预应力混凝土大跨连续梁桥隔震设计

Seismic Isolation Design for Long-span Prestressed Concrete Continuous Girder Bridge

大跨预应力混凝土连续梁桥由于质量庞大,地震作用往往成为控制该类结构设计的主要因素。理论分析表明,处于地震高烈度地区桥梁的地震反应对结构参数变动十分敏感。加大构件截面或增加固定墩数量虽可提高结构的抗震能力,但同时也会使结构的地震反应迅速增加,反而使结构抗震能力需求缺口进一步扩大,因此按常规抗震设计思路进行抗震设计往往无法达到抗震设防目标。选用具有隔震和耗能双重功能的摩擦摆支座对桥梁进行减隔震设计,可大幅降低墩底内力,并使主梁相对于墩顶的位移控制在可接受范围内,满足结构的抗震需求。通过对摩擦摆支座滑动曲面半径和摩擦面滑动摩擦系数等参数的优化分析,得出了减隔震装置参数选取的基本原则。

Earthquake action is often a major factor of structure continuous girder bridge for their huge mass. Theoretical analysis high-intensity earthquake regions is very. sensitive towards the design controlling of large-span prestressed concrete shows that the seismic response of the bridge in the structural parameter change. Although the seismic capacity of the structure can be improved by increasing cross-section area or the number of fixed piers, it will make the seismic effect of the structure increase rapidly which will enlarge the demand of seismic capacity, so seismic design in accordance with conventional thinking is often impossible to meet the goal of seismic fortification. Appling the friction pendulum isolators which have dual function of isolation and energy consumption for seismic design of the bridge can largely reduce the internal force of piers at the bottom and control the relative displacement between the girder and pier top within acceptable range to meet the demand of seismic design. Based on optimization analysis of friction pendulum isolator on the sliding curved surface radius and the sliding friction coefficient in sliding surface parameters, the basic principles of how to select isolator parameters were deduced.