located Fe-rich intermetallic (IM) particles. It occurred more extensively in sea water compared to atmospheric exposures. With increasing exposures, the pitting morphologies became more complex. Three types, i.e. hemispherical pits (Type 1), crystallographic pits (Type 2) and characteristic ¿petal¿-like pits (Type 3), were observed after 12 months. It is suggested that the formation of Type 2 and Type 3 pits occurs at an advanced corrosion stage, and are associated with large Fe-rich IM particles near the metal surface. The influence of marine growth on pitting was negligible.
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Nova |
2020 |
Melchers RE, 'Modelling durability of reinforced concrete structure (vol 55, pg 171, 2020)', CORROSION ENGINEERING SCIENCE AND TECHNOLOGY, 55 341-341 (2020)
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2020 |
Melchers RE, 'Long-term durability of marine reinforced concrete structures', Journal of Marine Science and Engineering, 8 (2020) [C1]
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Nova |
2020 |
De Baere K, Van Haelst S, Chaves I, Luyckx D, van den Bergh K, Verbeken K, et al., 'The influence of concretion on the long-term corrosion rate of steel shipwrecks in the Belgian North Sea', CORROSION ENGINEERING SCIENCE AND TECHNOLOGY, 56 71-80 (2020) [C1]
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Nova |
2019 |
Petersen RB, Melchers RE, 'Effect of moisture content and compaction on the corrosion of mild steel buried in clay soils', CORROSION ENGINEERING SCIENCE AND TECHNOLOGY, 54 587-600 (2019) [C1]
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Nova |
2019 |
Mokhtari M, Melchers RE, 'Next-generation fracture prediction models for pipes with localized corrosion defects', Engineering Failure Analysis, 105 610-626 (2019) [C1]
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Nova |
2019 |
Melchers RE, Petersen RB, Wells T, 'The effect of atmospheric precipitation on the corrosion of ferrous metals buried in soils', CORROSION ENGINEERING SCIENCE AND TECHNOLOGY, 54 28-36 (2019) [C1]
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Nova |
2019 |
Melchers RE, 'Predicting long-term corrosion of metal alloys in physical infrastructure', NPJ MATERIALS DEGRADATION, 3 (2019) [C1]
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Nova |
2019 |
Melchers RE, Chaves IA, 'Reinforcement Corrosion in Marine Concretes-1: Initiation', ACI MATERIALS JOURNAL, 116 57-66 (2019) [C1]
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Nova |
2019 |
Melchers RE, Petersen RB, Wells T, 'Empirical models for long-term localised corrosion of cast iron pipes buried in soils', Corrosion Engineering Science and Technology, 54 678-687 (2019) [C1]
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Nova |
2018 |
Melchers RE, 'Progress in developing realistic corrosion models', Structure and Infrastructure Engineering, 14 843-853 (2018) [C1]
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Nova |
2018 |
Chernov BB, Chaves IA, Nugmanov AM, Melchers RE, 'Corrosion Performance of Low Alloy Steels in Sub-Arctic Natural Seawater', CORROSION, 74 1466-1475 (2018) [C1]
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Nova |
2018 |
Mokhtari M, Melchers RE, 'A new approach to assess the remaining strength of corroded steel pipes', Engineering Failure Analysis, 93 144-156 (2018) [C1]
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Nova |
2018 |
Melchers R, 'A Review of Trends for Corrosion Loss and Pit Depth in Longer-Term Exposures', Corrosion and Materials Degradation, 1 42-58 [C1]
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Nova |
2018 |
Soltani Asadi Z, Melchers RE, 'Long-term external pitting and corrosion of buried cast iron water pipes', Corrosion Engineering Science and Technology, 53 93-101 (2018) [C1]
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Nova |
2018 |
Melchers RE, Petersen RB, 'A reinterpretation of the Romanoff NBS data for corrosion of steels in soils', Corrosion Engineering Science and Technology, 53 131-140 (2018) [C1]
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Nova |
2018 |
Petersen RB, Melchers RE, 'Bi-modal trending for corrosion loss of steels buried in soils', Corrosion Science, 137 194-203 (2018) [C1]
Corrosion loss data from the 1957 NBS study for steels buried in a large variety of soils and exposed over 12¿17 years are re-interpreted, supported with estimates for scatter in ... [more]
Corrosion loss data from the 1957 NBS study for steels buried in a large variety of soils and exposed over 12¿17 years are re-interpreted, supported with estimates for scatter in the data. This shows that losses predominantly are consistent with the bi-modal trending pattern also previously observed for steel exposed in a variety of other environments. For short-term and low time of wetness exposures the trends are consistent with mode 1 of the bi-modal trend. These reinterpretations should permit development of better understanding of the factors important for short- and-long term corrosion trends and for improved modelling and prediction.
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Nova |
2018 |
Rajabipour A, Melchers RE, 'Service life of corrosion pitted pipes subject to fatigue loading and hydrogen embrittlement', International Journal of Hydrogen Energy, 43 8440-8450 (2018) [C1]
The structural service life of brittle material pipes with exterior corrosion pits is likely to depend on crack initiation and crack development and this may be influenced by pres... [more]
The structural service life of brittle material pipes with exterior corrosion pits is likely to depend on crack initiation and crack development and this may be influenced by pressure loading fluctuations and the possibility of material hydrogen embrittlement. Recently developed methods are used to estimate the cracking pattern, the failure state of the crack development from external pits and the rate of Hydrogen-Assisted Cracking under fluctuating loadings. The effect of hydrogen from the surrounding environment on the cracking rate is formulated using a generalized form of Paris' law. The depth of cracks initiated from surface pits is estimated as a function of pipe age. A realistic example is presented and the results discussed.
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Nova |
2018 |
Liang M, Melchers R, Chaves I, 'Corrosion and pitting of 6060 series aluminium after 2 years exposure in seawater splash, tidal and immersion zones', CORROSION SCIENCE, 140 286-296 (2018) [C1]
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Nova |
2018 |
Melchers RE, Wells T, 'Correlation between soil electrical resistivity, polarisation resistance and corrosion of steel', Corrosion Engineering Science and Technology, 53 524-530 (2018) [C1]
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Nova |
2018 |
Liang M, Melchers RE, Chaves IA, 'Complex Pitting Corrosion in Long-Term Immersed Exposures of 6060 Aluminum Alloys in Temperate Natural Seawater', CORROSION, 74 1272-1287 (2018) [C1]
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Nova |
2018 |
Asadi ZS, Melchers RE, 'Clustering of corrosion pit depths for buried cast iron pipes', CORROSION SCIENCE, 140 92-98 (2018) [C1]
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Nova |
2017 |
Kovalenko R, Melchers RE, Chernov B, 'Long-term immersion corrosion of steel subject to large annual variations in seawater temperature and nutrient concentration', STRUCTURE AND INFRASTRUCTURE ENGINEERING, 13 978-987 (2017) [C1]
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Nova |
2017 |
Melchers RE, 'Post-perforation external corrosion of cast iron pressurised water mains', Corrosion Engineering Science and Technology, 52 541-546 (2017) [C1]
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Nova |
2017 |
Peng L, Stewart MG, Melchers RE, 'Corrosion and capacity prediction of marine steel infrastructure under a changing environment', STRUCTURE AND INFRASTRUCTURE ENGINEERING, 13 988-1001 (2017) [C1]
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Nova |
2017 |
Wang X, Melchers RE, 'Long-term under-deposit pitting corrosion of carbon steel pipes', OCEAN ENGINEERING, 133 231-243 (2017) [C1]
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Nova |
2017 |
Wang X, Melchers RE, 'Corrosion of carbon steel in presence of mixed deposits under stagnant seawater conditions', JOURNAL OF LOSS PREVENTION IN THE PROCESS INDUSTRIES, 45 29-42 (2017) [C1]
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Nova |
2017 |
Asadi ZS, Melchers RE, 'Pitting corrosion of older underground cast iron pipes', CORROSION ENGINEERING SCIENCE AND TECHNOLOGY, 52 459-469 (2017) [C1]
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Nova |
2017 |
Asadi ZS, Melchers RE, 'Extreme value statistics for pitting corrosion of old underground cast iron pipes', RELIABILITY ENGINEERING & SYSTEM SAFETY, 162 64-71 (2017) [C1]
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Nova |
2017 |
Melchers RE, Pape TM, Chaves IA, Heywood RJ, 'Long-term durability of reinforced concrete piles from the Hornibrook Highway Bridge', AUSTRALIAN JOURNAL OF STRUCTURAL ENGINEERING, 18 41-57 (2017) [C1]
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Nova |
2017 |
Melchers RE, Chaves IA, 'A comparative study of chlorides and longer-term reinforcement corrosion', MATERIALS AND CORROSION-WERKSTOFFE UND KORROSION, 68 613-621 (2017) [C1]
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Nova |
2016 |
Celikkol-Aydin S, Gaylarde CC, Lee T, Melchers RE, Witt DL, Beech IB, '16S rRNA gene profiling of planktonic and biofilm microbial populations in the Gulf of Guinea using Illumina NGS', Marine Environmental Research, 122 105-112 (2016) [C1]
16S rRNA gene profiling using a pipeline involving the Greengenes database revealed that bacterial populations in innermost (proximal to the steel surface) and outer regions of bi... [more]
16S rRNA gene profiling using a pipeline involving the Greengenes database revealed that bacterial populations in innermost (proximal to the steel surface) and outer regions of biofilms on carbon steel exposed 3 m below the surface at an offshore site in the Gulf of Guinea differed from one another and from seawater. There was a preponderance of gammaproteobacterial sequences, representing organisms known for hydrocarbon degradation. Total DNA from the innermost layer was 1500 times that recovered from the outermost. Stramenopiles (diatom) sequences were prevalent in the former. Rhodobacteriaceae, key biofilm formers, comprised 14.9% and 4.22% OTUs of inner and outer layers, respectively. Photosynthetic anaerobic sulfur oxidizer sequences were also prominent in the biofilms. Analysis of data using a different pipeline with Silva111 allowed detection of 0.3¿0.4% SRB in the biofilms. The high abundance of aerobic micro-algal sequences in inner biofilm suggests they are initial colonizers of carbon steel surfaces in a marine environment. This is the first time that the microbial population of the strongly attached inner layer of the biofilm on steel has been differentiated from the outer, readily removed layer. The accepted scraping removal method is obviously inadequate and the resulting microbial analysis does not offer complete information on the biofilm community structure.
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Nova |
2016 |
Comanescu I, Melchers RE, Taxén C, 'Corrosion and durability of offshore steel water injection pipelines', Ships and Offshore Structures, 11 424-437 (2016) [C1]
Carbon steel pipelines are widely used for injection of sea and other waters into oil and gas wells so as to increase the rate of recovery, particularly from mature fields. Intern... [more]
Carbon steel pipelines are widely used for injection of sea and other waters into oil and gas wells so as to increase the rate of recovery, particularly from mature fields. Internal corrosion usually is mild. However, cases of very aggressive channelling corrosion along the bottom of the pipeline have been observed. Practical experience and anecdotal observations have attributed this to microbiologically influenced corrosion even though extensive use is made of preventative measures including biocides, oxygen scavengers, corrosion and scale inhibitors, and pipeline pigging. Interpretation of data and observations for five water injection pipelines, made available by industry, indicate that microbiologically influenced corrosion may play a part in causing channelling corrosion but that the most likely cause is under-deposit corrosion under pipe debris that settles during periods of pipeline shut-downs and low water velocity.
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Nova |
2016 |
Baji H, Ronagh HR, Melchers RE, 'Reliability of ductility requirements in concrete design codes', Structural Safety, 62 76-87 (2016) [C1]
Ductility is an important limit state for the design of reinforced concrete beams. Its implementation varies considerably between design codes. This is investigated using reliabil... [more]
Ductility is an important limit state for the design of reinforced concrete beams. Its implementation varies considerably between design codes. This is investigated using reliability-based assessment with ductility defined by strain ratio. The modelling uncertainty for the ductility limit state typically is much greater than that for structural strength limit state. This is reflected in the corresponding reliability indices of limit state defined for ductility. Some of these could be considered unacceptably low.
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Nova |
2016 |
Melchers RE, Emslie R, 'Investigations for structural safety assessment of corroded cast iron bridge piers', Australian Journal of Structural Engineering, 17 55-66 (2016) [C1]
Cast iron bridge piers, often more than 100 years old, are still in service in rail and road bridges in many parts of Australia. Increasingly, the effect of corrosion on their pre... [more]
Cast iron bridge piers, often more than 100 years old, are still in service in rail and road bridges in many parts of Australia. Increasingly, the effect of corrosion on their present and future structural safety is of interest. Field investigations and observations to assess corrosion losses and pitting of the cast iron piers of four different operational railway bridges located in tidal marine exposure conditions are described, noting that direct visual examination usually is rendered difficult by immersion, marine growth and the presence of the graphitised layer. Measured corrosion losses and pit depths showed considerable variability between piers and between bridges. Evidence was found for the influence of microbiological corrosion, fostered by nitrogenous pollution. Implications for structural safety assessment are discussed and an example given of the estimation of likely future rate of (long-term) corrosion, necessary for assessment of remaining structural safe life.
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Nova |
2016 |
Melchers RE, Chaves IA, Jeffrey R, 'A conceptual model for the interaction between carbon content and manganese sulphide inclusions in the short-term seawater corrosion of low carbon steel', Metals, 6 (2016) [C1]
The critical role of manganese sulphide (MnS) inclusions for the initiation of the short-term growth of pitting or localized corrosion of low carbon steels has long been recognize... [more]
The critical role of manganese sulphide (MnS) inclusions for the initiation of the short-term growth of pitting or localized corrosion of low carbon steels has long been recognized. Classical results show that pitting probability and pitting severity increases with increased sulphide concentration for low carbon steels as a result of magnesium sulphides acting as local cathodes for initiating pitting corrosion. However, the iron carbides (cementite) in steels can also act as local cathodes for initiation of pitting corrosion. Herein it is proposed that there is competition between pits for cathodic area and that this will determine the severity of pitting and general corrosion observed in extended exposures. Preliminary experimental data for immersion exposures of up to 56 days in natural seawater of three low carbon steels show, contrary to conventional wisdom, greater pit depths for the steels with lower S content. However, the pit depth results are consistent with lower C/S ratios. This is considered to support the concept of cathodic competition between C and S. It is proposed that this offers explanations for a number of other phenomena, including the thus far unexplained apparently higher reactivity of some MnS inclusions.
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Nova |
2016 |
Chaves IA, Melchers RE, Peng L, Stewart MG, 'Probabilistic remaining life estimation for deteriorating steel marine infrastructure under global warming and nutrient pollution', Ocean Engineering, 126 129-137 (2016) [C1]
The longer-term serviceability and structural safety of steel infrastructure exposed to seawater conditions may be affected by global warming and by seawater nutrient pollution. T... [more]
The longer-term serviceability and structural safety of steel infrastructure exposed to seawater conditions may be affected by global warming and by seawater nutrient pollution. These may affect abiotic and biotic (microbial) corrosion. A model for long-term corrosion is developed from data obtained from steel piling exposed for 33 years in a seawater harbour. The effects on corrosion losses on the structural reliability of steel sheet piling as used in harbours world-wide were investigated as a function of seawater temperature rise from global warming and of seawater nutrient pollution. The results show that structural reliability is more sensitive to likely nutrient pollution than to predicted increases in seawater temperature, noting also that global warming also could increase nutrient pollution from anthropological sources.
