采用GB50199-94《水利电力工程结构可靠度设计统一标准》推荐的一次二阶矩法(亦称JC法)对DL/T5039-95《水利水电工程钢闸门设计规范》中的平面钢闸门主梁分别按弯曲、剪切及弯剪复合3种破坏形态进行了可靠度校准分析，初步了解了现行规范中组合主梁的总体可靠度水平，其中在对弯剪复合应力状态下的可靠度进行校准分析时，考虑了不同荷载效应比值B的影响，并采用非线性的极限状态方程按双重迭代的方法求得相应的可靠指标。

Using the method of first-order-second-moment recommended in GB50199-94 Unified Design Standard for Structural Reliability of Hydraulic Engineering, the authors analyze the reliabilities of composite main girder of plane steel gates in DL/T 5039-95 directing respectively at failure states of bending, shearing and combination bending with shearing. In the reliability analysis of failure state of combination bending with shearing, the authors consider the influences of different load-effect ratios ρτ, and using non-liner limit state equation and double-interation method, obtain the corresponding reliability index β.