先简支后连续技术在高速铁路PC桥中应用初探

The application of the technology converting simple support girder into continuous girder to PC bridge of high\|speed railway

高速铁路桥由于高速行车平顺性的需要 ,对桥梁的刚度、上拱度等提出很高的要求。高速铁路桥梁中大量采用的是预应力混凝土简支梁 ,为满足技术要求 ,梁高较大 ;连续梁桥的受力和变形性能优于简支梁桥 ,但由于连续梁施工的复杂性 ,影响其在 40m以下跨度铁路桥中的使用 ;采用先简支架设、后体系转换为连续梁的先简支后连续结构和工艺 ,综合了简支梁和连续梁的优点。以高速铁路桥作为应用背景 ,通过对比分析 ,对预应力混凝土先简支后连续梁的施工、构造、受力、刚度和后期徐变上拱度等进行初步的探讨 ,论证其在高速铁路桥梁中应用的优越性。

The stiffness and the camber of high-speed railway bridge is strictly required as demanded by high\|speed train running. Large quantities of PC simple support girders are used for high\|speed railway bridges. The girder depth is comparatively large to meet technical requirements. Continuous girder bridge has a better forcing performance and deforming performance than simple support girder bridge. However, the complexity of continuous girder construction restricts its use in railway bridges spanned fewer than 40m. The technology of erecting simple support girder first, then transforming it into continuous girder is adopted, which combines the advantages of both girders. The construction technology, structure, forcing, stiffness, late creepage, and camber are explored, and the advantages of the technology are demonstrated.