Inverse reliability based structural design for system dependent critical earthquake loads

The problem of reliability based design of structures subjected to partially specified random earthquake loads is considered. A procedure for the determination of structure-excitation pair that maximizes a specified response variable and, at the same time, achieves a target reliability is outlined. The procedure combines concepts from inverse first order reliability methods and methods for determining random critical earthquake loads. The formulation is shown to lead to a problem in constrained non-linear optimization. Issues related to spatial variability of earthquake loads are also addressed. Illustrative examples on a singly supported multi-degree of freedom system and a doubly supported single degree of freedom system are included.