研究目的:为了研究箱梁桥在预应力作用下的剪力滞效应，以承受预应力作用的简支箱梁为对象，基于能量变分法，结合预应力等效荷载法，建立了直线、折线和曲线布束方式的简支梁在预应力作用下的剪力滞效应解析解。针对算例简支箱梁，研究3种布束方式综合作用下箱梁的剪力滞效应，并和有限元板壳数值解进行对比分析。以高速铁路10种典型标准设计整孔简支箱梁为例，研究直线、折线和曲线布束下跨中部位应力最大点处的剪力滞系数。研究结论:通过研究得出:(1)通过本文解析方法与板壳有限元数值解的对比表明，本文解析方法可以有效计算简支梁在预应力作用下的剪力滞效应;(2)对既有高速铁路简支梁桥，直线布束在跨中引起的剪力滞效应最小、其次为曲线布束、折线布束最大;(3)本研究成果对预应力混凝土箱梁的预应力设计具有理论借鉴意义。

Research purposes:In order to calculate the shear lag effect of box girders due to prestressing, analytical solutions of shear lag effect of simple supported box girders due to straight, harped and draped prestressing tendons are presented based on energy variational principle and equivalent load method. Taking a simple supported box girder as an example, shear lag effect under three tendons arrangements are calculated and compared with numerical solution which using shell finite element method. For 10 typical standard box girders on high-speed railway bridges, shear lag coefficient at the point of maximum stress are calculated.
Research conclusions:The results show the following conclusions:(1) Compared with solution of finite element method, the analytical solutions can effectively calculate the shear lag effect of simply supported beams due to the prestressing action. (2) For typical standard box girders on high-speed railway bridges, the straight tendons arrangement can cause the minimum shear lag effect, followed by draped tendons, harped tendons are the maximum. (3) The research results have theoretical references for the design of prestressed concrete box girders.