Π形梁斜拉桥主梁剪力滞特性试验

Test on shear lag of cable-stayed bridge with П-shaped cross section main girder

为研究Π形截面斜拉桥主梁的剪力效应,通过在一新建Π形截面斜拉桥主梁中预埋钢弦式传感器,全程跟踪实测了主梁各施工阶段以及成桥状态下各测试截面的轴向应力;建立了该桥的三维实体有限元模型,并将计算结果与实测值进行了对比。结果表明:Π形截面斜拉桥主梁根部截面的剪力效应比跨中截面的更为显著;其主梁横截面轴向应力横向分布曲线存在多个拐点,剪力滞效应很难采用单个参数加以描述;预应力以及横坡对Π形截面斜拉桥主梁轴向应力的横向分布规律有明显影响,计算中不可忽略预应力束或横坡的影响。

In order to analyze the shear lag effect of cable-stayed bridge with H-shaped cross section girder, the axial stress distribution of test sections of a newly-built cable-stayed bridge with U-shaped cross section girder was tested by the steel string strain sensors, which were embedded in main girder during construction. A 3D solid finite element model of this bridge was established, and the finite element calculations were compared with the experimental investiga- tions. The results show that： the shear lag effect is more serious at the root of the H-shaped cross section girder than the one at its mid-span; the axial stress distribution curve of all sections has several knee points and so it is difficult to describe the shear lag with one parameter; the presstress and transverse slope of the girder have much effect on the shear lag, and they should not be neglected during calculation. 14 figs, 8 refs.