2024 |
Arango E, Nogal M, Sousa HS, Matos JC, Stewart MG, 'Improving societal resilience through a GIS-based approach to manage road transport networks under wildfire hazards', Transportation Engineering, 15 (2024) [C1]
Climate change is causing an increase in the frequency and intensity of wildfires, demonstrating that our capacity to respond to them is insufficient. Therefore, it is necessary t... [more]
Climate change is causing an increase in the frequency and intensity of wildfires, demonstrating that our capacity to respond to them is insufficient. Therefore, it is necessary to reconsider wildfire management policies, practices, and decision-support tools, extending beyond emergency measures. This study presents the extension of a GIS-based methodology for fire analysis, providing decision-making support for the implementation of new fire-related policies for road transportation infrastructure. It represents a novel contribution that facilitates the transition towards proactive wildfire policies. The framework is demonstrated to support informed decision-making, addressing both reactive actions, i.e., emergency response, and the evaluation of proactive adaptation measures at a system level. The results suggest that landscape management policies can play an important role in improving the resilience of road networks to wildfires.
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2024 |
Shi Z, Feng Y, Stewart MG, Gao W, 'Virtual modelling based fragility assessment of structures under bushfire propagation', Reliability Engineering and System Safety, 245 (2024) [C1]
Driven by increased human activities in rural-urban interfaces, the construction of residential or commercial buildings in these areas is experiencing a notable growing trend. In ... [more]
Driven by increased human activities in rural-urban interfaces, the construction of residential or commercial buildings in these areas is experiencing a notable growing trend. In comparison to those built in urban regions, these structures, constructed in rural-urban interfaces, are in closer proximity to natural vegetation, therefore facing a heightened bushfire risk. The timely execution of Structural Protection Plans (SPP) is of utmost importance in the case of bushfire threats, where a swift response within a short timeframe is necessary, considering the diverse fragility characteristics of structural components. To address this, the present study introduces a novel framework for assessing the fragility of typical residential structures under both low and high wind speed conditions, specifically focusing on three key structural components: window frames, walls, and roofs. The assessment of structural probability-based fragility is performed using the newly developed limit state function and takes into account the influence of multiple non-deterministic factors, including vegetative conditions, wind speed, different temperature thresholds of structural components, and fire response time. Furthermore, to enable rapid prediction of structural probability-based fragility on the fireground, a virtual modelling (VM) technique, named extended support vector regression (X-SVR), is introduced and incorporated into the proposed fragility assessment framework. The efficiency and accuracy of this virtual modelling technique in assessing the bushfire fragility of structures under different wind speed intervals have been investigated and validated through a comprehensive case study of a real Australian house. The proposed framework is poised to provide valuable insights into optimizing SPP by swiftly identifying the most fragile structural components in practice.
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2024 |
Stewart MG, Netherton MD, Qin H, Li J, 'Explosive field trial for repetitive testing of VBIEDs to probabilistically measure blast and fragmentation hazards', International Journal of Protective Structures,
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2024 |
Arango E, Jiménez P, Nogal M, Sousa HS, Stewart MG, Matos JC, 'Enhancing infrastructure resilience in wildfire management to face extreme events: Insights from the Iberian Peninsula', Climate Risk Management, 44 (2024)
Factors such as human activity and climate change are contributing to an increase in the frequency and intensity of wildfires. This problem has challenged society's knowledge... [more]
Factors such as human activity and climate change are contributing to an increase in the frequency and intensity of wildfires. This problem has challenged society's knowledge, response capacity, and resilience, revealing its inadequacy to cope with the new wildfire regime characterized by extreme wildfire events (EWE). Policies on wildfire management mainly focus on suppression and managing emergencies, which may be insufficient to reduce EWE's incidence and cope with its impact. Consequently, there is a lack of tools to support decision-making in wildfire management in other important aspects, such as prevention and protection. This study examines global wildfire policies specifically in the Iberian Peninsula (Portugal and Spain), including cross-border policies. A GIS-based tool to evaluate different normal and extreme wildfire management policies is applied to a cross-border case study, paying attention to the impact on critical land-based transport systems. A relevant outcome of the tool application is that suppression must be complemented with other wildfire management strategies in the analyzed area. The gained insights can help stakeholders to improve decision-making in wildfire management to successfully address EWE.
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2023 |
Arango E, Nogal M, Yang M, Sousa HS, Stewart MG, Matos JC, 'Dynamic thresholds for the resilience assessment of road traffic networks to wildfires', RELIABILITY ENGINEERING & SYSTEM SAFETY, 238 (2023) [C1]
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2023 |
Isfeld AC, Stewart MG, Masia MJ, 'Structural reliability and partial safety factor assessment of unreinforced masonry in vertical bending', Australian Journal of Structural Engineering, 24 191-205 (2023) [C1]
This paper focuses on a structural reliability-based assessment of clay brick unreinforced masonry (URM) walls subjected to uniformly distributed out-of-plane loads in one-way ver... [more]
This paper focuses on a structural reliability-based assessment of clay brick unreinforced masonry (URM) walls subjected to uniformly distributed out-of-plane loads in one-way vertical bending. Stochastic models combining finite element analysis (FEA) and Monte Carlo simulations (MCS) are used to account for spatial variability of the flexural tensile bond strength when estimating the wall failure loads. The strength of URM walls is known to be influenced by the flexural tensile bond strength, which is subject to high spatial variability as batching, workmanship, and environmental exposure alter the strength of this bond. For this assessment, single skin walls have been considered with bond strength statistics seen in typical construction. The model error statistics available for similar walls are combined with the results of the spatial stochastic FEA and probabilistic load models to determine the reliability index corresponding to the Australian Standard for Masonry Structures AS 3700 design of members in vertical bending. It was found that existing levels of reliability exceed target reliabilities, and the capacity reduction factor can be increased from 0.60 to 0.65 for URM walls in one-way vertical bending while still providing an acceptable level of reliability. A sensitivity analysis showed this finding to be robust.
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Nova |
2023 |
Muhit IB, Masia MJ, Stewart MG, 'Failure analysis and structural reliability of unreinforced masonry veneer walls: Influence of wall tie corrosion', Engineering Failure Analysis, 151 (2023) [C1]
Corrosion appears to be a very common problem in historical and aged structures with steel ties and anchorages. A potential rapid deterioration of the wall tie due to the corrosio... [more]
Corrosion appears to be a very common problem in historical and aged structures with steel ties and anchorages. A potential rapid deterioration of the wall tie due to the corrosion leading to a premature structural failure poses a serious threat to the built heritage infrastructures¿ safety. This paper describes an overview of the probabilistic failure analysis of the unreinforced masonry (URM) veneer wall system with flexible backup under uniformly distributed out-of-plane loadings. Moreover, a framework is proposed to consider the wall tie corrosion in the stochastic finite element analysis (FEA) while estimating the structural reliability. A probabilistic experimental study where 18 full-scale URM veneer wall systems with theoretically identical geometries and properties were tested under inward and outward lateral loading. Wall failure statistics along with the probabilistic characterisation of veneer wall constituent materials including mortar, wall tie and timber were accomplished. A stochastic computational model was then developed which combines the FEA and Monte Carlo simulation to evaluate the failure progression and system peak load (veneer capacity) while considering the spatial variability of veneer wall material properties. Two scenarios, with and without wall tie corrosion, are considered, and the probabilistic characterisation of the veneer capacities for these scenarios under inward and outward out-of-plane loading is also reported. The model error statistics were combined with the probabilistic load models to determine the reliability index corresponding to the Australian Standard for Masonry Structures AS 3700. Annual reliabilities are compared to target reliabilities recommended by ISO 2394. Capacity reduction factor and design minimum tie strength consideration for corroded wall tie is also discussed.
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Nova |
2023 |
Beck AT, Ribeiro LDR, Costa LGL, Stewart MG, 'Comparison of risk-based robustness indices in progressive collapse analysis of building structures', Structures, 57 105295-105295 (2023) [C1]
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2023 |
Stewart MG, 'Spatial variability of explosive blast loading and its effect on damage risks to reinforced concrete buildings', Engineering Structures, 285 115650-115650 (2023) [C1]
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2023 |
Feng Y, Wu D, Stewart MG, Gao W, 'Past, current and future trends and challenges in non-deterministic fracture mechanics: A review', Computer Methods in Applied Mechanics and Engineering, 412 (2023) [C1]
Structural systems are consistently encountering the variabilities in material properties, undesirable defects and loading environments, which may potentially shorten their design... [more]
Structural systems are consistently encountering the variabilities in material properties, undesirable defects and loading environments, which may potentially shorten their designed service life. To ensure a reliable structural performance, it is vital to track and quantify the effects of different random/uncertainty factors upon the structural fracture performance. In this research, a critical review of the past, current and future computational modelling of the non-deterministic fracture mechanics is presented. By considering the variously numerical solutions tackling the fracture problems, they are mainly categorized into the discrete and continuous approaches. This study discusses the quantification performance of the extended finite element method, the crack band method and the phase-field approaches combined with different sources of uncertainties. These well-known computational techniques are typical representatives of the common fracture modelling philosophies including the embedded, smeared and regularized ones. The essence of this work is to compare the main differences of the uncertainty quantification models (i.e., probabilistic, non-probabilistic) at the fracture formulation levels and investigate the major progress and challenges existing in the real-life applications for the past and future decades. Some critical remarks, which are denoting the advantages and major issues of various non-deterministic fracture models, are provided and explained in the practical structural failure conditions. Different fracture simulation cases are implemented with comparative results amongst analytical, numerical and experimental methods, and the corresponding fracture quantification ability is evaluated through the standards of the random fracture capacity, load¿deflection plots, crack propagation, crack mechanisms, and computational efficiency, etc.
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Nova |
2023 |
Arango E, Nogal M, Sousa HS, Matos JC, Stewart MG, 'GIS-based methodology for prioritization of preparedness interventions on road transport under wildfire events', International Journal of Disaster Risk Reduction, 99 (2023) [C1]
Climate change is leading to a rise in the occurrence and intensity of wildfires, exacerbated by the growing encroachment of communities into the natural environment, posing chall... [more]
Climate change is leading to a rise in the occurrence and intensity of wildfires, exacerbated by the growing encroachment of communities into the natural environment, posing challenges to our global capacity to respond to wildfires. During wildfire events, road transport infrastructure becomes crucial for the evacuation of people and accessibility to an emergency by first responders. Nevertheless, resilience management of transportation infrastructure affected by wildfires is poorly considered, despite its relevant role and high exposure to wildfires. Therefore, this study proposes a new methodology to estimate the priority level for wildfire preparation by combining exposure and criticality of road transportation infrastructure to wildfire hazards with consideration of different wildfire categories. The analysis is conducted at the system level considering interdependencies and redundancies among infrastructure components and using a geographic information system (GIS) to automate the modelling process and visualization of results. The proposed methodology is applied to a case study in the Leiria region of Portugal, demonstrating its utility in prioritizing economic resources and decision-making for areas requiring preparation. This approach can serve as a resilience-based tool for decision-making, supporting the implementation of effective adaptation strategies to enhance wildfire resilience.
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2023 |
Gooch LJ, Masia MJ, Stewart MG, Lam CY, 'Statistical assessment of tensile and shear properties of unreinforced clay brick masonry', Construction and Building Materials, 386 (2023) [C1]
This paper presents the results of an extensive set of material characterisation tests performed on unreinforced clay brick masonry. The results of these experiments allow for the... [more]
This paper presents the results of an extensive set of material characterisation tests performed on unreinforced clay brick masonry. The results of these experiments allow for the estimation of relationships between the measured material parameters. This study considers the relationships of flexural tensile bond strength to direct tensile bond strength, flexural to direct tensile strength of fired clay brick masonry units, and flexural tensile to shear bond strength. A mean ratio of flexural tensile bond strength to direct tensile bond strength of 2.06 and a COV of 31.5% were determined. For the flexural to direct tensile strength of fired clay brick masonry units, a mean ratio of 1.29 with a COV of 14.7% was estimated. Finally, considering the ratio of the shear bond to flexural tensile bond strengths, a mean ratio of 1.34 with a COV of 28.4% was found. In addition to these relationships, suitable probabilistic models were determined to describe the relationship between the flexural and direct tensile bond strengths, and the flexural tensile and shear bond strengths. These results may be used in future studies of URM structures, in particular finite element modelling and stochastic analyses of masonry.
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Nova |
2023 |
Stewart M, 'Risk-based thinking for extreme events: What do terrorism and climate change have in common?', Risk Management and Insurance Review, 26 467-484 (2023) [C1]
Terrorism and climate change debates are often characterized by worst-case thinking, cost neglect, probability neglect, and avoidance of the notion of acceptable risk. This is not... [more]
Terrorism and climate change debates are often characterized by worst-case thinking, cost neglect, probability neglect, and avoidance of the notion of acceptable risk. This is not unexpected when dealing with extreme events. However, it can result in a frightened public, costly policy outcomes, and wasteful expenditures. The paper will describe how risk-based approaches are well suited to infrastructure decision-making for extreme events. Risk management concepts will be illustrated with current research of risk-based assessment of climate adaptation engineering strategies including designing new houses in Australia subject to cyclones and extreme wind events. It will be shown that small improvements to house designs at a one-off cost of several thousand dollars per house can reduce damage risks by 70%¿80% and achieve billions of dollars of net benefit for community resilience¿this helps offset some the predicted adverse effects of climate change for a modest cost. The effect of risk perceptions, insurance, and economic incentives is explored for another climate adaption measure. The paper will also highlight that there is much to be optimistic about the future, and in the ability of risk-based thinking to meet many challenges.
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2023 |
Qin H, Mason M, Stewart MG, 'Fragility assessment for new and deteriorated portal framed industrial buildings subjected to tropical cyclone winds', Structural Safety, 100 (2023) [C1]
Low-rise portal framed industrial buildings are widely used as warehouses, workshops and storage facilities. Damage surveys following severe tropical cyclones have shown that both... [more]
Low-rise portal framed industrial buildings are widely used as warehouses, workshops and storage facilities. Damage surveys following severe tropical cyclones have shown that both structural and non-structural damage can occur to these buildings. While non-structural damage to the building envelope of portal framed industrial buildings are considered by several existing fragility models, almost none exist that include structural failures in the wind fragility assessment. This study develops a fragility assessment method for portal framed industrial buildings that accounts for wind-induced damage to both structural (steel portal frame and end wall frame) and non-structural (metal cladding system and fenestration) building components. Fragility curves are developed for a prototype industrial building located on the cyclone-prone east coast of Australia considering four damage states with increasing damage severity. A Monte Carlo simulation incorporating probabilistic models of the spatio-temporal variable wind pressures, wind-induced demands and component capacities is employed to conduct the fragility assessment for both individual building components and the building system under critical failure modes. It was found that the fragility of structural framing is non-negligible when wind speed exceeds 80% of the design level. Structural framing failure is a major contributor to the most severe damage state and is a necessary inclusion in the fragility assessment for this type of building. A sensitivity analysis also showed that fastener corrosion can significantly increase the fragility of deteriorated buildings near to coastlines, particularly for low levels of damage.
