Limit analysis of structures subjected to nonstationary dynamic excitations

A simplified approach is suggested to predict the response of structures to nonstationary dynamic excitations. In this approach, a structure is represented as a combination of collapsing elements and absolutely rigid blocks. The plastic deformation, accumulation of diffused damage, and degradation of the stiffness of elements and units in a dynamic process are taken into account by prescribing the diagrams of cyclic deformation. Finite displacements of rigid blocks are also taken into account. The choice ofthe computational schemes and influence of this choice on the final results are discussed. The results are used for the analysis of multistory buildings subjected to intensive seismic excitations in the deterministic and probabilistic formulations.