ABSTRACT

ABSTRACT: Recent surge in design and construction of cable stayed structures, especially bridges necessitates monitoring to assess structural health, safety and behavior for further improvements in design. Many of these structures are currently being monitored by using conventional sensors such as accelerometers, and strain gauges. Moreover, most of the sensors are installed within the deck system and employ vibration based structural health monitoring methodologies for assessment of structural characteristics. This approach has proven effective for certain types and sizes of bridges. However, effective condition monitoring of larger and more complicated structures require placement of multitudes of sensors in order to extract useful information beyond the signal to noise ratio levels experienced in such structures. Moreover, since stay cables contribute immensely to the capacity of the bridge in carrying the structural loads, direct monitoring of their health will be essential in structural health monitoring programs. The work presented here will discuss the collaborative research that has been undertaken by the University of Illinois at Chicago and the Polytechnic of Torino in assessment of fiber optic sensors in structural health monitoring of cables. This program aims at development and testing of robust field deployable fiber optic sensors based on Bragg gratings and interferometric principles for monitoring of cable forces, deformations and the dynamic response. Besides all the obvious advantages of optical fibers sensors in such applications, the very high signal to noise ratio levels in optical sensing will prove to be very effective in this application. Structural health monitoring analysis techniques are developed for direct assessment of the bridge condition based on monitoring of the cable stays. This research will potentially provide a cost effective approach in structural health monitoring of cable stayed bridges.