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2023 |
Stewart MG, 'Climate Adaptation Engineering: An Optimist's View', ASCE-ASME JOURNAL OF RISK AND UNCERTAINTY IN ENGINEERING SYSTEMS PART A-CIVIL ENGINEERING, 9 (2023)
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2023 |
Beck AT, Stewart MG, 'Risk-based cost-benefit analysis of structural strengthening to mitigate disproportionate collapse of buildings under abnormal blast loading', Structures, 57 105103-105103 (2023) [C1]
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2023 |
Qin H, Stewart MG, 'Mitigating casualty risks from primary fragmentation hazards', International Journal of Protective Structures, [C1]
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2023 |
Stewart MG, Thöns S, Beck AT, 'Assessment of risk reduction strategies for terrorist attacks on structures', Structural Safety, 104 (2023) [C1]
Attacks on infrastructure have been a common feature of terrorism over many decades. The weapon of choice is often a Vehicle-Borne Improvised Explosive Device (VBIED) or a person-... [more]
Attacks on infrastructure have been a common feature of terrorism over many decades. The weapon of choice is often a Vehicle-Borne Improvised Explosive Device (VBIED) or a person-borne or other type of IED. The consequences of a successful attack in terms of casualties, physical damage, and other direct and indirect costs including societal costs can be catastrophic. Protectives and other risk reduction measures can ameliorate the threat likelihood, vulnerability or consequences. There is a need for a rational approach to deciding how best to protect infrastructure, and what not to protect. Hence, this paper describes a probabilistic risk assessment for the protection of infrastructure from explosive attacks. This includes a description of terrorist threats and hazards, vulnerability assessment including progressive or disproportionate collapse, and consequences assessment. Illustrative examples of the decision analysis consider the optimal risk reduction and design strategies for bridges and the progressive collapse of buildings.
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2022 |
Muhit IB, Masia MJ, Stewart MG, 'Monte-Carlo laboratory testing of unreinforced masonry veneer wall system under out-of-plane loading', Construction and Building Materials, 321 (2022) [C1]
This paper presents the results of a probabilistic experimental study into the behaviour of full-scale unreinforced masonry (URM) veneer walls with flexible backup subjected to ou... [more]
This paper presents the results of a probabilistic experimental study into the behaviour of full-scale unreinforced masonry (URM) veneer walls with flexible backup subjected to out-of-plane loading. The actual safety and reliability of the contemporary Australian URM structures are unknown due to the absence of information regarding the probabilistic behaviour of the whole veneer wall system and material characterisation of the wall constituent materials. The study focused on masonry typologies representative of modern URM buildings in the Australian context. In this study, 18 full-scale URM veneer wall systems with theoretically identical geometries and properties were tested under inward and outward out-of-plane loading. For each loading type, one specimen was tested under semi-cyclic loading to check whether the monotonic loading can capture the overall behaviour of the cyclic response. For each mortar batch mixed, bond wrench testing was conducted at the same age as the test for the associated wall constructed using that mix. Batch to batch variabilities were statistically analysed, and probability distributions for flexural tensile strength were established. Lognormal distributions with aggregated means of 0.40 MPa and 0.42 MPa for inward and outward loading, respectively, were estimated for flexural tensile strengths. After the wall tests, all timber studs used to build the veneer walls were tested to evaluate the probabilistic characterisation of timber stiffness. This probabilistic information is essential for a stochastic finite element analysis (FEA) to conduct the reliability analysis. From the wall tests, veneer wall system behaviour was observed and measured until the collapse or 20% post-peak drop of the peak load. Outward loaded specimens exhibited higher variabilities for masonry cracking and system peak load compared to inward loading due to variabilities from materials, testing arrangements and failure mechanism. The true coefficient of variations of system peak loads were calculated as 0.10 and 0.19 for inward and outward loadings, respectively, considering the effect of testing variability.
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Nova |
2022 |
Orcesi A, O'Connor A, Bastidas-Arteaga E, Stewart MG, Imam B, Kreislova K, et al., 'Investigating the Effects of Climate Change on Material Properties and Structural Performance', Structural Engineering International, 32 577-588 (2022) [C1]
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2022 |
Galvão N, Matos JC, Hajdin R, Ferreira L, Stewart MG, 'Impact of construction errors on the structural safety of a post-tensioned reinforced concrete bridge', Engineering Structures, 267 (2022) [C1]
The ageing of bridge stock in developed countries worldwide and the increasing number of recorded bridge collapses have underlined the need for more sophisticated and comprehensiv... [more]
The ageing of bridge stock in developed countries worldwide and the increasing number of recorded bridge collapses have underlined the need for more sophisticated and comprehensive assessment procedures concerning the safety and serviceability of structures. In many recent failures, construction errors or deficiencies have contributed to the unfortunate outcome either by depleting the safety margin or speeding up the deterioration rate of structures. This research aims to quantify the impact of construction errors on the structural safety of a bridge considering corresponding models available in the literature that probabilistically characterise the occurrence rate and severity of some of these errors. The nominal probability of failure of structures, neglecting construction errors, is typically computed in numerous works in the literature. Therefore, the novelty of this paper lies in the consideration of an additional source of uncertainty (i.e., construction errors) combined with sophisticated numerical methods leading to a more refined estimation of the probability of failure of structures. Accordingly, some benchmark results focussing on error-free and error-included scenarios are established, providing useful information to close the gap between the nominal and the actual probability of failure of a railway bridge.
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Nova |
2022 |
Muhit IB, Stewart MG, Masia MJ, 'Probabilistic constitutive law for masonry veneer wall ties', Australian Journal of Structural Engineering, 23 97-118 (2022) [C1]
In a masonry veneer wall system, tie strengths and stiffnesses vary randomly and so are not consistent for all ties throughout the wall. To ensure an economical and safe design, t... [more]
In a masonry veneer wall system, tie strengths and stiffnesses vary randomly and so are not consistent for all ties throughout the wall. To ensure an economical and safe design, this paper uses tie calibration experimental approach in accordance with the standard AS2699.1 to investigate the tie failure load under compression and tension loading. Probabilistic wall tie characterisations are accomplished by estimating the mean, coefficient of variation and characteristic axial compressive and tensile strength from 50 specimens. The displacement across the cavity is recorded, which resulted the complete load versus displacement response. Using the maximum likelihood method, a range of probability distributions are fitted to tie strengths at different displacement histogram data sets, and a best-fitted probability distribution is selected for each case. The inverse cumulative distribution function plots are also used along with the Anderson-Darling test to infer a goodness-of-fit for the probabilistic models. An extensive statistical correlation analysis is also conducted to check the correlation between different tie strengths and associated displacement for both compression and tension loading. Based on the findings, a wall tie constitutive law is proposed to define probabilistic tie behaviour in numerical modelling.
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Nova |
2022 |
Stewart MG, 'Reliability-based design and robustness for blast-resistant design of RC buildings', ADVANCES IN STRUCTURAL ENGINEERING, 25 1402-1412 (2022) [C1]
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Nova |
2022 |
Stewart MG, 'Simplified reliability-based load design factors for explosive blast loading, weapons effects, and its application to collateral damage estimation', Journal of Defense Modeling and Simulation, 19 385-401 (2022) [C1]
The paper describes a simplified approach to quantifying a reliability-based design load factor (RBDF) for the variability of explosive blast loading. The user can select range an... [more]
The paper describes a simplified approach to quantifying a reliability-based design load factor (RBDF) for the variability of explosive blast loading. The user can select range and explosive mass variability and model errors to derive RBDFs for pressure and impulse. These algorithms may be easily programmed into a spreadsheet, computer code, or other numerical method. There is a need by military planners to increase the predictive accuracy of collateral damage estimation (CDE) to ensure maximum damage to the target while minimizing harm to nearby civilians. This present paper uses the CDE damage criterion adopted by the USA and NATO to assess damage and safety risks and recommend safe collateral damage distances. Hence, the present paper utilizes RBDFs to simulate collateral damage risks to a hypothetical reinforced concrete residential building from a 2000 lb bomb using the 99th percentile of blast loads, engineering models, and Monte Carlo simulation analysis that considers variabilities of load and resistance. It was found that CDE is sensitive to airblast model errors and variability of structural resistance. It is recommended that these considerations be incorporated into CDE methodology since existing CDE methodology may be non-conservative, resulting in higher risks of collateral damage.
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Nova |
2022 |
Muhit IB, Masia MJ, Stewart MG, Isfeld AC, 'Spatial variability and stochastic finite element model of unreinforced masonry veneer wall system under Out-of-plane loading', ENGINEERING STRUCTURES, 267 (2022) [C1]
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Nova |
2022 |
Stewart MG, 'Simplified calculation of airblast variability and reliability-based design load factors for spherical air burst and hemispherical surface burst explosions', International Journal of Protective Structures, 13 144-160 (2022) [C1]
There can be significant uncertainty and variability with explosive blast loading. Standards and codes of practice are underpinned by reliability-based principles, and there is li... [more]
There can be significant uncertainty and variability with explosive blast loading. Standards and codes of practice are underpinned by reliability-based principles, and there is little reason not to apply these to explosive blast loading. This paper develops a simplified approach where regression equations may be used to predict the probabilistic model of airblast variability and associated reliability-based design load factors (or RBDFs) for all combinations of range, explosive mass and model errors. These models are applicable to (i) hemispherical surface bursts, and (ii) spherical free-air bursts. The benefit of this simplified approach is that the equations can be easily programed into a spreadsheet, computer code or other numerical methods. There is no need for any Monte-Carlo or other probabilistic calculations. Examples then illustrate how model error, range and explosive mass uncertainty and variability affect the variability of pressure and impulse, which in turn affect the damage assessment of residential construction.
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Nova |
2022 |
Stewart MG, 'Systems thinking averts apocalypses now and in the future: why we should always look on the bright side of life', CIVIL ENGINEERING AND ENVIRONMENTAL SYSTEMS, 39 188-204 (2022) [C1]
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Nova |
2021 |
Ryan PC, Stewart MG, 'Regional variability of climate change adaptation feasibility for timber power poles', STRUCTURE AND INFRASTRUCTURE ENGINEERING, 17 579-589 (2021) [C1]
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Nova |
2021 |
Isfeld AC, Stewart MG, Masia MJ, 'Stochastic finite element model assessing length effect for unreinforced masonry walls subjected to one-way vertical bending under out-of-plane loading', Engineering Structures, 236 (2021) [C1]
The strength of unreinforced masonry (URM) walls subjected to one-way vertical bending under out-of-plane loading (no pre-compression) is known to be affected by the tensile bond ... [more]
The strength of unreinforced masonry (URM) walls subjected to one-way vertical bending under out-of-plane loading (no pre-compression) is known to be affected by the tensile bond strength. Factors such as batching, workmanship, and environmental exposure alter the strength of this bond, resulting in spatial variability for any URM assembly. In narrow wall panels a single weak joint may dictate the failure load of a masonry wall, whereas for longer walls there is higher potential for weak joints to occur and load redistribution. This paper focuses on a stochastic assessment of clay brick URM walls with spatially variable tensile bond strength subjected to uniformly distributed out-of-plane loads in one-way vertical bending and assessing the effect of wall length on the ultimate failure load. Stochastic computational modelling combining 3D non-linear Finite Element Analysis (FEA) and Monte Carlo Simulation (MCS) is used to account for bond strength variability when estimating the walls ultimate failure loads. For this assessment FEA MCS has been applied to a set of existing test data for walls 1, 2, 4, and 10 units long, by ten different masons. Models were also developed to consider walls in the intermediate length range, 7 units long, and walls outside of this range, 15 units long. For each set of simulations the peak pressure and load¿displacement data was extracted and analysed, showing agreement with the results of wall test data. The panel strength is shown to increase with wall length from 1 to 4 units, then stabilize with further length increase. The variability of the failure load is shown to decrease with increasing wall length.
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Nova |
2021 |
Melhem MM, Caprani CC, Stewart MG, 'Reliability updating of partial factors for empirical codes: Application to Super-T PSC girders designs at the ultimate limit state in bending', STRUCTURES, 35 233-242 (2021) [C1]
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Nova |
2021 |
Stewart MG, Li J, 'Risk-based assessment of blast-resistant design of ultra-high performance concrete columns', Structural Safety, 88 (2021) [C1]
In conventional structural protective design against blast loads conservative structural designs are anticipated. However, unknown factors that include threat uncertainty, blast l... [more]
In conventional structural protective design against blast loads conservative structural designs are anticipated. However, unknown factors that include threat uncertainty, blast load variation, construction methods, material quality, etc., could impact the accuracy of assessment and design, sometimes even leading to an overestimation of structural capacity to explosive blast effects or an underestimation of actual blast pressures. In the present study, structural safety and reliability analyses of Ultra-high Performance Concrete (UHPC) columns under varying blast scenarios are performed. The variation in column dimensions, steel reinforcement, UHPC material strength, explosive range and mass, and numerical and blast load model errors are considered. The peak reflected pressure and impulse from the selected blast scenarios are derived based on variation in the explosive mass and standoff distance. Failure probabilities of columns made of this emerging high performance concrete material are then estimated. It was found that for a UHPC column designed for blast the probability of major damage given an explosive blast load varies from 1 × 10-2 to 1 × 10-5 for explosive ordnance and terrorism blast scenarios. This provides a reasonable margin of safety against major structural damage. It was also found that the risk reducing benefit of blast-resistant UHPC columns can be considerable.
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Nova |
2021 |
Gooch LJ, Masia MJ, Stewart MG, 'Application of stochastic numerical analyses in the assessment of spatially variable unreinforced masonry walls subjected to in-plane shear loading', Engineering Structures, 235 (2021) [C1]
This paper develops a modelling strategy for the finite element analysis of perforated (arched) unreinforced masonry walls subjected to in-plane shear loading. An experimental bas... [more]
This paper develops a modelling strategy for the finite element analysis of perforated (arched) unreinforced masonry walls subjected to in-plane shear loading. An experimental baseline was used to facilitate an accurate calibration and assessment of the chosen modelling strategy. This study provides the procedure and the results relevant to a stochastic assessment of unreinforced masonry shear walls. These results may be used in future studies of the reliability of these structures and may be applied in the calibration of reliability-based design practices. Utilising a two-dimensional micro-modelling approach, the capacity of a monotonic loading scheme to capture the envelope of a cyclically applied load was examined. It was found that, while the elastic stiffness of the laboratory specimens was overestimated by the finite element models, the peak load and global response was accurately recreated by the monotonically loaded models. Once the applicability of this procedure had been established, a series of spatially variable stochastic finite element analyses were created by considering the stochastic properties of key material parameters. These analyses were able to estimate the mean load resistance of the experimentally tested walls with a greater accuracy than a deterministic model. Furthermore, these analyses produced an accurate estimate of the variability of shear capacity of and the observed damage to the laboratory specimens. Due to the fact that the tested walls failed almost exclusively in a rocking mode, a failure mechanism highly dependent upon the structures¿ geometry, the variability of the peak strength was minimal. However, the observed damage and presence of some sliding and stepped cracking indicates that the proposed methodology is likely to capture more variable and unstable failure modes in shear walls with a smaller height-to-length ratio or those more highly confined.
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Nova |
2021 |
Stewart MG, 'Terrorism Risks and Economic Assessment of Infrastructure Protection against Progressive Collapse', JOURNAL OF STRUCTURAL ENGINEERING, 147 (2021) [C1]
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Nova |
2021 |
Mueller J, Stewart MG, 'Terrorism and Bathtubs: Comparing and Assessing the Risks', Terrorism and Political Violence, 33 138-163 (2021) [C1]
The likelihood that anyone outside a war zone will be killed by an Islamist extremist terrorist is extremely small. In the United States, for example, some six people have perishe... [more]
The likelihood that anyone outside a war zone will be killed by an Islamist extremist terrorist is extremely small. In the United States, for example, some six people have perished each year since 9/11 at the hands of such terrorists¿vastly smaller than the number of people who die in bathtub drownings. Some argue, however, that the incidence of terrorist destruction is low because counterterrorism measures are so effective. They also contend that terrorism may well become more frequent and destructive in the future as terrorists plot and plan and learn from experience, and that terrorism, unlike bathtubs, provides no benefit and exacts costs far beyond those in the event itself by damagingly sowing fear and anxiety and by requiring policy makers to adopt countermeasures that are costly and excessive. This article finds these arguments to be wanting. In the process, it concludes that terrorism is rare outside war zones because, to a substantial degree, terrorists don¿t exist there. In general, as with rare diseases that kill few, it makes more policy sense to expend limited funds on hazards that inflict far more damage. It also discusses the issue of risk communication for this hazard.
