重载列车与既有铁路简支梁桥的适应性研究

The adaptability research of heavy haul trains and existing railway simply-supported bridge

以既有铁路双线24 m简支梁为例,建立普通铁路简支T梁和高速铁路简支箱梁空间有限元分析模型,分析两者在现行活载模式下的工作性能,将中国货运专线铁路荷载(ZH)组合加至24 m普铁简支T梁和高铁简支箱梁上,研究30 t重载荷载模式下的受力和变形情况,探讨在既有铁路简支梁桥上运行30 t轴重重载列车的可行性。研究结果表明:ZH荷载组合下,24 m普铁简支T梁和高铁简支箱梁抗弯强度系数分别为1.99和1.95,T梁下缘最大拉应力达到0.28 MPa,均无法满足现行铁路桥梁规范。通过比较几种活载模式作用下24 m简支梁的受力特性,提出适用于30 t重载列车的24 m简支T梁和箱梁结构形式。经验算,本文设计的2种简支梁均满足我国现行铁路桥梁规范和重载铁路规范。

Taking 24 m span existing double - track railroad bridge for example, the space FEM models constituted separately of common railway T - shaped beams and high - speed railway box girders were established. Then the working performance of two bridges was investigated under the existing live load. After that, the ZH live load was applied on the two models, in which the stress and deformation conditions were evaluated, and the applicability of existing railway simply - supported bridge traveled by trains with 30 t axle loads was analyzed. The research results show that, under the action of ZH live load, the bending strength coefficient of 24 m span common rail T - shaped beam and high - speed rail box girder is 1.99 and 1.95, respectively, and as to the common rail T - shaped beam, the maximum tension stress of bottom flange reaches 0.28 MPa, both of which cannot meet the existing requirements. By comparing the mechanical characteristics of 24m span simply - supported bridge under different live forces, the structural modes of a T - shaped beam and a box girder traveled by trains with 30 t axle loads were proposed. Through checking, two kinds of simply - supported bridges can satisfy the current requirements of railway bridges and heavy haul railway requirements in China.