成昆线钢拱桥运营性能试验测试与分析

Test and Analysis of Operation Performance of Steel Arch Bridge on Chengdu-Kunming Railway

成昆线桐模甸2号桥为钢拱桥,至今已使用超过40年。为掌握该桥的运营性能,开展了常规检定评估试验,包括测量上拱度、编组列车的动静载试验以及脉动试验。试验结果表明:桥梁的上拱度与设计的上拱度相比出现了下降,但整体线形基本圆顺;钢拱桥具有较高的强度储备,换算到中-活载时的跨中竖向挠跨比为1/1 481,竖向刚度满足规范要求;桥梁的动力系数、横向振幅、横向加速度均满足规范的要求;桥梁的横向一阶自振频率与桥梁建成时的频率基本接近。桥梁的结构状态满足运营要求。由于铁运函〔2014〕120号《铁路桥梁检定规范》没有涉及钢拱桥这种梁型,建议开展相关评价标准的研究。

Tongmodian No.2 bridge of Chengdu-Kunming railway is a steel arch bridge,which has been used for more than 40 years. In order to master the operation performance of the bridge,routine verification and evaluation tests were carried out,including the measurement of camber,dynamic and static load tests of marshalling trains and pulsation tests. The test results show that the camber of the bridge decreases compared with the designed camber,but the overall alignment is basically smooth. The steel arch bridge has a high strength reserve,and the vertical deflection span ratio of the middle span is 1/1 481 when converted to medium live load,and the vertical stiffness meets the requirements of the code. The dynamic coefficient,transverse amplitude and transverse acceleration of the bridge meet the requirements of the code. The first-order transverse natural vibration frequency is close to that of the bridge when it is built. The structural state of the bridge meets the operation requirements. As the steel arch bridge is not involved in railway transport letter〔2014〕No. 120 Code for rating existing railway bridges,it is suggested to carry out research on relevant evaluation standards.