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Nova |
2021 |
Kelly R, Huang J, Poulos H, Stewart MG, 'Geotechnical and Structural stochastic analysis of piled solar farm foundations', Computers and Geotechnics, 132 (2021) [C1]
Development of large scale solar farms supported by large numbers of short piles has created new challenges for engineers to address. Solar arrays are highly flexible structures a... [more]
Development of large scale solar farms supported by large numbers of short piles has created new challenges for engineers to address. Solar arrays are highly flexible structures and the piles can be designed to move to enable more cost effective design. The structural reliability of the above-ground pile can be assessed and probabilities of failure for different section sizes calculated. Economic analysis incorporating capital cost and whole-of-life maintenance cost can be performed to work out whether adopting smaller section sizes provide the best cost outcome. Assessment of pile movements using Monte-Carlo calculations, unsaturated soil mechanics and updating material parameters with suction have been performed. The results show that soil movements are typically larger than pile movements and that soil can slip past the pile with no pile movement when the limiting conditions occur. The results also highlight that the largest soil and pile movements occur infrequently as a result of extreme wetting or drying conditions. Structural reliability analyses showed that correlating wind speed and direction results in a lower probability of failure than if wind load is considered to be uncorrelated with wind direction. The outcomes of the assessment were sensitive to the adopted probabilistic model for pile durability. The main limitation of the analyses is that there is limited information in the literature relating to the types of probability distributions and their input parameters. This adds uncertainty to the stochastic analysis.
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Nova |
2021 |
Marks NA, Stewart MG, Netherton MD, Stirling CG, 'Airblast variability and fatality risks from a VBIED in a complex urban environment', Reliability Engineering and System Safety, 209 (2021) [C1]
Explosive blasts and prediction of fatality risks in urban environments is a complicated task due to the variability in blast wave reflection and propagation. The terrorist threat... [more]
Explosive blasts and prediction of fatality risks in urban environments is a complicated task due to the variability in blast wave reflection and propagation. The terrorist threats considered in this paper are vehicle-borne improvised explosive devices (VBIED) containing 225 kg or 450 kg of TNT or ammonium nitrate fuel oil (ANFO) detonated in an open street. This paper uses Viper::Blast CFD software to estimate the variability of explosive blast loads using Monte-Carlo sampling. To probabilistically model the blast wave, the paper takes into consideration the variability of explosive charge mass, detonation location, height of detonation, net equivalent quantity, atmospheric pressure and temperature, and model errors. The fatality risk assessment combines lung-rupture, whole-body displacement and skull fracture dependant on the pressure and impulse. It was found that the mean fatality risk for a 450 kg home-made ANFO explosive device detonated at a road T-intersection is 16% for people exposed in the street. If bollards were placed 10 m from the main street then fatality risk for people in the main street is reduced by over 90%. It was found that a deterministic analysis yielded fatality risks 10¿60% higher than a probabilistic analysis, leading to an overly conservative assessment of safety risks.
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Nova |
2021 |
Sielicki PW, Stewart MG, Gajewski T, Malendowski M, Peksa P, Al-Rifaie H, et al., 'Field test and probabilistic analysis of irregular steel debris casualty risks from a person-borne improvised explosive device', Defence Technology, 17 1852-1863 (2021) [C1]
Person-borne improvised explosive devices (PBIEDs) are often used in terrorist attacks in Western countries. This study aims to predict the trajectories of PBIED fragments and the... [more]
Person-borne improvised explosive devices (PBIEDs) are often used in terrorist attacks in Western countries. This study aims to predict the trajectories of PBIED fragments and the subsequent safety risks for people exposed to this hazard. An explosive field test with a typical PBIED composed of a plastic explosive charge and steel nut enhancements was performed to record initial fragment behaviour, including positions, velocity, and trajectory angles. These data were used to predict the full trajectory of PBIED fragments using a probabilistic analysis. In the probabilistic analyses a probability of fatality or serious injury was computed. Based on the results presented, many practical conclusions can be drawn, for instance, regarding safe evacuation distances if a person were exposed to a suspected PBIED.
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Nova |
2021 |
Qin H, Stewart MG, 'Casualty Risks Induced by Primary Fragmentation Hazards from High-explosive munitions', Reliability Engineering and System Safety, 215 (2021) [C1]
Fatalities and injuries are mainly attributed to primary fragmentation if accidental or malevolent detonation of high-explosive munitions occurs in an open space. This study aims ... [more]
Fatalities and injuries are mainly attributed to primary fragmentation if accidental or malevolent detonation of high-explosive munitions occurs in an open space. This study aims to develop a simulation-based approach to assess individual casualty risks from primary fragments naturally generated by detonation of high-explosive munitions, which enables a stochastic characterization of fragment generation, trajectories, modelling uncertainties, and human vulnerability. The proposed method is demonstrated by a numerical example estimating the fatality and injury risks for an individual in a standing position exposed to the detonation of a single 105 mm projectile. The results suggest that, as expected, the individual fatality and injury risks decrease with an increasing stand-off distance. At a stand-off distance greater than 40 m, an individual is more likely to suffer injuries rather than fatality. The safety distance obtained from the present study is 97 m which is close to but less conservative than a safety distance of 104 m in existing literature and standards.
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Nova |
2021 |
Agarwal A, Foster SJ, Stewart MG, 'Model error and reliability of reinforced concrete beams in shear designed according to the Modified Compression Field Theory', Structural Concrete, 22 3711-3726 (2021) [C1]
Model error (or model uncertainty) were probabilistically characterized for modified compression field theory (MCFT) Simplified and General Method approaches using experimental da... [more]
Model error (or model uncertainty) were probabilistically characterized for modified compression field theory (MCFT) Simplified and General Method approaches using experimental databases that contained reinforced concrete (RC) beams having shear failures with and without stirrups (168 and 368 specimens, respectively). It was found that when compared to the design shear model currently used in ACI-318, the General Method produced low model error variability indicating better consistency for the determination of shear strength. Structural reliabilities were then calculated for RC beams in shear designed to MCFT General Method (AASHTO LRFD, CSA A23.3-14, AS3600-2018) for a live-to-dead load ratio between 0 and 5, and for capacity reduction factor ¿¿=¿0.70, 0.75, and 0.80. It was concluded that the ¿-factor for shear failure for Australian standards can be increased from 0.70 to 0.75 for RC beams with stirrups, providing a 7.1% increase in the design shear capacity and contributing to sustainable design and reduction in greenhouse gas emissions due to more efficient usage of materials.
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Nova |
2021 |
Qin H, Stewart MG, 'Risk perceptions and economic incentives for mitigating windstorm damage to housing', Civil Engineering and Environmental Systems, 38 1-19 (2021) [C1]
Mitigation measures such as window shutters can substantially reduce windstorm damage to housing. However, the cost-effectiveness of wind mitigation measures remains unclear when ... [more]
Mitigation measures such as window shutters can substantially reduce windstorm damage to housing. However, the cost-effectiveness of wind mitigation measures remains unclear when considering influencing factors such as financial protection via insurance, individual risk perceptions and planning time horizons. Economic incentives may also be provided to motivate homeowners to invest in mitigation. In this study, the installation of cyclone-rated window shutters as a mitigation measure for homeowners in Australia is used as a case study. A life-cycle cost analysis in conjunction with a rank-dependent expected utility model are employed to identify economic incentives that are financially attractive to homeowners with different perceived risks and planning time horizons. The effect of home insurance is also taken into account. The results suggest that, as expected, the economic incentives needed to promote window shutters among homeowners decrease with the perceived storm damage risk and planning time horizon. A rebate for shutter installation cost or a discounted insurance premium have been found to be feasible economic incentives considering a typical planning time horizon of ten years. Statistical surveys are needed in future work to calibrate the parameters within the rank-dependent utility model to better represent the risk perceptions of different groups of homeowners.
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Nova |
2020 |
Qin H, Stewart MG, 'Risk-based cost-benefit analysis of climate adaptation measures for Australian contemporary houses under extreme winds', Journal of Infrastructure Preservation and Resilience, 1 (2020) [C1]
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Nova |
2020 |
Qin H, Stewart MG, 'Construction defects and wind fragility assessment for metal roof failure: A Bayesian approach', Reliability Engineering and System Safety, 197 (2020) [C1]
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Nova |
2020 |
Thöns S, Stewart MG, 'On the cost-efficiency, significance and effectiveness of terrorism risk reduction strategies for buildings', Structural Safety, 85 (2020) [C1]
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Nova |
2020 |
Stewart MG, Mueller J, 'Terrorism risks, chasing ghosts and infrastructure resilience', Sustainable and Resilient Infrastructure, 5 78-89 (2020) [C1]
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Nova |
2020 |
Stewart MG, Netherton MD, 'Statistical variability and fragility assessment of ballistic perforation of steel plates for 7.62 mm AP ammunition', DEFENCE TECHNOLOGY, 16 503-513 (2020) [C1]
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Nova |
2020 |
Qin H, Stewart MG, 'Wind and rain losses for metal-roofed contemporary houses subjected to non-cyclonic windstorms', Structural Safety, 86 (2020) [C1]
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Nova |
2020 |
Hawchar L, Naughton O, Nolan P, Stewart MG, Ryan PC, 'A GIS-based framework for high-level climate change risk assessment of critical infrastructure', Climate Risk Management, 29 (2020) [C1]
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Nova |
2020 |
Stewart MG, 'Professor Bruce R. Ellingwood - Mentor and Leader', STRUCTURAL SAFETY, 84 (2020)
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2020 |
Stewart MG, Netherton MD, Baldacchino H, 'Observed airblast variability and model error from repeatable explosive field trials', International Journal of Protective Structures, 11 235-257 (2020) [C1]
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Nova |
2020 |
Faber MH, Miraglia S, Qin J, Stewart MG, 'Bridging resilience and sustainability - decision analysis for design and management of infrastructure systems', SUSTAINABLE AND RESILIENT INFRASTRUCTURE, 5 102-124 (2020) [C1]
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Nova |
2019 |
Alterman D, Stewart MG, Netherton MD, 'Probabilistic assessment of airblast variability and fatality risk estimation for explosive blasts in confined building spaces', INTERNATIONAL JOURNAL OF PROTECTIVE STRUCTURES, 10 306-329 (2019) [C1]
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Nova |
2019 |
Qin H, Stewart MG, 'System fragility analysis of roof cladding and trusses for Australian contemporary housing subjected to wind uplift', Structural Safety, 79 80-93 (2019) [C1]
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Nova |
2019 |
Melhem MM, Caprani CC, Stewart MG, 'Reliability of Super-T PSC girders at serviceability limit state stresses across all span ranges', Structure and Infrastructure Engineering, 15 812-821 (2019) [C1]
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Nova |
2019 |
Thöns S, Stewart MG, 'On decision optimality of terrorism risk mitigation measures for iconic bridges', Reliability Engineering and System Safety, 188 574-583 (2019) [C1]
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Nova |
2019 |
Grant M, Stewart MG, 'Postal IEDs and risk assessment of work health and safety considerations for postal workers', International Journal of Risk Assessment and Management, 22 152-169 (2019)
Postal improvised explosive devices (IEDs) provide criminals and terrorists with a convenient mechanism for delivering an energetic payload to an intended victim with little opera... [more]
Postal improvised explosive devices (IEDs) provide criminals and terrorists with a convenient mechanism for delivering an energetic payload to an intended victim with little operational risk. Postal IEDs formed 7% of IED attacks reported in the West between 1998-2015, are often dispatched in groups and can bring postal systems to a standstill. Nearly 30% of postal IED explosions occur in the postal worker environment and a third of the casualties caused by postal IEDs are postal workers. Postal IEDs are debatably a reasonably foreseeable cause of harm to postal workers and should be considered under the work health and safety (WHS) constructs of many Western nations. This paper considers this problem, using a probabilistic risk assessment model to inform a cost-benefit analysis considering potential risk reduction options for postal workers. It identifies that the control measures identified were not cost-effective where only the direct WHS costs pertaining to unintentional postal IED detonation within the mail delivery system were considered given the risk levels identified.
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2019 |
Stewart MG, Netherton MD, 'A probabilistic risk-acceptance model for assessing blast and fragmentation safety hazards', Reliability Engineering and System Safety, 191 (2019) [C1]
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Nova |
2019 |
Stewart MG, Dorrough B, Netherton MD, 'Field testing and probabilistic assessment of ballistic penetration of steel plates for small calibre military ammunition', International Journal of Protective Structures, 10 421-438 (2019) [C1]
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Nova |
2019 |
Stewart MG, 'Reliability-based load factors for airblast and structural reliability of reinforced concrete columns for protective structures', Structure and Infrastructure Engineering, 15 634-646 (2019) [C1]
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Nova |
2018 |
Stewart MG, 'Reliability-based load factor design model for explosive blast loading', Structural Safety, 71 13-23 (2018) [C1]
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Nova |
2018 |
Bjarnadottir S, Li Y, Reynisson O, Stewart MG, 'Reliability-based assessment of climatic adaptation for the increased resiliency of power distribution systems subjected to hurricanes', Sustainable and Resilient Infrastructure, 3 36-48 (2018) [C1]
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Nova |
2018 |
Bayuaji R, Darmawan MS, Husin NA, Anugraha RB, Budipriyanto A, Stewart MG, 'Corrosion damage assessment of a reinforced concrete canal structure of power plant after 20 years of exposure in a marine environment: A case study', ENGINEERING FAILURE ANALYSIS, 84 287-299 (2018) [C1]
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Nova |
2018 |
Stewart MG, Mueller J, 'Risk and economic assessment of U.S. aviation security for passenger-borne bomb attacks', JOURNAL OF TRANSPORTATION SECURITY, 11 117-136 (2018) [C1]
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Nova |
2018 |
Stewart MG, Ginger JD, Henderson DJ, Ryan PC, 'Fragility and climate impact assessment of contemporary housing roof sheeting failure due to extreme wind', Engineering Structures, 171 464-475 (2018) [C1]
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Nova |
2017 |
Li J, Masia MJ, Stewart MG, 'Stochastic spatial modelling of material properties and structural strength of unreinforced masonry in two-way bending', STRUCTURE AND INFRASTRUCTURE ENGINEERING, 13 683-695 (2017) [C1]
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Nova |
2017 |
Zhi XD, Stewart MG, 'Damage and Risk Assessment for Single-Layer Reticulated Domes Subject to Explosive Blast Loads', INTERNATIONAL JOURNAL OF STRUCTURAL STABILITY AND DYNAMICS, 17 (2017) [C1]
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Nova |
2017 |
Olmati P, Vamvatsikos D, Stewart MG, 'Safety factor for structural elements subjected to impulsive blast loads', INTERNATIONAL JOURNAL OF IMPACT ENGINEERING, 106 249-258 (2017) [C1]
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Nova |
2017 |
Ryan PC, Stewart MG, 'Cost-benefit analysis of climate change adaptation for power pole networks', CLIMATIC CHANGE, 143 519-533 (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 |
Stewart MG, Mueller J, 'Risk and economic assessment of expedited passenger screening and TSA PreCheck', JOURNAL OF TRANSPORTATION SECURITY, 10 1-22 (2017) [C1]
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Nova |
2017 |
Grant MJ, Stewart MG, 'Benefit of Distributed Security Queuing for Reducing Risks Associated With Improvised Explosive Device Attacks in Airport Terminals', ASCE-ASME JOURNAL OF RISK AND UNCERTAINTY IN ENGINEERING SYSTEMS PART B-MECHANICAL ENGINEERING, 3 (2017) [C1]
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Nova |
2017 |
Stewart MG, 'Risk of Progressive Collapse of Buildings from Terrorist Attacks: Are the Benefits of Protection Worth the Cost?', JOURNAL OF PERFORMANCE OF CONSTRUCTED FACILITIES, 31 (2017) [C1]
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Nova |
2017 |
Grant MJ, Stewart MG, 'Modelling improvised explosive device attacks in the West - Assessing the hazard', RELIABILITY ENGINEERING & SYSTEM SAFETY, 165 345-354 (2017) [C1]
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Nova |
2016 |
Alam M, Sanjayan J, Zou PXW, Stewart MG, Wilson J, 'Modelling the correlation between building energy ratings and heat-related mortality and morbidity', Sustainable Cities and Society, 22 29-39 (2016) [C1]
Climate change has led to an increase in the frequency and intensity of heatwaves as well as the risk of heat stress within buildings. To provide habitable indoor conditions witho... [more]
Climate change has led to an increase in the frequency and intensity of heatwaves as well as the risk of heat stress within buildings. To provide habitable indoor conditions without air-conditioning during heatwave, residential building energy efficiency need to be upgraded. The aim of this research is to investigate the possible correlation of building energy rating upgrading with heat-related health hazard during heatwave, with case data drawing from Melbourne, Australia. Using building simulations, indoor heat stress conditions of different energy rated houses were calculated using wet bulb globe temperature and discomfort index under the Melbourne 2009 heatwave conditions. The results showed that during three days heatwave period, residents of 0.9 star energy rated house were exposed to extreme heat stress conditions for almost 25 h compared to only 6 h experienced by the occupants of 5.4 star energy rated house. Several robust empirical relationships were proposed to predict deaths, ambulance calls, emergency department presentations and after hour doctor calls during heatwave. It was concluded that mortality rate from a Melbourne 2009 type, as well as, future more intense heatwave may reduce by 90% if entire existing lower energy star rated houses can be upgraded to minimum 5.4 star energy rating.