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Nova |
2016 |
Machuca LL, Jeffrey R, Melchers RE, 'Microorganisms associated with corrosion of structural steel in diverse atmospheres', International Biodeterioration and Biodegradation, 114 234-243 (2016) [C1]
The influence of atmospheric conditions on the corrosion of steel and its associated microbial community was studied. Surface analysis revealed greater localized corrosion in stee... [more]
The influence of atmospheric conditions on the corrosion of steel and its associated microbial community was studied. Surface analysis revealed greater localized corrosion in steel exposed to near-ocean atmospheres with high chloride deposition compared to inland and subalpine sites. High-throughput sequencing analysis of corrosion products showed that dissimilar microbial communities and dominant species were deposited on steel in the different atmospheres. Close to the ocean, Brevundimonas diminuta were predominant whereas Clostridium and Pseudomonas species dominated for inland sites with agricultural or forestry activities. Bacillus and Enterococcus were dominant for sites close to a fertilizer plant and a sewage treatment plant, respectively. Actinobacteria species dominated at sub-alpine conditions. Results from this study indicate that microbial communities on corroding steel exposed to atmospheric conditions are the result of deposition of locally-generated aerosols. Acid-producing activity and exopolysaccharide (EPS) production was widespread and rapidly detected in microbial cultures from all the exposure sites. Sulphate-reducing bacteria were not detected in this study. These results suggest that acid production and EPS synthesis can be important mechanisms for microbial corrosion of steel under atmospheric conditions.
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Nova |
2016 |
Dockrill B, Melchers R, Ellasson B, Linton S, Herron C, 'Structural risk assessment of corroding infrastructure', Corrosion and Materials, 41 66-71 (2016) |
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2016 |
Melchers RE, Herron C, Emslie R, 'Long term marine corrosion of cast iron bridge piers', Corrosion Engineering Science and Technology, 51 248-255 (2016) [C1]
Cast iron piers of a disused 90 year old multispan railway bridge located close to the Pacific Ocean were extensively sampled for remaining wall thickness to determine corrosion l... [more]
Cast iron piers of a disused 90 year old multispan railway bridge located close to the Pacific Ocean were extensively sampled for remaining wall thickness to determine corrosion loss and pit depth. From this, a corrosion loss model for the full 90 years was developed. In addition, the statistics for uncertainty in corrosion loss were obtained. Corrosion varied with elevation relative to mean water level and was negligible in the atmospheric zone, about 2¿3 mm in the immersion zone and 5¿6 mm in the splash and lower tidal zones. This variation is consistent with accelerated low water corrosion. It indicates that water pollution occurred sometime during the life of the bridge. Maximum pit depths were determined and analysed using extreme value statistics. The corrosion model for such long term exposure and the related statistical results are unique and important for assessment of remaining life of the many other cast iron structures still in existence in many parts of the world.
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Nova |
2015 |
Wells T, Melchers RE, 'Modelling concrete deterioration in sewers using theory and field observations', Cement and Concrete Research, 77 82-96 (2015) [C1]
Abstract Samples of new and 70 year old pre-corroded OPC concrete were exposed for up to 48 months in 6 sewers throughout Australia. Corrosion losses at each site followed the bi-... [more]
Abstract Samples of new and 70 year old pre-corroded OPC concrete were exposed for up to 48 months in 6 sewers throughout Australia. Corrosion losses at each site followed the bi-linear trend originally proposed by Wells and Melchers [1]. During an initial phase (lasting < 2 years) negligible loss of material occurs however once the surface pH = 6 losses commence and accumulate linearly at a rate that is likely to remain constant over time. Corrosion rates were found to be sensitive to humidity but insensitive to concrete alkalinity. A first pass model which predicts the rate of concrete sewer pipe corrosion from a knowledge of local average sewer gas temperature, humidity and H<inf>2</inf>S concentrations was also developed. The equation predictions were in good agreement with rates determined from field observation and historical data.
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Nova |
2015 |
Melchers R, 'Corrosion research at the University of Newcastle', Corrosion and Materials, 40 42-43 (2015) [C3] |
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2015 |
Melchers RE, 'Trends in long-term corrosion of aluminium alloys in Marine, industrial and urban environments', Corrosion and Materials, 40 48-53 (2015)
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2015 |
Melchers RE, 'Using models to interpret data for monitoring and life prediction of deteriorating infrastructure systems', Structure and Infrastructure Engineering, 11 63-72 (2015) [C1]
For environmental and for economic reasons, there is increased emphasis on extending the life of existing infrastructure and to design new infrastructure for longer, safe and effe... [more]
For environmental and for economic reasons, there is increased emphasis on extending the life of existing infrastructure and to design new infrastructure for longer, safe and effective service lives. Increasing use is being made of monitoring of performance and estimation of long-term reliability and safety, allowing also for the likelihood of long-term deterioration. To obtain optimal decision outcomes, reliance should be placed not only on data but also on accumulated scientific and engineering knowledge. In engineering, this is embodied in mathematical models. Ideally, these are of good quality, calibrated to ¿real world¿ data and have prediction capabilities. Recently, developed models of this type are described for the corrosion of steel in marine environments and simplified to models suitable for engineering applications. An example is given of the prediction of the expected corrosion loss and of the likely future rate of corrosion for a mild steel structural element exposed to temperate seawater.
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Nova |
2015 |
Chaves IA, Jeffrey R, Melchers RE, 'Technical note: Rust removal from steel coupons after short-term marine immersion', Corrosion, 71 811-818 (2015) [C1]
The quantification of mass loss, surface topography, depth of pitting, and localized corrosion for steels subject to marine corrosion requires the removal of rusts, preferably wit... [more]
The quantification of mass loss, surface topography, depth of pitting, and localized corrosion for steels subject to marine corrosion requires the removal of rusts, preferably without causing additional mass loss, pitting, or other damage. Conventional procedures using inhibited hydrochloric acid or Clarke's solution are shown to remove short-term marine rusts but also to cause new corrosion including pitting and related rust products. Both increase with longer exposure to the cleaning solutions. Water washing with soft water left calcareous materials on the metal surface. Ultrasonic removal did not cause additional corrosion but was effective only for very light rusts. Although relatively slow, electrolytic cleaning (electrolysis) produced clean surfaces without new corrosion.
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Nova |
2015 |
Melchers RE, 'Bi-modal trends in the long-term corrosion of copper and high copper alloys', Corrosion Science, 95 51-61 (2015) [C1]
The evolution of corrosion loss and maximum pit depth of copper and copper alloys exposed for long periods of time in natural and industrial environments is shown to be more consi... [more]
The evolution of corrosion loss and maximum pit depth of copper and copper alloys exposed for long periods of time in natural and industrial environments is shown to be more consistent with a bi-modal functional form than with the classical power law. Data from several long-term exposure test programs supports this proposition. The bi-modal behaviour signals a change from mainly cathodic oxygen reduction to a subsequent transitory corrosion process that may be modelled as involving pitting under earlier copper corrosion products. Possible reasons for some data sets showing decreasing maximum pit depths with increasing exposure time are discussed.
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Nova |
2015 |
Rajabipour A, Melchers RE, 'Application of Paris' law for estimation of hydrogen-assisted fatigue crack growth', International Journal of Fatigue, 80 357-363 (2015) [C1]
Abstract Based on the general form of Paris' law a new method is proposed for estimating the rate of cracking of metals under Hydrogen-Assisted Fatigue. It is based on relati... [more]
Abstract Based on the general form of Paris' law a new method is proposed for estimating the rate of cracking of metals under Hydrogen-Assisted Fatigue. It is based on relating the fatigue crack growth rate of hydrogen embrittled metal to the fatigue crack growth rate of the metal without hydrogen embrittlement. One-dimensional hydrogen diffusion is assumed. Simulations using the proposed method on steel types X52, X70-80 and X80 are in agreement with published experimental tests results. The new method obviates numerical modelling of crack propagation and much reduces the computational costs.
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Nova |
2015 |
Lotfollahi Yaghin A, Melchers RE, 'Long-term inter-link wear of model mooring chains', Marine Structures, 44 61-84 (2015) [C1]
Chains usually form the upper part of moorings systems used for maritime structures such as floating production storage and offloading (FPSO) vessels, increasingly employed in the... [more]
Chains usually form the upper part of moorings systems used for maritime structures such as floating production storage and offloading (FPSO) vessels, increasingly employed in the offshore oil and gas industry particularly in very deep waters. Current design rules do not differentiate between corrosion and inter-link wear. Laboratory experiments are described to determine the rate of wear of model (i.e. small-scale) mooring chains for up to 200,000 wear cycles. Various axial loadings and specific angular displacement were used with testing under either dry or wet conditions and for un-corroded and corroded chain. The results show that tensile force has a significant but non-linear effect on the inter-link wear. The amount of wear is similar for un-corroded and for corroded chains and is lower in wet conditions.
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Nova |
2015 |
Melchers RE, 'Time Dependent Development of Aluminium Pitting Corrosion', Advances in Materials Science and Engineering, 2015 (2015) [C1]
Aluminium alloys have excellent corrosion resistance to a wide variety of exposure conditions. Usually they corrode by pitting rather than by uniform corrosion. For infrastructure... [more]
Aluminium alloys have excellent corrosion resistance to a wide variety of exposure conditions. Usually they corrode by pitting rather than by uniform corrosion. For infrastructure applications long-term corrosion behaviour is of interest. The relatively limited long-term pitting data that is available shows that maximum and average pit depths do not follow the power law function as conventionally assumed but tend to follow a bimodal trend with exposure time. This is consistent with the bimodal trends observed previously for corrosion mass loss of aluminium alloys. Most likely it is the result of the accumulation of corrosion products over the pit mouths, leading to the gradual development of localised anoxic conditions within pits. In turn this permits the development within the pits of anoxic autocatalytic conditions, consistent with established theory for pitting corrosion of aluminium. It also is consistent with observations of hydrogen evolution from pits. The implications of this for practical applications are discussed.
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Nova |
2015 |
Rajabipour A, Melchers RE, 'Capacity of pitting corroded pipes under hydrogen assisted cracking', International Journal of Hydrogen Energy, 40 9388-9399 (2015) [C1]
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Nova |
2015 |
Melchers RE, 'Effect of water nutrient pollution on long-term corrosion of 90:10 copper nickel alloy', Materials, 8 8047-8058 (2015) [C1]
Due to their good corrosion resistance, copper and copper alloys such as 90:10 Cu-Ni are used extensively in high-quality marine and industrial piping systems and also in marine, ... [more]
Due to their good corrosion resistance, copper and copper alloys such as 90:10 Cu-Ni are used extensively in high-quality marine and industrial piping systems and also in marine, urban, and industrial environments. Their corrosion loss and pitting behaviour tends to follow a bi-modal trend rather than the classic power law. Field data for 90:10 copper nickel immersed in natural seawater are used to explore the effect of water pollution and in particular the availability of critical nutrients for microbiologically induced corrosion. It is shown, qualitatively, that increased dissolved inorganic nitrogen increases corrosion predominantly in the second, long-term, mode of the model. Other, less pronounced, influences are salinity and dissolved oxygen concentration.
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Nova |
2014 |
Melchers RE, 'Microbiological and abiotic processes in modelling longer-term marine corrosion of steel', Bioelectrochemistry, 97 89-96 (2014) [C1]
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Nova |
2014 |
Wells T, Melchers RE, 'An observation-based model for corrosion of concrete sewers under aggressive conditions', CEMENT AND CONCRETE RESEARCH, 61-62 1-10 [C1]
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Nova |
2014 |
Melchers RE, Jeffrey RJ, 'Long-term corrosion of mild steel in natural and uv-treated coastal seawater', Corrosion, 70 804-818 (2014) [C1]
Highly polished coupons (25 by 25 by 1.5 mm) sourced from the same steel sheet were continuously immersion-exposed either to natural coastal seawater or to seawater from the same ... [more]
Highly polished coupons (25 by 25 by 1.5 mm) sourced from the same steel sheet were continuously immersion-exposed either to natural coastal seawater or to seawater from the same source subjected to filtration and UV irradiation to eliminate microbiologically influenced corrosion as much as possible. This was continued for 943 days (2.6 years). Dissolved oxygen levels were very similar in both environments. On average the UV-treated seawater was 2°C warmer, but all coupons exposed to it showed less localized corrosion than those exposed to natural seawater. The typical topographical difference was about 60% as measured by surface roughness parameter Sa. Mass losses in UV-treated seawater were about 10% higher than in natural seawater, but after temperature correction were similar to natural seawater for the first year and tended to be lower subsequently. At all exposure periods the rusts in UV-treated seawater were less voluminous than the rusts in natural seawater. Eventually they also contained a higher proportion of magnetite. © 2014, NACE International.
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Nova |
2014 |
Melchers RE, 'Long-term immersion corrosion of steels in seawaters with elevated nutrient concentration', Corrosion Science, (2014) [C1]
Data from a variety of field exposure programs is used to quantify the effect of concentration of dissolved inorganic nitrogen (DIN) on long-term seawater immersion corrosion loss... [more]
Data from a variety of field exposure programs is used to quantify the effect of concentration of dissolved inorganic nitrogen (DIN) on long-term seawater immersion corrosion loss of structural steels. A linear correlation model that asymptotes the long-term part of the previously proposed bi-modal corrosion loss model is used. It allows for average seawater temperature. Model parameters and their variability are determined and reported. The model permits prediction of long-term corrosion loss in nutrient polluted waters of known average temperature. An example shows that anthropological pollution of seawater potentially is a major hazard for corrosion of steel infrastructure. © 2013 Elsevier Ltd. All rights reserved.
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Nova |
2014 |
Chaves IA, Melchers RE, 'Extreme value analysis for assessing structural reliability of welded offshore steel structures', Structural Safety, 50 9-15 (2014) [C1]
Natural deterioration of mild steel exposed to marine environment compromises the long-term integrity, serviceability and safety of new and existing infrastructure and increases t... [more]
Natural deterioration of mild steel exposed to marine environment compromises the long-term integrity, serviceability and safety of new and existing infrastructure and increases the risk of structural failure. Welded structures are known to be prone to even higher risks as a result of adverse effects of pitting corrosion in weld-heated areas. A bi-modal model has been shown recently to be a better description for the long-term development of the maximum depth of pits. Also, the statistics of pit depth have been shown to be better represented, for long term exposures, by the Frechet extreme value distribution. Both new developments present challenges for structural reliability analysis. Herein a linearization is used to represent long-term development of pit depth. It is shown that data for maximum pit depths can be separated into those with Gumbel statistics and those for which a Frechet distribution is more appropriate. An example is given for the reliability analysis of a welded pipeline subjected to localized corrosion. The effect of random variable uncertainty is assessed using a sensitivity study. Results show the considerable influence on the probability of failure of pit diameter and the parameters describing the pitting corrosion model. © 2014 Elsevier Ltd.
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Nova |
2014 |
Melchers RE, Jeffrey RJ, Usher KM, 'Localized corrosion of steel sheet piling', Corrosion Science, 79 139-147 (2014) [C1]
When steel sheet piling suffers accelerated low water corrosion the webs and flange-web regions of individual piles often perforate first, for reasons not fully understood. To inv... [more]
When steel sheet piling suffers accelerated low water corrosion the webs and flange-web regions of individual piles often perforate first, for reasons not fully understood. To investigate this, samples of the cross-sections of typical U and Z profile sheet piling were exposed to natural seawater for 1, 2 and 3. years. They showed localized corrosion in the central region and also near the flange-web junctions. These locations were found to have more material defects and segregation and show composition differences. It is proposed these observations are linked to localized sheet pile perforation after long exposure to seawater. © 2013 Elsevier Ltd.
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Nova |
2014 |
Melchers RE, 'Bi-modal trend in the long-term corrosion of aluminium alloys', Corrosion Science, 82 239-247 (2014) [C1]
A wide range of literature data including in situ immersion, tidal, coastal atmospheric and industrial exposures is used to show that the trend for longer term corrosion of alumin... [more]
A wide range of literature data including in situ immersion, tidal, coastal atmospheric and industrial exposures is used to show that the trend for longer term corrosion of aluminium alloys is nearly always more consistent with a bi-modal model than with the classical power-law function. It is proposed the bi-modal characteristic results from the accumulation of corrosion products causing localised anoxic conditions. These permit a change from predominantly cathodic oxygen reduction to hydrogen ion reduction under anoxic autocatalytic conditions within pits. This mechanism is consistent with established theory for pitting corrosion in aluminium. © 2014 Elsevier Ltd.
