新型波形钢腹板组合箱梁温度效应

Temperature effect of new-type composite box girder with corrugated steel webs

针对由混凝土与钢材的热工参数差异显著而导致新型波形钢腹板组合箱梁温度效应突出的问题,考虑子梁微段平衡条件、子梁间变形协调条件和波形腹板剪切变形效应,建立竖向温度梯度作用下新型波形钢腹板组合箱梁相对滑移、内力和应力的理论计算方法.对大温差地区的新型波形钢腹板组合箱型试验梁进行温度长期观测,拟合结构竖向温度梯度函数,通过该理论方法计算实测温度梯度下的结构温度响应,利用有限元模拟对本文理论进行验证.结果表明,在实测温度梯度下,界面剪力、子梁弯矩和应力均沿梁纵向呈双曲余弦函数分布,层间相对滑移沿梁纵向呈双曲正弦函数分布.是否考虑腹板剪切变形效应对组合梁梁端向跨中0.8 m范围的温度效应影响较大,对组合梁中部的影响可以忽略.混凝土线膨胀系数、组合箱梁层间滑移刚度和界面温差对新型波形钢腹板组合箱梁温度效应的影响较大,在设计中应合理排布层间剪力连接件,考虑混凝土线膨胀系数的变异性对该类结构进行温度效应计算.

The temperature effect of new-type composite box girder with corrugated steel webs(CSWs)is prominent due to the significant difference of thermal parameters between concrete and steel.A theoretical calculation method for relative slip,internal force and stress of new composite box girder with CSWs under vertical temperature gradient was established.The equilibrium condition of sub-girder,deformation coordination condition between sub-girders and shear deformation effect of CSWs were considered.The temperature of new composite box test beam with CSWs in large temperature difference area was observed for a long time,and the vertical temperature gradient function of the structure was fitted.The temperature response of the structure under the measured temperature gradient was calculated by the theoretical method,and the theory was verified by finite element simulation.Results show that the interfacial shear force,the bending moment and the stress of the beam are all distributed as hyperbolic cosine function along the longitudinal direction of the beam under the measured temperature gradient.The relative slip between layers is distributed as hyperbolic sine function along the longitudinal direction of the beam.Whether the shear deformation effect of webs is considered greatly influences on the temperature effect in the range of 0.8 m from the end to the middle of the composite beam,and the effect on the middle of the composite beam can be ignored.The linear expansion coefficient of concrete,the sliding stiffness between layers and the interface temperature difference of composite box girder greatly influence on the temperature effect of the new composite box girder with CSWs.The interlayer shear connectors should be reasonably arranged in the design,and the temperature effect of the new composite box girder with CSWs should be calculated by considering the variation of the linear expansion coefficient of concrete.