Title: Fiber-Optic Sensors for Concrete Strain-Stress Measurement

Author(s): Antonio Nanni, C. C. Yang, Kun Pan, Jy Shiaw Wang, and Robert R. Michael Jr.

Publication: Materials Journal

Volume: 88

Issue: 3

Appears on pages(s): 257-264

Keywords: concretes; fiber optics; measurement; nondestructive tests; strains; stresses; structures; Materials Research

DOI: 10.14359/1785

Date: 5/1/1991

Abstract:
A nondestructive testing method based on fiber-optics for in situ measurement of strain-stress in concrete structures is presented. When an optical fiber is embedded in concrete and its refractive index, dimension, and/or shape are changed as a result of the surrounding matrix deformation, the characteristics of the light signal transmitted along the fiber are modified. Optical techniques capable of determining the changes in light characteristics (intensity, polarization, and phase) are described. The two most promising techniques for concrete structure diagnostics are demonstrated in the laboratory using concrete cylinders subjected to unconfined uniaxial compression with optical fibers embedded in the direction parallel and perpendicular to the applied strain (load). Experimental results are encouraging and indicate that fiber-optic sensors can be a feasible tool for determining strain-stress distribution in buildings and infrastructure.