公路桥梁限载标准的可靠性分析方法

RELIABILITY-BASED ANALYSIS ON THE VEHICLE WEIGHT LIMIT OF HIGHWAY BRIDGES

  • 摘要: 基于结构可靠度理论,建立了公路桥梁不同可靠水平下的车辆荷载限载标准。根据公路桥梁抗力及荷载效应概率分布函数与统计参数,采用最基本荷载组合形式与不同的活恒载标准值效应比值,从设计可靠水平与最低容许可靠水平两个层次,分别计算了按新老规范设计桥梁的超载影响系数。在此基础上,以三轴载重汽车和五轴载重汽车为不同汽车运行状态下的标准限载车辆模式,提出了基于典型限载车辆模式的公路桥梁安全限载标准与最大容许限载标准。最后,考虑实际抗力水平的差异,给出了基于不同规范设计桥梁限载标准的分析方法。研究结果表明,该文提出的基于可靠性的公路桥梁限载标准,与现行规范衔接紧密,可作为公路桥梁限载与超重运输通行审核的依据。

     

    Abstract: Vehicle weight limits of highway bridges at various reliability levels were established based on structural reliability theory. This study refers to the probability distribution of load effects and bridge resistances, and uses the basic load combination and the ratio of live to dead load effects to calculate the live load influence coefficients at the design level and the minimum permissible level of reliability. Then, taking the three axles and five axles trucks as standard vehicles, this study suggests the safe and the maximum permissible vehicle weights for highway bridges. Finally, considering the difference in bridge resistances, this study presents an analysis method to determine the weight limit for general highway bridges. Results show that the vehicle weight limits proposed in this paper are consistent with current bridge design specifications, and can be used in load posting and permit checking for overweight trucks.

     

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