宽幅矮塔斜拉桥箱梁剪力滞分析

Shear lag effect on wide box girder of cable-stayed bridge

以某宽幅箱梁独塔斜拉桥为例,对宽幅斜拉桥混凝土箱梁剪力滞效应进行评价,采用有限元法计算了单箱6室箱形截面的剪力滞效应,分析了典型施工阶段和移动荷载作用下截面的剪力滞分布规律。结果表明:箱梁各翼板间呈现明显的剪力滞效应,主跨剪力滞系数分布规律与边跨类似,主跨剪力滞效应较边跨更为显著。在典型施工阶段,正剪力滞效应非常明显,最大剪力滞系数位于支点附近截面,达1.7;在移动荷载作用下,负剪力滞效应显著,最小剪力滞系数达-3.5。

To evaluate the shear lag effect of cable-stayed bridge with concrete wide box girder, a cable-stayed bridge of single box girder with six cells was taken as an example and the shear lag effect was analyzed with finite element method. The distribution of shear lag under the typical construction stage and the moving load were studied. Results show that the shear lag effect in wide box girder is obvious, the shear lag coefficient distribution curve of the main span is similar to the side span and the shear lag effect of main span is more significant than the side span. In the typical construction stage, the positive shear lag effect is conspicuous, and the maximum shear lag coefficient is located at the section near the pivot point, reaching 1.7. Under the moving load, the negative shear lag effect is remarkable, and the minimum shear lag coefficient is -3.5.