Reliability of nonlinear structural frame under seismic excitation

Nonlinear deformations can occur when a structural frame is subjected to strong earthquake excitations, and they occur most frequently at the column-footing and/or column-beam junctions. A procedure is developed herein to analyze such a deformation and to obtain the probability of failure when it exceeds a prescribed critical limit. The problem is simplified by using two analytical principles, the slaving principle in synergetics and the quasi-conservative averaging principle in random vibration. Examples are given for illustration, in which the strong earthquake is modeled as a random pulse train, and numerical results are obtained using the method of path integration.