钢-混组合连续梁桥墩顶应力计算研究

Study on Stress Calculation of Pier’s Top of Steel-Concrete Composite Continuous Beam Bridge

基于有限元分析,对某4跨钢-混组合连续梁桥进行混凝土面板与钢梁的3个不同建模形式进行分析,对比规范要求的不同建模形式下墩顶负弯矩区混凝土面板钢筋应力与钢梁应力的变化关系。研究结果表明:将开裂区钢筋等效为混凝土,与钢梁形成组合截面的建模形式计算得到的钢筋换算应力与钢梁应力均适中,所以推荐采用该种建模方式进行计算;此外在偏保守的情况下,将开裂截面钢筋与钢梁形成组合截面,钢筋应力乘以大于1的修正系数μ这种建模形式适用于钢梁的设计;直接将开裂刚度设定为0.65倍混凝土刚度的建模形式适用于混凝土裂缝计算。

Three different modeling forms of concrete slab and steel beam were analyzed for a four-span steel-concrete composite continuous beam bridge by finite element.Under different modeling forms required by the code,the relationship between stress of concrete slab and steel beam of pier top is compared in negative moment zone.The results show:when the reinforcement in the cracking zone is equivalent to concrete,the composite section was formed by the reinforcement and steel beam,then the converted stress of steel bars and the steel beam stress are moderate by calculated.This modeling method is recommended to be used for calculation.In addition,under a little conservative condition,the composite section is formed by the reinforcement in the cracking section and steam beam.The modeling form that reinforcement stress times correction factor u greater than 1 is suitable for design of steel beam.The modeling form that the cracking is 0.65 times as stiff as concrete is suitable for the calculation of concrete cracks.