基于疲劳寿命的钢筋混凝土桥梁限载取值分析方法

发布时间：2018-03-18 19:05

本文选题：桥梁工程　切入点：桥梁限载　出处：《中国公路学报》2017年04期 　论文类型：期刊论文

【摘要】：为了确定钢筋混凝土桥梁限载的合理取值,针对钢筋混凝土桥梁的疲劳性能,考虑随机车流参数、超限车违规率等因素的影响,进行了基于疲劳寿命的桥梁限载取值分析方法研究,提出了一种基于S-N曲线和Palmgren-Miner线性累积损伤理论的桥梁限载取值分析方法。首先基于交通荷载资料和蒙特卡罗法进行随机车流模拟,根据桥梁限载试算值和超限车违规率剔除超限车得到修正的模拟随机车流;然后通过雨流计数法得到应力幅谱,根据S-N曲线和疲劳损伤准则计算桥梁疲劳寿命;最后取能使桥梁疲劳寿命达到期望值的限载试算值作为桥梁限载值。以某地区的交通荷载资料及跨径为20m的简支T梁桥为例,确定了在不同日均交通量和超限车违规率下能使桥梁疲劳寿命达到期望使用年限的桥梁限载值。研究结果表明:日均交通量和超限车违规率均显著影响桥梁的疲劳寿命及桥梁限载取值,日均交通量越大,桥梁的疲劳寿命越短;当日均交通量小于6 000veh时,在不同的桥梁限载值下桥梁的疲劳寿命均大于期望使用年限,当日均交通量大于8 000veh时,桥梁的疲劳寿命仅在特定桥梁限载值下才能达到期望使用年限;超限车违规率越大,通过调整桥梁限载值来提高桥梁疲劳寿命的效果越不明显,当超限车违规率较小时,桥梁的疲劳寿命随限载试算值的减小而大幅增长,当超限车违规率较大时,桥梁的疲劳寿命随桥梁限载试算值的减小,增幅并不明显。
[Abstract]:In order to determine the reasonable load limit value of reinforced concrete bridge, considering the influence of random traffic flow parameters and the rate of overrun, the fatigue behavior of reinforced concrete bridge is considered. In this paper, the analysis method of bridge load limit value based on fatigue life is studied. Based on S-N curve and Palmgren-Miner 's linear cumulative damage theory, a bridge load limit analysis method is proposed. Firstly, stochastic vehicle flow simulation is carried out based on traffic load data and Monte Carlo method. According to bridge load limit test value and overrun vehicle violation rate, the modified random vehicle flow is obtained, and then the stress amplitude spectrum is obtained by rain flow counting method, and the fatigue life of bridge is calculated according to S-N curve and fatigue damage criterion. Finally, the limited load test value, which can make the fatigue life of the bridge reach the expected value, is taken as the limited load value of the bridge. Taking the traffic load data of a certain area and the simply supported T-beam bridge with span of 20 m as an example, The bridge load limit values which can make the bridge fatigue life reach the expected service life under different daily average traffic volume and overrun vehicle violation rate are determined. The results show that the daily average traffic volume and the over-limit vehicle violation rate have a significant effect on the bridge fatigue. Fatigue life and bridge load limit, The fatigue life of the bridge is shorter when the daily average traffic volume is greater than 6 000 veh, and the fatigue life of the bridge is greater than the expected service life under different bridge limit values, and the average daily traffic volume is more than 8 000 veh. The fatigue life of the bridge can only reach the expected service life only under the limited load value of the specific bridge, and the greater the violation rate of the overrun vehicle, the less obvious the effect of improving the fatigue life of the bridge by adjusting the bridge load limit value, when the rate of over-limit vehicle violation is small, The fatigue life of the bridge increases greatly with the decrease of the limited load test value, but the increase of the fatigue life of the bridge is not obvious with the decrease of the limited load test value.
【作者单位】：湖南大学风工程与桥梁工程湖南省重点实验室;
【基金】：国家自然科学基金项目(51478176) 湖南省杰出青年基金项目(14JJ1014)
【分类号】：U441

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