设置BRB的双柱式桥墩弹塑性地震反应分析

Elastoplastic Seismic Response Analysis of Double-Column Piers with BRB

为研究防屈曲支撑(buckling-restrained brace,简称BRB)对双柱式桥墩抗震性能的影响,在双柱式桥墩间设置5种BRB布置方案以提高桥墩的抗侧刚度,并与原桥墩对比研究其抗震性能。首先,进行桥墩拟静力分析,通过与文献试验数据对比,验证数值模拟方法的正确性;其次,开展桥墩的抗震性能研究,通过对6种模型在不同地震动(0.2g,0.4g,0.8g)作用下的非线性时程分析,得到桥墩的损伤、内力和变形计算结果。经对比研究,提出一种最佳的BRB布置方案。研究表明:双柱式桥墩设置BRB可以有效提高桥墩的抗侧刚度,减小桥墩在地震作用下的墩顶位移响应,降低桥墩的损伤,减少钢筋屈服和桥墩塑性铰区域,大幅减小墩底弯矩,但不同的BRB设置有时会导致墩底剪力有所增加。

In order to explore the influence of buckling-restrained brace(BRB) on the seismic performance of double-column piers, five BRB arrangements are set up between double-column piers to improve the lateral stiffness of the piers, and the seismic performance is studied in comparison with the original piers. Firstly, the pseudo-static analysis of the bridge pier is carried out to verify the correctness of the numerical simulation method by comparing with the literature test data. Secondly, the seismic performance study of the bridge pier is carried out to obtain the damage, internal force and deformation calculation results of the bridge pier through the nonlinear time history analysis of six models under different ground motions(0.2g, 0.4g, 0.8g). After the comparative study, an optimal BRB arrangement scheme is proposed. The study shows that the BRB setting of the doublecolumn pier can effectively improve the lateral stiffness of the pier, reducing the displacement response of the pier top under the earthquake, reduce the damage of the pier, reducing the steel yielding and the plastic hinge area of the pier, and significantly reducing the bottom bending moment of the pier, but different BRB settings sometimes lead to an increase in the bottom shear force of the pier.