汽车荷载分项系数对桥梁构件可靠度的影响及修正

发布时间：2019-06-10 14:29

【摘要】：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。
[Abstract]:In order to determine the influence of the change of the sub-item coefficient of the vehicle load on the reliability level of the bridge member, the tension, the bending, the large eccentric compression (the short column), the axial compression (short column) and the shear-type 5 stress component are selected by the calibration method, and the six live dead load effect ratios of 0.1, 0.25, 0.5,1, 1.5, and 2.5 are selected, The reliability analysis of the component under the condition of the sub-coefficient of different vehicle loads is carried out. In this paper, the concept of reliability correction coefficient is put forward for the condition of non-uniform distribution of reliability index, and the calculation results of the reliability correction coefficient 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 is increased by the increment of 1.4 to 2.4. When the ratio of live and dead load is less than 1, the reliability index of the component is increased by 0.2, the reliability index of the component is increased by 0.1-0.3, and the live-dead-load effect ratio is greater than 1. the reliability index of the component is higher than the large component reliability index value, and the reliability index of the component is greatly influenced by the vehicle load sub-item coefficient; the proposed reliability correction coefficient can adjust the resistance value to meet the requirement of the target reliable index, The coefficient is distributed between 0.4 and 1.1, and the distribution of the reliability correction coefficient of each type component is consistent, and the coefficient is reduced with the increase of the live and constant load effect ratio and the vehicle load sub-item coefficient.
【作者单位】：长安大学公路学院;
【基金】：陕西省自然科学基础研究计划项目(2012JQ7004) 中央高校基本科研业务费创新团队项目(2013G3214010)
【分类号】：U441.2

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