重载铁路小跨度桥梁换梁施工及运营性能测试分析

在既有铁路扩能改造过程中发现中小跨径混凝土桥梁产生了较为严重的病害,通过常规加固技术(如粘贴碳纤维)难以满足长期重载运营要求。以一座跨度为8 m的钢筋混凝土重载铁路桥梁为工程背景,介绍了在役钢筋混凝土梁更换为钢梁的施工过程。通过对换梁改造后的桥梁进行运营性能试验,评价了该桥实际工作状态并检验了换梁效果。研究结果表明:换梁改造后桥梁跨中横向振幅、跨中动挠度动力系数、动应变动力系数远小于规范值;与更换前在役钢筋混凝土梁相比,主梁跨中横向振幅降低率约为74. 6%～85. 2%,桥墩墩顶横向振幅降低率约为11. 1%～50. 0%。

Beam Replacement Construction and Operational Performance Test Analysis for Small Span Bridge of Heavy Haul Railway

In the process of capacity expansion and transformation of existing railway,it is found that medium and small span concrete bridges have caused serious diseases,and it is diff icult to meet the long-term heavy haul operation requirements through conventional reinforcement techniques( such as carbon f iber bonding). Taking a reinforced concrete heavy haul railway bridge with a span of 8m as the engineering background,the construction process of replacing existing reinforced concrete beams with steel beams was introduced. Through the operational performance test of the bridge after beam replacement,the actual w orking state of the bridge was analyzed and evaluated.The results show that the dynamic strain coeff icient and transverse amplitude,dynamic def lection coeff icient in the midspan of the bridge after beam replacement are far less than the norm values. Compared with the existing reinforced concrete beam before beam replacement,the transverse amplitude reduction rate in the midspan of the main beam is about 74. 6% ~ 85. 2%,and the transverse amplitude reduction rate of pier top is about 11. 1% ~ 50. 0%.