Nonlinear Dynamic Analysis of Structures Subjected to Seismic Action

Abstract

It is widely recognized that nonlinear time-history analysis constitutes the most accurate way for simulating response of structures subjected to strong levels of seismic excitation. This analytical method is based on sound underlying principles and features the capability of reproducing the intrinsic inelastic dynamic behaviour of structures. Nonetheless, comparisons with experimental results from large-scale testing of structures are still needed, in order to ensure adequate levels of confidence in this numerical methodology. The fibre modelling approach employed in the current endeavour inherently accounts for geometric nonlinearities and material inelasticity, without a need for calibration of plastic hinges mechanisms, typical in concentrated plasticity models. The resulting combination of analysis accuracy and modelling simplicity, allows thus to overcome the perhaps not fully justifiable sense of complexity associated to nonlinear dynamic analysis. The fibre-based modelling approach is employed in the framework of a finite element program for seismic response analysis of framed structures, freely downloaded from the Internet. The reliability and the accuracy of the program are demonstrated by numerically reproducing pseudodynamic tests on full-scale structures. Modelling assumptions are discussed, together with their implications on numerical results of the nonlinear time-history analyses, which were found in good agreement with experimental results.