ABSTRACT
ABSTRACT: In this paper, a nonlinear approach for the life-cycle cost (LCC) analysis is proposed. Computational procedure for the analysis of LCC for seismically isolated bridges is established. To compute the failure probability of critical structural components, most probable failure modes for the structure-isolator system are defined as unseating failure of a superstructure, local shear failure of an isolator, and damage of a pier. Multi-level damage state for a pier is introduced according to the level and type of visual damages and the level of corresponding damage result. A relationship between the damage index and the damage state of a pier structure is established by performing quasi-static cyclic loading test. To calculate the failure or damage probability, instead of a large number of nonlinear dynamic analyses this study uses method that generates a sufficient number of response sets which preserve the correlation between the responses of interest by using the result of small number of nonlinear analyses. The proposed procedure is applied to the optimal design of seismically isolated bridge based on the minimum LCC. The cost-effectiveness of seismically isolated bridge designed optimally is investigated.
