Two hysteretic models for thin-walled pipe-section steel bridge piers

This paper is a comparative study of two hysteretic models for seismic analysis of thin-walled pipe-section steel bridge piers: the integrated 2-parameter model and the damage-based hysteretic model. Both models are of multi-linear type and both take into consideration strength and stiffness degradation of thin-walled steel structures due to local buckling and P-Δ effect. It is found that under short-duration accelerograms, the predicted responses by the two models come pretty close to each other and both models can simulate pseudodynamic tests adequately; under some long-duration accelerograms, however, there are some significant differences in the predicted responses especially in residual displacement. While such differences warrant further experimental study, the constitutional difference that causes the biggest disagreement is identified and recommendations are made as to the practical application of the two models.