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Nova |
2014 |
Chaves IA, Melchers RE, 'External Corrosion of Carbon Steel Pipeline Weld Zones', INTERNATIONAL JOURNAL OF OFFSHORE AND POLAR ENGINEERING, 24 68-74 (2014) [C1]
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Nova |
2014 |
Melchers RE, Jeffrey RJ, 'Corrosion of steel piling in seawater harbours', Proceedings of the Institution of Civil Engineers: Maritime Engineering, 167 159-172 (2014) [C1]
Unexpectedly high levels of corrosion of sheet and other steel piling were observed in UK harbours during the 1980s, and a phenomenon termed ¿accelerated low water corrosion¿ (ALW... [more]
Unexpectedly high levels of corrosion of sheet and other steel piling were observed in UK harbours during the 1980s, and a phenomenon termed ¿accelerated low water corrosion¿ (ALWC) caused considerable concern about the structural safety of harbour quays and facilities. This paper shows that the severity of corrosion of steel piling both in the tidal zone and in the immersion zone is correlated with the concentration of dissolved inorganic nitrogen (DIN) in the local seawater. In the lower tidal zone this is consistent with the thinning of piles associated with ALWC. Previously it has been shown that in the horizontal direction the ALWC phenomenon is associated with material variability. Models are developed to allow the prediction of expected average corrosion loss both in the immersion zone and for the lower tidal zone (the ALWC effect) as a function of DIN, water temperature and exposure period. Data are presented to show the relatively low beneficial effect of changes in steel composition. It is concluded that for long-term protection against corrosion reliance must be placed on protective and preventive measures.
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Nova |
2013 |
Melchers RE, Rootsey R, Stuetz R, Keller J, Yuan Z, 'Taking control of odours and corrosion in sewers', Water: Journal of the Australian Water Association, 40 89-94 (2013) [C3] |
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Nova |
2013 |
Melchers RE, 'Influence of dissolved inorganic nitrogen on accelerated low water corrosion of marine steel piling', Corrosion, 69 95-103 (2013) [C1]
Accelerated low water corrosion (ALWC) is the term given to unusually high levels of corrosion immediately below the low water level in seawater exposures of steel piling. It has ... [more]
Accelerated low water corrosion (ALWC) is the term given to unusually high levels of corrosion immediately below the low water level in seawater exposures of steel piling. It has been associated with microbiologically influenced corrosion but conclusive evidence is lacking. Using published data for the corrosion of steel piles exposed for periods up to 27 years at various U.S. harbor and other locations, it is shown that the severity of ALWC is correlated with the concentration of dissolved inorganic nitrogen, a critical nutrient for microbiological (bacterial) activity in seawater. This was shown previously for short-term exposures and establishes that ALWC is indeed microbiologically influenced. It also provides a means of assessing the likelihood of long-term risk of occurrence of ALWC. © 2013, NACE International.
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Nova |
2013 |
Melchers RE, 'Long-term corrosion of cast irons and steel in marine and atmospheric environments', CORROSION SCIENCE, 68 186-194 (2013) [C1]
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Nova |
2013 |
Rajabipour A, Melchers RE, 'A numerical study of damage caused by combined pitting corrosion and axial stress in steel pipes', CORROSION SCIENCE, 76 292-301 (2013) [C1]
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Nova |
2013 |
Pape TM, Melchers RE, 'Performance of 45-year-old corroded prestressed concrete beams', PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS-STRUCTURES AND BUILDINGS, 166 547-559 (2013) [C1]
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Nova |
2013 |
Melchers RE, 'Human intervention and the safety of complex structural systems', Civil Engineering and Environmental Systems, 30 211-220 (2013) [C1]
Structural reliability theory based on probability provides a systematic, logical and consistent means to make estimates of the safety of complex structural systems. However, its ... [more]
Structural reliability theory based on probability provides a systematic, logical and consistent means to make estimates of the safety of complex structural systems. However, its application currently leaves it open to criticism that its predictions do not necessarily compare with reality and with accepted risk criteria in other contexts. Herein, it is proposed that this is because applications have not dealt satisfactorily with the issues of human error and particularly human intervention in the management of loads and resistances. Probability-based models for loads can be modified to include the influence of human intervention such as through including the effect of the degree of enforcement of regulatory requirements. Similarly, the standard of enforcement of minimum standards of material quality should be added to probability-based models for resistances. This is relevant particularly for the assessment and prediction of the future reliability and safety of existing structures. © 2013 © 2013 Taylor & Francis.
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Nova |
2013 |
Melchers RE, Chernov BB, 'Corrosion of mild steel in elevated temperature hard freshwater', CORROSION ENGINEERING SCIENCE AND TECHNOLOGY, 48 130-135 (2013) [C1]
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Nova |
2013 |
Melchers RE, Jeffrey RJ, 'Accelerated low water corrosion of steel piling in harbours', CORROSION ENGINEERING SCIENCE AND TECHNOLOGY, 48 496-505 (2013) [C1]
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Nova |
2013 |
Chaves IA, Melchers RE, 'Long term localised corrosion of marine steel piling welds', Corrosion Engineering Science and Technology, 48 469-474 (2013) [C1]
Localised or pitting corrosion can be detrimental for steel pipes and containment structures, since wall perforation may cause system failure. Herein maximum pit depth quantificat... [more]
Localised or pitting corrosion can be detrimental for steel pipes and containment structures, since wall perforation may cause system failure. Herein maximum pit depth quantification and its development with time are considered for samples taken from longitudinal welds on 33-year-old tubulars exposed in Newcastle Harbour. Relationships between pit depth and material metallurgy and corrosion properties were investigated by means of standard macro-etching, rest potential and zero resistance ammetry techniques. It is considered that the observed results are the result of the lack of homogeneity at the corrosion interface caused by differences in grain size, grain structure and the potential for pitting to occur preferentially along boundaries. The results are compared to measurements for longitudinal welds obtained previously on samples of API X56 Spec 5L pipe exposed in similar waters for up to 3?5 years, showing a reasonable degree of consistency between the two sets of data. The reasons for this are discussed. © 2013 Institute of Materials, Minerals and Mining.
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Nova |
2013 |
Melchers R, 'Preface', Australian Journal of Structural Engineering, 14 (2013) |
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2012 |
Melchers RE, Jeffrey RJ, 'Corrosion of long vertical steel strips in the marine tidal zone and implications for ALWC', Corrosion Science, 65 26-36 (2012) [C1]
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Nova |
2012 |
Melchers RE, 'Modeling and prediction of long-term corrosion of steel in marine environments', International Journal of Offshore and Polar Engineering, 22 257-263 (2012) [C1]
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Nova |
2011 |
Pape TM, Melchers RE, 'The effects of corrosion on 45-year-old pre-stressed concrete bridge beams', Structure and Infrastructure Engineering, 7 101-108 (2011) [C1]
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Nova |
2011 |
Chaves IA, Melchers RE, 'Pitting corrosion in pipeline steel weld zones', Corrosion Science, 53 4026-4032 (2011) [C1]
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Nova |
2011 |
Melchers R, 'Discussion on the "Investigation of the Failure of the Newcastle Workers Club" by RE Melchers REPLY', AUSTRALIAN JOURNAL OF STRUCTURAL ENGINEERING, 12 182-183 (2011) |
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2011 |
Melchers RE, 'Investigation of the failure of the Newcastle Workers Club', Australian Journal of Structural Engineering, 11 163-176 (2011) [C1] |
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Nova |
2011 |
Melchers RE, Pape T, 'Aspects of long-term durability of reinforced concrete structures in marine environments', European Journal of Environmental and Civil Engineering, 15 969-980 (2011)
Much concern exists about the apparently short durability of reinforced concrete structures in marine environments. However, there are many examples of structures that have surviv... [more]
Much concern exists about the apparently short durability of reinforced concrete structures in marine environments. However, there are many examples of structures that have survived for long periods of time with little evidence of reinforcement corrosion. Some of these were made with seawater as mixing water. Others had very little concrete cover. Detailed examination has revealed that reinforced concrete structures made with fine or coarse aggregate consisting of calcium carbonates such as limestone or seashells or with non-reactive dolomite have extended times to commencement of corrosion initiation and to active corrosion. The reasons for this are explored herein. In addition it is shown that some structures can have serious localized reinforcement corrosion without obvious exterior signs such as concrete cracking and delamination. This requires urgent research. © 2011 Taylor & Francis Group, LLC.
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2010 |
Melchers RE, 'Estimating uncertainty in maximum pit depth from limited observational data', Corrosion Engineering Science and Technology, 45 240-248 (2010) [C1]
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Nova |
2010 |
Melchers RE, 'Transient early and longer term influence of bacteria on marine corrosion of steel', Corrosion Engineering Science and Technology, 45 257-261 (2010) [C1]
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Nova |
2010 |
Melchers RE, Paik JK, 'Effect of flexure on rusting of ship's steel plating', Ships and Offshore Structures, 5 25-31 (2010) [C1]
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Nova |
2010 |
Melchers RE, Chernov BB, 'Corrosion loss of mild steel in high temperature hard freshwater', Corrosion Science, 52 449-454 (2010) [C1]
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Nova |
2010 |
Melchers RE, Ahammed M, Jeffrey RJ, Simundic G, 'Statistical characterization of surfaces of corroded steel plates', Marine Structures, 23 274-287 (2010) [C1]
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Nova |
2010 |
Melchers RE, 'Carbonates, carbonation and the durability of reinforced concrete marine structures', Australian Journal of Structural Engineering, 10 215-226 (2010) [C1]
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Nova |
2009 |
Melchers RE, 'Validity and quality of deterioration models for structural reliability assessment', Structural Longevity, 1 17-36 (2009) [C1]
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Nova |
2009 |
Melchers RE, Li CQ, 'Reinforcement corrosion initiation and activation times in concrete structures exposed to severe marine environments', Cement and Concrete Research, 39 1068-1076 (2009) [C1]
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Nova |
2009 |
Jeffrey RJ, Melchers RE, 'Effect of vertical length on corrosion of steel in the tidal zone', Corrosion, 65 695-702 (2009) [C1]
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Nova |
2009 |
Melchers RE, Li CQ, 'Reinforcement corrosion in concrete exposed to the North Sea for more than 60 years', Corrosion, 65 554-566 (2009) [C1]
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Nova |
2009 |
Melchers RE, Paik JK, 'Effect of tensile strain on the rate of marine corrosion of steel plates', Corrosion Science, 51 2298-2303 (2009) [C1]
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Nova |
2009 |
Jeffrey RJ, Melchers RE, 'Corrosion of vertical mild steel strips in seawater', Corrosion Science, 51 2291-2297 (2009) [C1]
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Nova |
2009 |
Melchers RE, Li CQ, Davison MA, 'Observations and analysis of a 63-year-old reinforced concrete promenade railing exposed to the North Sea', Magazine of Concrete Research, 61 233-243 (2009) [C1]
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Nova |
2009 |
Ahammed M, Melchers RE, 'A convenient approach for estimating time-dependent structural reliability in the load space', Probabilistic Engineering Mechanics, 24 467-472 (2009) [C1]
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Nova |
2009 |
Melchers RE, 'Long-term corrosion of steels exposed to marine environments', European Journal of Environmental and Civil Engineering, 13 527-546 (2009)
This paper presents an overview of the principal features of the recently developed model for the short and the long-term marine corrosion of steels. In marine environments such a... [more]
This paper presents an overview of the principal features of the recently developed model for the short and the long-term marine corrosion of steels. In marine environments such as immersion, tidal and coastal atmospheric, chlorides conventionally are considered to play a major role in causing corrosion loss. The actual corrosion process is considerably more complex and besides oxidation by dissolved or atmospheric oxygen there is an important influence from the metabolic products of sulphate-reducing bacteria. The model also deals with temperature, oxygen availability, pollution and various other influences. Although the fundamental corrosion processes are all electrochemical in nature, the model does not deal specifically with these. Instead the model is built around the governing corrosion-rate controlling processes. For engineering purposes the rate of loss of material is the critical issue. The main emphasis is on the behaviour of structural and other low alloy steels. The paper closes with some observations about the applicability of the model to stainless and weathering steels and its recent extension to reinforcement corrosion in concrete structures. © 2009 Taylor & Francis Group, LLC.
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2008 |
Melchers RE, 'Rejoinder', Civil Engineering and Environmental Systems, 25 71-76 (2008) [C3]
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Nova |
2008 |
Melchers RE, 'Development of new applied models for steel corrosion in marine applications including shipping', Ships and Offshore Structures, 3 135-144 (2008) [C1]
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Nova |
2008 |
Paik JK, Thayamballi AK, Melchers RE, 'Some recent developments in corrosion assessment and management for steel ships and offshore structures', Marine Technology and SNAME News, 45 94-100 (2008) [C1]
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Nova |
2008 |
Paik JK, Melchers RE, 'Preface', Condition Assessment of Aged Structures, (2008)
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2008 |
Melchers RE, 'Extreme value statistics and long-term marine pitting corrosion of steel', Probabilistic Engineering Mechanics, 23 482-488 (2008) [C1]
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Nova |
2008 |
Melchers RE, Jeffrey RJ, 'Modeling of long-term corrosion loss and pitting for chromium-bearing and stainless steels in seawater', Corrosion, 64 143-154 (2008) [C1]
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Nova |
2008 |
Melchers RE, 'Discussion on 'Stochastic modeling of pitting corrosion: A new model for initiation and growth of multiple pits'', Corrosion Science, 50 1518-1519 (2008) [C3]
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Nova |
2008 |
Gudze MT, Melchers RE, 'Operational based corrosion analysis in naval ships', Corrosion Science, 50 3296-3307 (2008) [C1]
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Nova |
2008 |
Melchers RE, 'A new interpretation of the corrosion loss processes for weathering steels in marine atmospheres', Corrosion Science, 50 3446-3454 (2008) [C1]
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Nova |
2008 |
Melchers RE, Jeffrey RJ, 'The critical involvement of anaerobic bacterial activity in modelling the corrosion behaviour of mild steel in marine environments', Electrochimica Acta, 54 80-85 (2008) [C1]
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Nova |
2008 |
Melchers RE, Li CQ, Lawanwisut W, 'Probabilistic modeling of structural deterioration of reinforced concrete beams under saline environment corrosion', Structural Safety, 30 447-460 (2008) [C1]
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Nova |
2008 |
Li C-Q, Yang Y, Melchers RE, 'Prediction of reinforcement corrosion in concrete and its effects on concrete cracking and strength reduction', ACI Materials Journal, 105 3-10 (2008) [C1]
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Nova |
2008 |
Melchers RE, Jeffrey RJ, 'Probablistic models for steel corrosion loss and pitting of marine infrastructure', Reliability Engineering & System Safety, 93 423-432 (2008) [C1]
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Nova |
2008 |
Melchers RE, Frangopol DM, 'Probabilistic modelling of structural degradation', Reliability Engineering & System Safety, 93 363 (2008) [C3]
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Nova |
2008 |
Brown CB, Elms DG, Melchers RE, 'Assessing and achieving structural safety', Proceedings of the Institution of Civil Engineers-Structures and Buildings, 161 219-230 (2008) [C1]
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Nova |
2007 |
Li CQ, Zheng JJ, Lawanwisut W, Melchers RE, 'Concrete delamination caused by steel reinforcement corrosion', Journal of Materials in Civil Engineering, 19 591-600 (2007) [C1]
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2007 |
Melchers RE, Moan T, Gao Z, 'Corrosion of working chains continuously immersed in seawater', Journal of Marine Science and Technology, 12 102-110 (2007) [C1]
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2007 |
Melchers RE, 'Structural reliability theory in the context of structural safety', Civil Engineering and Environmental Systems, 24 55-69 (2007) [C1]
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Nova |
2007 |
Melchers RE, 'Development of new applied models for steel corrosion in marine applications including shipping', 10th International Symposium on Practical Design of Ships and other Floating Structures, PRADS 2007, 2 919-927 (2007)
Models for the prediction of corrosion mostly give the misleading impression that corrosion of steel in seawater environments is a linear function of time (the 'corrosion rat... [more]
Models for the prediction of corrosion mostly give the misleading impression that corrosion of steel in seawater environments is a linear function of time (the 'corrosion rate'). Non-linear functions have been proposed also, These have been calibrated to aggregated data from a wide variety of sources. This produces predictions with wide uncertainty and it is difficult to make assessments of the effect of steel composition and environmental influences. Recent research has produced a model based on the fundamental characteristics of steel corrosion, including the effect of biological influences. Detailed investigations show that the process controlling the (instantaneous) rate of corrosion changes as corrosion progresses. This is represented as a sequence of phases for which fundamental theoretical justifications and mathematical relationships have been derived. To ensure the model has practical validity it has been calibrated to actual field observations rather than laboratory data. Research findings for the effect of water temperature, dissolved oxygen levels, nutrient pollution, depth, water velocity, water salinity and steel composition are reviewed briefly. Some observations about applications and research directions are given. © 2007 American Bureau of Shipping.
