THEORY AND EXPERIMENTS ON BIREFRINGENT OPTICAL FIBERS EMBEDDED IN CONCRETE STRUCTURES

Theoretical and experimental results on birefringent optical fibers em bedded in concrete are presented and discussed. We study the effect of strain on the propagation of light in birefringent fibers embedded in a host material loaded under uniform compression. Both longitudinal a nd transverse deformations are considered in the analysis since the fi ber is embedded along a direction perpendicular to the strain load. Th e effects of the strain on the birefringence of the fiber and the rota tion of the optical axes are studied. The theoretical model is used to determine the best polarimetric system configuration to detect strain . Our experimental work was performed by embedding optical fibers in s tandard concrete cylinders, attaching resistive electric strain gauges on the surface, and testing the specimens under uniform compressive s tress. Optical transmission data from the fiber and readings from the electric strain gauges were simultaneously recorded.