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基于振动理论的桥梁损伤检测方法需要精确提取桥梁的动力参数,动力参数识别是桥梁损伤检测的首要步骤。为了提取5跨预应力混凝土简支梁桥的动力参数,在桥梁上进行了两组振动试验,分别研究了每跨桥梁的动力特征和5跨桥梁的整体振动特性。所有单跨的4阶动力参数将根据智能无线传感器测量结果,应用快速傅立叶变换、半功率带宽法和交叉反应谱法计算得到。同时也讨论了振动传输,激励跨桥梁和非激励跨桥梁之间的关系。研究结果表明:桥墩长度会影响桥梁的自振频率;存在碎石均布荷载的情况下振动可以在所有跨桥梁之间传播;受竖向激励的一跨桥梁主振型为弯曲模态,非激励跨桥梁主振型趋向于扭转模态。研究结果将作为桥梁健康监测技术的基础研究。
The bridge damage detection method based on the vibration theory needs accurate extraction of the dynamic parameters of the bridge. Dynamic parameter identification is the first step of the bridge damage detection. In order to extract the dynamic parameters of 5-span prestressed concrete simply supported beam bridge, two sets of vibration tests were conducted on the bridge, and the dynamic characteristics of each span of the bridge and the overall vibration characteristics of 5-span bridges were studied. The fourth-order dynamic parameters of all single spans will be calculated based on the measurement results of the smart wireless sensor using Fast Fourier Transform, half-power bandwidth method and cross-reaction spectrum method. Vibration transmission is also discussed, and the relationship between motivated and non-motivated bridges is discussed. The results show that the length of bridge piers will affect the natural frequency of the bridge, and the vibration can propagate across all bridges in the presence of uniform gravel load. The bending mode of a vertically-driven bridge is bending mode Excitation of the main vibration mode of the bridge tends to reverse the mode. The results will serve as the basic research of bridge health monitoring technology.