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Proceedings Paper

Applications of absolute extrinsic Fabry-Perot interferometer (EFPI) fiber optic sensing system for measurement of strain in pre-tensioned tendons for prestrained concrete
Author(s): Marten J. de Vries; Vikram Bhatia; Richard O. Claus; Kent A. Murphy; Tuan A. Tran
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Paper Abstract

The application of a state-of-the-art fiber optic sensing system for the quantitative analysis of strain in strands used in prestressed concrete is proposed. Compressive stress in concrete is used to counterbalance any tensile force due to loading, which might lead to cracking or deflection. In pre-tensioning prestressed concrete, a tendon is tensioned before concrete is placed and the prestress is transferred to the concrete after it has cured by releasing the tension on the tendon. In linear prestressing it is often required to determine the axial strain on the tendon during the initial procedure of pre-tensioning, so that the required longitudinal force to achieve maximum concrete strength, can be accurately determined. Conventional techniques for this purpose involve the use of conventional foil strain gages, which are not only expensive to use, but are also known for their failure rate in high strain environments. We discuss the absolute extrinsic Fabry-Perot interferometer (AEFPI) fiber optic sensing system for monitoring strain in pretensioned tendons while this tendon is being loaded. The experiments performed at the Turner Fairbanks Federal Highway Administration at McLean, Virginia exhibit the survivability of the EFPI sensor at strain in excess of 12,000 (mu) (epsilon) while being attached to the tendon surface. The results are compared to those obtained from a collocated foil strain gage and excellent correlation is obtained. Applications of the AEFPI system to high performance smart materials and structures are analyzed and future work in this area is discussed.

Paper Details

Date Published: 20 April 1995
PDF: 7 pages
Proc. SPIE 2446, Smart Structures and Materials 1995: Smart Systems for Bridges, Structures, and Highways, (20 April 1995); doi: 10.1117/12.207735
Show Author Affiliations
Marten J. de Vries, Virginia Polytechnic Institute and State Univ. (United States)
Vikram Bhatia, Virginia Polytechnic Institute and State Univ. (United States)
Richard O. Claus, Virginia Polytechnic Institute and State Univ. (United States)
Kent A. Murphy, Virginia Polytechnic Institute and State Univ. (United States)
Tuan A. Tran, Fiber and Sensor Technologies, Inc. (United States)


Published in SPIE Proceedings Vol. 2446:
Smart Structures and Materials 1995: Smart Systems for Bridges, Structures, and Highways
Larryl K. Matthews, Editor(s)

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