二次预应力组合结构在高速铁路桥梁上的应用研究

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。

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

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 reducing the creep camber and is worth popularizing.