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2007 |
Jeffrey RJ, Melchers RE, 'Influence of migration of iron particles, ions and compounds during long term marine immersion corrosion', Corrosion Engineering Science and Technology, 42 145-151 (2007) [C1]
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2007 |
Gudze MT, Melchers RE, 'Prediction of naval ship ballast tank corrosion using operational profiles', Transactions of the Royal Institution of Naval Architects Part A: International Journal of Maritime Engineering, 149 51-53 (2007) [C3] |
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2007 |
Melchers RE, 'Influence of Seawater nutrient content on the early immersion corrosion of mild steel - Part 1: Empirical observations', Corrosion, 63 318-329 (2007) [C1]
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2007 |
Melchers RE, 'Transition from marine immersion to coastal atmospheric corrosion for structural steels', Corrosion, 63 500-514 (2007) [C1]
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2007 |
Melchers RE, 'Influence of seawater nutrient content on the early immersion corrosion of mild steel - Part 2: The role of biofilms and sulfate-reducing bacteria', Corrosion, 63 405-415 (2007) [C1]
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2007 |
Jeffrey RJ, Melchers RE, 'Effect of orientation and shielding in the early corrosion of mild steel in tidal marine conditions', Corrosion, 63 872-879 (2007) [C1]
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2007 |
Melchers RE, 'Discussion: Statistical characterization of pitting corrosion - Part 1: Data analysis and part 2: Probabilistic modeling for maximum pit depth', Corrosion, 63 112-113 (2007) [C1] |
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2007 |
Melchers RE, 'The effects of water pollution on the immersion corrosion of mild and low alloy steels', Corrosion Science, 49 3149-3167 (2007) [C1]
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2007 |
Jeffrey RJ, Melchers RE, 'The changing topography of corroding mild steel surfaces in seawater', Corrosion Science, 49 2270-2288 (2007) [C1]
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2006 |
Melchers RE, Li CQ, Lawanwisut W, 'Modelling deterioration of structural behaviour of reinforced concrete beams under saline environment corrosion', Magazine of Concrete Research, 58 575-587 (2006) [C1]
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2006 |
Li CQ, Melchers RE, 'Time-dependent serviceability of corrosion-affected concrete structures', Magazine of Concrete Research, 58 567-574 (2006) [C1]
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2006 |
Melchers RE, Paik JK, 'Discussion: non-linear corrosion model for immersed steel plates', Society of Naval Architects and Marine Engineers Transactions, 323-325 (2006) [C1] |
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2006 |
Guedes Soares C, Garbatov Y, Zayed A, Wang G, Melchers RE, Paik JK, Cui W, 'Non-linear corrosion model for immersed steel plates accounting for environmental factors', Transactions - Society of Naval Architects and Marine Engineers, 113 306-329 (2006)
The effects of different marine environmental factors on the corrosion behavior of steel plates totally immersed in salt water are studied. A new corrosion wastage model is propos... [more]
The effects of different marine environmental factors on the corrosion behavior of steel plates totally immersed in salt water are studied. A new corrosion wastage model is proposed, based on a non-linear time-dependent function. This model accounts for the effects of various environmental factors, including salinity, temperature, dissolved oxygen, pH and flow velocity. A numerical example is illustrated for ships trading in different routes in the Pacific Ocean.
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2006 |
Fathi M, Daneshjoo F, Melchers RE, 'A method for determining the behaviour factor of moment-resisting steel frames with semi-rigid connections', Engineering Structures, 28 514-531 (2006) [C1]
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2006 |
Moareftadeh MR, Melchers RE, 'Nonlinear wave theory in reliability analysis of offshore structures', Probabilistic Engineering Mechanics, 21 99-111 (2006) [C1]
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2006 |
Gray WA, Melchers RE, 'Modifications to the 'directional simulation in the load space' approach to structural reliability analysis', Probabilistic Engineering Mechanics, 21 148-158 (2006) [C1]
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2006 |
Gray WA, Melchers RE, 'Load combination analysis by 'Directional simulation in the load space'', Probabilistic Engineering Mechanics, 21 159-170 (2006) [C1]
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2006 |
Melchers RE, Li CQ, 'Phenomenological modeling-of reinforcement corrosion in marine environments', ACI Materials Journal, 103 25-32 (2006) [C1]
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Nova |
2006 |
Li CQ, Melchers RE, Zheng JJ, 'Analytical model for corrosion-induced crack width in reinforced concrete structures', ACI Structural Journal, 103 479-487 (2006) [C1]
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Nova |
2006 |
Ahammed M, Melchers RE, 'Gradient and parameter sensitivity estimation for systems evaluated using Monte Carlo analysis', Reliability Engineering & System Safety, 91 594-601 (2006) [C1]
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2006 |
Melchers RE, 'The corrosion in seawater of structural steels in infrastructure applications', Australian Journal of Structural Engineering, 6 159-168 (2006) [C1] |
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2006 |
Melchers RE, Ahammed M, 'Statistical characterization of corroded steel plate surfaces', Advances in Structural Engineering, 9 83-90 (2006) [C1]
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2006 |
Melchers RE, 'Examples of mathematical modelling of long term general corrosion of structural steels in sea water', Corrosion Engineering Science and Technology, 41 38-44 (2006) [C1]
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Nova |
2006 |
Gudze MT, Melchers RE, 'Prediction of naval ship ballast tank corrosion using operational profiles', International Journal of Maritime Engineering, 148 77-86 (2006) [C1]
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2006 |
Melchers RE, 'The marine corrosion of structural steels in brackish and fresh waters', Structure and Infrastructure Engineering, 2 53-61 (2006) [C1]
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2006 |
Melchers RE, Jiang X, 'Estimation of models for durability of epoxy coatings in water ballast tanks', Ships and Offshore Structures, 1 61-70 (2006) [C1]
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2006 |
Melchers RE, 'Mathematical and probabilistic modelling of material deterioration with application to pitting corrosion in structural steel applications', Journal of Reliability of Structures and Materials, 2 1-8 (2006) [C1] |
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2006 |
Melchers RE, 'Recent progress in the modeling of corrosion of structural steel immersed in seawaters', Journal of Infrastructure Systems, 12 154-162 (2006) [C1]
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2006 |
Melchers RE, 'Pitting corrosion of mild steel under marine anaerobic conditions - Part 1: Experimental observations', Corrosion, 62 981-988 (2006) [C1]
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2006 |
Melchers RE, 'Pitting corrosion of mild steel under marine anaerobic conditions - Part 2: Statistical representation of maximum pit depth', Corrosion, 62 1074-1081 (2006) [C1]
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2006 |
Melchers RE, 'Modelling immersion corrosion of structural steels in natural fresh and brackish waters', Corrosion Science, 48 4174-4201 (2006) [C1]
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2006 |
Melchers RE, Wells PA, 'Models for the anaerobic phases of marine immersion corrosion', Corrosion Science, 48 1791-1811 (2006) [C1]
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Nova |
2005 |
Melchers RE, 'Effect of alloying on maximum depth of pits in mild steel in marine immersion environments', Corrosion, 61 355-363 (2005) [C1]
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2005 |
Melchers RE, 'Effect of nutrient-based water pollution on the corrosion of mild steel in marine immersion conditions', Corrosion, 61 237-245 (2005) [C1]
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2005 |
Melchers RE, 'Statistical characterization of pitting corrosion - Part 1: Data analysis', Corrosion, 61 655-664 (2005) [C1]
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2005 |
Melchers RE, 'Statistical characterization of pitting corrosion - Part 2: Probabilistic modeling for maximum pit depth', Corrosion, 61 766-777 (2005) [C1]
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Nova |
2005 |
Melchers RE, 'Effect Of Immersion Depth On Marine Corrosion Of Mild Steel', Corrosion, 61 895-906 (2005) [C1]
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2005 |
Melchers RE, Jeffrey RJ, 'Early corrosion of mild steel in seawater', Corrosion Science, 47 1678-1693 (2005) [C1]
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2005 |
Melchers RE, 'The effect of corrosion on the structural reliability of steel offshore structures', Corrosion Science, 47 2391-2410 (2005) [C1]
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2005 |
Melchers RE, 'Representation of uncertainty in maximum depth of marine corrosion pits', Structural Safety, 27 322-334 (2005) [C1]
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2005 |
Beck AT, Melchers RE, 'Barrier failure dominance in time variant reliability analysis', Probabilistic Engineering Mechanics, 20 79-85 (2005) [C1]
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Nova |
2005 |
Novikov A, Melchers RE, Shinjikashvili E, Kordzakhia N, 'First passage time of filtered Poisson process with exponential shape function', Probabilistic Engineering Mechanics, 20 57-65 (2005) [C1]
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2005 |
Li CQ, Melchers RE, 'Time-dependent reliability analysis of corrosion-induced concrete cracking', ACI Structural Journal, 102 543-549 (2005) [C1]
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Nova |
2005 |
Li CQ, Melchers RE, 'Time-dependent risk assessment of structural deterioration caused by reinforcement corrosion', ACI Structural Journal, 102 754-762 (2005) [C1]
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Nova |
2005 |
Li CQ, Melchers RE, Lawanwisut W, 'Vulnerability Assessment Of Corrosion-Affected Concrete Structures', Magazine Of Concrete Research, 57 557-565 (2005) [C1]
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2005 |
Jiang X, Melchers RE, 'Reliability analysis of maintained ships under correlated fatigue and corrosion', Royal Institution of Naval Architects. Transactions. Part A. International Journal of Maritime Engineering, 147 9-18 (2005) [C1] |
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2005 |
Melchers RE, 'On extending the range of Michell-like optimal topology structures', Structural and Multidisciplinary Optimization, 29 85-92 (2005) [C1]
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2005 |
Khennane A, Melchers RE, 'A meso-scale finite element model for environmental stress corrosion of GFRP', 4th Australasian Congress on Applied Mechanics, ACAM 2005, 573-578 (2005)
A stress corrosion model of a glass fibre is used within the framework of the finite element theory to predict the life of a unidirectional composite. The approach proposed here s... [more]
A stress corrosion model of a glass fibre is used within the framework of the finite element theory to predict the life of a unidirectional composite. The approach proposed here seeks to construct plausible models of comparative behaviour such that data and experience gained from short-term durability tests can be extrapolated and used to predict long-term behaviour. It is based on numerical simulation. Its significance comes from the fact that it makes use of the finite element method at the microstructural level. The finite element can capture reasonably well all aspects of damage mechanisms taking place in the microstructure. © Institute of Materials Engineering Australasia Ltd 2005.
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2004 |
Melchers RE, Jeffrey RJ, 'Influence Of Water Velocity On Marine Immersion Corrosion Of Mild Steel', Corrosion, Vol. 60 84-94 (2004) [C1]
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2004 |
Melchers RE, Jeffrey RJ, 'Surface 'Roughness' Effect On Marine Immersion Corrosion Of Mild Steel', Corrosion, Vol. 60 697-703 (2004) [C1]
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2004 |
Melchers RE, 'Mathematical Modeling Of The Effect Of Water Velocity On The Marine Immersion Corrosion Of Mild Steel Coupons', Corrosion, Vol. 60 471-478 (2004) [C1]
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2004 |
Melchers RE, 'Pitting Corrosion Of Mild Steel In Marine Immersion Environment - Part 2: Variability Of Maximum Pit Depth', Corrosion, Vol. 60 937-944 (2004) [C1]
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2004 |
Melchers RE, 'Effect Of Small Compositional Changes On Marine Immersion Corrosion Of Low Alloy Steels', Corrosion Science, Vol. 46 1669-1691 (2004) [C1]
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2004 |
Melchers RE, Ahammed M, 'A Fast Approximate Method For Parameter Sensitivity Estimation In Monte Carlo Structural Reliability', Computers and Structures, Vol 82 55-61 (2004) [C1]
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2004 |
Beck AT, Melchers RE, 'Overload Failure Of Structural Components Under Random Crack Propagation And Loading - A Random Process Approach', Structural Safety, Vol. 26 471-488 (2004) [C1]
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2004 |
Beck AT, Melchers RE, 'On The Ensemble Crossing Rate Approach To Time Variant Reliability Analysis Of Uncertain Structures', Probabilistic Engineering Mechanics, Vol. 19 9-19 (2004) [C1]
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2004 |
Melchers RE, 'Pitting Corrosion Of Mild Steel In Marine Immersion Environment - Part 1: Maximum Pit Depth', Corrosion, Vol. 60 824-836 (2004) [C1]
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2004 |
Masia MJ, Kleeman PW, Melchers RE, 'Modelling Soil/Structure Interaction For Masonry Structures', Journal of Structural Engineering, 130 641-649 (2004) [C1]
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Nova |
2003 |
Melchers RE, 'Modeling Of Marine Immersion Corrosion For Mild And Low-Alloy Steels - Part 1: Phenomological Model', Corrosion, Vol. 59 319-334 (2003) [C1]
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Nova |
2003 |
Melchers RE, 'Modeling Of Marine Immersion Corrosion For Mild And Low-Alloy Steels - Part 2: Uncertainty Estimation', Corrosion, Vol. 59 334-344 (2003) [C1]
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2003 |
Melchers RE, 'Mathematical Modelling Of The Diffusion Controlled Phase In Marine Immersion Corrosion Of Mild Steel', Corrosion Science, Vol. 45 923-940 (2003) [C1]
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2003 |
Jeffrey RJ, Melchers RE, 'Bacteriological Influence In The Development Of Iron Sulphide Species In Marine Immersion Environments', Corrosion Science, Vol. 45 693-714 (2003) [C1]
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Nova |
2003 |
Melchers RE, 'Modelling Of Marine Immersion Corrosion For Copper-Bearing Steels', Corrosion Science, Vol. 45 2307-2323 (2003) [C1]
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2003 |
Melchers RE, 'Effect On Marine Immersion Corrosion Of Carbon Content Of Low ALlow Steels', Corrosion Science, Vol. 45 2609-2625 (2003) [C1]
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2003 |
Melchers RE, Ahammed M, Middleton C, 'FORM For Discontinuous And Truncated Probability Density Functions', Structural Safety, Vol. 25 304-313 (2003) [C1]
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2003 |
Khennane A, Melchers RE, 'A micromechanics model for environmental stress corrosion in GFRP', International Journal of Materials and Product Technology, 19 2-14 (2003) [C1]
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2003 |
Melchers RE, 'Probabilistic Model For Marine Corrosion Of Steel For Structural Reliability Assessment', Journal Of Structural Engineering, Vol. 129 1484-1493 (2003) [C1]
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2003 |
Melchers RE, 'Probabilistic Models For Corrosion In Structural Reliability Assessment - Part 1: Empirical Models', Journal Of Offshore Mechanics And Arctic Engineering, Vol. 125 264-271 (2003) [C1]
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2003 |
Melchers RE, 'Probabilistic Models For Corrosion In Structural Reliability Assessment - Part 2: Models Based On Mechanics', Journal Of Offshore Mechanics And Arctic Engineering, Vol. 125 272-280 (2003) [C1]
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2003 |
Gardiner CP, Melchers RE, 'Corrosion Analysis Of Bulk Carriers: Part 1 - Operational Parameters Influencing Corrosion Rates', Marine Structures, Vol. 16 547-566 (2003) [C1]
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2003 |
Khennane A, Melchers RE, 'Durability Of Glass Polymer Composites Subject To Stress Corrosion', Journal Of Composites For Construction, Vol. 7 109-117 (2003) [C1]
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2002 |
Melchers RE, 'Effect Of Temperature On The Marine Immersion Corrosion Of Carbon Steels', Corrosion, Vol. 58, No. 9 768-782 (2002) [C1]
