ABSTRACT
ABSTRACT: The stiffness-reduction index proposed in this study can be efficiently used for the determination of second moment probabilistic descriptions of ZF , the natural logarithm of the minimum value of the intensity required to produce collapse of a complex nonlinear system and, therefore, for the determination of seismic reliability functions of those systems. This is achieved while avoiding the need to depend on the determination of a lateral deformation capacity, which is very sensitive to the strength and stiffness degradation of the system due to its cyclic response, as well as to its lateral configuration at the instant of impending collapse.
