基于风载激励下桥梁结构模态参数识别

Study on modal parameter identification method of bridge structure with wind load excitement

对桥梁结构长期运营造成的损伤进行检测时,传统的模态参数识别方法需要激振设备和中断交通,不仅复杂而且易给桥梁结构造成新的损伤。依据模态参数的变化可反映损伤程度的原理,提出无需激振设备的基于风载激励下随机减量/ITD法进行模态参数识别的在线检测方法,为桥梁结构损伤识别提供一种新的途径。识别的一阶固有频率及阻尼比的相对误差仅为1.39%和2.3%。

In long-term operation process, the bridge structure will be damaged. The traditional modal parameters identification methods need excitation devices and interrupt traffic, which will cause new damage to bridge structure. According to the principle of reflecting the damage defree by the changes of modal parameters, an on-line detection method without excitation devices is proposed based on random decrement/ITD method under the excitation of wind load, it provides a new path for damage identification of bridge structure. The relative error of identified first-order natural frequency and damping ratio is 1.39 % and 2. 3 % respectively.