重载运输下大跨度钢桁梁桥病害分析及试验研究

随着重载运输的不断发展，铁路钢桥病害日益凸显。以朔黄铁路64 m下承式钢桁梁为对象，对其出现的典型支座病害的成因、处理方法和病害对桥梁运营的影响进行了系统的分析研究。研究结果表明：由于4个支座之间存在高低不平，且支座表面存在一定程度的不平整，支座部位构件产生了一定程度的初始应力，在重载列车的反复作用下，导致支座联接构件出现疲劳断裂破坏，进而引起桥跨结构跨中横向加速度、竖向振幅的急剧增大和主桁杆件受力的显著变化，危及行车安全。通过更换结构部件和改变支座高程的方法能够消除支座病害影响，整治效果显著。

Analysis of Disease and Experimental Research of Long Span Steel Truss Bridge Under Heavy Haul Transport Conditions

With the development of heavy haul transportation , the disease of railway steel bridge is increas-ing prominently .Taking the 64 m through steel truss bridge of Shuohuang Railway as the research background , this paper makes a systematic analysis on the three aspects associated with the diseases of the bridge support , in-cluding the causes of the disease , the treatment method and the disease＇s impact on bridge operation .The results of the study show that because of the unevenness between the four bearing supports , and a certain degree of roughness of the support＇s surface , a certain degree of initial stress is produced in bearing components .The re-peated effect of heavy haul train would lead to the fatigue fracture of the support connection components , hence a sharp increase of transverse acceleration and vertical amplitude at the middle of the span , and significant chan-ges of primary truss stress , which would endanger the safety of train operation .The ill effect can be eliminated by replacing structural parts and changing elevation of the supports , and the treatment effect is remarkable .