港口公路桥梁疲劳荷载谱研究与应用
Research and application of fatigue load spectrum of port highway bridge

为了对港口公路桥梁疲劳荷载谱进行研究，以浙江沿海一座港口公路桥梁为背景，连续跟踪其1年内的通行车辆荷载信息，研究港口公路桥梁的疲劳荷载谱。首先根据车轴数量和轴距将桥上通行车辆划分为7类，从车流量、轴载质量和轴距3个方面分析港口公路桥梁车辆荷载的分布特征；然后根据等效疲劳损伤原理，计算各车型的等效轴载质量和等效轴距，得到港口公路桥梁疲劳荷载谱；最后应用得到的疲劳荷载谱，采用热点应力法对该港口公路桥梁正交异性钢桥板的3个关键疲劳细节进行寿命评估。结果表明：两侧慢车道车流量占主要地位，占比高达总量的79.5%；四轴以上货车（V4~V7）在总车流量中占比高达81.5%，以V4、V5和V7为主；其中四轴车轴载质量均服从混合高斯分布，轴距均服从典型高斯分布；在港口公路桥梁疲劳荷载谱中，所有等效疲劳车辆的质量均大于10 t，并且四轴以上货车占比高达85.9%；四轴以上货车对钢桥面板的疲劳损伤贡献率超过90%，其中五轴车和六轴2类车占比最高，约为70%，三轴2类车的疲劳损伤贡献率最低，占比不到1%；评估得到该桥钢桥面板的3个关键疲劳细节的疲劳寿命均小于设计使用寿命，并且疲劳细节P2和P3的疲劳寿命仅为4.4年和6.1年，后续应对其加强监测，以确保桥梁结构安全；得到的疲劳荷载谱对今后港口公路桥梁的抗疲劳设计和疲劳损伤评估具有较强的参考价值，疲劳寿命评估结果对该桥的后期维护具有指导意义。
In order to study the fatigue load spectrum of port highway bridge, a highway bridge in the port in Zhejiang coast was used as a background to continuously track its load information of vehicles within 1 year to study the fatigue load spectrum of port highway bridge. First, the vehicles of the port highway bridge were divided into 7 categories based on the number of axle and wheelbase, and the distribution characteristics on the vehicle load of port highway bridge were analyzed from traffic volumes, the quality of axle load and wheelbase. Then, according to the principle of equivalent fatigue damage, the quality of equivalent axle load and the equivalent wheelbase of every type of vehicles were calculated to obtain the fatigue load spectrum of port highway bridge. Finally, based on this fatigue load spectrum, the fatigue life of three key fatigue details of this bridge？？s orthotropic steel deck was evaluated by hot spot stress method. The results show that the traffic volume of the slow lanes on both sides accounts for 79.5% of the total, weight vehicles with four or more axles (V4 to V7) accounts for 81.5% of the total traffic volume and the dominating types are V4, V5, V7. The axle loads of the 4？？axle truck obey mixed Gauss distribution, and the wheelbase obey Gauss distribution, in the fatigue load spectrum of port highway bridge, the weight of all equivalent fatigue vehicles is bigger than 10 t, and four or more axles trucks account for 85.9%. The contribution rate of fatigue damage of four or more axle trucks to the steel deck is more than 90%, of which the ratio of the 5？？axle truck and the second type of 6？？axle truck accounts for 70% of the total traffic volume, while the ratio of second type of 3？？axle vehicle is the lowest, accounting for less than 1%. The fatigue life of this bridge？？s three key fatigue details is evaluated to be less than the designed service life, and the fatigue life of P2 and P3 is only 4.4 years and 6.1 years, so it？？s necessary