Z24桥阻尼比长期变化影响因素及影响规律  

Long-term characteristics of damping ratio of the Z24 bridge influenced by different factors

作　　者：尚志强 夏烨 孙利民[3,4,5] 辛公锋 SHANG Zhiqiang;XIA Ye;SUN Limin;XIN Gongfeng(Shandong Hi-Speed Group Innovation Research Institute,Jinan 250102,China;Shandong Key Laboratory of Highway Technology and Safety Assessment,Jinan 250102,China;College of Civil Engineering,Tongji University,Shanghai 200092,China;State Key Laboratory of Disaster Reduction in Civil Engineering,Tongji University,Shanghai 200092,China;Shanghai Qizhi Institute,Shanghai 200232,China)

机构地区：[1]山东高速集团有限公司创新研究院,济南250102 [2]山东省高速公路技术和安全评估省级重点实验室,济南250102 [3]同济大学土木工程学院,上海200092 [4]同济大学土木工程防灾国家重点实验室,上海200092 [5]上海期智研究院,上海200232

出　　处：《振动与冲击》2023年第14期287-295,共9页Journal of Vibration and Shock

基　　金：国家重点研发计划(2019YFB1600702);国家自然科学基金(52278313);山东省交通运输厅科技项目(2021B51)。

摘　　要：为研究Z24桥阻尼比长期变化的影响因素及影响规律,首先利用该桥长期监测数据,采用加速度时间序列语义分割获取了大量的加速度自由衰减响应,由指数衰减法得到了为期约10个月的一阶阻尼比识别结果;然后分析结构温度、振动剧烈程度、结构损伤对阻尼比的影响规律。结果表明:Z24桥一阶阻尼比与结构温度具有极强的相关性,0℃以下时段,阻尼比随结构温度降低呈先增大后减小的非线性变化;0℃以上时段,阻尼比随结构温度升高而线性减小,二者相关系数最高可达0.98;环境激励(桥下通行车辆)与重物坠落激励下,阻尼比受振动剧烈程度的影响均无明显规律可循;阻尼比对各种结构损伤的存在与否亦无确切的指示性作用,由阻尼比获取更有效的损伤特征仍有待于进一步的研究。上述因素的影响规律应在结构振动控制设计、损伤识别等阻尼比应用场景中得到考虑,以提升结果的合理性与可靠性。To investigate the long-term characteristics of damping ratio of the Z24 bridge influenced by different factors,a time series semantic segmentation method was introduced to extract free attenuation data segments from monitored accelerations of the Z24 bridge.Then,the data of about 10-month damping ratio of 1st vibration mode were calculated using exponential attenuation method.Based on the calculated damping ratio,the influences of three factors including temperature,vibration intensity,and structural damage were analyzed.The results show that there exists a strong correlation between the damping ratio of the Z24 bridge and temperature variation.Specifically,the damping ratio exhibits an increasing trend followed by a decreasing trend after the temperature drops below 0℃,while the damping ratio exhibits a linearly decreasing trend after the temperature goes beyond 0℃,and that the correlation coefficient even reaches 0.98.The vibration intensity presents little impact on the damping ratio under the simultaneous action of excitations:vehicles passing below the bridge and dropping weight on the bridge.The structural damage also exhibits very limited influence on the damping ratio,thus further investigation is still required in the future to obtain effective damage features based on the identified damping ratio.The influences of the above factors should be considered in damping ratio-related applications including structural control and damage detection to achieve reasonable and reliable results.

关 键 词：Z24桥 桥梁结构健康监测 指数衰减法 阻尼比 影响因素 

分 类 号：U446[建筑科学—桥梁与隧道工程]