A Curve Approximated Hysteresis Model for Steel Bridge Columns

In this paper，a curve approximated hysteresis model for SDF analysis is proposed to predict the nonlinear response of bridges supported by steel columns with suitable scope of severe damaged deterioration domain. Instead of multiple straight lines，a series of curves are adopted to precisely describe complicated force-displacement hysteresis behavior of the column. The P-δ effect, hardeing effect in unloading-reloading hysteresis loops, deterioration of strength and stiffness are taken into account. Parameters of proposed hysteresis model for three types of steel pier specimens used in this study are calibrated by six static cyclic tests. To verify the accuracy of the proposed model, eleven pseudo-dynamic tests are conducted. By comparing the simulation and the test results，the differences between the predicted nonlinear seismic response using the proposed model and pseudo-dynamic tests are found to be， averagely， 5% in maximum response displacement，22% in residual displacement and 4% in the amount of energy dissipation