钢桥面疲劳细节的车辆动力冲击响应研究

Vehicle-bridge Interaction Analysis of Orthotropic Steel Deck Bridge in Fatigue Details

选取佛陈新桥(三跨变截面连续钢箱梁桥)为研究对象,以35t标定三轴车进行跑车试验,结合有限元计算,对正交异性钢桥面疲劳细节的车桥动力性能展开研究.首先,将试验结果进行滤波处理,过滤掉噪声信号;然后,采用雨流法提取各个测点的应变幅值和循环次数;最后,按不同的疲劳细节计算出相应的冲击系数,并进行分析.研究发现:徐行与常速工况下,钢桥面均出现明显的车桥耦合现象.由于各疲劳细节处的局部刚度与构造的差异,各疲劳细节测点车桥动力冲击响应各不相同.其中,面板、U肋与隔板测点的冲击系数分别为0.219,0.245和0.394,均大于我国《正交异性钢桥面系统设计与维护指南》和美国AASHTO规定的0.15.研究结果表明目前的设计规范低估了车辆对钢桥面的动力冲击响应.

This paper studied the vehicle dynamic at fatigue details, based on a series of field tests on performance of orthotropic steel deck （OSD） bridge a 35 t 3-axle calibrated tractor across Fochen New Bridge （a three-span continuous steel box-girder OSD bridge） as well as finite element analysis. The results of the field tests were first filtered to remove the noise signal. The strain range and cycle times of each strain gauge were then obtained by using rain flow method. The impact factors of fatigue details were eventually calculated. The research shows that in both the crawl case and general speed case, the OSD bridge has obvious vehicle-bridge coupling vibration. Due to the differences in local stiffness and geometric construction at each fatigue detail, the impact factors at each fatigue detail exhibit different values. For in-stance, the impact factors of steel deck, U-rib, and cut-out in diaphragm are 0. 219, 0. 245, and 0. 394, respectively, which are all larger than 0.15 specified by ＂Orthotropic Steel Bridge Design and Maintenance Guide＂ and AASHTO specification. Therefore, the current vehicle design specification underestimates the vehicle dynamic response of the OSD bridges.