预拱度对大跨斜拉桥车辆动力特性影响研究

Research on the Influence of Pre-camber on Vehicle Dynamic Characteristics of Long-span Cable-stayed Bridge

研究目的:针对大跨斜拉桥成桥后线形易偏离理论设计线形,影响列车运行安全性和平稳性这一重难点问题,设置合适的预拱度是有效的方法之一。本文建立车辆-轨道-桥梁三维耦合动力学模型,对某主跨330 m特大桥在最不利荷载线形基础上叠加4种预拱度下的车辆动力响应进行分析,探究不同预拱方案对大跨斜拉桥车辆动力响应的影响规律。研究结论:(1)有无预拱度设计列车通过大跨桥时的安全性指标与舒适性指标均满足规范要求,且安全冗余较多;(2)设置预拱线形能够有效降低车体垂向加速度,提高列车乘坐舒适性;(3)大跨桥最不利位置为桥塔和主跨跨中处,需加强施工质量控制,在运营中注意观测养护,以保障列车的运行安全和乘坐舒适性;(4)本研究成果可为大跨斜拉桥的预拱度设计、施工及运维提供参考。

Research purposes:The actual alignment of the long-span cable bridges can easily deviate from the theoretical design alignment,which is a difficult critical issue that may affect the safety and smoothness of the train operation.Proper pre-camber is one of the effective approaches to this problem.In this paper,a three-dimensional vehicle-track-bridge coupling dynamic model is established to analyze the vehicle dynamic response of a 330 m long bridge with main span under four alignment of the most unfavorable load superposition with pre-camber,and the influence of different pre-camber schemes on vehicle dynamic response of long-span cable-stayed bridge is investigated.Research conclusions:(1)The safety index and comfort index of train passing through the long-span bridge meet the standard requirements under different pre-cambers,and there are many safety redundancy.(2)Setting pre-camber can effectively reduce the vertical acceleration of vehicle and improve passenger comfort.(3)The most unfavorable position for the smoothness of the long-span bridge is at tower and the middle of main span.It is necessary to strengthen the construction quality control and pay attention to the observation and maintenance during the operation to ensure the operation safety and riding passenger comfort.(4)The research result can provide a reference for the design,construction and maintenance of the long-span cable-stayed bridge.