This study proposes a micro vibration mitigation system using viscous dampers to solve the problem of vibration in a high-tech building. Due to the operating frequency of the air conditioners and fundamental mode of the fl oors, a resonant phenomenon is occasionally experienced at the upper levels of the structure. Several strategies were considered, and viscous dampers combined with a suspension system were chosen to mitigate this annoying situation. A theoretical analysis was fi rst executed to determine the optimal design value of the damper and the suspension spring. An effi cient reduction in fl oor velocity of approximately 50 % was achieved by the proposed system. Practical verifi cations including a performance test of the micro-vibration-oriented dampers, the pragmatic application result, and a comparison in one-third octave spectrum was then carried out. The performance of the system was demonstrated by the data measured. It alleviated more trembling than was numerically expected. The energy absorbed by the viscous dampers is illustrated by the hysteresis loops and the one-third octave spectrum. It is found that with the proposed system, the vibration can be effectively captured by the viscous damper and converted to lower frequency-content tremors. The success of this project greatly supports the proposed standard two-stage analysis procedure for mitigating micro-vibration problems in practice. This research extends the use of viscous dampers to a new fi eld.

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Following the 2008 Wenchuan (China) earthquake, the civil engineers association from Taiwan immediately dispatched a team to the affected region to collect information about the structural and geotechnical damage, and to provide information for seismic assessment, retrofitting and reconstruction planning. This team reached the damaged areas close to the epicenter—including Chengdu, Dujiangyan, Pongzhou, Xiaoyudong, Mianzhu, Zhiulong, Wudu, Hanwang, Hsuanko, Yingxiu (epicenter), and Highway 213—to survey the affected schools, hospitals, residential buildings, landslides, and bridges. More than 5,000 photos were taken to document the damage that resulted from the catastrophic earthquake ( http://www.ncree.gov.tw/eng/index.htm ). It is hoped that the information obtained can help us to develop a disaster mitigation plan. This paper focuses on the damage to different types of bridges, including those with simple support, arch, and continuous elements. The information shared in this study can help us build a community that will be safer in the future.