Dr Mukshed Ahammed

Research Associate

School of Engineering

Career Summary

Biography

Research Expertise
- Improved computational methods for structural reliability - Reliability and risk assessment of new and existing structures - Mathematical modelling of material corrosion and deterioration - Failure probability estimation of steel structures subjected to fatigue crack growth - Design life estimation of deteriorating reinforced concrete structures - Strength and life assessment of pipelines subjected to pressure, corrosion and soil movement - Reliability fatigue analysis of offshore structures

Qualifications

  • PhD (Civil Engineering & Surveying), University of Newcastle
  • Master of Engineering Science, Monash University

Keywords

  • Civil Engineering
  • Resources Engineering
  • Structural Engineering

Fields of Research

Code Description Percentage
090599 Civil Engineering not elsewhere classified 100

Professional Experience

UON Appointment

Title Organisation / Department
Casual Academic University of Newcastle
School of Engineering
Australia
Research Associate University of Newcastle
School of Engineering
Australia
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Publications

For publications that are currently unpublished or in-press, details are shown in italics.


Journal article (19 outputs)

Year Citation Altmetrics Link
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, 1-13 (2016)

© 2016 Engineers AustraliaCapacity reduction factors (¿) for flexure, shear and axial loadings are derived for reinforced concrete (RC) structures based on a reliability-based c... [more]

© 2016 Engineers AustraliaCapacity 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.

DOI 10.1080/13287982.2016.1246215
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, 1-12 (2016)

© 2016 Engineers AustraliaAssessment of the reliability of design models developed for Australian Standards is of paramount importance for determination of public safety. Poorly ... [more]

© 2016 Engineers AustraliaAssessment 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.

DOI 10.1080/13287982.2016.1246793
2010 Melchers RE, Ahammed M, Jeffrey RJ, Simundic G, 'Statistical characterization of surfaces of corroded steel plates', Marine Structures, 23 274-287 (2010) [C1]
DOI 10.1016/j.marstruc.2010.07.002
Citations Scopus - 22Web of Science - 17
Co-authors Rob Melchers, Goran Simundic, Robert Jeffrey
2009 Ahammed M, Melchers RE, 'A convenient approach for estimating time-dependent structural reliability in the load space', Probabilistic Engineering Mechanics, 24 467-472 (2009) [C1]
DOI 10.1016/j.probengmech.2009.01.003
Citations Scopus - 7Web of Science - 5
Co-authors Rob Melchers
2006 Ahammed M, Melchers RE, 'Gradient and parameter sensitivity estimation for systems evaluated using Monte Carlo analysis', Reliability Engineering & System Safety, 91 594-601 (2006) [C1]
DOI 10.1016/j.ress.2005.04.005
Citations Scopus - 43Web of Science - 21
Co-authors Rob Melchers
2006 Melchers RE, Ahammed M, 'Statistical characterization of corroded steel plate surfaces', Advances in Structural Engineering, 9 83-90 (2006) [C1]
DOI 10.1260/136943306776232828
Citations Scopus - 1Web of Science - 1
Co-authors Rob Melchers
2004 Melchers RE, Ahammed M, 'A Fast Approximate Method For Parameter Sensitivity Estimation In Monte Carlo Structural Reliability', Computers and Structures, Vol 82 55-61 (2004) [C1]
DOI 10.1016/j.compstruc.2003.08.003
Citations Scopus - 140Web of Science - 73
Co-authors Rob Melchers
2003 Melchers RE, Ahammed M, Middleton C, 'FORM For Discontinuous And Truncated Probability Density Functions', Structural Safety, Vol. 25 304-313 (2003) [C1]
DOI 10.1016/S0167-4730(03)00002-X
Citations Scopus - 17Web of Science - 16
Co-authors Rob Melchers
2002 Melchers RE, Ahammed M, 'Gradient Estimation For Applied Monte Carlo Analyses', Reliability Engineering And System Safety, Vol. 78 283-288 (2002) [C1]
Citations Scopus - 12Web of Science - 6
Co-authors Rob Melchers
2001 Melchers RE, Ahammed M, 'Estimation of failure probabilities for intersections of non-linear limit states', Structural Safety, 23 123-135 (2001) [C1]
Citations Scopus - 15Web of Science - 12
Co-authors Rob Melchers
1998 Ahammed M, 'Probabilistic estimation of remaining life of a pipeline in the presence of active corrosion defects', International Journal of Pressure Vessels and Piping, Vol. 75 321-329 (1998) [C1]
Citations Scopus - 122Web of Science - 80
1997 Ahammed M, Melchers RE, 'Probabilistic analysis of underground pipelines subject to combined stresses and corrosion', ENGINEERING STRUCTURES, 19 988-994 (1997)
DOI 10.1016/S0141-0296(97)00043-6
Citations Scopus - 75Web of Science - 47
Co-authors Rob Melchers
1997 Ahammed M, 'Prediction of remaining strength of corroded pressurised pipelines', INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING, 71 213-217 (1997)
DOI 10.1016/S0308-0161(96)00081-6
Citations Web of Science - 20
1996 Ahammed M, Melchers RE, 'Reliability estimation of pressurised pipelines subject to localised corrosion defects', INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING, 69 267-272 (1996)
DOI 10.1016/0308-0161(96)00009-9
Citations Scopus - 76Web of Science - 51
Co-authors Rob Melchers
1996 Ahammed M, Melchers RE, 'Reliability of underground pipelines subject to corrosion - Closure', JOURNAL OF TRANSPORTATION ENGINEERING-ASCE, 122 408-408 (1996)
DOI 10.1061/(ASCE)0733-947X(1996)122:5(408)
Citations Web of Science - 1
Co-authors Rob Melchers
1995 AHAMMED M, MELCHERS RE, 'PROBABILISTIC ANALYSIS OF PIPELINES SUBJECTED TO PITTING CORROSION LEAKS', ENGINEERING STRUCTURES, 17 74-80 (1995)
DOI 10.1016/0141-0296(95)92637-N
Citations Scopus - 34Web of Science - 17
Co-authors Rob Melchers
1994 AHAMMED M, MELCHERS RE, 'RELIABILITY OF UNDERGROUND PIPELINES SUBJECT TO CORROSION', JOURNAL OF TRANSPORTATION ENGINEERING-ASCE, 120 989-1002 (1994)
DOI 10.1061/(ASCE)0733-947X(1994)120:6(989)
Citations Scopus - 45Web of Science - 30
Co-authors Rob Melchers
1992 Melchers RE, Ahammed M, 'Linearisation and offshore fatigue reliability', Probabilistic Mechanics and Structural and Geotechnical Reliability, Proceedings of the Specialty Conference, 5-8 (1992)

