既有桥梁改造加固方案设计

Design of renovation and reinforcement plan for existing bridges

为提升既有桥梁的结构安全与使用寿命,需对已出现病害的桥梁进行改造加固,根据其病害特征研究最佳的加固设计方案。文章以某预应力混凝土组合箱梁桥作为研究对象,发现其主要病害表现为梁底裂缝,通过建立有限元模型,深入探究其病害原因是桥梁承载力不足,选择采用体外预应力和粘贴钢板相结合的方案进行改造加固。将加固前后的桥梁进行对比分析,试验结果表明,加固后桥梁的正截面抗弯承载力与应力均符合设计规范要求,设计结果合理。

In order to improve the structural safety and service life of existing bridges,it is necessary to renovate and reinforce bridges that have already suffered from diseases,and determine the optimal reinforcement design scheme based on their disease characteristics.This article takes a prestressed concrete composite box girder bridge as the research object,and finds that its main disease is manifested as cracks at the bottom of the beam.By establishing a finite element model,the reason for the disease is deeply explored,which is the insufficient bearing capacity of the bridge.The plan of combining external prestressing and pasting steel plates is chosen for renovation and reinforcement.A comparative analysis was conducted on the bridge before and after reinforcement.The test results showed that the flexural bearing capacity and stress of the reinforced bridge’s normal section met the requirements of the design specifications,and the design results were reasonable.