Abstract
A dual vibration monitoring system of a base-isolated building is developed to observe both strong earthquake response and continual long-term ambient vibration. The advantage of the monitoring system is to obtain a complete set of an earthquake record and the ambient vibration records before and after the earthquake, which are useful to establish vibration-based techniques for structural heslth monitoring (SHM). This paper presents the detail of the monitoring system and its recent results on SHM studies by the authors. The results show that the day fluctuations in the first and second natural frequencies are mutually independent, and slight change of the modal parameters between ambient vibration tests conducted at the different time, which can be introduced only by the long-term vibration monitoring.
