City Research Online

Abstract

One of the major uncertainties in performance-based seismic design (PBSD) of structures using nonlinear response history analyses (NLRHAs) is record-to-record (RTR) variability of ground motions. The probabilistic optimisation approaches used in the context of PBSD, such as reliability-based and robust design optimisation frameworks, are established not only to minimise the design economic cost but also to account for uncertainties associated with input design parameters including RTR variability. However, these optimisation frameworks are associated with strengths and limitations. In this paper, a two-objective optimisation framework is proposed for PBSD of reinforced concrete (RC) bridge piers. In this approach, the first objective is to minimise the cost of construction material and the second objective is to minimise the probability of limit state exceedance (Pviol). The Pviol represents the probability that the pier seismic demands obtained at a seismic action level exceed the corresponding limit state capacity thresholds. The optimisation constraints are defined to satisfy the recommendations of fib Model Code 2010. To estimate the seismic demands, NLRHAs are performed on the structural model using a suite of ground motions to account for RTR variability. In adidtion, the uncertainties associated with structural parameters are taken into account. The application of the proposed framework is demonstrated using a cantilever RC bridge pier case study. At the end, sensitivity of the pier design solutions to the variability of the ground motion suite selected for the NLRHAs is discussed, and need for a robust optimisation approach to account for such variability is highlighted.

Publication Type:	Conference or Workshop Item (Paper)
Publisher Keywords:	probabilistic optimisation, performance-based seismic design, reinforced concrete bridge piers, ground motion record variability
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) T Technology > TG Bridge engineering T Technology > TH Building construction
Departments:	School of Science & Technology School of Science & Technology > Department of Engineering
SWORD Depositor:	Symplectic Administrator

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