Ali Mehrabian

Some lessons learned from post‐earthquake damage survey of structures in Bam, Iran earthquake of 2003

Purpose – Some lessons learned from post‐earthquake damage survey of structures affected by the Bam earthquake of December 26, 2003 in Iran are encapsulated in this paper. The Bam earthquake caused catastrophic structural damage in the region.Design/methodology/approach – A method similar to that of rapid evaluation procedure (REP), recommended by the Applied Technology Council (ATC‐20) in the USA, was used for damage survey.Findings – Bam represents a typical ancient city in many countries around the world. Most of the structures in the region are made of adobe, unreinforced masonry, steel, and unreinforced/reinforced concrete. Some of the main types of structural damage, their causes, and potential remedial measures are characterized with an emphasis on the very basic fundamental principles of earthquake‐resistant design.Practical implications – The research reported has considerable implications for other seismic‐affected regions of the world.Originality/value – A first hand‐account of the catastrophic...

Time-domain seismic reliability of nonlinear structures

A novel reliability analysis technique is presented to estimate the reliability of real structural systems. Its unique feature is that the dynamic loadings can be applied in time domain. It is a nonlinear stochastic finite element logarithm combined with the response surface method (RSM). It generates the response surface around the most probable failure point and incorporates information of the distribution of the random variables in the RSM formulation. It is verified using the Monte Carlo simulation technique, and is found to be very efficient and accurate. Most sources of nonlinearlity and uncertainty can be explicitly incorporated in the formulation. The flexibility of connections, represented by moment-relative rotation(M-θ) curves, is addressed. After the Northridge earthquake of 1994, several improved steel connections were proposed. Structural Sesimic Design Associates (SSDA) tested several full-scale proprietory slotted web beam-column connections. The authors suggested(M-θ) curves for this connection using actual test data. Behaviours of steel frames, assuming the connections are fully restrained, partially restrained, consisting of pre and post-Northridge connections are evaluated and compared. Desirable features of the post-Northridge connections observed during testing are analytically confirmed. Laterally weak steel frame is then strengthened with concrete shear walls. Capabilities and the advanced nature of the method are demonstrated with the help of realistic examples.

Structural engineering in the new millennium: Opportunities and challenges

Purpose – Structural engineering as a part of civil engineering has over 5,000 years of distinguished history, as documented in this paper. An attempt is made in this paper to define structural engineering as it exists at present, then some historical structures are identified.Design/methodology/approach – The advances of structural engineering are discussed in chronological order, encompassing the development of the concept, analysis, the use of innovative construction materials, and construction. The developments which necessitated the change of design philosophies are presented, and the current status of structural engineering is discussed in terms of several specific topics. Opportunities and challenges in the new millennium in structural engineering are then presented in terms of education, service to society, and research.Findings – In the past, structural engineering always met the challenges it faced. It helped to improve our quality of life, and its role in society is not expected to change in th...

Reliability Evaluation Using Finite Element Method

A robust and sophisticated structural reliability evaluation procedure is presented. Reliability of any structural systems represented by finite elements can be evaluated using the algorithm. The authors called it a stochastic finite element method. Despite the significant recent progress in the risk and reliability analysis techniques, a large segment of the engineering profession is not familiar with them and thus fails to use them in everyday practices. The procedure is expected to fill that vacuum. Many sources of nonlinearity generally overlooked in the profession can be incorporated in the algorithm. Uncertainties in the load and resistance-related variables are modeled as realistically as possible. The estimation of the failure, probability implies that structural behavior just before failure needs to be captured as accurately as possible. The algorithm is capable of evaluating the probability of failure addressing all the related issues. With the help of four informative examples, the application potential of the procedure is clearly demonstrated. It is similar to the deterministic methods and is not expected to be complicated to the practicing engineers; thus, promoting its wider applications. It is shown that the observations made in laboratory experiments can be explained with the procedure. It is hoped that the method will be used in the future to estimate the reliability of real structures.Copyright