组合减隔震技术在大跨重载钢连桥中的应用

Application of seismic mitigation and isolation technology in large-span and heavy-load steel bridge

减隔震技术可以有效降低结构地震动响应,提高结构抗震性能。某实际大跨重载钢连桥采用了摩擦摆支座结合黏滞阻尼器的减隔震方案,摩擦摆支座可以阻断大部分水平地震作用,黏滞阻尼器可以在适当减小水平地震作用的基础上有效地减小连桥因摆动而产生的位移。采用Midas Gen有限元软件建立该连桥的空间有限元模型,采用非线性时程分析方法分别对不隔震、只用摩擦摆隔震、采用摩擦摆与黏滞阻尼器减隔震的连桥结构响应进行对比。计算表明,摩擦摆可以将减震系数控制在0.26左右,黏滞阻尼器可在此基础上将减震系数降低到0.20左右;黏滞阻尼器还可以将罕遇地震下摩擦摆支座的最大位移降低20%左右;罕遇地震工况下摩擦摆支座和黏滞阻尼器滞回曲线饱满,减隔震效果显著。

Seismic mitigation and isolation technology can effectively reduce the seismic response and improve the seismic performance of structures.Friction pendulum bearings and viscous dampers were used in a large-span and heavy-load steel bridge.Friction pendulum bearings can block most of the horizontal seismic action,and viscous dampers can effectively reduce the displacement of the bridge due to swinging on the basis of properly reducing the horizontal seismic action.The spatial finite element model of the bridge was set up by the Midas Gen finite element software.The structural responses of the bridge without isolation,isolation only with friction pendulum bearings,and isolation with friction pendulum bearings and viscous dampers were analyzed and compared by the nonlinearity time-history analysis method.Calculations show that friction pendulum bearings can control the seismic reduction factor to about 0.26,and viscous dampers can reduce the seismic reduction factor to about 0.20 on this basis.Viscous dampers can also reduce the maximum displacement of friction pendulum bearings by about 20%under rare earthquakes.The friction pendulum bearings and the viscous dampers have full hysteresis curves under rare earthquake conditions,and the seismic isolation effect is obvious.