摩擦摆支座在大跨度预应力混凝土梁桥中的应用

Application of Friction Pendulum Bearings in Long-span Prestressed Concrete Beam Bridge

摘要:

以在建江平东路东延涉铁应急工程上跨太平河 72 m+128 m +72 m 连续梁为例，结合桥梁特点，分别采用摩擦摆球形支座和球形支座建立三维模型，进行时程波抗震分析，并对计算结果进行对比。结果表明：采用摩擦摆支座可有效延长结构周期，远离地震能量集中的频率区段，降低结构地震效应；摩擦摆销轴剪断后，支座开始摆动，对桥墩内力进行了重新分配，在纵向地震力作用下固定墩内力减小约88%，非固定墩内力增大为原来的4倍左右；固定墩和非固定墩受力和截面配筋更加均匀，且不会引起结构损伤；支座位移相应增大，但梁缝和挡块间隙应能满足支座的变形需求；横向地震力作用下固定墩和非固定墩内力均有减小，减少了78%左右，可大幅减小结构配筋。

Abstract:

Taking the 72 m + 128 m + 72 m continuous beam spanning the Taiping River of the East Jiangping Road East Extension Railway-related Emergency Project under construction as an example, the three-dimensional models are established by using the friction pendulum bearing and spherical bearing respectively based on the characteristics of the bridge to carry out the time-history seismic analyses, and the results are compared. The results show that the adoption of friction pendulum bearings can effectively extend the structural period, and keep the structure away from the frequency zone where the seismic energy is concentrated, and reduce the seismic effect of the structure. After the friction-pendulum pin shaft is cut, the bearing begins to swing, and the internal forces of the piers are redistributed. Under the action of longitudinal seismic forces, the internal force of the fixed pier is reduced by approximately 88%, while the internal force of the non-fixed pier increases about four times. The forces and sectional reinforcement of fixed and non-fixed piers are more uniform, and will not cause the structural damage. The bearing displacement increases accordingly, but the beam joint and block clearance still meet the deformation requirements of the bearings. Under the action of transverse seismic forces, the internal forces of the fixed and non-fixed piers are reduced by about 78%, and the structural reinforcement can be greatly reduced.