钢-混凝土组合简支箱梁桥活载效应计算方法

Computation Method of Live Load Effect of Simply-supported Steel-concrete Composite Box Girder Bridge

为准确计算多梁式宽幅钢-混凝土组合简支箱梁的活载效应,基于Bredt扭转方程推导了钢-混凝土组合箱梁的抗扭刚度计算公式,研究了偏心压力法、刚接板法2种现行横向分布算方法对于该类桥梁的适用性,并与梁格法以及ABAQUS三维数值仿真的结果进行了对比分析。数值计算结果表明:计算边主梁的活载效应时,修正偏心压力法计算结果与空间实体有限元的结果相比偏于安全;计算中主梁的活载效应时,刚接板法与空间实体有限元结果吻合较好;梁格法也是一种较精确的计算方法。在进行此类桥梁的设计中,采用考虑横向分布系数的半解析算法仍然是可行的。

In order to compute the live load effect of ＇wide simply-supported multi-girder steel-concrete composite box girder accurately, the computing formula of torsional stiffness of steel-concrete composite box girder was derived based on the Bredt torsional equation. The suitability of the eccentric compression method and the rigid-joint-plate method, the two cun＇ent algorithms of load transverse distribution, to the bridge was studied. Then a comparative analysis of these methods with the results of the grillage analytical method and ABAQUS 3D numerical simulation was made. The numerical calculation results show that （ 1 ） the result of modified eccentric compression method is safer compared with that of spatial finite element method in computing the live load effect of side beam; （2） the results of rigid-joint-plate method and spatial finite element method corresponds well in computing the live load effect of middle beam ; （3） the grillage analytical method is also a relatively precise method. Half analytical algorithm considering transverse distribution coefficient is still feasible for this type of bridge.