考虑双向碰撞效应的连续斜交桥地震响应研究

为研究双向碰撞效应对连续斜交桥地震响应的影响,采用Kelvin-Voigt模型模拟桥台伸缩缝处的纵向碰撞现象,采用简化滞回模型模拟挡块与主梁的横向碰撞过程,针对某三跨连续斜交桥进行参数对比研究。研究表明,双向碰撞对主梁横向位移的影响远比纵向位移大,其中桥台间隙对主梁平面转角的影响最大,且平面转角随桥台间隙的增大而减小;横向碰撞对墩柱曲率变形的影响远比纵向碰撞大,其中挡块强度的影响特别大,当挡块强度由0%增至50%时,墩柱纵、横向曲率均值分别增大13.43倍、7.21倍。随着斜交角的增大,梁端纵向位移不断增大,横向位移和平面转角则先增后减;墩底纵向曲率不断增大,横向曲率经历先增后减,再增的过程;纵向碰撞效应先减弱后增强,而横向碰撞效应则先增强后减弱。由于横向碰撞对墩柱的影响远大于纵向碰撞,因此在斜交角为15°～45°时,宜设法降低横向碰撞效应。

Seismic Response of Continuous Skewed Bridges Consideringthe Bidirectional Pounding Effect

To study the influence of bidirectional collision on the seismic response of continuous skew girder bridges, the Kelvin-Voigt model was used to simulate the longitudinal collision phenomenon at the expansion joint of the abutment, and the simplified hysteresis model was used to simulate the lateral collision process between the link stopper and main beam. Therefore, a parametric comparison study on a three-span skew continuous bridge was conducted. The study shows that the effect of bidirectional collision on the lateral displacement of the main beam is much larger than that of longitudinal collision, and the abutment clearance has the greatest influence on the plane angle of the main beam:the plane angle decreases with the increase of the abutment clearance. The effect of lateral collision on the curvature deformation of the pier is much larger than that of the longitudinal collision, particularly the influence of the intensity of the link stopper. When the intensity of the link stopper increases from 0% to 50%, the mean values of the longitudinal and lateral curvatures of the pier increase 13.43 times and 7.21 times, respectively. With the increase of the skew angle, the longitudinal displacement of the butt of beam increases continuously, and the lateral displacement and plane rotation angle first increase and then decrease; the longitudinal curvature of the bottom of the pier continues to grow, and the lateral curvature alternately increases and decreases. The longitudinal collision effect first weakens and then increases, which is opposite of the lateral collision effect. Because the effect of the lateral collision on the pier is much larger than that of the longitudinal collision, it is advisable to reduce the lateral collision effect when the skew angle is 15°-45°.