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Nova |
2016 |
Hajializadeh D, OBrien EJ, Stewart MG, 'The sensitivity of bridge safety to spatial correlation of load and resistance', Structures, 5 23-34 (2016) [C1]
Random Field theory has emerged in recent years to model the statistical correlation of resistance in concrete structures and to determine its influence on the probability of stru... [more]
Random Field theory has emerged in recent years to model the statistical correlation of resistance in concrete structures and to determine its influence on the probability of structural failure. A major shortcoming in the work carried out to date is the spatial variability and corresponding correlation associated with applied traffic loads. In this paper the influence of spatial correlation of both traffic load and resistance is considered in the context of bridge safety assessment. The current study, explores, the nature of the problem by three theoretical examples. As a general trend, examples show that while traffic loads are weakly correlated, load effects are strongly correlated as the same heavy vehicle often causes extremes of load effect in different parts of the bridge which is due to the transverse sharing of load (measured here using a load sharing factor). It is found that the strength of correlation of load effect depends greatly on the load sharing factor which is treated in a simple way in many studies. In a more sophisticated beam-and-slab bridge example, load sharing factors are derived from a finite element analysis to assess transverse load sharing, and are shown to vary by girder number, girder segment and by load location. Despite the fact that load effect at points along the length of a bridge is strongly correlated, the combined influence of correlation in load and resistance on probability of failure is small.
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Nova |
2016 |
Bastidas-Arteaga E, Stewart MG, 'Economic assessment of climate adaptation strategies for existing reinforced concrete structures subjected to chloride-induced corrosion', STRUCTURE AND INFRASTRUCTURE ENGINEERING, 12 432-449 (2016) [C1]
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Nova |
2016 |
Stewart MG, Reid S, 'Decision-making in a changing climate', STRUCTURE AND INFRASTRUCTURE ENGINEERING, 12 431-431 (2016)
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2016 |
Mueller J, Stewart MG, 'The curse of the Black Swan', Journal of Risk Research, 19 1319-1330 (2016) [C1]
When unexpected and emotion-engaging events become Black Swans and carry an ¿extreme impact,¿ this derives not so much those qualities or from their intrinsic size or importance a... [more]
When unexpected and emotion-engaging events become Black Swans and carry an ¿extreme impact,¿ this derives not so much those qualities or from their intrinsic size or importance as from reaction, or overreaction, they generate; but one that is often as extreme and unpredictable as the event itself. Most consequential development in human history, however, stems not from such events, but from changes in thinking and behavior that are gradual and often little-noticed as they occur. In addition, when an unexpected, emotion-grabbing event becomes a Black Swan, the response is likely to become internalized, and getting people to re-evaluate through sensible risk analysis and risk communication is extremely difficult. As part of this, events that are aberrations are often unwisely taken instead to be harbingers ¿ and continue to be so even in the face of repeated disconfirming evidence. An examination of the 9/11 response in the US illustrates these points.
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Nova |
2016 |
Mueller J, Stewart MG, 'Misoverestimating ISIS: Comparisons with Al-Qaeda', Perspectives on Terrorism, 10 32-41 (2016) [C1] |
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Nova |
2016 |
Stewart MG, 'Climate change impact assessment of metal-clad buildings subject to extreme wind loading in non-cyclonic regions', SUSTAINABLE AND RESILIENT INFRASTRUCTURE, 1 32-45 (2016)
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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 |
Netherton MD, Stewart MG, 'Risk-based blast-load modelling: Techniques, models and benefits', International Journal of Protective Structures, 7 430-451 (2016) [C1]
There are many deterministic blast-load methods currently in use, such as (1) those for the ready calculation of explosive pressure, impulse and duration; (2) the derivation of ex... [more]
There are many deterministic blast-load methods currently in use, such as (1) those for the ready calculation of explosive pressure, impulse and duration; (2) the derivation of explosive safety distances; or (3) the determination of safety hazards (and other consequences) following an explosive¿s detonation. In this article, we argue that deterministic blast-loading methods do not fully account for society¿s usual acceptance (or rejection) of the risks associated with damage, safety and/or injury as a result of an explosive blast-load. This article details the state of the art of probabilistic blast-load modelling that supports a quantitative calculation of risk, with respect to damage, safety and injury. The probabilistic models draw data from the literature and from our own field trials. The article details the benefits that flow from this form of blast-load characterisation and concludes with a discussion on how probabilistic methods be used to derive cost¿benefit advice with respect to any proposed risk mitigation solution.
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Nova |
2016 |
Ryan PC, Stewart MG, Spencer N, Li Y, 'Probabilistic analysis of climate change impacts on timber power pole networks', INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS, 78 513-523 (2016) [C1]
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2016 |
Peng L, Stewart MG, 'Climate change and corrosion damage risks for reinforced concrete infrastructure in China', Structure and Infrastructure Engineering, 12 499-516 (2016) [C1]
A changing climate which leads to increases in atmospheric CO2 concentration, and changes in temperature and relative humidity (RH), especially in the longer term, will accelerate... [more]
A changing climate which leads to increases in atmospheric CO2 concentration, and changes in temperature and relative humidity (RH), especially in the longer term, will accelerate the deterioration processes and consequently decline the safety, serviceability and durability of reinforced concrete (RC) infrastructure. This paper presents an investigation of carbonation-induced deterioration in three typical Chinese cities (Kunming, Xiamen and Jinan) under a changing climate. The changing trends of atmospheric CO2, local temperature and RH of typical Chinese cities are projected based on the latest CO2 emission scenarios. The time-dependent analysis is based on Monte Carlo simulation, and includes the uncertainty of climate projections, deterioration processes, material properties, dimensions and accuracy of predictive models. Deterioration of RC structures is represented by the probabilities of reinforcement corrosion initiation and damage. It was found that the mean carbonation depths by 2100 may increase by up to 45% for RC structures in China due to a changing climate. It was also found that climate change can cause an additional 7¿20% of carbonation-induced damage by 2100 for RC buildings in temperate or cold climate areas in China. The findings provide a basis for the development of climate adaptation strategies through the improved design of concrete structures.
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Nova |
2016 |
Hajializadeh D, Stewart MG, Enright B, OBrien E, 'Spatial time-dependent reliability analysis of reinforced concrete slab bridges subject to realistic traffic loading', STRUCTURE AND INFRASTRUCTURE ENGINEERING, 12 1137-1152 (2016) [C1]
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Nova |
2016 |
Stewart MG, Foster S, Ahammed M, Sirivivatnanon V, 'Calibration of Australian Standard AS3600 concrete structures part II: reliability indices and changes to capacity reduction factors', Australian Journal of Structural Engineering, 17 254-266 (2016) [C1]
Capacity reduction factors (¿) for flexure, shear and axial loadings are derived for reinforced concrete (RC) structures based on a reliability-based calibration of the Australian... [more]
Capacity reduction factors (¿) for flexure, shear and axial loadings are derived for reinforced concrete (RC) structures based on a reliability-based calibration of the Australian Concrete Structures Standard AS3600. The structural reliability analysis considers the bias and variability of material properties, dimensions, loads and model error. The target reliabilities (ßT) are selected based on consideration of past practice and Australian and international standards. The capacity reduction factors (¿) for the new code AS3600-2009 are selected using the most recent statistical parameters for material strengths for 20¿100 MPa strength concrete using Class N (ductile) 500N reinforcement. The reliability-based calibration found that the ¿-factor can be increased from 0.80 to 0.85 for members in bending, and increased from 0.60 to 0.65 for axial loading of short (stocky) columns where the ratio of the live load to the dead load is at least 0.25. No changes are recommended for shear or torsion, at this time, or for slender columns; further research is needed to better refine the design models for these cases and reduce the variation in their model error. The proposed increases in capacity reduction factors will result in up to an 8.3% increase in design strength that, in turn, provides efficiency in the use of materials. The proposed changes provide for modest savings in greenhouse gas emissions.
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Nova |
2016 |
Foster SJ, Stewart MG, Loo M, Ahammed M, Sirivivatnanon V, 'Calibration of Australian Standard AS3600 Concrete Structures: part I statistical analysis of material properties and model error', Australian Journal of Structural Engineering, 17 242-253 (2016) [C1]
Assessment of the reliability of design models developed for Australian Standards is of paramount importance for determination of public safety. Poorly calibrated models and safet... [more]
Assessment of the reliability of design models developed for Australian Standards is of paramount importance for determination of public safety. Poorly calibrated models and safety factors can lead to overly safe and uneconomic construction or, worse, to an insufficient level of safety. This study investigates the reliability of the models used in the Australian Concrete Structures Standard AS3600¿2009 for the design of beams and slabs in bending and shear and columns under combined bending and axial loading. The study is in two parts; in Part I, strength and variability of over 20,000 concrete cylinders cured under standard conditions and tested at 28¿days are statistically analysed. The data were collected from all cities and regional areas in Australia and for all concrete strength grades; similarly, variability of reinforcement product is analysed. Next, reliable databases of laboratory tests for beams, slabs and columns were established for members failing in flexure, shear and compression and model errors, and their variability, determined for the code design models. It is concluded that improvements in the production of concrete and of bar products, over time, have led to reduced variability in their materials properties¿with potential for increasing code strength reduction factors and, thus, reducing excessive conservatism in design. This is assessed in Part II of this study.
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Nova |
2016 |
Li J, Stewart MG, Masia MJ, Lawrence SJ, 'Spatial Correlation of Material Properties and Structural Strength of Masonry in Horizontal Bending', JOURNAL OF STRUCTURAL ENGINEERING, 142 (2016) [C1]
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Nova |
2016 |
Stewart MG, Ryan PC, Henderson DJ, Ginger JD, 'Fragility analysis of roof damage to industrial buildings subject to extreme wind loading in non-cyclonic regions', Engineering Structures, 128 333-343 (2016) [C1]
A fragility analysis is conducted for loss of roof cladding for low rise metal-clad industrial buildings located in non-cyclonic regions of Australia. The stochastic analysis incl... [more]
A fragility analysis is conducted for loss of roof cladding for low rise metal-clad industrial buildings located in non-cyclonic regions of Australia. The stochastic analysis includes possible component and connection failures, load redistribution based on progressive failure, spatial distribution of wind load, and internal pressure variation caused by roof sheeting failure. This spatial and time-dependent reliability analysis will enable fragility curves to be developed that relate likelihood and extent of roof cover damage with wind speed. Industrial buildings representative of new construction in the Australian cities of Brisbane, Sydney and Melbourne are considered. Fragility functions are proposed for industrial buildings designed and constructed to existing codes, and also for improperly designed or constructed buildings where a roller door or other dominant opening prematurely fails during a storm for a building designed as nominally sealed. It was found that damage risks double if a roller door or other dominant opening prematurely fails during a storm.
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Nova |
2015 |
Konthesingha KMC, Stewart MG, Ryan P, Ginger J, Henderson D, 'Reliability based vulnerability modelling of metal-clad industrial buildings to extreme wind loading for cyclonic regions', Journal of Wind Engineering and Industrial Aerodynamics, 147 176-185 (2015) [C1]
This paper presents an approach for developing a vulnerability model to predict the probability and extent of damage to metal-clad industrial buildings due to extreme wind loading... [more]
This paper presents an approach for developing a vulnerability model to predict the probability and extent of damage to metal-clad industrial buildings due to extreme wind loading. Structural reliability-based methods that describe the spatially distributed wind load and component/connection strengths probabilistically are used in the model. Two failure mechanisms are considered for the roof envelop, namely; failure of roof cladding, and purlin failure. Interdependency between the failure mechanisms, load sharing effects due to connection/component failure, and internal pressure variation due to roof cladding failure are also considered. The industrial building examined in the study is a hot rolled structural steel, metal-clad, gable-end building designed for cyclonic regions in Australia. The likelihood and extent of roof damage for this buildings is presented using wind vulnerability curves obtained from the probabilistic model. It is found that internal pressure (e.g. an open door) and the use of cyclone washers has a significant effect on wind vulnerability. The utilisation of cyclone washers is found to reduce damage risks by over 70%.
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Nova |
2015 |
Ginger J, Henderson D, Humphreys M, Konthesingha C, Stewart MG, 'Wind loads on the frames of industrial buildings', Australian Journal of Structural Engineering, 16 169-177 (2015) [C1]
The structural response of typical, gable-end, low roof pitch industrial buildings, in a windstorm is dependent on the wind loads used in the design of cladding and the portal fra... [more]
The structural response of typical, gable-end, low roof pitch industrial buildings, in a windstorm is dependent on the wind loads used in the design of cladding and the portal frame structure. Critical, structural wind load effects derived from wind loads measured on a wind tunnel model show that standards such as AS/NZS 1170.2 can produce unconservative design load effects on the heavily loaded fi rst internal frame. This paper forms part of wider study that assesses the vulnerability of hot rolled steel, industrial buildings to wind loads. The knee and ridge bending moments and horizontal and vertical reactions at the base of the frame are the critical load effects that are used in the design of structural members and connections of these types of buildings. This study found that some of these load effects based on external pressures are under-estimated by about 30%, when the building is located in a suburban environment. A dominant windward wall opening can effectively double the design load effects, thus signifi cantly increasing the vulnerability, especially if this scenario has not been considered by the designer.
