桥墩裂纹对铁路桥梁结构振动及行车性能影响分析

Influence of the Pier Crack on the Dynamic Response of the Railway Bridge and Train Operation

建立了某铁路桥梁桥墩开裂前后的有限元模型,并通过车-桥耦合振动分析对桥梁的结构动力响应以及行车安全性进行了研究。计算结果表明,桥梁墩顶横向抗推度减少约15%,桥梁横向、纵向自振频率降幅在3%以内。C62列车和准高速列车过桥时,桥墩墩顶横向振幅增加约10%,最大振幅远小于规范要求的通常值;列车的脱轨系数及减载率在桥墩开裂前后变化不大,也满足规范的安全性要求。建议仅对桥墩进行裂缝封闭处理,无需进一步加固桥墩刚度或限制列车车速。

The finite element model is used to simulate a railway bridge before and after pier crack. Then,the vehicle-bridge interaction analysis is used to study the dynamic response of the bridge and the operation security of the train. The research shows the lateral stiffness of the pier top is reduced by about 15 percent after the pier crack, and the reduction of the natural frequency of the bridge is within 3 percent. The lateral amplitude of the pier top is increased by about 10 percent during the passage of C62 trains and the quasi-high- speed trains, which is smaller than the value in the code. The derail factor and load reduction rate of the trains vary insignificantly after the pier crack, which also meets the requirement of the code. Related measures can be conducted to enclosure the crack on the pier, and no further reinforcement measures or train speed limit are needed.