Research on the multi-shear spring model for circular-section steel piers

Abstract

The main damage caused by earthquakes to single-column circular-section steel piers is the bulged deformation at the bottom, generated by local instability. The refined shell-based finite element (FE) model can accurately simulate the deformational behavior, but it is still cumbersome and time-consuming to apply to the engineering design currently. Further, the existing simplified methods cannot be used in seismic response analyses under horizontal bidirectional earthquakes. Therefore, this paper uses the multi-shear spring (MSS) mechanical model as the basic model and proposes an MSS calculation model for circular-section steel piers. This model is applicable for horizontal bidirectional seismic response analysis and considers the local instability effect of steel plates. In this study, the load–deformation relationship of the modified Menegotto-Pinto model is employed in all directions as the hysteresis curve equation of the springs. The basic parameters of the corresponding models for different structures are determined according to the calculation results of the refined-shell models. In addition, the Ibarra-Krawinkler degradation rule is employed to simulate the degradation process of structural bearing capacity and stiffness, and the degradation parameters are identified. The pseudostatic and seismic time-history response analyses of steel piers with different width-to-thickness ratios verify that the proposed model has reliable calculation accuracy and greatly improved efficiency. The research in this paper provides a practical calculation method for the seismic response analysis of steel bridge piers.