In determining the force effects due to wave action on offshore structures it is conventional to use an equivalent linearisation to convert wave velocities to forces via Morison's... [more]

In determining the force effects due to wave action on offshore structures it is conventional to use an equivalent linearisation to convert wave velocities to forces via Morison's equation. Different linearisations have been suggested. However, it is not, a priori, clear which is appropriate when structural fatigue is to be estimated. A (theoretical) criterion is introduced herein and examined in relation to a simple offshore structure.

Co-authors Rob Melchers
1992 Melchers RE, Ahammed M, 'Equivalent linearisation and fatigue reliability estimation for offshore structures 531-536 (1992)

The force effects due to wave action on offshore structures are conventionally determined using Morison's equation. This is a nonlinear relation in velocity, conventionally repres... [more]

The force effects due to wave action on offshore structures are conventionally determined using Morison's equation. This is a nonlinear relation in velocity, conventionally represented by an equivalent linearisation for converting wave velocities to forces, necessary to allow structural dynamic analysis by frequency domain methods (the most commonly applied approach). The suggested approaches for the linearisation can be shown to be of essentially two classes; those equivalent to Borgman's approach and those equivalent to Bolotin's. In general, it is not clear, a priori, which is more the appropriate. Nor is it clear whether these classical linearisations are relevant, particularly when structural fatigue is to be estimated (e.g., through the Palmgren-Miner rule). A criterion for derivation of a linearisation constant under fatigue considerations can be derived relatively simply. Unfortunately the criterion is not easily applied except by iteration. A sensitivity study has been performed for a simple but realistic offshore structure to estimate the relative importance of correctly estimating the linearisation constant.

