静风荷载下大跨斜拉桥上无缝线路受力与变形

Stress and deformation of seamless CWR on large-spancable-stayed bridge under static wind load

大跨度斜拉桥在自然风场中易因自身柔度特性发生位移变形。为研究静风荷载作用下大跨斜拉桥上CRTS(China Railway Track System)双块式无砟轨道无缝线路桥梁及轨道结构在空间三向的力学性能分布规律,参照某一四线预应力混凝土斜拉桥工程实例,基于有限元法建立了大跨斜拉桥上无缝线路精细化空间耦合模型,分析了横桥向静风荷载作用下桥梁体系及桥上轨道结构的力学性能。分析结果表明:桥梁及桥上轨道结构三向(应)力最大值基本分布在斜拉桥跨中及边墩附近;各结构三向(应)力中,底座板、桥梁结构纵向应力峰值最大,约为横向应力峰值的8倍,约为竖向应力峰值的7倍、15倍,轨道板结构表现为横向应力峰值最大,且与其余两向应力峰值之间差距较小;各结构三向位移中,横向、竖向位移均在跨中及附近达到最大值,纵向位移在斜拉桥边墩附近达到最大值,其中,横向位移峰值是其余两向位移峰值的20余倍;桥梁两侧构件竖向、纵向位移方向相反,即桥梁表现为静风作用下的倾覆、弯曲倾向。研究成果可为风环境中大跨斜拉桥上线路设计、维护检修以及健康监测提供理论依据。

Large-span cable-stayed bridge is easy to have displacements and deformations due to their own flexibility characteristics in natural wind field. Here, to study spatial distribution law of mechanical properties of CRTS (China Railway Track System) double-block ballast-less track continuous welded rail (CWR) and track structure on large-span cable-stayed bridge under static wind loads in 3 directions, referring to an engineering example of a 4-line prestressed concrete cable-stayed bridge, a refined spatial coupled model for CWR on a large-span cable-stayed bridge was established based on finite element method to analyze mechanical properties of the bridge system and track structure on bridge under static wind load in bridge lateral direction. The analysis results showed that the maximum 3D stress values of the bridge and track structure on bridge are basically distributed at span middle of cable-stayed bridge and near side piers;in 3D stresses of each structure, longitudinal stress peak values at base plate and bridge structure are the highest and about 8 times lateral stress peak values, and about 7 and 15 times vertical stress peak values;track plate structure has the highest lateral stress peak value, and differences between peak lateral stress and the other two directional stresses, respectively are smaller;in 3D displacements of each structure, lateral and vertical displacements reach their maximum values at span middle and near, while longitudinal displacement reaches its maximum value near side piers of cable-stayed bridge, among them, peak lateral displacement is more than 20 times peak displacements in the other two directions;vertical and longitudinal displacement directions of components on both sides of bridge are opposite, so the bridge has trends to overturn and bend under action of static wind;the study results can provide theoretical basis for design, maintenance and health monitoring of CWRs on large-span cable-stayed bridge in wind environment.