基于模型修正的特殊行车状态下桥梁动态响应研究

Study on the Dynamic Response of Bridge under Special Driving Condition Based on Model Updating

针对目前桥梁特殊行车方面的研究不足,本文基于模型修正对车辆特殊行车状态下桥梁的动力响应进行了研究。建立依托工程桥梁的ANSYS初始模型,并结合现场试验数据和灵敏度分析对桥梁主要参数进行修正,从而获得反映桥梁真实状态的基准有限元模型。然后进行跳车、刹车试验采集动应变、加速度等实测数据,并与模型理论数据进行对比分析。结果表明:修正后的模型与实桥动力特性基本吻合,跳车工况下,跨中加速度峰值随着障碍物高度和行车速度的增加而变大,且冲击系数可达到1.84左右。刹车工况下,随着车速的增加纵向加速度和梁端纵向位移呈现增大的趋势,且L/2和3/4处刹车动力响应明显大于L/4处。

In view of the lack of research on bridge special driving at present,the dynamic response of bridge under special vehicle driving condition is studied based on model modification in this paper.ANSYS initial model based on engineering bridge is established,and the main parameters of the bridge are modified by combining the field test data and sensitivity analysis,and the benchmark finite element model reflecting the real state of the bridge is obtained.Then,the actual measured data such as dynamic strain and acceleration are collected by jumping and braking test,and compared with the theoretical data of the model.The results show the modified model is basically consistent with the dynamic characteristics of the real bridge.Under the condition of jumping,the peak value of the acceleration in the middle of the bridge span increases with the increase of obstacle height and driving speed,the impact coefficient can reach about 1.84.Under braking condition,the longitudinal acceleration and the longitudinal displacement of beam show an increasing trend with the increase of speed,and the braking dynamic response in L/2 and 3/4 position is significantly greater than that at L/4.