空间双向折线钢桁梁顶推施工过程受力分析

Mechanical Analysis of Spatial Two-Way Broken Line Steel Truss Girder During Jacking Construction Process

桥梁顶推施工法以其对桥下净空无要求,且不影响桥下通车的优点得到了广泛应用,然而,空间双向折线钢桁梁在顶推过程中面临“弯扭耦合”效应引起主梁受力不明确的技术难题。针对这一问题,本文依托莆田站顶推钢桁梁天桥工程,建立了全桥有限元模型,对顶推施工工况进行计算,结合现场测试数据,进行了受力分析,分析结果表明实测值与理论值基本吻合,顶推施工过程中钢桁梁是安全的,据此得出桥梁不同的斜度在顶推阶段对主梁应力的影响规律,保证桥梁顶推施工的安全。

The bridge jacking construction method has been widely used because it has no requirements for the clearance under the bridge and does not affect the traffic under the bridge. However, the spatial two-way broken line steel truss girder faces the technical problem of unclear stress of the main beam caused by the “bending torsion coupling” effect in the jacking process. Aiming at this problem, this paper establishes the finite element model of the whole bridge based on the Putian station jacking steel truss overpass project, the working conditions of jacking construction are calculated, and the stress analysis is carried out in combination with the field test data. The analysis results show that the measured values are basically consistent with the theoretical values, and the steel truss girder is safe in the process of jacking construction. Based on this, the influence law of different inclination of the bridge on the stress of the main beam in the jacking stage is obtained to ensure the safety of bridge jacking construction.