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Nova |
2015 |
Ginger J, Henderson D, Humphreys M, Konthesingha C, Stewart MG, 'Wind loads on the frames of industrial buildings', Australian Journal of Structural Engineering, 16 169-178 (2015)
The structural response of typical, gable-end, low roof pitch industrial buildings, in a windstorm is dependent on the wind loads used in the design of cladding and the portal fra... [more]
The structural response of typical, gable-end, low roof pitch industrial buildings, in a windstorm is dependent on the wind loads used in the design of cladding and the portal frame structure. Critical, structural wind load effects derived from wind loads measured on a wind tunnel model show that standards such as AS/NZS 1170.2 can produce unconservative design load effects on the heavily loaded first internal frame. This paper forms part of wider study that assesses the vulnerability of hot rolled steel, industrial buildings to wind loads. The knee and ridge bending moments and horizontal and vertical reactions at the base of the frame are the critical load effects that are used in the design of structural members and connections of these types of buildings. This study found that some of these load effects based on external pressures are under-estimated by about 30%, when the building is located in a suburban environment. A dominant windward wall opening can effectively double the design load effects, thus significantly increasing the vulnerability, especially if this scenario has not been considered by the designer.
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2015 |
Shi Y, Stewart MG, 'Spatial reliability analysis of explosive blast load damage to reinforced concrete columns', Structural Safety, 53 13-25 (2015) [C1]
Columns are the key load-bearing elements in frame structures and exterior columns are probably the most vulnerable structural components to terrorist attack. In this paper, a spa... [more]
Columns are the key load-bearing elements in frame structures and exterior columns are probably the most vulnerable structural components to terrorist attack. In this paper, a spatial reliability analysis is conducted to predict the damage for reinforced concrete (RC) columns subject to explosive blast loading. The spatial variability of material and dimensional properties of RC columns are modelled by stationary and non-stationary random fields. The variability of blast loading is also taken into consideration. Monte Carlo simulation and numerical methods are used to derive Blast Reliability Curves for RC columns under explosive loading for a number of terrorism threat scenarios, based on a high-fidelity physics-based computer programme LS-DYNA to estimate design and residual axial load-carrying capacity of RC columns. It was found that spatial variability has a significant effect on structural reliabilities and the spatial model will lead to more accurate predictions of damage and safety risks.
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Nova |
2015 |
Stewart MG, 'Risk and economic viability of housing climate adaptation strategies for wind hazards in southeast Australia', Mitigation and Adaptation Strategies for Global Change, 20 601-622 (2015) [C1]
A changing climate and higher wind speeds means that residential construction is likely to receive more damage in the future if design standards are maintained at the current leve... [more]
A changing climate and higher wind speeds means that residential construction is likely to receive more damage in the future if design standards are maintained at the current level. The vulnerability of residential construction may be reduced by an adaptation strategy that increases design wind speeds specified by Australian standards. The paper applies break-even analysis to compare the risks, costs and benefits of climate adaptation strategies for new housing in the three largest cities in Australia: Brisbane, Sydney and Melbourne. These cities are located in southeast Australia where wind hazard is dominated by synoptic winds (thunderstorms and east-coast lows). Break-even estimates of risk reduction and adaptation cost for designing new housing to enhanced standards were calculated for three synoptic wind pattern scenarios to 2070: (1) no change, (2) B1 and (3) A1FI emission scenarios. If the actual cost of adaptation exceeds the predicted break-even value, then adaptation is not cost-effective. It was found that this adaptation strategy can lead to risk reductions of 50¿80¿% at a cost of approximately 1¿% of house replacement value. If risk reduction is over 50¿%, discount rate is 4¿%, and there is no change of climate, the break-even analysis shows that adaptation is cost-effective for Sydney if the adaptation cost is less than 5¿9¿% of house replacement cost. Designing new housing to enhance wind classifications is also likely to be a cost-effective adaptation strategy for Brisbane and Melbourne.
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Nova |
2015 |
Mojsilovic N, Stewart MG, 'Probability and structural reliability assessment of mortar joint thickness in load-bearing masonry walls', Structural Safety, 52 209-218 (2015) [C1]
Mortar joint thickness has a significant effect on capacity of structural masonry. Data on mortar joint thickness (bed and head joints) were collected from twelve typical storey-h... [more]
Mortar joint thickness has a significant effect on capacity of structural masonry. Data on mortar joint thickness (bed and head joints) were collected from twelve typical storey-high walls at three different building sites and from four walls built in a research laboratory in Switzerland. The data obtained allowed an analysis of the spatial distribution of the joint thickness in each wall and the characterization of the probability distribution of joint thickness. The data has been statistically analysed and the results discussed: the central and dispersion measures were calculated and several probability distributions have been fitted to the sample data and subsequently tested using standard methods of statistical theory. Further, the results obtained from all four building sites have been compared, thus providing quantitative information about the quality of the work on different sites. The presented probabilistic information is then used to define reliability-based limit state specifications where the joint thickness acts as an important random variable. The reliability of the structural masonry subjected to a concentric normal force found that probabilistic modelling of bed joint thickness results in higher reliability indices.
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Nova |
2015 |
Stewart MG, Deng X, 'Climate Impact Risks and Climate Adaptation Engineering for Built Infrastructure', ASCE-ASME Journal of Risk and Uncertainty in Engineering Systems, Part A: Civil Engineering, 1 (2015) [C1]
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Nova |
2015 |
Stewart M, Netherton M, 'Preface', International Journal of Protective Structures, 6 iii (2015)
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2015 |
Stewart MG, Deng X, 'Closure to "Climate Impact Risks and Climate Adaptation Engineering for Built Infrastructure" by Mark G. Stewart and Xiaoli Deng', ASCE-ASME JOURNAL OF RISK AND UNCERTAINTY IN ENGINEERING SYSTEMS PART A-CIVIL ENGINEERING, 1 (2015)
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2015 |
Shi Y, Stewart MG, 'Damage and risk assessment for reinforced concrete wall panels subjected to explosive blast loading', International Journal of Impact Engineering, 85 5-19 (2015) [C1]
The structural integrity of reinforced concrete (RC) structures in blast events is important for critical facilities. In this paper, a structural reliability analysis is conducted... [more]
The structural integrity of reinforced concrete (RC) structures in blast events is important for critical facilities. In this paper, a structural reliability analysis is conducted to predict the damage and risk reduction for RC wall panels subjected to explosive blast loading. Due to considerable uncertainties associated with material properties, dimensions, structural response, blast loading, as well as expected damage, probabilistic methods are used in quantifying the probability of damage for conventional and blast-resistant RC precast cladding wall panels by incorporating spatial and non-spatial variables. The variability of blast loading is also taken into consideration. Monte Carlo simulation and numerical methods are utilized to predict damage of RC wall panels subject to various threat scenarios, based on a physics-based computer programme LS-DYNA to estimate maximum support rotations. It was found that spatial variability of concrete compressive strength and concrete cover has little effects on the structural reliability for precast concrete panels, and the blast-resistant wall has 5%-100% lower probability of hazardous failure than the corresponding value for a conventional wall.
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Nova |
2015 |
Bastidas-Arteaga E, Stewart MG, 'Damage risks and economic assessment of climate adaptation strategies for design of new concrete structures subject to chloride-induced corrosion', Structural Safety, 52 40-53 (2015) [C1]
Reinforced concrete (RC) structures are subject to environmental actions affecting their performance, serviceability and safety. Among these actions, chloride ingress leads to cor... [more]
Reinforced concrete (RC) structures are subject to environmental actions affecting their performance, serviceability and safety. Among these actions, chloride ingress leads to corrosion initiation and its interaction with service loading could reduce its operational life. Experimental evidence indicates that chloride ingress is highly influenced by weather conditions in the surrounding environment and therefore by climate change. Consequently, both structural design and maintenance should be adapted to these new environmental conditions. This work focuses on the assessment of the costs and benefits of two climate adaptation strategies for new RC structures placed in chloride-contaminated environments under various climate change scenarios. Their cost-effectiveness is measured in terms of the benefit-to-cost ratio (BCR) and the probability that BCR exceeds unity - i.e., Pr(BCR. > 1). It was found that increasing concrete strength grade is more cost-effective than increasing design cover. The results also indicate that the cost-effectiveness of a given adaptation strategy depends mainly on the type of structural component, exposure conditions and climate change scenarios.
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Nova |
2015 |
Stewart MG, Mueller J, 'Responsible policy analysis in aviation security with an evaluation of PreCheck', Journal of Air Transport Management, 48 13-22 (2015) [C1]
Officials serving the public are tasked at the most fundamental level to spend funds in a manner that most effectively and efficiently keeps people safe. To do otherwise is irresp... [more]
Officials serving the public are tasked at the most fundamental level to spend funds in a manner that most effectively and efficiently keeps people safe. To do otherwise is irresponsible. In the case of counterterrorism policy-making, it is important, then, to evaluate the degree to which any gains in security afforded by counterterrorism measures are great enough to justify their cost. Risk analysis is an aid to responsible decisionmaking that does exactly that. We deal with four elements central to this approach-the cost per saved life, acceptable risk, cost-benefit analysis, and risk communication-and we discuss the degree to which risk analysis has been applied within the government to evaluate counterterrorism measures. We summarize our findings when this approach is used to assess the cost-effectiveness of airline and airport security measures, and then conclude by applying it to PreCheck, a measure that seems likely to bring considerable efficiencies to the screening process and great benefits to passengers, airports, and airlines while actually enhancing security somewhat.
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Nova |
2015 |
Stewart MG, Netherton MD, 'Reliability-based design load factors for explosive blast loading', Journal of Performance of Constructed Facilities, 29 (2015) [C1]
Reliability-based design allows the decision maker to select the level of reliability for a specific blast loading scenario and key to this is an understanding of airblast uncerta... [more]
Reliability-based design allows the decision maker to select the level of reliability for a specific blast loading scenario and key to this is an understanding of airblast uncertainty. Hence, explosive field trials have been conducted in Australia that measured the variability of free-field blast loading caused by military standard plastic explosives. The results have revealed a high level of variability of peak incident pressure, impulse, and time of positive phase duration for repeatable tests where variability would be expected to be a minimum. The accuracy of predictive blast load models (model error) was also assessed. A probabilistic blast load computer model is revised to capture these observed variabilities. The effect of a 20% mass-increase safety factor typically applied to explosive mass on the probability of exceeding a design blast load is assessed. Reliability-based load factors are calculated where the nominal load is multiplied by the load factor to ensure that the actual load is equal to the reliability level. Reliability-based load factors are estimated for reliability levels of 0.05-0.99, for a range of scaled distances for military munitions. The load factor can be as low as 0.66 for a 0.05 reliability level and as high as 1.30 for a 0.99 reliability level.
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Nova |
2015 |
Grant M, Stewart MG, 'Probabilistic risk assessment for improvised explosive device attacks that cause significant building damage', Journal of Performance of Constructed Facilities, 29 (2015) [C1]
Most vulnerability assessments assume that an improvised explosive device (IED) will reach maximum TNT equivalency, and that the IED will successfully detonate. These assumptions ... [more]
Most vulnerability assessments assume that an improvised explosive device (IED) will reach maximum TNT equivalency, and that the IED will successfully detonate. These assumptions will tend to overestimate actual blast-load effects. The paper develops an IED probabilistic risk-assessment model using a systems model for IED attacks based on the reliability of IEDs and by characterizing the human aspects of an IED attack's operational effectiveness from existing databases of terrorist incidents. The analysis includes estimates of the probability of threat, hazard, and loss for large commercial buildings in the United States. It was found that annual fatality risk for building occupants is similar to acceptable risk criteria. This suggests that strengthening buildings against progressive collapse may not be warranted unless there is a specific threat against a building.
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Nova |
2015 |
Salman AM, Li Y, Stewart MG, 'Evaluating system reliability and targeted hardening strategies of power distribution systems subjected to hurricanes', Reliability Engineering and System Safety, 144 319-333 (2015) [C1]
Over the years, power distribution systems have been vulnerable to extensive damage from hurricanes which can cause power outage resulting in millions of dollars of economic losse... [more]
Over the years, power distribution systems have been vulnerable to extensive damage from hurricanes which can cause power outage resulting in millions of dollars of economic losses and restoration costs. Most of the outage is as a result of failure of distribution support structures. Over the years, various methods of strengthening distribution systems have been proposed and studied. Some of these methods, such as undergrounding of the system, have been shown to be unjustified from an economic point of view. A potential cost-effective strategy is targeted hardening of the system. This, however, requires a method of determining critical parts of a system that when strengthened, will have greater impact on reliability. This paper presents a framework for studying the effectiveness of targeted hardening strategies on power distribution systems subjected to hurricanes. The framework includes a methodology for evaluating system reliability that relates failure of poles and power delivery, determination of critical parts of a system, hurricane hazard analysis, and consideration of decay of distribution poles. The framework also incorporates cost analysis that considers economic losses due to power outage. A notional power distribution system is used to demonstrate the framework by evaluating and comparing the effectiveness of three hardening measures.
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Nova |
2015 |
Mueller J, Stewart MG, 'Terrorism, counterterrorism, and the Internet: The American cases', Dynamics of Asymmetric Conflict: Pathways toward Terrorism and Genocide, 8 176-190 (2015) [C1]
This article assesses the cases that have come to light since 9/11 of Islamist extremist terrorism, whether based in the United States or abroad, in which the United States itself... [more]
This article assesses the cases that have come to light since 9/11 of Islamist extremist terrorism, whether based in the United States or abroad, in which the United States itself has been, or apparently has been, targeted. Information from them is used to evaluate how the Internet (including various forms of electronic communication) has affected several aspects of the terrorism enterprise in the United States: radicalization, communication, organization, and the gathering of information. In general, it is found that the Internet has not been particularly important. Although it has been facilitating in some respects, it has scarcely ever been necessary. In some respects, the Internet more fully aids efforts to police terrorism ¿ although this is mainly due to the incompetence and amateurishness of would-be terrorists. In other respects, however, the Internet, and the big data compilations it makes possible, greatly increase the costs and complications of the counterterrorism quest.
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Nova |
2014 |
Mueller J, Stewart MG, 'Evaluating counterterrorism spending', Journal of Economic Perspectives, 28 237-248 (2014) [C1]
In this article, we present a simple back-of-the-envelope approach for evaluating whether counterterrorism security measures reduce risk sufficiently to justify their costs. The a... [more]
In this article, we present a simple back-of-the-envelope approach for evaluating whether counterterrorism security measures reduce risk sufficiently to justify their costs. The approach uses only four variables: the consequences of a successful attack, the likelihood of a successful attack, the degree to which the security measure reduces risk, and the cost of the security measure. After measuring the cost of a counterterrorism measure, we explore a range of outcomes for the costs of terrorist attacks and a range of possible estimates for how much risk might be reduced by the measure. Then working from this mix of information and assumptions, we can calculate how many terrorist attacks (and of what size) would need to be averted to justify the cost of the counterterrorism measure in narrow cost-benefit terms. To illustrate this approach, we first apply it to the overall increases in domestic counterterrorism expenditures that have taken place since the terrorist attacks of September 11, 2001, and alternatively we apply it to just the FBI's counterterrorism efforts. We then evaluate evidence on the number and size of terrorist attacks that have actually been averted or might have been averted since 9/11.
