远场长周期地震动对自复位高墩地震反应的影响

Influence of far-field long-period ground motion on seismic response of self-centering high piers

为研究远场长周期地震动对自复位高墩地震反应的影响,开展了自复位高墩的缩尺模型振动台试验,得到了模型桥墩在远场长周期地震动和普通地震动作用下的墩顶位移和墩底弯矩等数据,并对已有的两弹簧数值分析模型的有效性进行了验证。以一座典型的桥梁为例,利用已验证的两弹簧模型基于OpenSees平台建立数值分析模型,进行了自复位高墩在远场长周期地震动下的地震反应分析,并与普通地震动结果进行了比较。结果表明:自复位桥墩在远场长周期地震动下仍具有较好的隔震性能,但远场长周期地震动会增大自复位高墩地震反应;自复位桥墩在远场长周期地震动下的墩顶位移和墩底提离位移及转角都明显大于普通地震动,而墩底弯矩则与普通地震动相差不大。在自复位高墩的应用中,需要注意远场长周期地震动带来的不利影响。

In order to study the influence of far-field long-period ground motion on seismic response of self-centering high piers,a scale model shaking table test of self-centering high piers was carried out.The pier top acceleration,the pier top displacement and the bending moment of the pier bottom were obtained,and the validity of the existing two spring numerical analysis model was verified.Then taking a typical bridge as an example,using the verified two-spring model to establish a numerical analysis model based on the OpenSees platform,and the seismic response analysis of the self-centering high pier under far-field long-period ground motion was carried out and compared with the results of common ground motions.The results show that the self-centering bridge piers still have good seismic isolation performance under far-field long-period ground motions,but the far field long-period ground motion will increase the seismic response of the self-centering high pier.The displacement of the pier top and vertical displacement and the rotation angle of the pier bottom of the self-centering bridge pier under the far-field long-period ground motion are significantly greater than those of the common ground motion,while the moment of the pier bottom is almost the same as the common ground motion.In the use of self-centering high piers,it is necessary to pay attention to the adverse effects caused by the far field long-period ground motions.