桥台混凝土挡块对连续梁桥地震响应的影响

Effect of Concrete Shear Keys at Abutment on Seismic Response of Continuous Girder Bridge

摘要:

为研究桥台混凝土挡块对中小跨径连续梁桥横向地震响应的影响，以一座连续桥梁为背景建立了有限元模型，采用非线性时程方法分析了桥台混凝土挡块的峰值强度对全桥地震响应的影响.研究结果表明：随着桥台混凝土挡块峰值强度的增强，桥台顶剪力需求逐渐增大，桥墩处支座位移需求逐渐减小，但减小幅值随着挡块峰值强度增加而减小并趋向于零.合理选取桥台处混凝土挡块的峰值强度能有效地减少桥墩的支座位移需求，并且能避免对桥台造成严重地震损伤.

关键词:连续梁桥; 桥台; 混凝土挡块; 横向地震响应

Abstract:

To investigate the effect of the concrete shear keys at abutment on transverse seismic reaction of a short and medium span continuous girder bridge, a finite element model was built based a continuous girder bridge. The effects of peak strength of the concrete shear keys at abutment on transverse seismic reaction of a continuous girder bridge were analyzed using the nonlinear time history method. The results show that when the peak strength of the concrete shear key at abutment increases, the shear demand of the top of abutment increases while the displacement demand of bearing at pier decreases, but the decrease amplitude declined to zero. A reasonable selection of the peak strength of the concrete shear key at abutment can effectively reduce the displacement demand of bearing at the pier, and avoid the severe seismic damage on the abutment.

Key words:continuous girder bridge ;abutment; concrete shear keys; transverse seismic response