钢桁加劲PC箱梁在高铁斜拉桥中的应用研究

Application of Prestressed Concrete Box Girder Stiffed by Steel Truss in Cable-stayed Bridges of High-speed Railway

研究目的:针对大跨混凝土梁及钢梁斜拉桥的不足,结合西安至十堰铁路汉江特大桥,本文主要研究钢桁加劲PC箱梁斜拉桥的受力特点,分析各主要受力构件的刚度贡献,与混合梁斜拉桥比较优缺点,并深入分析工后徐变,最后探讨该桥型在温度荷载下主梁的挠曲变形和行车平顺性。研究结论:(1)钢桁加劲PC箱梁斜拉桥具有良好的静、动力性能,能够充分发挥各主要受力构件的作用;(2)相比混合梁斜拉桥方案,钢桁加劲PC箱梁斜拉桥方案有更好的刚度和经济性;(3)通过一些工程措施可有效解决其工后徐变较大的技术难题;且行车舒适性"优",动力性能良好;(4)钢桁加劲PC箱梁斜拉桥是一种非常具有竞争力的高铁大跨桥式结构,综合性能优异,同时也能为大跨铁路桥梁铺设无砟轨道提供新的解决方案。

Research purposes:According to the deficiency of cable-stayed bridge with pre-stressed concrete girder or steel girder,the stress characteristics of cable-stayed bridge with pre-stressed concrete box girder stiffed by steel truss as well as the stiffness contribution of the main stressed member are analyzed based on Han River super large bridge on Xi’an-Shiyan railway.Its advantages and disadvantages with hybrid girder cable-stayed bridge are compared,and the creep after construction is deeply analyzed,and finally the deflection and ride comfort of the main beam under the temperature load are discussed.Research conclusions:(1)The cable-stayed bridge with pre-stressed concrete girder stiffed by steel truss has good performance of static and dynamic behavior by playing the main stressed member’s role.(2)Compared with hybrid girder,it has better stiffness and economy.(3)Deformation control of creep and shrinkage can be achieved by taking effective measures,and the driving comfort is excellent and the dynamic performance is good.(4)The cable-stayed bridge with pre-stressed concrete girder stiffed by steel truss is a competitive bridge structure in high speed railway with excellent comprehensive performance,and can also provide a new solution for the laying of ballastless track of long-span railway bridge.