曲线箱梁剪力滞效应的弹性分析

Analysis of Elastic Behaviors of Share Lag Effect in Curved Box Girders

为准确分析曲线箱梁的受力特点,采用变分法对曲线箱梁的剪力滞效应进行弹性分析,同时考虑弯、扭、剪力滞耦合作用、曲率半径沿梁宽的变化和荷载横向分布等因素的影响,建立了曲线箱梁的总势能的表达式,推导出曲线箱梁的弹性控制微分方程和边界条件,并采用工程中常用的伽辽金法对微分方程进行近似求解。计算结果与有限条法计算结果和已有的试验值进行了对比验证,结果吻合良好,证明该分析方法能较为全面地反映薄壁曲线箱梁真实的力学性能。当曲率半径趋于无穷大时,可得到直线箱梁剪力滞效应的分析结果,因此,也是对直线梁桥剪力滞理论分析作了进一步补充,分析方法具有一定的通用性。

In order to analyze the mechanical characteristic of curved box girder, the elastic behavior of shear lag in curved box girder was analyzed based on variational method. Taking into account of factors such as coupling effect of bend, twist and shear lag, difference of curvature radius with the width of girder and the transverse distribution of load and so on simultaneously, the expression of general potential energy for curved box girder was established, the elastic differential equation and boundary conditions were derived, and solutions of equations were obtained by using Calerkin method. Compared with conclusions of finite strip method and experiment, the solutions are in good agreement with them. It indicates that the analysis method is able to reflect the true mechanical performance of thin -walled curved box girder comprehensively and exactly. In the meantime, when the curvature radius is infinite, the shear lag effect of straight box girders can be also obtained. Therefore, the proposed method is a complementary for shear lag theory for straight box girder bridge, and it has general character.