地铁运营期箱梁缺陷处置技术

Treatment Technology of Box Girder Defects During Subway Operation

贵阳市地铁1号线军山大桥8#—9#墩间箱梁右侧预应力齿块起弯点混凝土开裂与脱落。综合考虑箱梁缺陷处置各种方法的特点和城市地铁运营要求,确定采用增设横隔板法。首先利用有限元软件对箱梁缺陷处置前后受力情况进行了数值分析,采用增设横隔板法处置箱梁缺陷不影响结构受力。然后总结了预应力齿块缺陷处置要点,并通过静载试验证实缺陷处置后桥梁结构处于良好弹性工作状态,强度满足要求且有一定安全储备。处置完成后经过一年的监测,最大沉降-1.93 mm,验证了该处置方案的合理性。

The concrete at the bending point of the prestressed tooth block on the right side of the box girder between 8#and 9#piers of Junshan Bridge of Guiyang Subway Line No.1 cracks and falls off. Considering the characteristics of various treatment methods for box girder defects and the operation requirements of urban subway,the method of adding diaphragms was selected. Firstly,the finite element software was used to conduct numerical analysis on the stress of the box girder before and after the treatment of the defects. The method of adding diaphragms to treat box girder defects does not affect the structural stress. The key techniques of defect treatment of prestressed tooth block were summarized. The static load test proves that the bridge structure is in good elastic working condition after defect treatment,the strength meets the requirements and the structure has certain safety reserves. After one year of monitoring,the maximum settlement was-1.93 mm,which verified the rationality of the treatment scheme.