Evaluation of Computational Tools for Performing Nonlinear Seismic Analyses of Structural Collapse

Nonlinear seismic analysis techniques have increasingly been used in performance-based seismic engineering to analyze and design new and existing structures, especially in the case of analyzing structural collapse. It is evident that any engineered structure will experience significant nonlinear response prior to collapse, and this nonlinear response requires inclusion of both geometric nonlinearity and material nonlinearity in the analysis. All analysis software packages today, both commercial and non-commercial, claim to possess both geometric and material nonlinearity capabilities, but so far no study has been done to demonstrate that these software packages give reasonably consistent matching results. In this research, nonlinear response history analyses of two simplified structural models subjected to seismic excitation are performed to evaluate the output consistency of different computational software tools that are commonly used in research and practice today, in addition to the nonlinear modal analysis algorithm. To do so, simulated results are compared with one another to demonstrate the relative precision and consistency of these computing tools for analyzing structural collapse, and the pros and cons of the assumptions made among these tools are also identified.