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为了研究交通量对悬索桥钢箱梁细节疲劳安全水平的影响,基于实测车流数据分析了悬索桥钢箱梁顶板-U肋的细节疲劳可靠度;基于S-N曲线和线性累积损伤准则建立了考虑交通量参数的钢桥细节疲劳可靠度模型;在WIM(动态称重系统)实测车流数据的基础上建立了随机车流模型,分析了车辆运行状态和交通量增长对钢箱梁构造细节疲劳可靠度的影响。研究结果表明:密集运行状态下悬索桥跨中顶板-U肋细节的等效应力幅和日循环次数分别是稀疏运行状态下的1.52倍和2.50倍,实际运行状态下的疲劳可靠指标在1~100年内由6.25降至3.58;交通量和运营期的增长致使钢箱梁细节疲劳损伤和疲劳可靠指标显著下降,当交通量线性增长系数达到6%时,100年后钢箱梁细节疲劳可靠指标仅为2.96。在运营期,通过实测车流数据评估钢箱梁细节疲劳可靠度尤为重要。
In order to study the influence of traffic on the fatigue safety level of the steel box girder, the fatigue reliability of the steel roof-U rib of the suspension bridge is analyzed based on the measured traffic flow data. Based on the SN curve and the linear cumulative damage criterion, Based on the data of WIM (Dynamic Weighing System) measured traffic flow, a random traffic flow model was established, and the influence of vehicle running status and traffic volume on the fatigue reliability of the structural details of steel box girders was analyzed. The results show that the equivalent stress amplitude and the number of daily cycles of the -U rib detail of the mid-span suspension bridge under intensive operation are 1.52 times and 2.50 times respectively under the sparse operation condition, and the fatigue reliability index under the actual operation condition is between 1 and 100 During the year, the number of steel box girders decreased from 6.25 to 3.58. The increase of traffic volume and operation period resulted in the obvious decrease of fatigue damage and fatigue reliability of steel box girder. When the linear growth coefficient of traffic volume reached 6%, the fatigue reliability index of steel box girder 100 years later was only Is 2.96. During the operation period, it is particularly important to evaluate the fatigue reliability of the steel box girder through the measured flow data.