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2002 |
Gardiner CP, Melchers RE, 'Corrosion Of Mild Steel In Porous Media', Corrosion Science, Vol. 44 2459-2478 (2002) [C1]
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2002 |
Gardiner CP, Melchers RE, 'Corrosion Of Mild Steel By Coal And Iron Ore', Corrosion Science, Vol. 44 2665-2673 (2002) [C1]
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2002 |
Guan X-L, Melchers RE, 'Effect Of Response Surface Parameter Variation On Structural Reliability Estimates', Structural Safety, Vol. 23 429-444 (2002) [C1]
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2002 |
Melchers RE, 'Safety And Risk In Structural Engineering', Progress In Structural Engineering And Materials, Vol. 4 193-202 (2002) [C1] |
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2002 |
Masia MJ, Melchers RE, Kleeman PW, 'Probabilistic Crack Prediction For Masonry Structures On Expansive Soils', Journal of Structural Engineering, 128 1454-1461 (2002) [C1]
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Nova |
2002 |
Melchers RE, Ahammed M, 'Gradient Estimation For Applied Monte Carlo Analyses', Reliability Engineering And System Safety, Vol. 78 283-288 (2002) [C1]
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2002 |
Melchers RE, 'Probabilistic Risk Assessment For Structures', Proceedings Of The Institution Of Civil Engineers: Structures And Buildings, Issue 4 351-359 (2002) [C1]
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2002 |
O Rourke M, De Angelis C, 'Snow Drifts at Windward Roof Steps', Journal of Structural Engineering, 128 1330-1336 (2002)
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2002 |
Khennane A, Melchers RE, 'Stress corrosion of glass fibre reinforced polymers for infrastructure applications', Corrosion and Materials, 27 S5-S8 (2002) [C1] |
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2002 |
Jeffrey RJ, Melchers RE, 'Shape And Size Effects For Marine Immersion Coupons', British Corrosion Journal, Vol. 37, No. 2 99-104 (2002) [C1]
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2001 |
Melchers RE, Soares CG, 'Special issue - Risk assessment of engineering facilities', RELIABILITY ENGINEERING & SYSTEM SAFETY, 74 225-225 (2001) [C3]
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2001 |
Melchers RE, 'Influence of temperature on sea water immersion corrosion of aluminium', British Corrosion Journal, 36 201-204 (2001) [C1]
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2001 |
Gardiner CP, Melchers RE, 'Enclosed atmospheric corrosion in ship spaces', British Corrosion Journal, 36 272-276 (2001) [C1]
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2001 |
Melchers RE, 'Temperature effect on seawater immersion corrosion of 90:10 copper-nickel alloy', Corrosion, 57 440-451 (2001) [C1]
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2001 |
Melchers RE, Ahammed M, 'Estimation of failure probabilities for intersections of non-linear limit states', Structural Safety, 23 123-135 (2001) [C1]
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2001 |
Guan X-L, Melchers RE, 'Effects of response surface parameter variation on structural reliability estimates', Structural Safety, 23 429-444 (2001) [C1] |
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2001 |
Melchers RE, 'Assessment of Existing Structures - Approaches and Research Needs', Journal of Structural Engineering, Vol 127, No. 4 406-411 (2001) [C1]
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2001 |
Melchers RE, Soares CG, 'Special issue - Risk assessment of engineering facilities', RELIABILITY ENGINEERING & SYSTEM SAFETY, 74 225-225 (2001)
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2001 |
Melchers RE, 'Rational optimization of reliability and safety policies', Reliability Engineering & System Safety, 73 263-268 (2001) [C1]
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2001 |
Melchers RE, 'On the ALARP approach to risk management', Reliability Engineering & System Safety, 71 201-208 (2001) [C1]
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2001 |
Melchers RE, Feutrill WR, 'Risk assessment of LPG automotive refuelling facilities', Reliability Engineering & System Safety, 74 283-290 (2001) [C1]
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2001 |
Melchers RE, 'Optimality-criteria-based probabilistic structural design', Structural and Multidisciplinary Optimization, 23 34-39 (2001) [C1]
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2000 |
Melchers RE, 'Discussion on 'The strategies and value of risk based structural safety analysis' - Special issue of Structural Safety, Vol. 21, No. 4, 1999', STRUCTURAL SAFETY, 22 281-286 (2000)
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2000 |
Melchers RE, 'Discussion on 'The strategies and value of risk based structural safety analysis'', Structural Safety, Vol 22 281-286 (2000) [C1] |
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2000 |
Son KS, Melchers RE, Kal WM, 'An analysis of safety control effectiveness', Reliability Engineering & System Safety, Vol 68 187-194 (2000) [C1]
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2000 |
Val DV, Stewart MG, Melchers RE, 'Life-cycle performance of reinforced concrete bridges: probabilistic approach', Computer-Aided Civil and Infrastructure Engineering, 15 14-25 (2000) [C1]
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2000 |
Melchers RE, Jefferis M, 'Australian Journal of Structural Engineering', Australian Journal of Structural Engineering, Vol. 3, Nos. 1 & 2 1-109 (2000) [C2] |
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1999 |
Melchers RE, 'Corrosion uncertainty modelling for steel structures', Journal of Constructional Steel Research, Vol. 52 3-19 (1999) [C1]
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1999 |
Moarefzadeh MR, Melchers RE, 'Directional importance sampling for ill-proportioned spaces', STRUCTURAL SAFETY, 21 1-22 (1999)
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1999 |
Guan X-L, Melchers RE, 'A load space formulation for probabilistic finite element analysis of structural reliability', Porbabilistic Engineering Mechanics, 14 73-81 (1999) [C1]
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1999 |
Melchers RE, 'Research needs in structural engineering: changes and challenges', Australian Journal of Structural Engineering, 2 85-94 (1999) [C1] |
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1998 |
Val DV, Stewart MG, Melchers RE, 'Effect of reinforcement corrosion on reliability of highway bridges', Engineering Structures, Vol. 20, No.11 1010-1019 (1998) [C1]
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1997 |
Ahammed M, Melchers RE, 'Probabilistic analysis of underground pipelines subject to combined stresses and corrosion', ENGINEERING STRUCTURES, 19 988-994 (1997)
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1997 |
Guan XL, Melchers RE, 'Multitangent-plane surface method for reliability calculation', JOURNAL OF ENGINEERING MECHANICS-ASCE, 123 996-1002 (1997)
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1997 |
Val DV, Melchers RE, 'Reliability of deteriorating RC slab bridges', JOURNAL OF STRUCTURAL ENGINEERING-ASCE, 123 1638-1644 (1997)
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1997 |
Melchers RE, 'Modeling of marine corrosion of steel specimens', ASTM Special Technical Publication, 1300 20-33 (1997)
Phenomenological modeling of the long term general corrosion of mild and low alloy steel specimens under marine conditions is considered, using weight loss as a function of time. ... [more]
Phenomenological modeling of the long term general corrosion of mild and low alloy steel specimens under marine conditions is considered, using weight loss as a function of time. A conceptual model for immersion corrosion, tidal corrosion and atmospheric corrosion under marine conditions is proposed. The model uses accepted theories for short term surface corrosion and employs modern understanding of the action of bacterial colonisation of the surfaces of specimens, including the development of anaerobic conditions. Kinetic, diffusion, nutrient and anaerobic components of the model are identified and mathematical descriptions given. The model is compared to some data available in the literature. Some observations are made about data requirements for further development of models of the type proposed.
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1996 |
Frangopol DM, Melchers RE, 'Special issue on reliability-based evaluation and design of masonry, steel, and reinforced concrete structures', STRUCTURAL SAFETY, 18 65-65 (1996)
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1996 |
Moarefzadeh MR, Melchers RE, 'Sample-specific linearization in reliability analysis of off-shore structures', STRUCTURAL SAFETY, 18 101-122 (1996)
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1996 |
Ahammed M, Melchers RE, 'Reliability estimation of pressurised pipelines subject to localised corrosion defects', INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING, 69 267-272 (1996)
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1996 |
Ahammed M, Melchers RE, 'Reliability of underground pipelines subject to corrosion - Closure', JOURNAL OF TRANSPORTATION ENGINEERING-ASCE, 122 408-408 (1996)
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1995 |
MELCHERS RE, 'LOAD SPACE RELIABILITY FORMULATION FOR POISSON PULSE PROCESSES', JOURNAL OF ENGINEERING MECHANICS, 121 779-784 (1995)
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1995 |
AHAMMED M, MELCHERS RE, 'PROBABILISTIC ANALYSIS OF PIPELINES SUBJECTED TO PITTING CORROSION LEAKS', ENGINEERING STRUCTURES, 17 74-80 (1995)
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1995 |
LI CQ, MELCHERS RE, 'FAILURE PROBABILITY OF REINFORCED-CONCRETE COLUMNS UNDER STOCHASTIC LOADS', ENGINEERING STRUCTURES, 17 419-424 (1995)
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1995 |
CHAN HY, MELCHERS RE, 'TIME-DEPENDENT RESISTANCE DETERIORATION IN PROBABILISTIC STRUCTURAL SYSTEMS', CIVIL ENGINEERING SYSTEMS, 12 115-132 (1995)
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1995 |
Melchers RE, Feutrill WR, 'Risk assessment for automotive LPG facilities', American Society of Mechanical Engineers, Pressure Vessels and Piping Division (Publication) PVP, 296 457-462 (1995)
Experiences are described of the use and application of quantified risk analysis (QRA) for medium size liquefied petroleum gas (LPG) facilities associated with automotive service ... [more]
Experiences are described of the use and application of quantified risk analysis (QRA) for medium size liquefied petroleum gas (LPG) facilities associated with automotive service (gas) stations in suburban and rural areas. The facilities consist primarily of one or more 7.5 kilolitre pressure vessels, pumps, pipework, dispensing facilities and various types of safety equipment. QRA was required to show compliance with recently introduced Australian national regulatory risk criteria for land use planning purposes. A description is given of the risk analysis procedure, the various hazard scenarios considered, the determination and application of appropriate data for initiating events and for rates of failure of mechanical components, the pressure vessel and various human operations. Various tests were performed to estimate matters such as flame length and flame impingement on pressure vessels. Some observations are made regarding the standard of conventional industry quantified risk analysis techniques and the way they are often applied. An area of particular concern is the use of 'conservative best estimates' widely used in the industry but inconsistent with the interpretation of risk criteria derived from expected (observed) risks.
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1994 |
GUAN XL, MELCHERS RE, 'AN EFFICIENT FORMULATION FOR LIMIT STATE FUNCTION GRADIENT CALCULATION', COMPUTERS & STRUCTURES, 53 929-935 (1994)
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1994 |
MELCHERS RE, LI CQ, 'A BENCHMARK STUDY ON IMPORTANCE SAMPLING TECHNIQUES IN STRUCTURAL RELIABILITY - ENGELUND,S. RACKWITZ,R. (MUNCHEN, GERMANY), STRUCTURAL SAFETY, 12(4)(1993) 255-276 - DISCUSSION', STRUCTURAL SAFETY, 14 299-302 (1994)
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1994 |
MELCHERS RE, 'STRUCTURAL SYSTEM RELIABILITY ASSESSMENT USING DIRECTIONAL SIMULATION', STRUCTURAL SAFETY, 16 23-37 (1994)
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1994 |
LI CQ, MELCHERS RE, 'RELIABILITY-ANALYSIS OF CREEP AND SHRINKAGE EFFECTS - CLOSURE', JOURNAL OF STRUCTURAL ENGINEERING-ASCE, 120 1050-1050 (1994)
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1994 |
AHAMMED M, MELCHERS RE, 'RELIABILITY OF UNDERGROUND PIPELINES SUBJECT TO CORROSION', JOURNAL OF TRANSPORTATION ENGINEERING-ASCE, 120 989-1002 (1994)
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1994 |
Melchers RE, 'On intra-plate earthquakes and existing structures', Transactions of the Institution of Engineers, Australia. Civil engineering, CE36 265-272 (1994)
Although the risk of damage to buildings and structures and the risk of personal death and injury due to earthquakes in Australia is relatively low, the 1989 Newcastle earthquake ... [more]
Although the risk of damage to buildings and structures and the risk of personal death and injury due to earthquakes in Australia is relatively low, the 1989 Newcastle earthquake did point to the need to reexamine existing structural design and construction standards. There is a danger, however, that tough regulations will affect adversely the continued viability of existing building stock, in particular historical buildings. Commercial interests also may be affected. For buildings which have a projected life which is short relative to the recurrence rate of serious ground shaking, it is argued that the total structural life-time risk is low and might be ignored. This would appear to be the situation under Australian intra-plate earthquake conditions. The conclusion is relevant for structurally adequate existing buildings and for new buildings constructed in the first few years after the occurrence of major ground shaking.
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1994 |
LI CW, MELCHERS RE, 'STRUCTURAL SYSTEMS RELIABILITY UNDER STOCHASTIC LOADS', PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS-STRUCTURES AND BUILDINGS, 104 251-255 (1994)
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1994 |
LI CQ, MELCHERS RE, 'STRUCTURAL SYSTEMS RELIABILITY UNDER STOCHASTIC LOADS (VOL 104, PG 251, 1994)', PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS-STRUCTURES AND BUILDINGS, 104 489-489 (1994) |
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1993 |
CHAN HY, MELCHERS RE, 'A SIMULATION METHOD FOR TIME-DEPENDENT STRUCTURAL RELIABILITY', COMPUTERS & STRUCTURES, 49 989-996 (1993)
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1993 |
LI CQ, MELCHERS RE, 'GAUSSIAN UPCROSSING RATE SOLUTION FOR STRUCTURAL SERVICEABILITY', STRUCTURAL SAFETY, 12 293-303 (1993)
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1993 |
LI CQ, MELCHERS RE, 'OUTCROSSINGS FROM CONVEX POLYHEDRA FOR NONSTATIONARY GAUSSIAN-PROCESSES', JOURNAL OF ENGINEERING MECHANICS-ASCE, 119 2354-2359 (1993)
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1993 |
Chan HY, Melchers RE, 'Reliability of time-dependent structural systems', Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE, 2 39-46 (1993)
A corrosion process acting on an individual structural member may be modelled as a time-dependent resistance deterioration mechanism. This leads to a deteriorating structural syst... [more]
A corrosion process acting on an individual structural member may be modelled as a time-dependent resistance deterioration mechanism. This leads to a deteriorating structural system, which may be subjected to one or more stochastic load processes. When resistances are modelled as Gaussian random variables, the loads as Gaussian random processes and deterioration is considered to be a simple function of time, some progress can be made in evaluation of structural system reliability using an outcrossing formulation. This was checked using numerical integration. The results are compared to purely simulation results both for the outcrossing rate and for various sensitivity results. Good agreement is demonstrated.
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1993 |
Melchers RE, 'Reliability and risk assessments for LPG facilities - a view of the state of the art', Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering - OMAE, 2 13-19 (1993)
Quantitative risk analysis procedures increasingly are being applied to potentially hazardous industrial operations and facilities. A review of QRA analyses carried out for land-b... [more]
Quantitative risk analysis procedures increasingly are being applied to potentially hazardous industrial operations and facilities. A review of QRA analyses carried out for land-based LPG facilities has shown that the failure probabilities obtained for specific events may differ considerably between risk analyses and between analists. The present paper reviews possible reasons for the disparities and what might be done to produce more consistent results. It is necessary that the limitations of current QRA techniques be recognized and be made known. This is important because there is a distinct danger that quantified risk analysis in general may be discredited as a result of unfavourable experiences by industry, decision-makers and legislators. This may have implications also for the offshore industry.
