金沙江河门口大桥抗震性能分析

Analysis on anti-earthquake feature of Hemenkou bridge on Jinsha river

在桥梁设计时,应针对当地情况,专门进行桥梁抗震设计。金沙江河门口大桥位于Ⅶ度地震烈度区,抗震设防烈度为Ⅷ度,抗震设防措施为9级。根据该桥所处地的地震情况和抗震要求以及桥的具体情况,建立了桥梁的有限元模型,分析了几种地震波形条件下,桥梁的受力情况,找出塔柱根部为地震响应最大位置。针对桥梁受力情况,分析了加设阻尼器和不加设阻尼器情况下桥梁的位移。分析结果表明:增设阻尼器可以减小位移和弯矩的峰值,这有助于该桥的抗震设计。

Earthquake can cause severe damage of bridge, or produce catastrophic result, so, in the time of bridge design, special anti - earthquake design for bridge should be conducted according to local earthquake condition. Hemenkou bridge on Jinsha river is located at 7 degree earthquake area and its anti - earthquake design is that the bridge is not damaged for middle earthquake and it can be repair for large earthquake. Based on the local earthquake condition and anti - earthquake design requirement as well as concrete bridge condition, FEM model for force action analysis is established and the forcing action of the bridge under several earthquake - type is analyzed by the model and the maximum forcing locations are find out. In the light of forcing condition, the displacement conditions of the bridge are analyzed for 2 conditions of damper supplement and without damper. The analysis result shows that damper can reduce the peak values of displacement and bending moment. The analysis result facilitate to the anti - earthquake design of the bridge.