采用拉索支座的桥梁振动台试验

Shaking Table Test of a Bridgewith Cablesliding Isolation Bearing

摘要:

以南昌朝阳大桥为背景，设计了半结构振动台模型试验，介绍了模型设计的过程.根据桥梁是否采用拉索支座，将模型分为拉索支座体系与摩擦支座体系两种，选取了南昌朝阳大桥场地人工波与El Centro地震波进行两种体系下模型振动台试验加载.分析了各工况下结构关键位置的响应，分析解释了拉索支座限位原理.结果表明，在地震作用下，墩梁位移响应较小时，拉索支座具备与普通摩擦支座相似的减震特性；而在墩梁位移响应较大时，拉索支座通过为主梁提供瞬时加速度，控制墩梁位移，限制其进一步增加.

关键词:桥梁; 抗震设计; 减隔震设计; 振动台试验; 拉索减震支座

Abstract:

A halfstructure shaking table test based on Nanchang Chaoyang Bridge was designed and a detailed introduction of the designing process was performed. Two types of isolated system, i.e., cablesliding bearing system and friction bearing system, were introduced and applied to the structure according to whether or not cablesliding bearings were used. Two sets of seismic wave including the Nanchang artificial wave and El Centro seismic wave were induced as seismic loads during the test. The peak seismic responses of each key node of the structure were analyzed, so were the principle of how the cables could restrict the relative displacement between girder and piers. The results show that, under the seismic load, when the relative displacement response between girder and pier is small, cablesliding bearings have similar isolation features with ordinary sliding bearings. When the relative displacement is large, the cables can provide a momentary acceleration to the girder which can help limit the relative displacement and restrict it from increasing.

Key words:bridge; seismic design; isolation design; shaking table test; cablesliding isolation bearing