融合多模态信息的中小跨径公路连续梁桥负弯矩冲击系数计算方法重构研究

中小跨径桥梁在国内公路桥梁中占比88.4%，与大跨径桥梁相比，中小跨径桥梁自重轻，受汽车的冲击作用影响非常显著。重车压垮桥梁的事故屡发，开展汽车荷载研究非常迫切，冲击系数是中小跨径桥梁汽车荷载效应中非常重要的组成部分。项目拟建立负弯矩冲击系数随机车辆荷载谱模型，揭示冲击系数计算的力学机理，提出负弯矩冲击系数计算方法。研究方法以理论、数值、试验并重，基于交通量调查提出公路连续梁桥负弯矩区的随机车辆荷载谱，为冲击系数理论计算提供真实荷载模型；基于机器学习算法，联合加权平均与数字滤波法提出冲击系数分析方法，对负弯矩冲击系数灵敏度进行数值演化分析，采用模态叠加法揭示负弯矩冲击系数力学作用机理；基于现场实测和Hilbert-Huang变换进行数据的盲源分离，提出冲击系数计算的概率统计模型，重构连续梁负弯矩冲击系数的多模态分析方法。预期成果可为桥梁冲击系数及荷载系统研究奠定理论基础。

There are plenty of small and medium span bridges in China, accounting for 88.4% of highway bridges. Compared with long-span bridges, small and medium-span bridges have lighter dead weight and are greatly affected by the impact of vehicle loads. It is very urgent to study the vehicle load because of the frequent accidents of bridge collapse caused by heavy trucks. The dynamic load allowance(DAL) is a very important part of the vehicle load effect of medium and small span bridges. The project intends to establish a random vehicle spectrum model for negative moment DLA, reveal the mechanics mechanism of DLA, and propose a calculation method of negative moment DLA. The research method is based on the combination of theory, numerical calculation and experiment. Firstly, the vehicle load spectrum for negative moment of bridges will be studied by traffic flow survey to give a reasonable vehicle model for theoretical analysis. Then, the weighted average method combining with numerical filter method will be explored, and sensitive parameters will be studied by machine-learning method. Next, based on the mode superposition, DLA calculation methodology will be presented in the continuous bridges, which will reveal the mechanics mechanism of negative moment DLA. Finally, uninterrupted dynamic response records in the field bridge is to be tested, using Hilbert-Huang transform(HHT) and statistics probability principle of the negative moment DLA formula will be proposed, and analysis method based on muti-mode for negative moment DLA of continuous girder bridges is to be reconstructed. The expected results can provide a theoretical foundation for the systematic study of DLA and vehicle load of bridges.