Implementation of EFPI-based optical-fiber sensor instrumentation for the NDE of concrete structures

This paper reports on the design and implementation of an optical-fiber sensor based on the extrinsic Fabry-Perot interferometer (EFPI) for the non-destructive quantitative evaluation of advanced concrete-based civil structures. The performance of the EFPI sensor is demonstrated in two different applications. In the first implementation, performed with researchers in the Civil Engineering Department at the University of Southern California in Los Angeles, optical-fiber sensors were used to obtain quantitative strain information from reinforced concrete interior and exterior column-to-beam connections. The second implementation, performed in co-operation with researchers at the Turner Fairbanks Federal Highway Administration Center in McLean, Virginia, used optical-fiber sensors, attached to composite prestressing strands used for reinforcing concrete, to obtain absolute strain information. The paper is concluded with a discussion of practical considerations that need to be taken into account when implementing optical-fiber sensors in a concrete civil structure environment.