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Nova |
2014 |
Li J, Masia MJ, Stewart MG, Lawrence SJ, 'Spatial variability and stochastic strength prediction of unreinforced masonry walls in vertical bending', Engineering Structures, 59 787-797 (2014) [C1]
The flexural bond strength of unreinforced masonry (URM) is a key material property affecting wall out-of-plane lateral load capacity. It is well known that the unit flexural bond... [more]
The flexural bond strength of unreinforced masonry (URM) is a key material property affecting wall out-of-plane lateral load capacity. It is well known that the unit flexural bond strength (defined here as the flexural strength of the bond between the brick and lower mortar bed joint associated with any given masonry unit (brick)) varies considerably between units, and that this spatial variability might significantly affect the structural performance and reliability of URM walls in flexure. The paper develops a computational method to predict the strength for non-load bearing single skin URM walls subject to one-way vertical bending considering unit-to-unit spatial variability of flexural bond strength. We characterise the probability distributions of wall strength and examine how spatial variability in unit flexural bond strength affects the variability of base cracking load, mid-height cracking load, peak load and behaviour of clay brick URM walls. This is done using 3-D non-linear Finite Element Analyses (FEA) and stochastic analysis in the form of Monte Carlo simulations. Varying COVs (0.1, 0.3 and 0.5) of unit flexural bond strength are considered. The mean and variance of wall strength are estimated to show the effect of spatial variability of flexural bond strength on wall strength. The failure modes of the wall are compared to show the significant differences between non-spatial and spatial analyses. © 2013.
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Nova |
2014 |
Peng L, Stewart MG, 'Spatial time-dependent reliability analysis of corrosion damage to RC structures with climate change', Magazine of Concrete Research, 66 1154-1169 (2014) [C1]
The environment around concrete structures may be influenced by a changing climate, especially in the long run, leading to an acceleration of deterioration. Therefore, the safety,... [more]
The environment around concrete structures may be influenced by a changing climate, especially in the long run, leading to an acceleration of deterioration. Therefore, the safety, serviceability and durability of concrete infrastructure may decline at a faster rate than expected. Carbonation-induced deterioration to concrete structures constructed in Sydney, Australia and Kunming, China under a changing climate is investigated in this paper. Two emissions scenarios are considered - RCP 8.5 and RCP 4.5, representing high and medium greenhouse gas emissions scenarios respectively. The spatial time-dependent reliability analysis includes time-dependent climate scenarios and deterioration processes, as well as a large number of random variables and spatial random fields of material properties and dimensions. The surface of concrete structures is discretised into a large number of elements and the likelihood and extent of corrosion damage is calculated by tracking the evolution of the corrosion process of each element using Monte Carlo simulations. The results show that a changing climate could cause the extent of damage to increase by up to 6% for reinforced concrete infrastructure in Kunming. The findings may be used to assess climate adaptation measures in the design stage, as well as a cost-benefit analysis of climate adaptation measures.
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Nova |
2014 |
Stewart MG, Mueller J, 'Cost-benefit analysis of airport security: Are airports too safe?', JOURNAL OF AIR TRANSPORT MANAGEMENT, 35 19-28 (2014) [C1]
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Nova |
2014 |
Peng L, Stewart Mark G, 'Climate change effects on carbonation-induced corrosion and damage risks of RC infrastructure in China', Tumu Gongcheng Xuebao/China Civil Engineering Journal, 47 61-69 (2014) [C1]
Climate change may increase atmospheric CO2 concentration and temperature, change relative humidity (RH), and consequently change RC infrastructures' surrounding environment.... [more]
Climate change may increase atmospheric CO2 concentration and temperature, change relative humidity (RH), and consequently change RC infrastructures' surrounding environment. Especially in the long run, the decline of the safety, serviceability and durability of RC structures may be accelerated. Carbonation induced corrosion damage of RC infrastructure in Xiamen and Shaoguan under a changing climate is investigated for time period 2010~2100. The projection of atmospheric CO2 concentration, temperature and RH in both cities are based on the representative concentration pathways (RCPs). The time-dependent reliability analysis was conducted by Monte Carlo simulation and includes the uncertainty of dimensions, material properties, climate projections, and predictive models. The corrosion damage risks of RC structures are represented by the probability of severe cracking of concrete cover. Results show that climate change may increase mean carbonation depth by 8 mm by 2100. Moreover, carbonation-induced damage risk for RC buildings in temperate areas can be increased by 12%~19%. This research provides a reference for impacts of future climate change on RC structures and development of climate adaptation strategies.
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Nova |
2014 |
Peng L, Stewart MG, 'Climate change and corrosion damage risks for reinforced concrete infrastructure in China', Structure and Infrastructure Engineering, (2014)
A changing climate which leads to increases in atmospheric CO2 concentration, and changes in temperature and relative humidity (RH), especially in the longer term, will accelerate... [more]
A changing climate which leads to increases in atmospheric CO2 concentration, and changes in temperature and relative humidity (RH), especially in the longer term, will accelerate the deterioration processes and consequently decline the safety, serviceability and durability of reinforced concrete (RC) infrastructure. This paper presents an investigation of carbonation-induced deterioration in three typical Chinese cities (Kunming, Xiamen and Jinan) under a changing climate. The changing trends of atmospheric CO2, local temperature and RH of typical Chinese cities are projected based on the latest CO2 emission scenarios. The time-dependent analysis is based on Monte Carlo simulation, and includes the uncertainty of climate projections, deterioration processes, material properties, dimensions and accuracy of predictive models. Deterioration of RC structures is represented by the probabilities of reinforcement corrosion initiation and damage. It was found that the mean carbonation depths by 2100 may increase by up to 45% for RC structures in China due to a changing climate. It was also found that climate change can cause an additional 7-20% of carbonation-induced damage by 2100 for RC buildings in temperate or cold climate areas in China. The findings provide a basis for the development of climate adaptation strategies through the improved design of concrete structures. © 2014 © 2014 Taylor & Francis.
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2014 |
Mueller J, Stewart MG, 'Terrorism and counterterrorism in the US: the question of responsible policy-making', International Journal of Human Rights, 18 228-240 (2014) [C1]
Officials serving the public are tasked at the most fundamental level to spend funds in a manner that most effectively and efficiently keeps people safe. To do otherwise is irresp... [more]
Officials serving the public are tasked at the most fundamental level to spend funds in a manner that most effectively and efficiently keeps people safe. To do otherwise is irresponsible and, because human lives are at stake, immoral. In the case of counterterrorism policy-making, it is important to evaluate the degree to which any gains in security afforded by counterterrorism measures have been great enough to justify their cost. Risk analysis is an aid to responsible decision-making that does exactly that. We deal with four issues central to this approach, applying them to the hazard presented by terrorism: the cost per saved life, acceptable risk, cost-benefit analysis, and risk communication. We also assess the degree to which risk analysis has been coherently applied to counterterrorism efforts in the US in making or evaluating decisions that have cost taxpayers many hundreds of billions of dollars over the past dozen years. © 2014 Taylor & Francis.
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Nova |
2014 |
Stewart MG, Wang X, Willgoose GR, 'Direct and indirect cost-and-benefit assessment of climate adaptation strategies for housing for extreme wind events in Queensland', Natural Hazards Review, 15 (2014) [C1]
The intensity of tropical cyclones and severe storms is likely to increase due to climate change. Brisbane and the northeast coast of Queensland are regions where design wind spec... [more]
The intensity of tropical cyclones and severe storms is likely to increase due to climate change. Brisbane and the northeast coast of Queensland are regions where design wind specifications may be inadequate under either current or likely future climate conditions. An appropriate adaptation strategy may be one that increases wind classifications for new houses, which leads to a reduced vulnerability of new construction. The present paper will assess the damage risks, adaptation costs, and cost-effectiveness of these adaptation measures for residential construction in Cairns, Townsville, Rockhampton, and South East Queensland, assuming time-dependent changes in the frequency and intensity of cyclonic and noncyclonic winds to 2100. Loss functions are also developed for direct and indirect losses. It was found that increasing design wind loads for new houses in Brisbane and South East Queensland will lead to a net benefit [net present value (NPV)] of up to $10.5 billion by 2100, assuming a discount rate of 4%, which includes approximately 95% of a direct benefit and 5% of an indirect benefit. The benefits are highest for Brisbane due to its large population and the high vulnerability of existing residential construction, and have a 90-100% likelihood of achieving a net benefit by 2100.
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Nova |
2014 |
Bjarnadottir S, Li Y, Stewart MG, 'Risk-based economic assessment of mitigation strategies for power distribution poles subjected to hurricanes', Structure and Infrastructure Engineering, 10 740-752 (2014) [C1]
This paper presents a risk-based framework to assess the hurricane damage risks to distribution poles, and investigates the risks, costs and benefit of different mitigation strate... [more]
This paper presents a risk-based framework to assess the hurricane damage risks to distribution poles, and investigates the risks, costs and benefit of different mitigation strategies. It is estimated that power outages due to storms cause approximately $270 million in repair/replacement costs annually in the USA. Hurricane Irene alone left approximately 6 million residents without power along the east coast of the USA in 2011, causing an estimated $5-$7 billion in damages. These high repair/replacement costs warrant an investigation of mitigation strategies that may aid in reducing replacement and damage costs. This paper describes the reliability analysis of typical timber distribution poles and probabilistic wind models to determine failure probabilities for specific locations. Furthermore, in order to more accurately portray the behaviour of distribution poles, the proposed framework includes the degradation and service-proven reliability of timber distribution poles. Four mitigation strategies are developed, and the cost effectiveness of each strategy is evaluated. In order to assess the cost effectiveness, a life cycle cost analysis is conducted for each mitigation strategy. This paper finds that appropriate mitigation strategies can reduce replacement costs of distribution poles associated with hurricane wind by 2060. © 2013 © 2013 Taylor & Francis.
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Nova |
2014 |
Bjarnadottir S, Li Y, Stewart MG, 'Regional loss estimation due to hurricane wind and hurricane-induced surge considering climate variability', Structure and Infrastructure Engineering, 10 1369-1384 (2014) [C1]
This paper presents a framework to assess the potential hurricane damage risks to residential construction. Studies show that hurricane wind, frequency and/or hurricane-induced su... [more]
This paper presents a framework to assess the potential hurricane damage risks to residential construction. Studies show that hurricane wind, frequency and/or hurricane-induced surge may change as a result of climate change; therefore, hurricane risk assessments should be capable of accounting for the impacts climate change. The framework includes a hurricane wind field model, hurricane-induced surge height model and hurricane vulnerability models. Three case study locations (Miami-Dade County, FL; New Hanover County, NC and Galveston County, TX) are presented for two types of analyses: annual regional loss estimation and event-based regional loss estimation. Demographic information, such as median house value and changes in house numbers, and distribution of houses for different exposures, is used to estimate the time-dependent probability of damage with or without possible climate change-induced change in wind speed, frequency and/or surge height. Through both analyses, it was found that climate change may have a significant impact on regional hurricane damage losses.
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Nova |
2014 |
Stewart MG, Mueller J, 'Terrorism risks for bridges in a multi-hazard environment', International Journal of Protective Structures, 5 275-289 (2014) [C1]
The paper will assess terrorist threats to new and existing bridges and the cost-effectiveness of protective counter-terrorism measures. This analysis will consider threat likelih... [more]
The paper will assess terrorist threats to new and existing bridges and the cost-effectiveness of protective counter-terrorism measures. This analysis will consider threat likelihood, cost of security measures, risk reduction and expected losses to compare the costs and benefits of protective measures to bridges to decide which protective measures are cost-effective. In this paper, a break-even cost-benefit analysis determines the minimum probability of an attack, absent the protective measures, that is required for the benefit of the protective measures to equal their cost for new and existing bridges. It was found that unless terrorist threat probabilities are high, then typical protective measures are not cost-effective. Bridges and other critical infrastructure are subject to a range of natural and man-made hazards, and terrorism is most likely not as important a threat as natural hazards. It was found that economic risks to bridges from floods, earthquakes, and ship impact are higher than threats from terrorism.
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Nova |
2014 |
Ryan PC, Stewart MG, Spencer N, Li Y, 'Reliability assessment of power pole infrastructure incorporating deterioration and network maintenance', Reliability Engineering & System Safety, 132 261-273 (2014) [C1]
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Nova |
2013 |
Netherton MD, Stewart MG, 'What are some of the problems associated with the current methods of calculating explosive blast loads?', 10th International Conference on Shock and Impact Loads on Structures 2013, 65-74 (2013)
The most common methods for calculating explosive blast loads are deterministic; in that, the output will always be the same for given model-inputs. However, a statistical analysi... [more]
The most common methods for calculating explosive blast loads are deterministic; in that, the output will always be the same for given model-inputs. However, a statistical analysis of actual explosive blast loading field (test) data reveals a high level of variability of peak reflected pressure, impulse and time of positive phase duration from repeated tests where variability would be expected to be a minimum. Given that blast-loads from similar events are highly variable, and that the most common blast-load models do not account for such circumstances, the question we should now be asking is this: How can we improve our methods for predicting blast loads, such that (known) variability and uncertainty is appropriately considered, to ensure that we continue to give useful, usable and robust information to decision makers? In other words: What exactly is the best available method for giving your Boss advice on the risks associated with explosive blast loads? This paper explores the deterministic nature of commonly used blast-load models and discusses their limitations with respect to matters such as: explosive safety distances, the design loads on protective structures and the military's deliberate use of munitions. We argue that deterministic models do not adequately account for society's usual acceptance (or rejection) of the risks associated with damage and/or injury. A new probabilistically based blast-load model is developed which does take into account the observed (and very real) variability of explosive blast loads. Following which, new forms of risk-based advice are presented. This new probabilistic blast-load model uses statistical and probabilistic information taken from the literature as well as from our own explosive trials. Explosive scenarios of future interest could be from blast-loads resulting from (possible) terrorist activity, or, from current in-service military munitions. In either case, we argue that these new forms of risk-based advice (eg: the most probable blast-load or cost-effective mitigation) provides additional - and unique - utility for decision makers involved in the production, storage and operational use of explosives. The paper concludes with a discussion on how the new probabilistic blast-loading model can improve a decision maker's confidence with respect to explosive safety distances, magazine design, protective structures design, weaponeering and collateral damage estimation.
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2013 |
Bastidas-Arteaga E, Schoefs F, Stewart MG, Wang X, 'Influence of global warming on durability of corroding RC structures: A probabilistic approach', ENGINEERING STRUCTURES, 51 259-266 (2013) [C1]
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Nova |
2013 |
Stewart MG, Mueller J, 'Terrorism Risks and Cost-Benefit Analysis of Aviation Security', RISK ANALYSIS, 33 893-908 (2013) [C1]
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Nova |
2013 |
Stewart MG, Mueller J, 'Aviation Security, Risk Assessment, and Risk Aversion for Public Decisionmaking', JOURNAL OF POLICY ANALYSIS AND MANAGEMENT, 32 615-+ (2013) [C1]
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Nova |
2013 |
Stewart MG, O'Callaghan D, Hartley M, 'Review of QTRA and risk-based cost-benefit assessment of tree management', Arboriculture and Urban Forestry, 39 165-172 (2013) [C1]
Quantified Risk Assessment (QRA) has been in wide use in risk management since the 1960s for systems ranging from aviation, nuclear power, and offshore platforms to medical treatm... [more]
Quantified Risk Assessment (QRA) has been in wide use in risk management since the 1960s for systems ranging from aviation, nuclear power, and offshore platforms to medical treatment and pharmaceuticals. The Quantified Tree Risk Assessment (QTRA) system is examined considering the principles of QRA. A case study of 14 fig trees in Newcastle, Australia, illustrates some limitations of the QTRA process, and extrapolating risks for a single tree to a group of trees. There is a need for any risk management process involving trees, not only to assess the risk, but to weigh the benefits provided by trees by a risk-based cost-benefit analysis. Tree risk assessors should rely on benchmarks to ensure that their assessment is not outside of the realms of reality or scientific rigor. © 2013 International Society of Arboriculture.
