单室箱桥的剪力滞分析

Analysis of Shear Lag Effect in Single Cell Box Girder Bridges

本文用翘曲位移法分析单室箱桥的剪力滞效应,其中考虑了翼板宽度和到形心轴的距离对翘曲位移模式的影响以及轴力平衡,构造了一般对称的有任意宽度外伸板的单室箱粱,并可蜕变为开口截面梁的翘曲位移模式。用最小势能原理推出了控制微分方程及其解,计算简便。同时考虑剪力滞效应和铁摩辛柯梁剪切效应对挠度影响,则能改善计算精度。文中将有限条解析的数值计算与翘曲位移法作了比较,最后还应用模型实验资料作验证,验证比较表明,本文方法的通用性较好,精度较高。

In this paper, the warping displacement function method is adopted to analyse the shear lag effect in single cell box girder bridges. The influence due to the width of the flange plate and the distance to the central axis, and the equilibrium of axial forces are both considered to form a warping displacement function for a single cell box girder with overhanging plates of varied width. It could be transformed into a warping displacement function for open-type beams. The differential equationis derivd form the theory of minimum potential energy and its solution is then obtained. The Calculating process is simple and fast. It is good useful to precision of calculated deflection that the effect of not only shear lag but S. Timoshenko's beam shear strain energy on deflection is considered. In this paper, the results obtained from the finite strip method are used to compare with the results obtained from the warping displacement method. Finally the calculated results are compared with the data from model tests. It shows that the method given in this paper is universal and precise.