Abstract
This paper presents a new high-density structural health monitoring system and its application to earthquake recording in a high-rise seismic isolated building. The monitoring system consists of many smart sensors that have automated data acquisition and data communication functions. The smart sensors are e precisely synchronized with a time server by using Network Time Protocol. The system shows its accuracy of time synchronization meets the requirement for synchronized multipoint measurement; time lag between the sensors verified less than 1 millisecond on standalone use, and about 4 milliseconds in multilayer network equal to actual network of the target building. The system observed greater than 90 earthquakes during two years from October 2011. Due to precise synchronization and dense placement of seismometers, relative story displacements among each level can be estimated from a series of acceleration record and show the good agreement with the records obtained by contact displacement meters.
