Critical buildings such as hospitals and police stations must remain functional immediately following a major earthquake event. Due to earthquake effects, they often experience large strains, leading to progressive collapses. Therefore, monitoring and assessing the large strain condition of critical buildings is of paramount importance to post-earthquake responses and evacuations in earthquake-prone regions. In this study, a novel large strain sensor based on the long period fiber grating (LPFG) technology is proposed and developed. CO2 laser induced LPFG sensors are characterized for such mechanical properties as strain sensitivity in extension and flexure, sensor stability, and measurement range. For practical applications, the need for LPFG sensor packaging is identified and verified in laboratory implementations. By introducing various strain transfer mechanisms, the strain sensitivity of LPFG sensors can be customized for different applications at corresponding strain transfer ratios.

Meeting Name

Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems (2009: Mar. 9-12, San Diego, CA)


Civil, Architectural and Environmental Engineering

Second Department

Electrical and Computer Engineering

Keywords and Phrases

Bending Effect; Large Strain; Long Period Fiber Grating (LPFG); Strain Sensitivity; Strain Transfer; Concrete Bridges; Earthquakes; Fiber Lasers; Law Enforcement; Mechanical Properties

International Standard Book Number (ISBN)


International Standard Serial Number (ISSN)


Document Type

Article - Conference proceedings

Document Version

Final Version

File Type





© 2009 SPIE, All rights reserved.

Publication Date

01 Mar 2009