变截面波形钢腹板组合箱梁腹板剪应力实用计算方法研究

Research on practical shear stress calculation of variable cross-section composited box-girder with corrugated steel webs

为了计算变截面波形钢腹板组合箱梁腹板中的剪应力及其承剪比,考虑变截面效应,通过弹性微元段的受力平衡方程,计入弯矩和轴力引起的附加剪应力,导出变截面波形钢腹板组合箱梁的腹板剪应力计算公式;依据节段施工的波形钢腹板组合箱梁桥结构的建造特点,考虑节段内梁底线形为线性变化,将公式中各参数的微分运算转化为简单的代数运算,给出实用求解方法;最后通过算例对所推导公式的计算结果与等截面计算公式和有限元数值结果进行对比。研究结果表明:变截面梁的梁高和底板厚度的变化对剪应力有较大影响,波形钢腹板剪应力计算应当考虑变截面效应影响,波形钢腹板剪应力实用计算方法能方便工程应用。

To calculate shear stress and shear ratio of corrugated steel webs, considering the effect of the variable cross-section, using the equilibrium equation of the elastic infinitesimal segment, adding the additional shear stress caused by the bending moment and axial force, the shear stress formula of variable cross-section composite box-girder with corrugated steel webs is derived. In accordance with the construction characteristics of the variable cross-section composited box-girder with corrugated steel webs, considering linear shaped of girder bottom surface, transforming the parameters’ differential operation to algebraic operation in the formula, the practical method is given. Through the example, the method is used at last, and the result of the derived formula is compared with the results of the constant section’s calculation formula and finite element numerical analysis, respectively. From the results, it is indicated that the beam’s section height and bottom plate thickness have great influence on the shear stress. And the effect of the variable cross-section should be considered when the corrugated steel webs shear stress is calculated. Then the method can be provided to be a convenient practical method for the engineering applications.