铁路预应力混凝土32m T梁纵向裂缝修补效果评价

Assessment of Repair Effect for Longitudinal Cracks in Railway Prestressed Concrete 32m T-beam

在日常维护管理过程中,发现32 m预应力混凝土简支T梁在开通运营1~2年内裂缝病害量多、面广、发展较快,裂缝主要分布于梁体腹板及下翼缘处,裂缝走向主要沿预应力管道方向。针对此病害,通过结构基本状态检测、无损检测等工作,掌握了裂缝的分布、形态和宽度,钢筋及钢绞线锈蚀情况等;通过桥梁运营性能检验,分析桥梁结构竖向和横向刚度是否满足《铁路桥梁检定规范》(铁运函[2004]120号)中的要求。封闭涂装处理后经过10年的运营,部分裂缝重新开裂,但复测结果显示,梁体混凝土碳化深度未超过钢筋保护层厚度,钢筋锈蚀电位及混凝土电阻率测试显示钢筋锈蚀较慢,不存在大规模锈蚀的可能;上部结构横向振幅及横向加速度均满足《铁路桥梁检定规范》的要求。

In the daily maintenance management process,some diseases of 32 mprestressed concrete simply supported T-beamwere found in the operation stage of 1 - 2 years,such as crack volume,wide range,rapid development.The cracks were mainly distributed in the web and flange,the crack propagation was mainly along the direction of prestressed pipe.Aimed at these diseases,structural basic state inspection,nondestructive test and other inspection works were used to master the crack distribution,crack morphology,crack width,reinforcement and steel wire corrosion.The operation performance inspection of the bridge structure was analyzed to prove whether it had enough vertical and horizontal stiffness to meet the Code for rating existing railway bridges（Railway-transportation document[2004]120） in compliance requirements.The cracks were closed coating.After 10 years of operation,some cracks appeared again.Retest results showthat concrete carbonation depth does not exceed the thickness of reinforcement protection layer.Corrosion potential and resistivity tests showthat the resistivity of reinforcement is slow.There is no large-scale corrosion potential.The transverse amplitude and lateral acceleration of superstructure meet the requirements of code.