高烈度区长联大跨连续梁减隔震设计研究

摘要

Since the inertial force of long span and super long unit continuous beam bridge is rather large, the traditional ductility seismic design method cannot meet the needs of seismic performance of bridge seismic design. The seismic isolation technology is one of the effective ways to solve the problem. In this paper, the design on the use of seismic isolators for long span prestressed concrete continuous beam was discussed and the seismic mitigation of fluid viscous dampers, seismic isolation of double spherical seismic bearing were investigated in comparison with the seismic resistance of rubber pot bearings. The finite element calculation model for the whole example bridge was established by ANSYS, the COMBIN37 unit was used to simulate the fluid viscous dampers and the COMBIN40 unit and COMBIN14 were used to simulate the double spherical seismic bearing. By inputting 3 seismic waves with the 50-year exceedance probability of 2.5%, the nonlinear time-history response analysis was carried out. The results demonstrate that the effect of seismic mitigation is obvious by applying the fluid vicious damper, but it is hard to repair after the earthquake without the self-resetting capacity. The application of the double spherical seismic bearing can make the rest piers to bear the earthquake load uniformly besides the side piers. It can effectively improve the seismic performance of the piers, and the damping effect is better than the one using the fluid vicious dampers; meanwhile they are easy to repair after the earthquake with the self-re-setting capacity. Based on the above analysis, this scheme is optimal and can give references for seismic design of long span and super long unit continuous beam bridge in high seismic intensity area.%长联大跨连续梁上部结构惯性力较大,传统延性抗震设计方法很难满足桥梁抗震性能需求,减隔震技术是解决这一问题的有效途径之一.对大跨度预应力混凝土连续梁的减隔震设计进行探讨,以传统盆式橡胶支座抗震方案作为对比对象开展液体黏滞阻尼器减震、双曲面球型隔震支座隔震研究.利用 ANSYS 建立全桥有限元计算模型,采用非线性弹簧单元COMBIN37模拟液体黏滞阻尼器,非线性弹簧单元COMBIN40及弹簧单元COMBIN14模拟双曲面球型隔震支座,输入50年超越概率2.5%的3条地震波进行非线性时程反应分析.研究结果表明:液体黏滞阻尼器减震效果明显,但其自复位功能差,震后残余变形大,不利于震后的修复;采用双曲面球型隔震支座,除边墩外其余各墩较均匀分担了地震荷载,墩身抗震性能得到充分发挥,减震效果优于液体黏滞阻尼器方案,且其具备自复位功能,震后修复难度较低,因此双曲面球型隔震支座方案为本桥的减隔震设计最优方案,该方案可为高烈度区大跨连续梁的抗震设计提供参考.