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Nova |
2013 |
Bjarnadottir S, Li Y, Stewart MG, 'Hurricane Risk Assessment of Power Distribution Poles Considering Impacts of a Changing Climate', JOURNAL OF INFRASTRUCTURE SYSTEMS, 19 12-24 (2013) [C1]
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Nova |
2012 |
Chernin L, Val DV, Stewart MG, 'Prediction of cover crack propagation in RC structures caused by corrosion', Magazine of Concrete Research, 64 95-111 (2012) [C1]
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Nova |
2012 |
Oven KJ, Curtis SE, Reaney S, Riva M, Stewart MG, Ohlemuller R, et al., 'Climate change and health and social care: Defining future hazard, vulnerability and risk for infrastructure systems supporting older people's health care in England', Applied Geography, 33 16-24 (2012) [C1]
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Nova |
2012 |
Mueller J, Stewart MG, 'The terrorism delusion: America's overwrought response to September 11', International Security, 37 81-110 (2012) [C1]
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Nova |
2012 |
Stewart MG, Wang X, Nguyen MN, 'Climate change adaptation for corrosion control of concrete infrastructure', Structural Safety, 35 29-39 (2012) [C1]
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Nova |
2012 |
Mueller J, Stewart MG, 'Civil liberties, fear and terrorism', Notre Dame Journal of International and Comparative Law, 3 282-288 (2012) [C2] |
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2012 |
Stewart MG, O'Connor A, 'Probabilistic risk assessment and service life performance management of load bearing biomedical implants', Reliability Engineering and System Safety, 108 49-55 (2012) [C1]
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Nova |
2012 |
Zhai X, Zhong Z, Stewart MG, 'Structural reliability for reinforced concrete block masonry walls in shear force', Journal of Harbin Engineering University, 33 313-319 (2012) [C2]
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2012 |
Mullard JA, Stewart MG, 'Life-cycle cost assessment of maintenance strategies for RC structures in chloride environments', Journal of Bridge Engineering, 17 353-362 (2012) [C1]
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Nova |
2012 |
Stewart MG, Netherton MD, Shi Y, Grant M, Mueller J, 'Probabilistic terrorism risk assessment and risk acceptability for infrastructure protection', Australian Journal of Structural Engineering, 13 1-17 (2012) [C1]
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Nova |
2012 |
Correa MRS, Masia MJ, Stewart MG, Heffler LM, 'An experimental and statistical analysis of the flexural bond strength of masonry walls', Australian Journal of Structural Engineering, 13 139-148 (2012) [C1]
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Nova |
2012 |
Stewart MG, Hao H, 'Security and protective structures research in Australia', Australian Journal of Structural Engineering, 13 i (2012) [C6] |
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2012 |
Zhai X, Zhong Z, Stewart MG, 'Model error and structural reliability for reinforced concrete block masonry walls in shear', Advances in Structural Engineering, 15 389-398 (2012) [C1]
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Nova |
2012 |
Stewart MG, 'Spatial and time-dependent reliability modelling of corrosion damage, safety and maintenance for reinforced concrete structures', Structure and Infrastructure Engineering, 8 607-619 (2012) [C1]
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Nova |
2012 |
Grant MJ, Stewart MG, 'A systems model for probabilistic risk assessment of improvised explosive device attacks', International Journal of Intelligent Defence Support Systems, 5 75-93 (2012) [C1] |
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Nova |
2011 |
Li Y, Stewart MG, 'Cyclone damage risks caused by enhanced greenhouse conditions and economic viability of strengthened residential construction', Natural Hazards Review, 12 9-18 (2011) [C1]
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Nova |
2011 |
Stewart MG, Mueller J, 'Cost-benefit analysis of advanced imaging technology full body scanners for airline passenger security screening', Journal of Homeland Security and Emergency Management, 8 1-18 (2011) [C1]
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Nova |
2011 |
Mueller J, Stewart MG, 'Balancing the risks, benefits, and costs of Homeland Security', Homeland Security Affairs, 7 16 (2011) [C1] |
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Nova |
2011 |
Stewart MG, 'Life-safety risks and optimisation of protective measures against terrorist threats to infrastructure', Structure and Infrastructure Engineering: Maintenance, Management, Life-Cycle Design and Performance, 7 431-440 (2011) [C1]
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Nova |
2011 |
Mueller J, Stewart MG, 'Witches, communists and terrorists: Evaluating the risks and tallying the costs', Human Rights, 38 20-22 (2011) [C3] |
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2011 |
Al-Harthy AS, Stewart MG, Mullard J, 'Concrete cover cracking caused by steel reinforcement corrosion', Magazine of Concrete Research, 63 655-667 (2011) [C1]
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Nova |
2011 |
Mueller J, Stewart MG, 'The price is not right: The U.S. spends too much money to fight terrorism', Playboy, 58 149-150 (2011) [C3] |
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2011 |
Stewart MG, Wang X, Nguyen MN, 'Climate change impact and risks of concrete infrastructure deterioration', Engineering Structures, 33 1326-1337 (2011) [C1]
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Nova |
2011 |
Wang X, Stewart MG, Nguyen M, 'Impact of climate change on corrosion and damage to concrete infrastructure in Australia', Climatic Change, 110 941-957 (2011) [C1]
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Nova |
2011 |
Bjarnadottir S, Li Y, Stewart MG, 'A probabilistic-based framework for impact and adaptation assessment of climate change on hurricane damage risks and costs', Structural Safety, 33 173-185 (2011) [C1]
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Nova |
2011 |
Mullard JA, Stewart MG, 'Corrosion-induced cover cracking: New test data and predictive models', ACI Structural Journal, 108 71-79 (2011) [C1]
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Nova |
2011 |
Bjarnadottir S, Li Y, Stewart MG, 'Social vulnerability index for coastal communities at risk to hurricane hazard and a changing climate', Natural Hazards, 59 1055-1075 (2011) [C1]
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Nova |
2011 |
Lawrence S, Stewart MG, 'Model error and structural reliability for unreinforced masonry walls in vertical bending', Masonry International, 24 23-30 (2011) [C1] |
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Nova |
2011 |
Stewart MG, Lawrence S, 'When buildings are too safe', MATERIALS WORLD, 19 30-31 (2011) [O1] |
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2011 |
Stewart MG, Mueller J, 'Assessing the risks, costs, and benefits of counter-terrorism protective measures for infrastructure', The CIP Report, 10 3-5, 31 (2011) [C3] |
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2011 |
Stewart MG, Ellingwood BR, Mueller J, 'Homeland security: A case study in risk aversion for public decision-making', International Journal of Risk Assessment and Management, 15 367-386 (2011) [C1]
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Nova |
2010 |
Stewart MG, 'Risk-informed decision support for assessing the costs and benefits of counter-terrorism protective measures for infrastructure', International Journal of Critical Infrastructure Protection, 3 29-40 (2010) [C1]
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Nova |
2010 |
Hao H, Stewart MG, Zhong-Xian L, Shi Y, 'RC column failure probabilities to blast loads', International Journal of Protective Structures, 1 571-591 (2010) [C1]
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Nova |
2010 |
Netherton MD, Stewart MG, 'Blast Load Variability and Accuracy of Blast Load Prediction Models', International Journal of Protective Structures, 1 543-570 (2010) [C1]
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Nova |
2010 |
Stewart MG, 'Acceptable Risk Criteria for Infrastructure Protection', International Journal of Protective Structures, 1 23-40 (2010) [C1]
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Nova |
2010 |
Mueller J, Stewart MG, 'Hardly existential: Thinking rationally about terrorism', Foreign Affairs, 1-5 (2010) [C2] |
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2010 |
Zhai X, Stewart MG, 'Structural reliability analysis of reinforced grouted concrete block masonry walls in compression', Engineering Structures, 32 106-114 (2010) [C1]
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Nova |
2010 |
Wei X, Stewart MG, 'Model validation and parametric study on the blast response of unreinforced brick masonry walls', International Journal of Impact Engineering, 37 1150-1159 (2010) [C1]
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Nova |
2010 |
Stewart MG, 'Reliability safety assessment of corroding reinforced concrete structures based on visual inspection information', ACI Structural Journal, 107 671-679 (2010) [C1]
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Nova |
2010 |
Stewart MG, Peng J, 'Life cycle cost assessment of climate change adaptation measures to minimise carbonation-induced corrosion risks', International Journal of Engineering Under Uncertainty: Hazards, Assessment and Mitigation, 2 35-46 (2010) [C2] |
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Nova |
2010 |
Stewart MG, Li Y, 'Methodologies for economic impact and adaptation assessment of cyclone damage risks due to climate change', Australian Journal of Structural Engineering, 10 121-135 (2010) [C1]
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Nova |
2009 |
Stewart M, Reid S, 'Disaster & hazard mitigation', Australian Journal of Structural Engineering, 9 (2009) |
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2009 |
Stewart MG, Suo Q, 'Extent of spatially variable corrosion damage as an indicator of strength and time-dependent reliability of RC beams', Engineering Structures, 31 198-207 (2009) [C1]
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Nova |
2009 |
Stewart MG, 'Mechanical behaviour of pitting corrosion of flexural and shear reinforcement and its effect on structural reliability of corroding RC beams', Structural Safety, 31 19-30 (2009) [C1]
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Nova |
2009 |
Netherton MD, Stewart MG, 'Probabilistic modelling of safety and damage blast risks for window glazing', Canadian Journal of Civil Engineering, 36 1321-1331 (2009) [C1]
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Nova |
2009 |
Val DV, Chemin L, Stewart MG, 'Experimental and numerical investigation of corrosion-induced cover cracking in reinforced concrete structures', Journal of Structural Engineering, 135 376-385 (2009) [C1]
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Nova |
2009 |
Mullard JA, Stewart MG, 'Stochastic assessment of timing and efficiency of maintenance for corroding RC structures', Journal of Structural Engineering, 135 887-895 (2009) [C1]
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Nova |
2009 |
Netherton MD, Stewart MG, 'The effects of explosive blast load variability on safety hazard and damage risks for monolithic window glazing', International Journal of Impact Engineering, 36 1346-1354 (2009) [C1]
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Nova |
2009 |
Suo Q, Stewart MG, 'Corrosion cracking prediction updating of deteriorating RC structures using inspection information', Reliability Engineering & System Safety, 94 1340-1348 (2009) [C1]
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Nova |
2009 |
Val DV, Stewart MG, 'Reliability assessment of ageing reinforced concrete structures: Current situation and future challenges', Structural Engineering International, 19 211-219 (2009) [C1]
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Nova |
2009 |
Stewart MG, Reid S, 'Preface: Disaster & hazard mitigation', Australian Journal of Structural Engineering, 9 i (2009) [C3] |
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Nova |
2009 |
Lawrence S, Stewart MG, 'Reliability-based calibration of the capacity reduction factor for design of masonry in compression to AS3700', Australian Journal of Structural Engineering, 9 97-110 (2009) [C1]
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Nova |
2008 |
Stewart MG, Mueller J, 'A risk and cost-benefit assessment of Australian aviation security measures', Security Challenges, 4 45-61 (2008) [C1]
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Nova |
2008 |
Stewart MG, Mueller J, 'A risk and cost-benefit assessment of United States aviation security measures', Journal of Transportation Security, 1 143-159 (2008) [C1]
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Nova |
2008 |
Stewart MG, O'Rourke A, 'Probabilistic risk assessment of mine subsidence', Australian Geomechanics, 43 1-12 (2008) [C1]
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Nova |
2008 |
Stewart MG, 'Cost effectiveness of risk mitigation strategies for protection of buildings against terrorist attack', Journal of Performance of Constructed Facilities, 22 115-120 (2008) [C1]
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Nova |
2008 |
Heffler LM, Stewart MG, Masia MJ, Correa MRS, 'Statistical analysis and spatial correlation of flexural bond strength for masonry walls', Masonry International: Journal of the International Masonry Society, 21 59-70 (2008) [C1]
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Nova |
2008 |
Stewart MG, Al-Harthy A, 'Pitting corrosion and structural reliability of corroding RC structures: Experimental data and probabilistic analysis', Reliability Engineering & System Safety, 93 373-382 (2008) [C1]
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Nova |
2008 |
Stewart MG, Netherton MD, 'Security risks and probabilistic risk assessment of glazing subject to explosive blast loading', Reliability Engineering and System Safety, 93 627-638 (2008) [C1]
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Nova |
2008 |
Stewart MG, 'Risk acceptability and cost-effectiveness of protective measures against terrorist threats to built infrastructure considering multiple threat scenarios', Transactions of Tianjin University, 14 313-317 (2008) [C1]
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Nova |
2007 |
Stewart MG, Lawrence S, 'Model error, structural reliability and partial safety factors for structural masonry in compression', Journal of the British Masonry Society Masonry International, 20 107-116 (2007) [C1] |
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2007 |
Stewart MG, Mullard JA, Drake BJ, Al-Harthy AS, 'Utility of spatially variable damage performance indicators for improved safety and maintenance decisions of deteriorating infrastructure', Civil Engineering and Environmental Systems, 24 149-163 (2007) [C1]
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2007 |
Darmawan MS, Stewart MG, 'Effect of pitting corrosion on capacity of prestressing wires', Magazine of Concrete Research, 59 131-139 (2007) [C1]
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2007 |
Stewart MG, Mullard JA, 'Spatial time-dependent reliability analysis of corrosion damage and the timing of first repair for RC structures', Engineering Structures, 29 1457-1464 (2007) [C1]
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2007 |
Darmawan MS, Stewart MG, 'Spatial time-dependent reliability analysis of corroding pretensioned prestressed concrete bridge girders', Structural Safety, 29 16-31 (2007) [C1]
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2006 |
Stewart MG, 'Risk assessment and optimization of blast mitigation strategies for design and strengthening of built infrastructure', Transactions of Tianjin University, 12 8-15 (2006) [C1]
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Nova |
2006 |
Darmawan MS, Stewart MG, 'Effect of spatially variable pitting corrosion on structural reliability of prestressed concrete bridge girders', Australian Journal of Structural Engineering, 6 147-158 (2006) [C1]
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2006 |
Stewart MG, Netherton MD, 'Performance, reliability and security risks of glazing subject to explosive blast loading', Australian Journal of Structural Engineering, 7 23-36 (2006) [C1] |
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2006 |
Stewart MG, Netherton MD, Rosowsky DV, 'Terrorism risks and blast damage to built infrastructure', Natural Hazards Review, 7 114-122 (2006) [C1]
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Nova |
2006 |
Stewart MG, 'Spatial variability of damage and expected maintenance costs for deteriorating RC structures', Structure and Infrastructure Engineering, 2 79-90 (2006) [C1]
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Nova |
2006 |
Stewart MG, Mullard JA, 'Reliability based assessment of the influence of concrete durability on the timing of repair for RC bridges', Proceedings of the 3rd International Conference on Bridge Maintenance, Safety and Management - Bridge Maintenance, Safety, Management, Life-Cycle Performance and Cost, 519-520 (2006)
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2005 |
Tolhurst HM, Stewart MG, 'Becoming a GP a qualitative study of the career interests of medical students', Australian Family Physician, 34 204-206 (2005) [C1]
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2005 |
