根据编制中国《钢-混凝土桥梁设计与施工细则》的需要,对钢-混凝土组合桥梁中组合梁的承载力进行了可靠度分析,其中承载力包括抗弯承载力、纵向抗剪承载力和竖向抗剪承载力。利用最大熵函数构造的凝聚函数,将分段表达的抗弯承载力和纵向抗剪承载力集成为一个计算公式,进而计算了钢-混凝土组合梁抗力的统计参数。给出了材料分项系数sγ取1.1、1.15和1.2时3种抗力统计参数的计算结果,其中车辆荷载按汽车一般运行状态和密集运行状态2种情况考虑。可靠度分析结果表明:组合梁抗弯承载力和纵向抗剪承载力的可靠指标比较接近,当sγ=1.15时,一般运行状态可靠指标在5.0~5.9之间,密集运行状态可靠指标在5.4~6.5之间;竖向抗剪承载力的可靠指标较小,当sγ=1.15时,一般运行状态可靠指标在4.1~5.0之间,密集运行状态可靠指标在4.0~5.5之间。
For the purpose of revising Guidance of Design and Construction of Steel-concrete Composite Bridge, the bearing capacity reliability of steel-concrete composite bridge was analyzed, and bearing capacity consisted of bending capacity, longitudinal and vertical shear bearing capacity. In order to obtain statistical parameters of steel-concrete composite girder expediently, using coherency function formed by the maximum entropy principle, the expressions of bending capacity and longitudinal shear bearing capacity, which are multi-piece function were integrated into one formula. The statistical parameters of bearing capacity under the conditions that 7s equals to 1.1, 1.15 and 1.2 were calculated. General operation state and dense operation state were considered for vehicle load. It indicates that the reliability index of bending capacity is close to that of longitudinal shear bearing capacity. When γ equals to 1.15, the reliability index of general operation state is between 5.0 and 5.9 and dense operation state is between 5.4 and 6.5; the reliability index of vertical shear bearing capacity is correspondingly small; general operation state is between 4.1 and 5.0 and dense operation state is between 4.0 and 5.5.