Structurally embedded fiber Bragg gratings: civil engineering applications

Philipp M. Nellen; Rolf Broennimann; Andreas Frank; Pascal Mauron; Urs J. Sennhauser

doi:10.1117/12.372954

9 December 1999 Structurally embedded fiber Bragg gratings: civil engineering applications

Philipp M. Nellen, Rolf Broennimann, Andreas Frank, Pascal Mauron, Urs J. Sennhauser

Proceedings Volume 3860, Fiber Optic Sensor Technology and Applications; (1999) https://doi.org/10.1117/12.372954
Event: Photonics East '99, 1999, Boston, MA, United States

Abstract

In civil engineering it is of interest to monitor long-term performance of structures made of new lightweight materials like glass or carbon fiber reinforced polymers (GFRP/CFRP). In contrast to surface applied optical fiber sensors, embedded sensors are expected to be better protected against rough handling and harsh environmental conditions. We report on two recently done fiber optical sensor applications in civil engineering. Both include structurally embedded fiber Bragg grating (BG) arrays but have different demands with respect to their operation. For the first application fiber BGs were embedded in GFRP rockbolts of 3 - 5 m in length either of 3, 8, or 22 mm diameter. The sensor equipped rockbolts are made for distributed measurements of boulder motion during tunnel construction and operation and should withstand strain up to 1.6%. Rockbolt sensors were field tested in a tunnel near Sargans in Switzerland. For a second application fiber BGs were embedded in CFRP wires of 5 mm diameter used for the pre- stressing cables of a 56 m long bridge near Lucerne in Switzerland. The permanent load on the cable corresponds to 0.8% strain. Due to the embedded sensors, strain decay inside the cable anchoring heads could be measured for the first time during loading and operation of the cables. For both applications mechanical and thermal loading tests were performed to assess the function of these new elements. Also, temperature and strain sensitivity were calibrated. Reliability studies with respect to stress transfer, fiber mechanical failure, and wavelength shift caused by thermal BG decay as well as monitoring results of both applications are presented.

Citation Download Citation

Philipp M. Nellen, Rolf Broennimann, Andreas Frank, Pascal Mauron, and Urs J. Sennhauser "Structurally embedded fiber Bragg gratings: civil engineering applications", Proc. SPIE 3860, Fiber Optic Sensor Technology and Applications, (9 December 1999); https://doi.org/10.1117/12.372954

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available