Vu KAT, Stewart MG, 'Predicting the likelihood and extent of reinforced concrete corrosion-induced cracking', Journal of Structural Engineering, 131 1681-1689 (2005) [C1]
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2005 |
Stewart MG, Love A, 'Uncertainty, Economic Risk Analysis And Risk Acceptance Criteria For Mine Subsidence', Australian Geomechanics, 40 79-89 (2005) [C1]
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2005 |
Vu K, Stewart MG, Mullard JA, 'Corrosion-induced cracking: Experimental data and predictive models', ACI Structural Journal, 102 719-726 (2005) [C1]
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Nova |
2005 |
Val DV, Stewart MG, 'Decision analysis for deteriorating structures', Reliability Engineering & System Safety, 87 377-385 (2005) [C1]
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2004 |
Stewart MG, 'Spatial Variability Of Pitting Corrosion And Its Influence On Structural Fragility And Reliability Of RC Beams In Flexure', Structural Safety, Vol. 26 453-470 (2004) [C1]
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2004 |
Stewart MG, Estes AC, Frangopol DM, 'Bridge Deck Replacement For Minimum Expected Cost Under Multiple Reliability Constraints', Journal of Structural Engineering, Vol. 130 1414-1419 (2004) [C1]
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2004 |
Epaarachchi DC, Stewart MG, 'Human Error And Reliability Of Multistory Reinforced-Concrete Building Construction', Journal of Performance of Constructed Facilities, 18 12-20 (2004) [C1]
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2004 |
Stewart MG, 'Risk Assessment As A Decision-Making Tool To Mitigate Blast Damage To Built Infrastructure', Australian Journal of Multi-Disciplinary Engineering, Not Known 1-11 (2004) [C1] |
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2004 |
Epaarachchi DC, Stewart MG, 'Human Error and Reliability of Multistory Reinforced-Concrete Building Construction', Journal of Performance of Constructed Facilities, 18 12-20 (2004)
This paper develops probabilistic and human reliability models to estimate the probability of structural collapse (system risk) during the construction of typical multistory reinf... [more]
This paper develops probabilistic and human reliability models to estimate the probability of structural collapse (system risk) during the construction of typical multistory reinforced-concrete buildings in the presence of human error. Results obtained from the human reliability analysis suggest that errors related to concrete cover and concreting workmanship are more detrimental to system risk than any other errors. Errors related to reinforcement area have a minor effect on system risk, provided that the existing effectiveness of engineering inspections is maintained. The results also show that errors related to installation of steel shores/reshores do not significantly affect the system risk. © 2004
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2003 |
Stewart MG, Rosowsky DV, Huang Z, 'Hurricane Risks And Economic Viability Of Strengthened Construction', Natural Hazards Review, Vol. 4 12-19 (2003) [C1]
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2003 |
Val DV, Stewart MG, 'Life-Cycle Cost Analysis Of Reinforced Concrete Structures In Marine Environments', Structural Safety, 25 343-362 (2003) [C1]
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2003 |
Stewart MG, 'Cyclone Damage And Temporal Changes To Building Vulnerablity And Economic Risks For Residential Construction', Journal Of Wind Engineerng And Industrial Aerodynamics, Vol. 91 671-691 (2003) [C1]
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2003 |
Faber M, Stewart MG, 'Risk Assessment For Civil Engineering Facilities: Critical Overview And Discussion', Reliability Engineering and System Safety, Vol. 80 173-184 (2003) [C1]
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2003 |
Stewart MG, Val DV, 'Multiple Limit States And Expected Failure Costs For Deteriorating Reinforced Concrete Bridges', Journal Of Bridge Engineering, Vol. 8 405-415 (2003) [C1]
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2002 |
Epaarachchi DC, Stewart MG, Rosowsky DV, 'Structural Reliability of Multistory Buildings During Construction', Journal of Structural Engineering, Vol. 128, No. 2 205-213 (2002) [C1]
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2002 |
Val DV, Stewart MG, 'Safety Factors For Assessment of Existing Structures', Journal of Structural Engineering, Vol. 128, No. 2 258-265 (2002) [C1]
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2002 |
Stewart MG, Lawrence S, 'Structural Reliability of Masonry Walls in Flexure', Masonry International, Vol. 15, No. 2 48-52 (2002) [C1] |
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2002 |
Pukl R, Teply B, Novak D, Stewart MG, 'Modeling Of Precast Prestressed Bridge Girder Under Corrosion Attack', Beton TKS, 3/2002 5 (2002) [C3] |
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2002 |
Hossain NB, Stewart MG, 'Serviceability Reliability and Expected Costs of RC Beams Designed to Serviceability Specifications of AS3600', Australian Journal of Structural Engineering, Vol. 4, No. 1 17-27 (2002) [C1] |
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2001 |
Khor EH, Rosowsky DV, Stewart MG, 'Probabilistic analysis of time-dependent deflections of RC flexural members', Computers & Structures, 79 1461-1472 (2001) [C1]
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2001 |
Stewart MG, Rosowsky DV, Val DV, 'Reliability-based bridge assessment using risk-ranking decision analysis', Structural Safety, 23 397-405 (2001) [C1]
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2001 |
Stewart MG, 'Effect of Construction and Service Loads on Reliability of Existing RC Buildings', Journal of Structural Engineering, 127 1232-1235 (2001) [C1]
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2001 |
Rosowsky DV, Stewart MG, 'Probabilistic Construction Load Model for Multistory Reinforced-Concrete Buildings', Journal of Performance of Constructed Facilities, 15 145-152 (2001) [C1]
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2001 |
Hossain NB, Stewart MG, 'Probabilistic Models of Damaging Deflections for Floor Elements', Journal of Performance of Constructed Facilities, 15 135-140 (2001) [C1]
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2001 |
Stewart MG, 'Reliability-based assessment of ageing bridges using risk ranking and life cycle cost decision analyses', Reliability Engineering & System Safety, 74 263-273 (2001) [C1]
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2000 |
Faber MH, Val DV, Stewart MG, 'Proof load testing for bridge assessment and upgrading', Engineering Structures, Vol 22 1677-1689 (2000) [C1]
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2000 |
Vu KAT, Stewart MG, 'Structural reliability of concrete bridges including improved chloride-induced corrosion models', Structural Safety, Vol 22 313-333 (2000) [C1]
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2000 |
Rosowsky DV, Stewart MG, Khor EH, 'Early-Age Loading and Long-Term Deflections of Reinforced Concrete Beams', ACI Structural Journal, No.97, No. 3 517-524 (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 |
Epaarachchi DC, Stewart MG, Rosowsky DV, 'Design, Workmanship and System Risk of Multi-Storey Buildings During Construction', Australian Journal of Structural Engineering, Vol. 3 Nos. 1& 2 43-53 (2000) [C1] |
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2000 |
Stewart MG, 'Risk-based optimisation of repair strategies for concrete structures considering life-cycle cost analysis', Concrete in Australia, Vol 26, No. 2 21-25 (2000) [C3] |
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1999 |
Stewart MG, Val DV, 'Role of load history in reliability-based decision analysis of aging bridges', Journal of Structural Engineering, July 1999 776-783 (1999) [C1]
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1999 |
Stewart MG, Attard MM, 'Model Errors and Structural Reliability for High Strength Concrete Column Design', Australian Journal of Structural Engineering, Vol. SE1, No. 3 167-177 (1999) [C1] |
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1999 |
Stewart MG, Attard MM, 'Reliability and model accuracy for high-strength concrete column design', Journal of Structural Engineering, March 1999 290-300 (1999) [C1]
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1998 |
Attard MM, Stewart MG, 'A Two Parameter Stress Block for High-Strength Concrete', ACI Structural Journal, VOl. 95, No. 3 305-317 (1998) [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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1998 |
Stewart MG, Rosowksy DV, 'Structural Safety and Serviceability of Concrete Bridges subject to corrosion', Journal of Infrastructure Systems, Vol. 4 146-155 (1998) [C1]
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1998 |
Stewart MG, 'Reliability-based bridge design and assessment', Progress in Structural Engineering and Materials, Vol. 1 No. 2 214-222 (1998) [C1] |
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1998 |
Stewart MG, Rosowsky DV, 'Time-dependent reliability of deteriorating reinforced concrete bridge decks', Structural Safety, Vol. 20 91-109 (1998) [C1]
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1997 |
Stewart MG, 'Time-dependent reliability of existing RC structures', JOURNAL OF STRUCTURAL ENGINEERING-ASCE, 123 896-902 (1997)
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1997 |
Stewart MG, 'Concreting workmanship and its influence on serviceability reliability', ACI MATERIALS JOURNAL, 94 501-509 (1997)
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1996 |
Stewart MG, 'Optimization of serviceability load combinations for structural steel beam design', STRUCTURAL SAFETY, 18 225-238 (1996)
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1996 |
Stewart MG, 'Optimization of serviceability load combinations for structural steel beam design', Structural Safety, 18 225-238 (1996)
In Australia, typical design load combinations for serviceability are ¿sQ and G + ¿sQ (D and D + L in the US) where G and Q are design dead and live loads, respectively, and ¿s is... [more]
In Australia, typical design load combinations for serviceability are ¿sQ and G + ¿sQ (D and D + L in the US) where G and Q are design dead and live loads, respectively, and ¿s is a short-term live load factor. Code calibration is conducted herein for Australian and US serviceability load combinations, for structural steel beams in flexure. The effects that office, retail, domestic and car parking loads and tributary areas have on serviceability reliability is described. It was found that serviceability reliabilities for different floor uses vary considerably for Australian and US serviceability load combinations; whereas the differences between serviceability reliabilities for one year and duration of a single tenancy reference periods were not great. Short-term live load factors for most floor uses were adjusted (sometimes significantly) to ensure that serviceability reliabilities exceed the minimum target level of 1.65. Consequently, the present paper provides suggested values for short-term live load factors that may be used in Australian and possibly in US codes. Copyright © 1996 Elsevier Science Ltd.
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1995 |
STEWART MG, 'WORKMANSHIP AND ITS INFLUENCE ON PROBABILISTIC MODELS OF CONCRETE COMPRESSIVE STRENGTH', ACI MATERIALS JOURNAL, 92 361-372 (1995)
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1993 |
STEWART MG, 'STRUCTURAL RELIABILITY AND ERROR CONTROL IN REINFORCED-CONCRETE DESIGN AND CONSTRUCTION', STRUCTURAL SAFETY, 12 277-292 (1993)
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1993 |
STEWART MG, 'MODELING HUMAN-PERFORMANCE IN REINFORCED-CONCRETE BEAM CONSTRUCTION', JOURNAL OF CONSTRUCTION ENGINEERING AND MANAGEMENT-ASCE, 119 6-22 (1993)
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1992 |
STEWART MG, 'A HUMAN RELIABILITY-ANALYSIS OF REINFORCED-CONCRETE BEAM CONSTRUCTION', CIVIL ENGINEERING SYSTEMS, 9 227-247 (1992)
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1992 |
Stewart MG, 'Simulation of human error in reinforced concrete design', Research in Engineering Design, 4 51-60 (1992)
Available statistical data suggest that human error in design causes a significant proportion of performance failures; namely, structural failure, cost overruns, and delays. A Hum... [more]
Available statistical data suggest that human error in design causes a significant proportion of performance failures; namely, structural failure, cost overruns, and delays. A Human Reliability Analysis (HRA) model has been developed to simulate the effect of human error on the design computations of a reinforced concrete beam. The proposed HRA model incorporates the effect of "self-corrections"; this is a process where tasks are re-evaluated if the result appears to be not within "reasonable" expectations. Calculation, table look-up, chart look-up, and table ranking microtasks were incorporated into the proposed HRA model; human perormance data are described for each of these microtasks. It was found that human error, particularly multiple errors, lead to a significant loss of structural safety. © 1992 Springer-Verlag New York Inc.
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1992 |
STEWART MG, 'MODELING HUMAN ERROR RATES FOR HUMAN RELIABILITY-ANALYSIS OF A STRUCTURAL DESIGN TASK', RELIABILITY ENGINEERING & SYSTEM SAFETY, 36 171-180 (1992)
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1991 |
STEWART MG, 'PROBABILISTIC RISK ASSESSMENT OF QUALITY-CONTROL AND QUALITY ASSURANCE MEASURES IN STRUCTURAL DESIGN', IEEE TRANSACTIONS ON SYSTEMS MAN AND CYBERNETICS, 21 1000-1007 (1991)
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1991 |
STEWART MG, 'SAFE LOAD TABLES - A DESIGN AID IN THE PREVENTION OF HUMAN ERROR', STRUCTURAL SAFETY, 10 269-282 (1991)
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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 |
STEWART MG, MELCHERS RE, 'CHECKING MODELS IN STRUCTURAL DESIGN - CLOSURE', JOURNAL OF STRUCTURAL ENGINEERING-ASCE, 117 2188-2189 (1991)
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1991 |
Stewart MG, 'Human dimension and risk analysis in structural design', Transactions of the Institution of Engineers, Australia. Civil engineering, CE33 195-202 (1991)
The 'human dimension' is the unpredictable nature of human behaviour. In structural engineering tasks it can be shown that human errors result from this behaviour, for t... [more]
The 'human dimension' is the unpredictable nature of human behaviour. In structural engineering tasks it can be shown that human errors result from this behaviour, for the incidence of design error is a major cause of structural failure. A Probabilistic Risk Analysis (PRA) model has been developed to simulate the effects of human error on a typical design task. The design task considered is the design of a flexural member. A computer simulation technique and event-tree methods were employed. This model provides the basis for an investigation into the efficiency of two quality management measure; namely, (i) design checking and (ii) the use of safe load tables as a design aid. Comparisons between the efficiency of design checking and the use of safe load tables will be made. It is indicated that a designer using safe load tables (or similar design aids) will be more 'cost-effective' and less prone to error than designers not using such design aids.
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1990 |
STEWART MG, 'HUMAN ERROR IN STEEL BEAM DESIGN', CIVIL ENGINEERING SYSTEMS, 7 94-101 (1990)
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1990 |
Stewart MG, 'Prevention and control of human errors in structural design', National Conference Publication - Institution of Engineers, Australia, 156-160 (1990)
Reviews of statistical surveys of structural failures indicate that human error is a major cause of failure. These surveys show that human error may occur in the planning, design,... [more]
Reviews of statistical surveys of structural failures indicate that human error is a major cause of failure. These surveys show that human error may occur in the planning, design, construction, or utilisation of a structure. However, the available data suggest that design error causes a significant proportion of structural failures. An investigation of the efficiency of a quality control measure (e.g., design checking) is reported which includes design checking guidelines for the structural engineering profession. The use of safe load tables (for steel member design) as a quality assurance measure is also investigated. It is indicated that a designer using safe load tables (or similar design aids) will be more 'cost effective' and less prone to error than designers not using such design aids. Comparisons between the efficiency of design checking and the use of safe load tables will be made.
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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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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 |
STEWART MG, MELCHERS RE, 'ERROR CONTROL IN MEMBER DESIGN', STRUCTURAL SAFETY, 6 11-24 (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 |
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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1988 |
STEWART MG, MELCHERS RE, 'SIMULATION OF HUMAN ERROR IN A DESIGN LOADING TASK', STRUCTURAL SAFETY, 5 285-297 (1988)
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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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