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为了明确汽车荷载分项系数变化对桥梁构件可靠度水平的影响规律,利用校准法对受拉、受弯、大偏心受压(短柱)、轴心受压(短柱)、受剪共5类受力构件,选取0.1,0.25,0.5,1,1.5,2.5六种活恒载效应比,进行了不同汽车荷载分项系数条件下构件的可靠度分析。对于可靠度指标分布不均匀的状况,提出了可靠度修正系数的概念并进行了验证计算,对不同类型构件按照活恒载效应比给出了可靠度修正系数的计算结果。结果表明:汽车荷载分项系数由1.4递增至2.4时,各类构件可靠指标均呈增大趋势;活恒载效应比小于1时,该分项系数每增加0.2,构件可靠指标随之增大0.1~0.3,活恒载效应比大于1时,该分项系数每增加0.2,构件可靠指标随之增大约0.4;活恒载效应比大的构件可靠指标值偏高,且该类构件可靠指标受汽车荷载分项系数的影响也较大;所提出的可靠度修正系数能够调整抗力值以达到目标可靠指标的要求,该系数分布于0.4~1.1之间,各类型构件可靠度修正系数分布规律一致,均随活恒载效应比及汽车荷载分项系数的增大而减小。
In order to clarify the influence of sub-coefficient changes of automobile load on the reliability of bridge components, the calibration method is used to calculate the influence of tension, bending, big eccentric compression (short column), axial compression (short column) Six kinds of six kinds of live load effect ratio of 0.1, 0.25, 0.5, 1, 1.5, 2.5 are chosen to carry out the reliability analysis of the components under different load factors. For the uneven distribution of reliability index, the concept of reliability correction coefficient is proposed and validated. The calculation results of reliability correction coefficients are given for different types of components according to the live-dead load effect ratio. The results show that the reliability index of all kinds of components increases when the partial load factor of automobile increases from 1.4 to 2.4. When the ratio of live load to load is less than 1, the reliability index increases with the increase of sub-coefficient of 0.2 0.1 ~ 0.3. When the ratio of live load to dead load is greater than 1, the reliability index of components increases by about 0.4 with each additional factor of 0.2. The reliability index of components with larger live load than that of larger ones is higher, Which is affected by the sub-coefficient of the vehicle load. The proposed reliability correction coefficient can adjust the resistance value to meet the requirements of the target reliability index. The coefficient is distributed between 0.4 and 1.1. The distribution rules of the reliability correction coefficients of various types of components Are consistent with the live constant load effect and the car load sub-coefficient increases.