Long Gage-Length Interferometric Optical Sensors for Condition Assessment in Bridge Structures

Optical sensor technology is a potentially important element in the development of a bridge monitoring system. The present research has utilized the inherent characteristics of fiber-optic cable to develop a variable gage-length interferometric sensor. The major objective of the research was to develop a sensor for detecting changes in bridge structure dynamic response to be used in conjunction with pattern recognition techniques. Because sensor location is critical when using point sensors, long gage-length sensors are expected to be more effective in detecting changes in global dynamic response, effectively integrating the response along predetermined lengths of the structure.