用结构可靠性理论探讨了影响钢筋砼简支梁桥上部结构承载能力可靠指标的主要参数,并用电算程序定量地分析了它们的影响程度。计算结果表明,除了荷载及某些不便于自行确定的统计参数外,对可靠指标影响较大的依次是截面有效高度、不定性系数、钢筋截面面积、钢筋抗拉设计强度及砼轴心抗压设计强度。 With the theory of structural reliability, the main parameters that affect the reliability index of the bearing capacity of the superstructure of the simply-supported reinforced concrete girder bridge are discussed. The degree of influence is quantitatively analyzed by using the computer program. The calculated results show that except for the load and some statistical parameters which are inconvenient to be determined by themselves, the effective factors such as the effective cross-section height, the coefficient of uncertainty, the cross-sectional area of ​​reinforcing bars, the tensile strength of steel bars and the compressive strength of concrete axis Design strength.