浅述梁缝间落砟对铁路混凝土桥梁承载能力的影响

A Brief Analysis on the Influence of the Ballasts Between Gaps on the Bearing Capacity of the Concrete Railway Bridges

本文以中小跨度铁路混凝土桥梁梁缝间落砟这一常见病害对混凝土桥梁承载能力的影响为研究对象,以专桥(88)1024定型图中8m跨度板梁为背景,建立简化的理论计算模型,分别计算了在中-活载及温度恒载作用下梁缝间落砟对梁体内力和位移的影响,并用工程实例8m板梁的荷载试验结果来验证。得出了梁缝间道砟可以大幅减小梁体跨中弯矩、挠度,提高梁体的竖向刚度,然而同时增加了梁端负弯矩和温度恒载作用下的轴压力,这些都对梁体产生极为不利的影响。

The ballasts between the gaps of the medium and small span concrete railway bridge have an influence on its bearing capacity. Taking this common problem as a research object and setting in the eight-meter plate girder in the bridge pattern(88)1024, this thesis created a simplified theoretical calculation model, and respectively calculated the influence of the ballasts between gaps on the bridge’s internal force and displacement under the CR-live and temperature dead loads. It was tested by taking the result of the eight-meter plate girder as engineering example. It was proved that the ballasts could sharply reduce the mid-span moment and deflection, improve its vertical stiffness, and at the same time increase the hogging moment on the ends and the axial pressure under the temperature dead loads, all of which are supposed to have a negative influence on the bridge.