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1992 |
MELCHERS RE, 'COLUMN-BASE RESPONSE UNDER APPLIED MOMENT', JOURNAL OF CONSTRUCTIONAL STEEL RESEARCH, 23 127-143 (1992)
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1992 |
Melchers RE, 'Rotational stiffness of shallow footings', Computers and Geotechnics, 13 21-35 (1992)
The details of footing design, the soil stiffness and the soil resistance all affect the rotation characteristics of column bases of structural frames. This can have a considerabl... [more]
The details of footing design, the soil stiffness and the soil resistance all affect the rotation characteristics of column bases of structural frames. This can have a considerable influence on structural economics (strength design), structural deflections (serviceability design) and on structural stability. Of particular and increasing importance in structural design is the ability to predict structural deformations under serviceability load level conditions. However, only limited theoretical and experimental attention has been given to understanding the footing-soil interface behaviour of shallow footings for realistic foundation conditions. In this paper, a set of experimental results for shallow footing behaviour under load reversal is presented. Based on this work and on previous modelling attempts, a relatively simple theoretical model for predicting rotation behaviour of simple pad footings under the first loading condition is described. © 1992.
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1992 |
MELCHERS RE, 'LOAD-SPACE FORMULATION FOR TIME-DEPENDENT STRUCTURAL RELIABILITY', JOURNAL OF ENGINEERING MECHANICS-ASCE, 118 853-870 (1992)
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1992 |
LI CQ, MELCHERS RE, 'RELIABILITY-ANALYSIS OF CREEP AND SHRINKAGE EFFECTS', JOURNAL OF STRUCTURAL ENGINEERING, 118 2323-2337 (1992)
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1992 |
Melchers RE, 'On earthquake design standards for Australia', Transactions of the Institution of Engineers, Australia. Civil engineering, CE34 63-71 (1992)
The setting of structural engineering design standards for earthquakes in Australia is particularly difficult. The country lies within a ``continental'' plate and eviden... [more]
The setting of structural engineering design standards for earthquakes in Australia is particularly difficult. The country lies within a ``continental'' plate and evidence from other such regions uggests that Australia is therefore a relatively low risk country with only rare occurrences of major earthquakes. By comparison to other countries Australia also has a very short recorded history relative to the frequency of significant earthquakes. A discussion is given herein of factors which influence seismic zoning, the underlying assumptions and limitations which apply to the methods used and how these matters should relate to the development of design codes for earthquake forces. The discussion should be seen as a contribution towards understanding the background and assumptions and not as criticism of present code-development efforts.
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1992 |
Li CQ, Melchers RE, 'Simulation of load effect due to creep and shrinkage', Transactions of the Institution of Engineers, Australia. Civil engineering, CE34 107-113 (1992)
Mathematical models for creep and shrinkage of concrete are used in the paper to present a whole-process analysis of creep and shrinkage effects in reinforced concrete structures,... [more]
Mathematical models for creep and shrinkage of concrete are used in the paper to present a whole-process analysis of creep and shrinkage effects in reinforced concrete structures, allowing in particular for various uncertainties. A simulation method is proposed to predict the time-dependent load effect due to creep and shrinkage under stochastic loads. It is shown through the formulation and by example that the method has the advantage that all the random variability can be included in the load effect at any point in time. Because of the uncertainties of concrete material properties and the applied loads, all parameters that describe the properties of the structures and the nature of load at any point in time are treated as random variables.
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1992 |
MELCHERS RE, PAGE AW, 'THE NEWCASTLE EARTHQUAKE', PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS-STRUCTURES AND BUILDINGS, 94 143-156 (1992)
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1992 |
Melchers RE, Ahammed M, 'Linearisation and offshore fatigue reliability', Probabilistic Mechanics and Structural and Geotechnical Reliability, Proceedings of the Specialty Conference, 5-8 (1992)
In determining the force effects due to wave action on offshore structures it is conventional to use an equivalent linearisation to convert wave velocities to forces via Morison&a... [more]
In determining the force effects due to wave action on offshore structures it is conventional to use an equivalent linearisation to convert wave velocities to forces via Morison's equation. Different linearisations have been suggested. However, it is not, a priori, clear which is appropriate when structural fatigue is to be estimated. A (theoretical) criterion is introduced herein and examined in relation to a simple offshore structure.
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1992 |
Melchers RE, 'Sampling techniques for time-variant reliability problems', Probabilistic Mechanics and Structural and Geotechnical Reliability, Proceedings of the Specialty Conference, 100-103 (1992)
Time-variant structural reliability problems arise when the structural resistance may change with time (such as in structural deterioration) or when the system is acted upon by tw... [more]
Time-variant structural reliability problems arise when the structural resistance may change with time (such as in structural deterioration) or when the system is acted upon by two or more stochastic load processes. This paper reviews current trends in using sampling based techniques to solve such problems.
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1992 |
Melchers RE, Ahammed M, 'Equivalent linearisation and fatigue reliability estimation for offshore structures 531-536 (1992)
The force effects due to wave action on offshore structures are conventionally determined using Morison's equation. This is a nonlinear relation in velocity, conventionally r... [more]
The force effects due to wave action on offshore structures are conventionally determined using Morison's equation. This is a nonlinear relation in velocity, conventionally represented by an equivalent linearisation for converting wave velocities to forces, necessary to allow structural dynamic analysis by frequency domain methods (the most commonly applied approach). The suggested approaches for the linearisation can be shown to be of essentially two classes; those equivalent to Borgman's approach and those equivalent to Bolotin's. In general, it is not clear, a priori, which is more the appropriate. Nor is it clear whether these classical linearisations are relevant, particularly when structural fatigue is to be estimated (e.g., through the Palmgren-Miner rule). A criterion for derivation of a linearisation constant under fatigue considerations can be derived relatively simply. Unfortunately the criterion is not easily applied except by iteration. A sensitivity study has been performed for a simple but realistic offshore structure to estimate the relative importance of correctly estimating the linearisation constant.
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1992 |
Melchers RE, 'Developments in structural reliability assessment under complex load conditions (1992)
The paper outlines some new directions in the assessment of structural reliability for structures subject to a number of loading processes and which may be deteriorating or changi... [more]
The paper outlines some new directions in the assessment of structural reliability for structures subject to a number of loading processes and which may be deteriorating or changing their resisting values with time. In particular, attention is given to modern methods of simulation to solve the surface integral required for 'time-dependent' reliability evaluation. As is indicated, the computations involved are not necessarily significantly more complex than those which are currently required for so-called 'time-independent' reliability assessments. (from Author)
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1991 |
Melchers RE, 'Vulnerability and seismic risk assessment of buildings following the 1989 newcastle, Australia earthquake', Bulletin of the New Zealand Society for Earthquake Engineering, 24 341-343 (1991)
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1991 |
Melchers RE, 'Directional simulation for time-dependent reliability problems', Lecture Notes in Engineering, 261-272 (1991)
While there has been significant progress in the assessment of structural reliability for complex structures (e.g., offshore oil platforms) in the time independent domain, signifi... [more]
While there has been significant progress in the assessment of structural reliability for complex structures (e.g., offshore oil platforms) in the time independent domain, significant problems remain in dealing with structures subject to time varying loading. The crux of the problem lies in the fact that the loads are time dependent (e.g., wave loading, wind loading, etc.) but the material properties can be considered to be time independent. A procedure utilizing refined Monte Carlo simulation in the hyper-polar co-ordinate space of the load processes is described herein.
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1991 |
STEWART MG, MELCHERS RE, 'THE CHOICE OF OPTIMAL CHECKING STRATEGIES FOR ERROR CONTROL IN STRUCTURAL-ENGINEERING', CIVIL ENGINEERING SYSTEMS, 8 59-59 (1991)
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1991 |
AHMAD MZ, DATTA TK, MELCHERS RE, 'MINIMUM REINFORCEMENT SOLUTION FOR FLAT SLABS - DISCUSSION', PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS PART 2-RESEARCH AND THEORY, 91 609-615 (1991)
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1991 |
STEWART MG, MELCHERS RE, 'CHECKING MODELS IN STRUCTURAL DESIGN - CLOSURE', JOURNAL OF STRUCTURAL ENGINEERING-ASCE, 117 2188-2189 (1991)
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1991 |
MELCHERS RE, 'NON-INVARIANT FAILURE PROBABILITIES WITH INVARIANT RELIABILITY INDEX - DISCUSSION', RELIABILITY ENGINEERING & SYSTEM SAFETY, 33 315-318 (1991)
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1991 |
Melchers RE, 'Discussion on 'non-invariant failure probabilities with invariant reliability index'', Reliability Engineering and System Safety, 33 315-318 (1991)
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1991 |
Melchers RE, 'New methods for structural reliability assessment', Proceedings of the First International Offshore and Polar Engineering Conference, 254-258 (1991)
The reliability of offshore structures under ultimate load conditions is considered under a potentially diverse load process scenario. An 'outcrossing' formulation in wh... [more]
The reliability of offshore structures under ultimate load conditions is considered under a potentially diverse load process scenario. An 'outcrossing' formulation in which the loads are modelled as processes rather than only as random variables is developed in the (hyper-) polar co-ordinate space. This has distinct advantages for problems, such as involving offshore structures, for which the structural analysis for safety checking is complex (e.g., requiring a finite element analysis or dynamic analysis etc.).
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1990 |
DITLEVSEN O, MELCHERS RE, GLUVER H, 'GENERAL MULTIDIMENSIONAL PROBABILITY INTEGRATION BY DIRECTIONAL SIMULATION', COMPUTERS & STRUCTURES, 36 355-368 (1990)
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1990 |
CHAN HY, MELCHERS RE, 'WAVE LOADING EFFECT IN OFFSHORE STRUCTURAL RELIABILITY', STRUCTURAL SAFETY, 7 1-10 (1990)
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1990 |
MELCHERS RE, 'SEARCH-BASED IMPORTANCE SAMPLING', STRUCTURAL SAFETY, 9 117-128 (1990)
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1990 |
MELCHERS RE, TURNER RC, 'STRUCTURAL RELIABILITY ASSESSMENT FOR MAJOR STRUCTURES - DISCUSSION', PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS PART 2-RESEARCH AND THEORY, 89 439-442 (1990)
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1990 |
Melchers RE, 'Assesment of structural reliability. A review', National Conference Publication - Institution of Engineers, Australia, 6-11 (1990)
Considerable progress has been made in the theory of structural reliability in the last 15-20 years, particularly in relation to the analytical treatment of information. Much of t... [more]
Considerable progress has been made in the theory of structural reliability in the last 15-20 years, particularly in relation to the analytical treatment of information. Much of this has gone relatively unnoticed by the engineering profession, even though the potential for structural reliability assessments in certain practical problems is now significant. Structural reliability theory has been applied, of course, to structural design code calibration, but has a much wider potential. Particularly in the offshore industry and in large projects it is being used where risk must be specifically considered and where to do so may yield considerable design and construction cost savings. In this paper the basic concepts of structural reliability theory will be reviewed and related to the standard and type of information usually availabel in engineering studies. An overview will also be given of the various calculation technique now available.
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1990 |
Page AW, Kleeman PW, Stewart MG, Melchers RE, 'Structural aspects of the Newcastle earthquake', National Conference Publication - Institution of Engineers, Australia, 305-312 (1990)
On 28 December, 1989 the city of Newcastle was struck by a magnitude 5.6 earthquake killing 12 people and causing losses estimated at $1000 million. It was the first time a major ... [more]
On 28 December, 1989 the city of Newcastle was struck by a magnitude 5.6 earthquake killing 12 people and causing losses estimated at $1000 million. It was the first time a major Australian city has been so extensively damaged as a result of an earthquake, and the first time that deaths have occurred. With a few exceptions, most of the damage was to older loadbearing masonry construction or to infill masonry in modern framed construction. There was relatively little structural damage to modern buildings, industrial facilities and lifelines. This paper reviews the damage to structures and brings out the main points to be considered in future design and construction.
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1990 |
MELCHERS RE, 'RADIAL IMPORTANCE SAMPLING FOR STRUCTURAL RELIABILITY', JOURNAL OF ENGINEERING MECHANICS, 116 189-203 (1990)
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1990 |
Melchers RE, 'Discussion of paper', Civil Engineering Systems, 7 242-243 (1990)
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1989 |
Stewart MG, Melchers RE, 'Structural design and design checking', Civil engineering transactions, CE31 63-69 (1989)
The process of structural design has received very little attention from the research community despite its centralness in day-to-day structural engineering. Much of the research ... [more]
The process of structural design has received very little attention from the research community despite its centralness in day-to-day structural engineering. Much of the research which has been done has been carried out in Australia over a number of years and with the co-operation of many structural engineers. The present paper reviews the reasons for being engaged in this relatively unusual research activity and provides an overview of the work to date. A review is given of the incidence and type of errors made in basic design tasks such as calculations, table look-up and table interpolation, and how these errors relate to results obtained for more comprehensive tasks such as loading determination and member design. One of the outcomes of the work has been to suggest areas in certain current design codes which are prone to misinterpretation by practitioners. Preliminary results related to design computation checking and inspection are also reviewed. This work potentially has major implications for quality assurance programmes.
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1989 |
MELCHERS RE, 'IMPORTANCE SAMPLING IN STRUCTURAL SYSTEMS', STRUCTURAL SAFETY, 6 3-10 (1989)
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1989 |
STEWART MG, MELCHERS RE, 'ERROR CONTROL IN MEMBER DESIGN', STRUCTURAL SAFETY, 6 11-24 (1989)
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1989 |
MELCHERS RE, 'ADAPTIVE SAMPLING - AN ITERATIVE FAST MONTE-CARLO PROCEDURE - DISCUSSION', STRUCTURAL SAFETY, 6 65-66 (1989)
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1989 |
Melchers RE, 'Discussion to: Bucher, C.G. adaptive sampling-an iterative fast Monte Carlo procedure. Structural safety, 5 (1988) 119-126', Structural Safety, 6 65-66 (1989)
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1989 |
Stewart MG, Melchers RE, 'Decision model for overview checking of engineering designs', International Journal of Industrial Ergonomics, 4 19-27 (1989)
Overview checking occurs whenever an engineering design is reviewed by another engineer without specifically carrying out checking calculations or following through the design pro... [more]
Overview checking occurs whenever an engineering design is reviewed by another engineer without specifically carrying out checking calculations or following through the design process in detail. Results are reported herein of a survey examining the effectiveness of overview checking. The respondents were requested to assess whether a structural design should be considered "undersized", "correct" or "oversized". Using the responses as a basis, a decision model is proposed for the effectiveness of overview checking as a function of error magnitude and of checker's experience. It is concluded that correct assessment of a design as "safe" is not a function of experience. However, it appears that more experience is beneficial in selecting economical designs. © 1989.
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1989 |
MELCHERS RE, 'STRUCTURAL RELIABILITY ASSESSMENT FOR MAJOR STRUCTURES', PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS PART 2-RESEARCH AND THEORY, 87 343-356 (1989)
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1989 |
MELCHERS RE, 'HUMAN ERROR IN STRUCTURAL DESIGN TASKS', JOURNAL OF STRUCTURAL ENGINEERING, 115 1795-1807 (1989)
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1989 |
STEWART MG, MELCHERS RE, 'OPTIMIZATION OF STRUCTURAL DESIGN CHECKING', JOURNAL OF STRUCTURAL ENGINEERING-ASCE, 115 2448-2460 (1989)
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1989 |
STEWART MG, MELCHERS RE, 'CHECKING MODELS IN STRUCTURAL DESIGN', JOURNAL OF STRUCTURAL ENGINEERING-ASCE, 115 1309-1324 (1989)
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1989 |
Melchers RE, 'On probabilistic absolute optimum design', Structural Optimization, 1 107-112 (1989)
Absolute structural optimization problems such as leastweight and layout problems become both more realistic and more complex when their parameters are described probabilistically... [more]
Absolute structural optimization problems such as leastweight and layout problems become both more realistic and more complex when their parameters are described probabilistically. The theoretical framework for absolute optimal design of sandwich beams, grillages and reinforced slabs is extended herein to deal with probabilistic parameters. It is shown that using a simplified probabilistic framework (socalled First Order Second Moment), some classical solutions for optimal layout remain valid. Remarks about the more general problem and the difficulty of its solution close the paper. © 1989 Springer-Verlag.
