既有整体桥的加固设计方案研究  

Strengthening Design of Existing Integral Abutment Bridges

作　　者：苗建宝 邵恒 薛俊青[2] 王旭 陈宝春[2] 黄福云[2] MIAO Jian-bao;SHAO Heng;XUE Jun-qing;WANG Xu;CHEN Bao-chun;HUANG Fu-yun(Xi’an Highway Research Institute Co.Ltd.,Xi’an 710065,China;College of Civil Engineering,Fuzhou University,Fuzhou 350108,China)

机构地区：[1]西安公路研究院有限公司,西安市710065 [2]福州大学土木工程学院,福州市350108

出　　处：《公路》2023年第12期94-100,共7页Highway

基　　金：国家自然科学基金项目,项目编号51508103;陕西省交通科技项目,项目编号14-20K,20-04K;福建省土木工程多灾害防治重点实验室开放课题,项目编号MPMC-2022-4。

摘　　要：当既有整体桥的受力性能无法满足规范验算要求时,需进行加固设计,其加固技术与常规有缝桥存在不同。以某预应力混凝土连续T梁整体桥为背景工程,采用MIDAS/Civil软件建立有限元模型,通过与实桥静载试验结果对比验证有限元模型的准确性。采用新规范开展该桥受力性能的验算校核,并基于验算结果提出适用的加固设计方案并验算加固效果。研究发现,有限元计算结果与静载试验结果吻合较好,有限元模型可精确模拟背景工程的受力特性。由于新规范对于温度作用、汽车荷载以及容许应力值等的要求提高,该桥的上部结构无法满足新规范的要求,其原因是桥台处主梁截面底缘和桥墩处主梁截面顶缘出现过大的拉应力,桥台处主梁截面顶缘出现过大的压应力;但下部结构可以满足新规范的要求。采用体外预应力法与混凝土扩大截面法加固,可使主梁的受力性能满足新规范要求。该加固方案同样适用于既有有缝桥的整体式无缝化改造。When the mechanical performance of the existing integral abutment bridge(IAB)can not meet the checking requirements according to the specifications,the strengthening design should be conducted,which is different to the bridge with expansion joints.One IAB with continuous prestressed concrete(PC)T-girder is chosen as the case study.The MIDAS/Civil software is used to build the finite element model(FEM).The accuracy of the FEM is verified by the static field test results on site.The new specifications are used to check the mechanical performance of the IAB.Based on the checking results,the suitable strengthening design scheme is proposed.The mechanical performance of the IAB after strengthening is also checked by using the new specifications.The results show that the results calculated by the FEM agree well with static field test results.The FEM can be used to accurately simulate the mechanical performance of the IAB.Because the requirements on the temperature action,traffic load,and allowable stress are improved in the new specifications,the girders of the IAB can not meet the requirements.The tension stresses on the bottom surfaces of the girders near abutments and the top surfaces of the girders near piers,and the compression stress on the top surfaces of the girders near abutments are too large.The substructure of the IAB can meet the requirements based on the new specifications.The strengthening methods with external prestressing and concrete section enlargement are proposed to let the mechanical performance of the girders meet the requirements of the new specifications.The strengthening methods can be also applied for the integral abutment type jointless retrofit of existing jointed bridges.

关 键 词：桥梁加固 整体式桥台桥梁 有限元模拟 规范验算 主被动组合加固 

分 类 号：U445.72[建筑科学—桥梁与隧道工程]