PROBABILISTIC IDENTIFICATION OF FAILURE MODES FOR NONLINEAR STRUCTURES

Identification of dominant failure modes based on an incremental nonlinear finite element analysis procedure for structural systems undergoing progressive collapse is described. The basic random variables considered are the external load parameters and yield stresses of the members. A specific failure path is formed by load incrementation, where each increment is determined by a probabilistic ranking of all potential failure surfaces (yield hinges). The method is illustrated by application to a portal frame and an X-brace system. Probabilistic modelling of the load path for representation of piecewise proportional external loading is discussed.