中文摘要：

介绍一种新型的预应力混凝土叠合梁——二次预应力混凝土叠合梁,分析其设计特点;并应用于高速铁路无碴轨道桥梁中,根据设计实例进行应力分析,与相同截面尺寸的常规预应力混凝土梁的应力进行对比。结果表明：与常规预应力混凝土梁相比,二次预应力混凝土叠合梁受力合理,可以明显减小截面应力梯度,对减小梁的徐变上拱非常有利;并可以节约预应力筋约10%,具有明显经济优势。

英文摘要：

A new type of prestressed concrete composite beam（double prestressed composite beam）was introduced,its design feature was analyzed.The new type prestressed concrete composite beam was proposed to be applied to high-speed railway ballastless track bridge.Whose stresses in different construction stages were analyzed according to the design of an actual project and contrasted to conventional prestressed concrete beam.The results show double prestressed composite beam has a smaller stress gradient which is propitious to decrease the creep camber of prestressed concrete beam;about 10% of the tendon can be saved by the double prestressed composite beam,which has obvious economic advantages.