Structural health monitoring (SHM) is becoming critical in structural engineering and geotechnical engineering applications in recent years. The use of fiber optic distributed sensors for SHM has the advantage of long sensing distance, distributed sensing information and small size. Distributed fiber optic sensors can be used to monitor distributed temperature and strain information but also has application for used in detection of seismic activity, security sensing, and traffic/railway/bridge monitoring.
UC Berkeley researchers have developed methods and sensors for distributed dynamic strain measurement using optical fiber that results in a larger sensing signal, better signal-to-noise ratio and longer sensing distance up to a few km lengths. The system can take strain readings at every 4m along an 1km length optical fiber at 2.5 kHz sampling speed with a strain resolution of 30 microstrain.