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1989 |
Melchers RE, 'Improved importance sampling methods for structural system reliability calculation 1185-1192 (1989)
Improvements can be made to importance sampling by recognising some of the essential features of the time-independent structural reliability problem. Thus non-interesting regions ... [more]
Improvements can be made to importance sampling by recognising some of the essential features of the time-independent structural reliability problem. Thus non-interesting regions in the integration domain can be deleted from consideration using a priori information and updating techniques. These can also be used to obtain the point(s) of maximum likelihood, a central parameter for importance sampling in cartesian co-ordinates.
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1988 |
HON KK, MELCHERS RE, 'EXPERIMENTAL BEHAVIOR OF STEEL COLUMN BASES', JOURNAL OF CONSTRUCTIONAL STEEL RESEARCH, 9 35-50 (1988)
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1988 |
MELCHERS RE, 'A CRITICAL-APPRAISAL OF METHODS TO DETERMINE FAILURE PROBABILITIES - DISCUSSION', STRUCTURAL SAFETY, 5 155-156 (1988)
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1988 |
STEWART MG, MELCHERS RE, 'SIMULATION OF HUMAN ERROR IN A DESIGN LOADING TASK', STRUCTURAL SAFETY, 5 285-297 (1988)
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1988 |
Melchers RE, 'Discussion to Schuëller, G.I. and Stix, R., A critical appraisal of methods to determine failure probabilities. Structural Safety, 4 (1987) 293-309', Structural Safety, 5 155-156 (1988)
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1988 |
TANG K, MELCHERS RE, 'INCREMENTAL FORMULATION FOR STRUCTURAL RELIABILITY-ANALYSIS', CIVIL ENGINEERING SYSTEMS, 5 153-158 (1988)
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1987 |
Melchers RE, 'MONTE-CARLO METHODS FOR STRUCTURAL RELIABILITY ANALYSES.', Civil engineering transactions, 29 219-222 (1987)
Elementary Monte-Carlo sampling as a technique to artificially replicate an experimental program has been used successfully for relatively simple problems, provided the failure pr... [more]
Elementary Monte-Carlo sampling as a technique to artificially replicate an experimental program has been used successfully for relatively simple problems, provided the failure probability to be calculated is relatively large. The present paper reviews the elementary Monte-Carlo method and describes little known, but improved approach known as Importance Sampling.
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1987 |
TANG LK, MELCHERS RE, 'IMPROVED APPROXIMATION FOR MULTINORMAL INTEGRAL', STRUCTURAL SAFETY, 4 81-93 (1987)
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1987 |
MELCHERS RE, MORLEY CT, WOOD RH, GURLEY CR, 'EQUILIBRIUM DESIGN SOLUTIONS FOR TORSIONLESS GRILLAGES OR HILLERBORG SLABS UNDER CONCENTRATED LOADS - DISCUSSION', PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS PART 2-RESEARCH AND THEORY, 83 669-682 (1987) |
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1987 |
YEE YL, MELCHERS RE, 'MOMENT ROTATION CURVES FOR BOLTED CONNECTIONS - CLOSURE', JOURNAL OF STRUCTURAL ENGINEERING-ASCE, 113 2327-2329 (1987)
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1987 |
TANG LK, MELCHERS RE, 'DOMINANT MECHANISMS IN STOCHASTIC PLASTIC FRAMES', RELIABILITY ENGINEERING & SYSTEM SAFETY, 18 101-115 (1987)
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1987 |
Chan HY, Melchers RE, 'Wave load modelling for offshore structural reliability.', IN: FIRST NAT. STRUCTURAL ENGINEERING CONF. 1987, PREPRINT OF PAPERS, (MELBOURNE, AUSTRALIA: AUG. 26-28, 1987), 1 , Barton, Australia, Inst. Engrs. Australia, 1987 152-157 (1987)
The modelling of applied wave loading for steel tubular offshore platforms and appropriate statistical models are discussed. For the purposes of reliability analysis, the fact tha... [more]
The modelling of applied wave loading for steel tubular offshore platforms and appropriate statistical models are discussed. For the purposes of reliability analysis, the fact that wave trains reach the various structural components at different times, and the effect this may have on the sequence of most likely member failure, is considered.
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1987 |
Hon KK, Melchers RE, 'MOMENT-ROTATION CURVES FOR 'PINNED' COLUMN-BASES.', Structural Engineer, Part B: R&D Quarterly, 65 B 54-59 (1987)
A mathematical model, based on the physical properties of nominally 'pinned' column-bases and intended to describe the moment-rotation characteristics for given eccentri... [more]
A mathematical model, based on the physical properties of nominally 'pinned' column-bases and intended to describe the moment-rotation characteristics for given eccentricity of axial load, is presented. The model uses three main parameters to describe the characteristic: elastic stiffness, strain hardening stiffness, and plastic moment capacity. In addition, an empirically determined 'shape' factor allows for the transition from elastic to inelastic behavior. The model is compared to a series of full-sized test results for a range of practical column-base connection. The behavior of soil under the footing is not considered.
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1987 |
Chan HY, Melchers RE, 'RELIABILITY OF COMPLEX STRUCTURES UNDER WAVE LOADS. (1987)
The reliability analysis of multi-membered structures such as steel tubular offshore platforms has been largely confined to considerations of structural member behavior and given ... [more]
The reliability analysis of multi-membered structures such as steel tubular offshore platforms has been largely confined to considerations of structural member behavior and given loading uncertainty. However realistic modelling of wave forces may require account to be taken of the effect of wave forces varying with the incident wave location as it passes through the structure. Such an analysis is described in the present paper, using the Truncated Enumeration technique previously described. Main emphasis is given to structures composed of elastic-brittle members: the analysis for elastic-plastic structures degenerates to that of a probabilistic adaptation problem.
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1987 |
Melchers RE, 'STRUCTURAL RELIABILITY ASSESSMENT AND HUMAN ERROR. (1987)
Realistic assessment of reliability must take account of the possibility of human error in the design and execution of the project of interest. This is also true for structural re... [more]
Realistic assessment of reliability must take account of the possibility of human error in the design and execution of the project of interest. This is also true for structural reliability assessment, even though for some applications, such as design code writing, a nominal reliability measure, largely ignoring human error, may well be sufficient. The present paper reviews, briefly, the principles by which human error information may be taken into account in reliability assessment, and, in a little more detail, both empirical models and data for some types of human error which may arise in structural design processes. Attention is also given to three forms of checking: independent, self- and overview checking. Only recently has some indicative data for checking processes become available; in all aspects the reported research must seem as preliminary rather than definitive.
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1986 |
Evans EP, Baker KN, Cairnes TH, Clyde DH, Johnson R, Kavanagh KT, et al., 'STRUCTURAL CODES AND THE PROFESSION - REPORT OF A WORKING PARTY.', Civil engineering transactions, 28 106-121 (1986)
Debate concerning the role, authority and complexity of contemporary structural codes has persisted in Australia and overseas for many years. The Report examines contemporary lite... [more]
Debate concerning the role, authority and complexity of contemporary structural codes has persisted in Australia and overseas for many years. The Report examines contemporary literature and assesses the results of a request for opinion. Conflicting views of different user groups are identified. The traditional roles of codes as multi-user documents, vehicles for communicating information, and educational resources are examined. The profession's view of codes is interpreted and a proposal put forward as to what should be the Institution of Engineers' position on the philosophy, form and drafting of codes.
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1986 |
Melchers RE, 'RELIABILITY THEORY AS A TOOL IN OFFSHORE STRUCTURAL DESIGN AND CONSTRUCTION.', National Conference Publication - Institution of Engineers, Australia, 177-181 (1986)
Traditional design methods for offshore structures have, on the whole, worked well, but there are now moves to develop probabilistically-based design rules. This is a sound strate... [more]
Traditional design methods for offshore structures have, on the whole, worked well, but there are now moves to develop probabilistically-based design rules. This is a sound strategy since uncertainties in information can be rationally incorporated in the design and analysis process. The application of reliability theory extends, however, also to the sphere of analysis and decision making in the construction stages. The paper briefly reviews the essential concepts of structural reliability theory and then indicates the various ways in which it has been or can be applied in practical situations. This includes analysis for peak loading and for fatigue as well as other criteria. Some ongoing research areas will be noted.
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1986 |
YEE YL, MELCHERS RE, 'MOMENT-ROTATION CURVES FOR BOLTED CONNECTIONS', JOURNAL OF STRUCTURAL ENGINEERING-ASCE, 112 615-635 (1986)
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1986 |
Melchers RE, 'Reliability theory as a tool in offshore structural design and construction.', IN: FIRST AUSTRALASIAN PORT, HARBOUR & OFFSHORE ENGINEERING CONFERENCE 1986, (SYDNEY, AUSTRALIA: SEP. 29-OCT. 2, 1986), BARTO, (1986)
Offshore structures are subject to poorly defined hazards such as storms, continued wave action, corrosion and ship impact and are themselves not well defined in terms of their st... [more]
Offshore structures are subject to poorly defined hazards such as storms, continued wave action, corrosion and ship impact and are themselves not well defined in terms of their strength or resistance. Traditional design methods for offshore structures have, on the whole, worked well, but there are now moves to develop probabilistically based design rules. This is a sound strategy since uncertainties in information can be rationally incorporated in the design and analysis process. The application of reliability theory extends, however, also to the sphere of analysis and decision making in the construction stages. The paper briefly reviews the essential concepts of structural reliability theory and then indicates the various ways in which it has been or can be applied in practical situations. This includes analysis for peak loading and for fatigue as well as other criteria. Some ongoing research areas will be noted. (A)
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1986 |
Melchers RE, 'HUMAN INFLUENCES IN QUALITY ASSURANCE.', Reports of the Working Commissions (International Association for Bridge and Structural Engineering), 50 107-116 (1986)
The effectiveness of quality assurance depends largely on the effectiveness of the facilitative measures it provides and the control measures it imposes. These are related to stru... [more]
The effectiveness of quality assurance depends largely on the effectiveness of the facilitative measures it provides and the control measures it imposes. These are related to structural safety and structural performance through human error. Both empirical data about human error and models are selectively reviewed herein and directions of some ongoing research outlined.
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1986 |
Hon KK, Melchers RE, 'INITIAL INVESTIGATION OF COLUMN BASE BEHAVIOUR. 73-79 (1986)
A common feature of many steel building frames is the use of two bolts to anchor a baseplate welded to the column end to the concrete foundation. Such a connection is typically as... [more]
A common feature of many steel building frames is the use of two bolts to anchor a baseplate welded to the column end to the concrete foundation. Such a connection is typically assumed to represent a pinned connection, meaning that it is assumed for design purposes that the connection is incapable of transferring bending moment. However, virtually no experimental observations about the behaviour of such connections have been reported. The paper presents some initial experimental findings for connection capacity under axial load and bending moment and reports on preliminary mathematical modelling of the behaviour of the connection using physical parameters such as endplate thickness and bolt characteristics as input.
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1986 |
Melchers RE, 'Reliability theory as a tool in offshore structural design and construction.', IN: FIRST AUSTRALASIAN PORT, HARBOUR & OFFSHORE ENGINEERING CONFERENCE 1986, (SYDNEY, AUSTRALIA: SEP. 29-OCT. 2, 1986), BARTO, (1986)
Offshore structures are subject to poorly defined hazards such as storms, continued wave action, corrosion and ship impact and are themselves not well defined in terms of their st... [more]
Offshore structures are subject to poorly defined hazards such as storms, continued wave action, corrosion and ship impact and are themselves not well defined in terms of their strength or resistance. Traditional design methods for offshore structures have, on the whole, worked well, but there are now moves to develop probabilistically based design rules. This is a sound strategy since uncertainties in information can be rationally incorporated in the design and analysis process. The application of reliability theory extends, however, also to the sphere of analysis and decision making in the construction stages. The paper briefly reviews the essential concepts of structural reliability theory and then indicates the various ways in which it has been or can be applied in practical situations. This includes analysis for peak loading and for fatigue as well as other criteria. Some ongoing research areas will be noted. (A)
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1985 |
Cugley RC, Kennedy B, Melchers RE, 'DYNAMIC STABILITY OF UNRESTRAINED PILES DURING DRIVING.', Structural Engineer, 63 A 173-178 (1985)
The response of an initially curved cantilever strut with a lumped mass at the tip subject to arbitrary axial impact loads is described, as a model for the dynamic response of unr... [more]
The response of an initially curved cantilever strut with a lumped mass at the tip subject to arbitrary axial impact loads is described, as a model for the dynamic response of unrestrained piles during driving. The differential equation of motion defining the lateral movement of impact-loaded cantilever struts is derived. This equation includes the effect of inertial resistance to motion provided by both the strut self-mass and the mass of the pile hammer. The shape of force pulses produced during pile driving was approximated by an equivalent trapezoidal force pulse. The differential equation of motion was solved for this force pulse using the Runge-Kutta technique. The solution was found to agree with observed pile behavior during driving. Is is shown that the magnitude of lateral displacements reduces as the mass of the pile hammer increases, because of inertial effects.
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1985 |
Tang LK, Melchers RE, 'RELIABILITY OF LARGE STRUCTURAL SYSTEMS.', Institution of Engineers, Australia, Civil Engineering Transactions, 27 136-142 (1985)
For structural systems, calculation of the structural failure probability requires the determination of all the failure modes contributing significantly to the overall failure pro... [more]
For structural systems, calculation of the structural failure probability requires the determination of all the failure modes contributing significantly to the overall failure probability. For large systems it is not practical to enumerate fully all modes. The paper presents a procedure, termed the Truncated Enumeration Method, which has been shown to be derivable rigorously from exhaustive enumeration when truncation of solution possibilities, not significant for the reliability assessment, is imposed. The method has been able to reproduce independently all known solutions obtained by others, but usually in a more systematic manner. The relationship of this method to other system reliability calculation techniques is discussed, some limitations are noted and some calculation results are presented.
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1985 |
Harrington MV, Melchers RE, 'TIME DEPENDENT STRUCTURAL RELIABILITY WITH REFERENCE TO LOW-CYCLE FATIGUE.', Institution of Engineers, Australia, Civil Engineering Transactions, 27 130-135 (1985)
This paper presents an exploratory example of the way structural reliability may change with time, in this case due to the effect of low-cycle fatigue. This may be of interest for... [more]
This paper presents an exploratory example of the way structural reliability may change with time, in this case due to the effect of low-cycle fatigue. This may be of interest for structures subject to the possibility of high overload during their design lives. Inelastic fracture mechanics theory is reviewed in the first part of the paper. This is followed by a discussion of distributions appropriate for use in a reliability analysis. Monte-Carlo simulation is then employed to show how, typically, the failure probability changes with the number of load applications to the structure, i. e. with time.
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1985 |
Melchers RE, 'RELIABILITY CALCULATION FOR STRUCTURES.', Institution of Engineers, Australia, Civil Engineering Transactions, 27 124-129 (1985)
Structures are composed of many members and connections, each with individual properties. When the member properties and the loadings applied to the structure are specified in sta... [more]
Structures are composed of many members and connections, each with individual properties. When the member properties and the loadings applied to the structure are specified in statistical terms, the determination of structural system reliability becomes a problem of multi-fold integration. Since direct integration is feasible only for extremely simple structures, several alternative approaches to the problem have been suggested; either through simplifying the integration process itself or through simplified reliability theory. These approaches are discussed in the context of use of computer programs and computer usage.
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1985 |
Melchers RE, Tang LK, 'RELIABILITY ANALYSIS OF MULTI-MEMBER STRUCTURES. 763-772 (1985)
For structural systems composed of many individual members each perhaps having a nonlinear constitutive relationship, the calculation of the probability of structural failure unde... [more]
For structural systems composed of many individual members each perhaps having a nonlinear constitutive relationship, the calculation of the probability of structural failure under applied random loading requires a knowledge of all failure modes which contribute significantly to the failure probability. For large structural systems this may present a formidable problem, even with modern computers. A calculation procedure which systematically generates failure modes and eliminates those of little significance is described, together with appropriate procedures for calculating the necessary modal failure probabilities. (Author abstract. ) Refs.
