预应力薄壁箱梁受弯剪力滞效应分析

首先对剪力滞效应的原理进行了综述，理清了概念，运用有限元软件ANSYS对某薄壁箱梁的剪力滞效应进行数值分析，与相关文献数值解、实测值和理论值进行对比，验证了模型的正确性。然后通过分析受弯箱梁本身受力特点，得到各影响因素对于其剪力滞系数的影响，并总结剪力滞系数沿跨径纵向分布的规律。再进一步分析了仅轴力、纯弯作用下剪力滞系数的纵向分布和翼缘板剪力流的关系，然后结合工程实践中的恒载、活载和预应力三者进行对比分析，得出全预应力结构有均衡剪力滞系数纵向分布及降低峰值的优点。最后对箱梁进入塑性状态后的剪力滞效应进行了研究并得出了相应结论，目的在于研究预应力作用下箱梁剪力滞特点及塑性状态箱梁剪力滞的变化规律，为工程实践提供一定理论基础。

Analysis of Shear Lag Effect in Prestressed Thin-walled Box Girder

Firstly, the principle of the bending load shear lag effect is reviewed, and numerical analysis is made of a thin-walled box girder shear lag effect with software ANSYS. The literature numerical solution and the measured and theoretical values are compared to verify the correctness of the model. Then through mechanical characteristics analysis of bending box girder, the influence of each factor on shear lag coefficient is obtained, and the shear lag coefficient vertical distribution laws along the span are summarized. The relationship of longitu- dinal distribution of shear lag coefficient and the flange plate shear flow Further analyzed in the case of axial force only and pure bending. Then combined with engineering practice, comparative analyses are made the cases under dead load, live load and prestressed load, concluding that full prestressed structure can reduce the peak of shear lag coefficient. Finally, shear lag effect of box girder plastic state is discussed and conclusions are drawn. The purpose of this paper is to study prestressed box girder shear lag feature and plastic state shear lag variation. The conclusions are helpful for engineering practice.