Co-authors Rob Melchers
Show 16 more journal articles

Conference (6 outputs)

Year Citation Altmetrics Link
2016 Melchers RE, Ahammed M, 'Pitting corrosion of offshore water injection steel pipelines', Proceedings of the International Offshore and Polar Engineering Conference (2016) [E1]

© Copyright 2016 by the International Society of Offshore and Polar Engineers (ISOPE).The internal corrosion and pitting of water injection pipelines (WIP) is of much interest in... [more]

© Copyright 2016 by the International Society of Offshore and Polar Engineers (ISOPE).The internal corrosion and pitting of water injection pipelines (WIP) is of much interest in the oil and gas industry. Water injection is used to aid the recovery of oil or gas from reservoirs that are nearing depletion. Most pipelines are low alloy high strength steels, many kilometres in length, not cathodically protected and placed on the seafloor. In some cases after some years service very severe internal corrosion, mainly pitting and channeling corrosion is observed, typically at the 6 o'clock position and sometimes at transverse welds. Various causes have been proposed. However, a critical issue is the depth of corrosion pitting that is likely to occur as the pipeline continues in use. Data extracted from intelligent pigging records for a number of water injection pipelines is presented. It is examined in the framework of conventional Extreme Value analysis. The data do not follow a Gumbel EV distribution as would be expected from fundamental theory and from (some, shortterm) past experience. All the pipelines considered show similar trends for departure from the ideal, theoretical Gumbel distribution. As a result, extrapolation to longer pipelines or longer exposure periods is problematic. The reasons for these observations are considered and recommendation made as to how the data can be used in the most productive way for estimation of likely future maximum pit depth.

Co-authors Rob Melchers
2011 Melchers RE, Ahammed M, Jeffrey RJ, Simundic G, 'Statistical analysis of the surfaces of corroded mild steel plates', Proceedings of the 11th International Conference on Applications of Statistics and Probability in Civil Engineering (2011) [E1]
Co-authors Rob Melchers, Robert Jeffrey, Goran Simundic
2005 Ahammed M, Melchers RE, 'New Bounds For Highly Correlated Structural Series System', 9th International Conference On Structural Safety And Reliability (ICOSSAR 2005) (2005) [E1]
Co-authors Rob Melchers
2004 Melchers RE, Ahammed M, 'Characterization Of Corroded Steel Plate Surfaces', Proceedings of the 18th Australasian Conference on the Mechanics of Structures and Materials (2004) [E1]
Co-authors Rob Melchers
2003 Melchers RE, Ahammed M, 'Numerical Estimation Of Sensitivities For Complex Probabilistically-Described Systems', Proceedings Of The Ninth International Conference On Civil And Structural Engineering Computing (2003) [E2]
Co-authors Rob Melchers
1993 AHAMMED M, MELCHERS RE, 'PROBABILISTIC ASSESSMENT OF PIPELINE SERVICE LIFE BASED ON PITTING CORROSION LEAKS', PROBABILISTIC RISK AND HAZARD ASSESSMENT (1993)
Co-authors Rob Melchers
Show 3 more conferences
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Grants and Funding

Summary

Number of grants 3
Total funding $2,254

Click on a grant title below to expand the full details for that specific grant.


19971 grants / $648

Corrosion and Prevention 97, Brisbane, 9-12 November 1997$648

Funding body: University of Newcastle

Funding body University of Newcastle
Project Team Doctor Mukshed Ahammed
Scheme Travel Grant
Role Lead
Funding Start 1997
Funding Finish 1997
GNo G0179391
Type Of Funding Internal
Category INTE
UON Y

19951 grants / $663

Australasian Conference on the Mechanics of Structures & Materials (ACMSM) - Hobart - 11-13/12/95$663

Funding body: University of Newcastle

Funding body University of Newcastle
Project Team Doctor Mukshed Ahammed
Scheme Travel Grant
Role Lead
Funding Start 1995
Funding Finish 1995
GNo G0176035
Type Of Funding Internal
Category INTE
UON Y

19931 grants / $943

'Pressure Vessel and Piping Technology' - Marina Mandarin Hotel, Singapore - 24 - 25 May 1993$943

Funding body: University of Newcastle

Funding body University of Newcastle
Project Team Doctor Mukshed Ahammed
Scheme Travel Grant
Role Lead
Funding Start 1993
Funding Finish 1993
GNo G0174318
Type Of Funding Internal
Category INTE
UON Y
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Dr Mukshed Ahammed

Positions

Research Associate
School of Engineering
Faculty of Engineering and Built Environment

Casual Academic
School of Engineering
Faculty of Engineering and Built Environment

Contact Details

Email mukshed.ahammed@newcastle.edu.au
Phone (02) 4921 6960
Fax (02) 4921 6991

Office

Room ES339
Building Engineering ES
Location Callaghan
University Drive
Callaghan, NSW 2308
Australia
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