二次预应力组合结构在高速铁路桥梁上的应用研究

Application of twice-prestressed composite structure to high-speed railway bridges

针对高速铁路桥梁对于徐变上拱度有着严格的限值,若徐变上拱过大将严重地影响铁路桥梁的使用性能,甚至危及行车安全等问题,提出将新型二次预应力组合结构应用于高速铁路桥梁。这种结构将混凝土分2次浇筑,与之相应的预应力筋分2次张拉,以此既分散结构的预应力度,又使结构满足受力要求,最终使上拱变形减少。通过对这种结构与常规预应力结构铁路桥梁的分析比较,证明二次预应力组合结构可大大减小徐变上拱度,而且具有良好的受力性能,值得推广应用。

Based on the fact that the creep camber of the high - speed railway bridge should be carefully considered, a new- type twice prestressed composite structure applied to high - speed railway bridge was proposed. The creep camber has a severe effect on the serviceability and traffic safety of the railway bridge. This new - typed structure was constructed by two steps of casting and prestressing. In the case of satisfying the mechanical performance , the structure has the advantages of reducing the creep camber via the disperse of the prestress. Comparing with the conventional PC railway bridge structure, the new- type structure with the perfect mechanical characteristics is capable of remarkably re- ducing the creep camber and is worth popularizing.