Seismic response of a suspension bridge: Insights from long‐term full‐scale seismic monitoring system
Seismic response of a suspension bridge: Insights from long‐term full‐scale seismic monitoring system
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DOI：
10.1002/stc.2252
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发表时间：
2018-08
影响因子：
5.4
通讯作者：
D. Siringoringo;Y. Fujino
中科院分区：
文献类型：
--
作者：
D. Siringoringo;Y. Fujino
本文描述了基于长期监测系统获得的数据对白鸟吊桥地震反应的评估。该桥总跨长1,380 m，拥有由27通道加速度计组成的永久监测系统，自1998年开通以来一直记录地震反应。1998年至2006年间，监测系统记录了约213次不同震级的地震，其中包括2003年十胜冲、2004年钏路冲、2004年钏路冲等主要地震。钏路和2005年 宫城冲地震。通过多输入多输出时域系统识别、时频分析和反演分析来研究地震响应特性。从记录的四次最大地震中可以看出，梁响应通常以频率在 0.3 至 0.6 Hz 之间的模式为主，对应于高阶垂直弯曲模式。还观察到与低阻尼的 0.6 Hz（塔同相）和 0.8 Hz（塔异相）独立塔横向频率相对应的显着塔振动。 213组地震记录的系统识别结果显示了主梁模态的固有频率和阻尼比对地震动振幅的依赖性。观察到随着地震动振幅的增加阻尼增加和固有频率减少的趋势。这种行为可以通过使用不同激励幅度下识别的模态参数的逆分析方法来解释。此外，还阐明了轴承摩擦力引起的刚度和阻尼变化的影响。
This paper describes an assessment of seismic responses of Hakucho Suspension Bridge based on data obtained from long‐term monitoring system. The bridge with a total span length of 1,380 m has a permanent monitoring system consisting of 27 channels of accelerometers, and seismic responses have been recorded from its opening in 1998. Between 1998 and 2006, the monitoring system has recorded about 213 earthquakes with various amplitude, including the major ones such as the 2003 Tokachi‐Oki, the 2004 Kushiro‐Oki, the 2004 Kushiro, and the 2005 Miyagi‐Oki earthquakes. Studies by multi‐input multi‐ouput time‐domain system identifications, time–frequency analysis, and inverse analysis were conducted to investigate seismic response characteristics. From the four largest recorded earthquakes, it was observed that girder responses are generally dominated by the modes with frequencies between 0.3 and 0.6 Hz corresponding to the higher order of vertical bending modes. Significant pylon vibration that corresponds to stand‐alone pylon lateral frequencies at 0.6 Hz (pylon in phase) and 0.8 Hz (pylon out of phase) with low damping was also observed. Results of system identifications from 213 sets of seismic record show dependency of natural frequencies and damping ratios of girder‐dominant modes on the amplitude of ground motion. The trends of increase in damping and decrease in natural frequency as the ground motion amplitude increases were observed. This behavior is explained by an inverse analysis method using identified modal parameters at different amplitude of excitation. Furthermore, effect of stiffness and damping variation caused by the friction force at the bearings was clarified.