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1985 |
Melchers RE, Cugley RC, 'TRAINSIENT STABILITY OF STEEL PILES DURING DRIVING. 755-762 (1985)
Some dynamic elastic buckling formulations for driven piles are given and some solutions presented. These are compared to limited model tests. Suggestions for an improved formulat... [more]
Some dynamic elastic buckling formulations for driven piles are given and some solutions presented. These are compared to limited model tests. Suggestions for an improved formulation and for practical implications are made. (Author abstract. )
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1985 |
Melchers RE, Tang LK, 'FAILURE MODES IN COMPLEX STOCHASTIC SYSTEMS. 97-106 (1985)
For large structural systems, calculation of the structural failure probability requires a knowledge of all relevant failure modes. The so-called 'truncated enumeration metho... [more]
For large structural systems, calculation of the structural failure probability requires a knowledge of all relevant failure modes. The so-called 'truncated enumeration method' to systematically derive the dominant failure modes is described. The derivation of the limit state expressions for each mode is through an incremental load approach, which allows member behaviour including strain hardening, strain softening and residual strength to be handled. It is noted that elastic-plastic member behaviour does not necessarily converge to rigid-plastic behaviour. Finally, the numerical problems associated with the procedures outlined are discussed and two examples given.
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1985 |
Melchers RE, Stewart MG, 'DATA-BASED MODELS FOR HUMAN ERROR IN DESIGN. 51-60 (1985)
To predict the reliability of structures it is necessary to make reasonable allowances in the assessment for the influence of human error in the design, construction and use of th... [more]
To predict the reliability of structures it is necessary to make reasonable allowances in the assessment for the influence of human error in the design, construction and use of the structure. The present paper deals with an attempt to model mathematically the human errors introduced into the structural design process and the effect they may have on structural safety. Preliminary data collection for use in the model is reported, and an outline of the model being developed is given.
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1984 |
MELCHERS RE, TANG LK, 'DOMINANT FAILURE MODES IN STOCHASTIC STRUCTURAL SYSTEMS', STRUCTURAL SAFETY, 2 127-143 (1984)
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1984 |
MELCHERS RE, 'HUMAN ERROR IN STRUCTURAL RELIABILITY ASSESSMENTS', RELIABILITY ENGINEERING & SYSTEM SAFETY, 7 61-75 (1984)
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1984 |
Harrington MV, Melchers RE, 'TIME DEPENDENT STRUCTURAL RELIABILITY. 301-305 (1984)
This paper presents an example of the way structural reliability may change with time, in this case due to the effect of low-cycle fatigue. This may be of interest for structures ... [more]
This paper presents an example of the way structural reliability may change with time, in this case due to the effect of low-cycle fatigue. This may be of interest for structures subject to the possibility of high overload during their design lives. Inelastic fracture mechanics theory is reviewed in the first part of the paper. This is followed by a discussion of distributions appropriate for use in a reliability analysis. Monte-Carlo simulation is then employed to show how, typically, the failure probability changes with the number of load applications to the structure, i. e. with time.
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1984 |
Tang LK, Melchers RE, 'RELIABILITY OF LARGE STRUCTURAL SYSTEM. 295-300 (1984)
For structural systems, calculation of the structural failure probability requires the determination of all the failure modes contributing significantly to the overall failure pro... [more]
For structural systems, calculation of the structural failure probability requires the determination of all the failure modes contributing significantly to the overall failure probability. For large systems it is not practical to enumerate fully all modes. The paper will present a procedure, termed the 'Truncated Enumeration Method', which has been shown to be derivable rigorously from exhaustive enumeration when truncation of solution possibilities, not significant for the reliability assessment, is imposed.
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1983 |
Cugley RC, Melchers RE, 'DYNAMIC STABILITY OF STEEL PILES.', National Conference Publication - Institution of Engineers, Australia, 128-132 (1983) |
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1983 |
Melchers RE, Yee YL, 'DEFLECTION OF FRAMES WITH BOLTED END-PLATE CONNECTIONS.', National Conference Publication - Institution of Engineers, Australia, 176-180 (1983)
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1983 |
Melchers RE, 'RELIABILITY CALCULATION FOR MAJOR STRUCTURAL SYSTEMS.', National Conference Publication - Institution of Engineers, Australia, 95-99 (1983)
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1983 |
Brownlee RT, Melchers RE, 'ULTIMATE LIMIT STATE FOR REINFORCED CONCRETE FRAMES.', National Conference Publication - Institution of Engineers, Australia, 105-110 (1983) |
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1983 |
MELCHERS RE, 'RELIABILITY OF PARALLEL STRUCTURAL SYSTEMS', JOURNAL OF STRUCTURAL ENGINEERING-ASCE, 109 2651-2665 (1983)
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1983 |
Melchers RE, Baker MJ, Moses F, 'EVALUATION OF EXPERIENCE.', Reports of the Working Commissions (International Association for Bridge and Structural Engineerin, 47 21-38 (1983)
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1983 |
Melchers RE, Harrington MV, 'STRUCTURAL RELIABILITY AS AFFECTED BY HUMAN ERROR. 683-694 (1983)
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1983 |
Melchers RE, 'STATIC THEOREM APPROACH TO THE RELIABILITY OF PARALLEL PLASTIC STRUCTURES. 1313-1324 (1983)
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1982 |
MELCHERS RE, 'DEFLECTION OF STATICALLY INDETERMINATE STRUCTURES', INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES, 24 341-347 (1982)
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1982 |
MELCHERS RE, 'DEFLECTION OF HYPERSTATIC THERMOELASTIC STRUCTURES', JOURNAL OF STRUCTURAL MECHANICS, 10 227-240 (1982)
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1982 |
Melchers RE, 'CORRELATION EFFECTS IN THE RELIABILITY ANALYSIS OF PARALLEL STRUCTURES. (1982)
For the reliability assessment of structures which may fail in one of several failure modes, bounds on the probability of failure of the structure have been developed. It is well ... [more]
For the reliability assessment of structures which may fail in one of several failure modes, bounds on the probability of failure of the structure have been developed. It is well known that even the best of these bounds are dependent on the correlation between the failure modes and that this correlation is, in turn, dependent on the correlation between member properties. Relatively little appears to be known about the importance of member property correlation effects in reliability analysis, nor about the actual values of correlation coefficients. Before attempts are made to increase our knowledge of member correlation, the importance of correlation effects in structural reliability calculations should be assessed. The paper describes a simple study of the sensitivity of structural reliability assessments to variations in correlation coefficients for parallel structures. It is demonstrated that the structural reliability for the structure considered is sensitive mainly to correlation between different locations within the same member or related members.
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1982 |
Melchers RE, Kaur D, 'BEHAVIOUR OF FRAMES WITH FLEXIBLE CONNECTIONS. (1982)
The so-called 'rigid' connections in real frames are seldom rigid, and instead contribute to the deflection behaviour of the frame. In conventional practice this is usua... [more]
The so-called 'rigid' connections in real frames are seldom rigid, and instead contribute to the deflection behaviour of the frame. In conventional practice this is usually ignored. The present paper is a first step in the analysis of the significance of connection flexibility, allowing for both elastic and plastic behaviour of frame members. It is shown that existing formulae for prediction of connection behaviour of bolted end plated connections are inadequate and that connection flexibility can make a significant contribution to frame deflection. However, this contribution varies in magnitude with load level and frame flexibility. A wide spectrum of realistic frames needs to be examined to assess the importance of connection flexibility for designers.
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1981 |
MELCHERS RE, 'REINFORCEMENT MINIMIZATION OF BEAMS WITH AXIAL FORCES', INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES, 23 607-617 (1981)
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1981 |
MELCHERS RE, 'APPROXIMATE DEFLECTIONS IN PLASTIC DESIGN', JOURNAL OF THE STRUCTURAL DIVISION-ASCE, 107 1359-1364 (1981) |
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1981 |
Melchers RE, Clarke GJ, 'DETERMINING SERVICEABILITY DEFLECTIONS IN PLASTICALLY DESIGNED STRUCTURES.', Institution of Engineers, Australia, Civil Engineering Transactions, CE 23 74-79 (1981)
Methods for determining the deflections at service loads in plstically designed structures are presented. A number of approaches to calculating these deflections are considered, s... [more]
Methods for determining the deflections at service loads in plstically designed structures are presented. A number of approaches to calculating these deflections are considered, since the usual method of performing a completely separate elastic analysis of the plastically designed structure is generally very cumbersome unless a computer is available. The alternative methods considered are: (a) direct estimation from plastic bending moment distribution; (b) correction approach; (c) exact calculation using a newly developed theorem; and (d) an approximate procedure using estimates of the bending moment diagrams for use in the unit dummy load method. Several examples are worked to illustrate the methods. It is shown that method (c) is a powerful direct and accurate technique for most simple structures.
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1980 |
MELCHERS RE, 'REINFORCEMENT MINIMIZATION OF CYLINDRICAL-SHELLS', INTERNATIONAL JOURNAL OF NON-LINEAR MECHANICS, 15 505-516 (1980)
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1980 |
MELCHERS RE, 'A FUZZY SAFETY MEASURE', JOURNAL OF THE ENGINEERING MECHANICS DIVISION-ASCE, 106 856-857 (1980) |
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1980 |
MELCHERS RE, 'SERVICE LOAD DEFLECTIONS IN PLASTIC STRUCTURAL DESIGN', PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS PART 2-RESEARCH AND THEORY, 69 157-174 (1980)
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1980 |
Melchers RE, 'EXAMINATION OF PUBLISHED CASES OF STRUCTURAL FAILURE.', Institution of Engineers, Australia, Civil Engineering Transactions, CE22 222-230 (1980)
Study of cases of structural failure show these to be inconsistent between various investigators. To resolve these problems, detailed studies of the causes and underlying mechanis... [more]
Study of cases of structural failure show these to be inconsistent between various investigators. To resolve these problems, detailed studies of the causes and underlying mechanisms for structural failure are required, even though this severely limits the data that can be employed. Starting from the development of a quite general model of the causes of structural failure, implications are derived for the type of information that can be obtained using limited data. The study of well-reported cases of failure can be useful in identifying ¿error-causing-potentials¿ , but only socially weighted relative values can be established from such a study. Particular attention is given to the relative importance of so-called ¿uncertainty¿ type (or ¿gross¿ ) errors compared to errors arising from natural variability. It is suggested that the manipulation of control processes is likely to be an effective practical means of reducing structural failure.
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1980 |
Melchers RE, 'SOCIENTAL OPTIONS FOR ASSURANCE OF STRUCTURAL PERFORMANCE. 983-988 (1980)
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1979 |
MELCHERS RE, 'VALIDITY OF YIELD-LINE THEORY FOR POLYHEDRAL SHELLS', JOURNAL OF THE ENGINEERING MECHANICS DIVISION-ASCE, 105 107-126 (1979) |
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1979 |
MELCHERS RE, ARMER GST, 'INFLUENCE OF CONTROL PROCESSES IN STRUCTURAL ENGINEERING', PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS PART 2-RESEARCH AND THEORY, 67 551-552 (1979)
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1979 |
Melchers RE, 'SELECTION OF CONTROL LEVELS FOR MAXIMUM UTILITY OF STRUCTURES.', National Bureau of Standards, Special Publication, 2 839-849 (1979)
The role of human error in the effective implementation and use of structural engineering projects is reviewed and shown to be underestimated in conventional treatments of probabi... [more]
The role of human error in the effective implementation and use of structural engineering projects is reviewed and shown to be underestimated in conventional treatments of probabilistic structural design. Both suitable organization and control are required for project success. The concept of maximizing total expected socio-economic utility is employed to derive criteria for selecting the levels of control required on the various tasks constituting the construction and use sequence of a structural engineering project. These criteria are applied to a hypothetical example using both the limited experimental evidence available and hypothesized data. Refs.
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1978 |
MELCHERS RE, 'STRUCTURAL-ANALYSIS OF REINFORCED-CONCRETE TANKS', JOURNAL OF THE STRUCTURAL DIVISION-ASCE, 104 609-611 (1978) |
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1978 |
FERNANDO JS, KEMP KO, LOWE PG, CLARK LA, BHATT P, MELCHERS RE, HARROP J, 'GENERALIZED STRIP DEFLECTION METHOD OF REINFORCED-CONCRETE SLAB DESIGN', PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS PART 2-RESEARCH AND THEORY, 65 719-724 (1978)
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1978 |
MELCHERS RE, 'INFLUENCE OF CONTROL PROCESSES IN STRUCTURAL ENGINEERING', PROCEEDINGS OF THE INSTITUTION OF CIVIL ENGINEERS PART 2-RESEARCH AND THEORY, 65 791-807 (1978)
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1977 |
MELCHERS RE, 'INFLUENCE OF ORGANIZATION ON PROJECT IMPLEMENTATION', JOURNAL OF THE CONSTRUCTION DIVISION-ASCE, 103 611-625 (1977)
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1976 |
MELCHERS RE, 'MINIMUM REINFORCEMENT OF NONUNIFORM PLATES', JOURNAL OF THE ENGINEERING MECHANICS DIVISION-ASCE, 102 943-955 (1976)
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1975 |
MELCHERS RE, 'OPTIMALLY REINFORCED AXISYMMETRIC PLATES', JOURNAL OF THE ENGINEERING MECHANICS DIVISION-ASCE, 101 143-149 (1975)
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1975 |
Melchers RE, 'OPTIMALLY REINFORCED AXISYMMETRIC PLATES', ASCE J Eng Mech Div, 101 143-149 (1975)
A sandwich plate is considered in which the reinforcement fibers are located entirely within the outer faces of the plate. The layout of the fibers is determined within the faces ... [more]
A sandwich plate is considered in which the reinforcement fibers are located entirely within the outer faces of the plate. The layout of the fibers is determined within the faces of the plate to minimize the total fiber consumption. The variation of fiber material within the optimal plate to resist the internal stress resultants due to a given loading may be obtained once the fiber layout has been determined. Only one loading case is considered for a simply supported plate, clamped plate, and simply supported annular plate.
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1974 |
MELCHERS RE, 'THEORY OF OPTIMAL, CONSTANT THICKNESS FIBER-REINFORCED PLATES .2. - REPLY', INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES, 16 264-266 (1974)
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1974 |
LOWE PG, MELCHERS RE, 'THEORY OF OPTIMAL, EDGE BEAM SUPPORTED, FIBER-REINFORCED PLATES', INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES, 16 627-641 (1974)
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1973 |
Melchers RE, 'OPTIMAL DESIGN OF VARIABLE THICKNESS REINFORCED PLATES. (1973)
A general optimality condition is indicated for laterally loaded plates reinforced with fibers in their outer faces only. This result is applied to two examples. The first is a si... [more]
A general optimality condition is indicated for laterally loaded plates reinforced with fibers in their outer faces only. This result is applied to two examples. The first is a simply supported circular plate for which the thickness variation is specified. It is found that an optimal design has only radial fibres. The second problem is a simply supported square plate under arbitrary loading, for which the reinforcement fibers have different internal lever-arms in bending for different orientations within the plan of the plate.
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1973 |
Melchers RE, 'OPTIMAL DESIGN OF VARIABLE THICKNESS REINFORCED PLATES. (1973)
A general optimality condition is indicated for laterally loaded plates reinforced with fibers in their outer faces only. This result is applied to two examples. The first is a si... [more]
A general optimality condition is indicated for laterally loaded plates reinforced with fibers in their outer faces only. This result is applied to two examples. The first is a simply supported circular plate for which the thickness variation is specified. It is found that an optimal design has only radial fibres. The second problem is a simply supported square plate under arbitrary loading, for which the reinforcement fibers have different internal lever-arms in bending for different orientations within the plan of the plate.
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1973 |
LOWE PG, MELCHERS RE, 'THEORY OF OPTIMAL CONSTANT THICKNESS FIBER-REINFORCED PLATES .2.', INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES, 15 157-169 (1973)
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1973 |
LOWE PG, MELCHERS RE, 'THEORY OF OPTIMAL, CONSTANT THICKNESS FIBER-REINFORCED PLATES .3.', INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES, 15 711-726 (1973)
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1972 |
LOWE PG, MELCHERS RE, 'THEORY OF OPTIMAL, CONSTANT THICKNESS, FIBER-REINFORCED PLATES', INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES, 14 311-& (1972)
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