Seismic reliability analysis of reinforced concrete structures with stochastic properties

The paper investigates the potentialities of the method of equivalent stochastic linearization (ESL) as a tool for reliability analyses of nonlinear hysteretic structures with random mechanical properties, in view of its possible use for the probabilistic calibration of the safety elements used in seismic design. In particular, behavior factor a and capacity design (CD) factors are investigated. For this purpose, the method is extended in the paper to cover the case of a response process with a non-zero mean, a situation occurring even for a zero mean input due to the combined presence of the seismic loads with the gravitational ones, which in turn leads to unsymmetrical force-deformation laws at both local and global level. To show the practicality of the method, two problems for which code provisions are still largely judgmental have been considered with a few examples: the quantification of the q values for structures with setbacks, and of the CD factors for structures with relatively large vertical loads. The results allow some considerations of practical interest to be drawn, while confirming the ESL: as an appropriate and economical tool for a systematic support of seismic codes. Copyright (C) 1996 Elsevier Science Ltd.