Abstract: In view of the serious shortage the baring capacity caused by the long-term disrepair of some important trunk highway bridges , low standard of design load and rapid increase of traffic flow, the construction scheme of external prestressed reinforcement can effectively improve the bearing capacity of the main girder structure, reduce the impact of construction on traffic to the greatest extent, and has good economic effect. In this paper, based on the introduction of the external prestressed structural design of Wusugou Bridge, MIDAS Civil finite element numerical simulation analysis, the load-bearing capacity and normal service limit state of the main beam structure before and after reinforcement are checked. Finally, combined with the actual engineering construction monitoring, the maximum deflection measured after the completion of tension is 15.63mm. It appears at the position of 2# beam in the middle section of the test T beam, and the variation of deflection is basically consistent with the theoretical calculation value and the measured value of the bottom stress of the main beam. The results show that it is feasible and effective to use external prestress to reinforce highway simply supported T beam. Therefore, from the technical feasibility, effect reliability and construction simplicity, this study can provide reference for similar construction projects.

Key words: simply supported T beam, external prestress, reinforcement design, MIDAS Civil finite element, construction monitoring

摘要： 针对于一些重要干线公路桥梁年久失修、设计荷载标准低以及交通量迅速增加导致的承载力严重不足现象，采用体外预应力加固的施工方案，可有效提高桥梁主梁结构的承载能力，并在最大程度上降低施工对交通的影响，具有很好的经济效果。文中介绍了克黄线乌苏沟大桥体外预应力加固结构设计方案和通过MIDAS Civil有限元模型对加固前后主梁结构的承载能力和正常使用极限状态进行验算结果；对工程施工实际监控数据进行了分析，结果显示实测张拉完成后的挠度最大值为15.63 mm，出现在试验孔跨跨中截面2#梁位置处，且挠度变化和主梁梁底应力的理论计算值与实测值基本相符。研究结果表明：采用体外预应力加固公路简支T梁加固效果良好，是切实可行的。因此，从技术可行性、效果可靠性以及施工简便性出发，该研究可为类似施工工程提供参考依据。

关键词: 简支T梁, 体外预应力, 加固设计, MIDAS Civil有限元, 施工监控