多肋式梁桥模态参数分解识别与试验研究

针对现役大量的多肋式钢筋混凝土板梁和T梁桥在横、纵桥向表现出的明显正交异性构造特征,将多肋梁等效成比拟正交异性板,应用动力分析有限条方法,建立起系统自由振动数值模型,从而实现整桥模态参数向单肋梁的分解和识别。根据模型试验桥从完整到破坏不同荷载等级作用下室内动力试验成果,选取能够反映钢筋混凝土梁振动响应特性的截面等效动刚度作为目标参数进行预测。通过对结果规律对比分析,验证了本方法在该类桥梁结构检测评估中应用的可行性和高效性。

Modal Parameter Identification for Multi-rib Beam Bridges and Experiment Study

Due to distinct orthotropic property along longitudinal and transverse directions of existing pre-cast RC slab beams or T-beam bridges, they are simplified as assimilated orthotropic plates. By means of finite strip method, the numerical model for the free vibration of the system is found. Furthermore, the modal parameter identification can be achieved. According to the experimental data obtained using dynamic tests on an indoor bridgemodel with diffenent loads from intact to destroying levels, the equivalent dynamic stiffnesses reflecting the vibration behavior of a RC single beam are predicted as the objective index. Through analyzing the study results, the feasibility and efficiency of the proposed method are verified.