Design methodology and modified shear constitutive model of the shear pin connection

Abstract

Currently, the shear pin connection (SPC) is a structural measure in the double spherical seismic isolation bearing (DSSIB). However, there is no unified design methodology for the SPC. In addition, the existing shear constitutive model is the linear elastic model (LEM). Its drawback is the inability to capture the gap in the bearing and the plasticity, damage, as well as fracture behavior of the SPC. Therefore, based on the performance requirements for two-level seismic fortification, a detailed design methodology for the SPC is proposed. With the SPC in the Fuzhou Daoqingzhou Bridge as a prototype, the finite element model of the SPC is developed in order to discuss the applicability of the LEM for predicating the shear behavior of SPC. The results showed that the fracture displacement and absorbed energy obtained by the finite element analysis were significantly larger than those predicted by the LEM. Then, to compensate the drawback of the LEM, a tri-linear model (TLM) is proposed as the modified shear constitutive model of the SPC. Finally, the effects of TLM and LEM of the SPC on seismic performance of the isolated bridge were investigated. Obviously, the maximum displacement of the bearing calculated by the TLM is up to 1.38 times that calculated by the LEM. This suggests that the TLM has accurate predictions of mechanical property of the SPC.