In this paper, we describe the development and realization of a sensing system using a high-resolution temperature and strain sensor with fiber Bragg grating (FBG) technology and a simple and low-cost long-period grating (LPG) sensor for the water level measurement in pavement structures. The FBG sensor consists of a reference fiber grating and a grating pair scheme that could offer the potential of simultaneous measurement of strain and temperature for monitoring pavement structures. For FBG sensor, experimental results have shown that measurement errors of 6 micro strains and 0.13 Celsius for strain and temperature could be achieved, respectively. The LPG sensor was extremely sensitive to the refractive index of the medium surrounding the cladding surface of the sensing grating, thus allowing it to be used as an ambient index sensor. A LPG-type water level sensor with a resolution was of ~5 mm was demonstrated to distinguish between in the air and under water. This integrated FBG and LPG sensing system is expected to benefit the health monitoring of multi-layer pavement structures especially for the evaluation and application of new materials, mix design procedures or construction technology.

Date Published: 8 April 2008
PDF: 11 pages
Proc. SPIE 6932, Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2008, 69323Z (8 April 2008); doi: 10.1117/12.776532

Published in SPIE Proceedings Vol. 6932:
Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems 2008
Masayoshi Tomizuka, Editor(s)