Bridge monitoring by interferometric deformation sensors

Daniele Inaudi; Samuel Vurpillot; Nicoletta Casanova

doi:10.1117/12.252146

24 September 1996 Bridge monitoring by interferometric deformation sensors

Daniele Inaudi, Samuel Vurpillot, Nicoletta Casanova

Proceedings Volume 2895, Fiber Optic Sensors V; (1996) https://doi.org/10.1117/12.252146
Event: Photonics China '96, 1996, Beijing, China

Abstract

In many concrete bridges, the deformations are the most relevant parameter to be monitored in both short and long- terms. Strain monitoring gives only local information about the material behavior and too many such sensors would therefore be necessary to gain a complete understanding of the bridge behavior. We have found that fiber optic deformation sensors, with measurement bases of the order of one to a few meters, can give useful information both during the first days after concrete pouring and in the long term. In a first phase it is possible to monitor the thermal expansion due to the exothermic setting reaction and successively the thermal and drying shrinkages. Thanks to the long sensor basis, the detection of a crack traverse to the measurement region becomes probable and the evolution of cracks can therefore be followed with a reduced number of sensors. In the long-term it is possible to measure the geometric deformations and therefore the creeping of the bridge under static loads, especially under its own weight. In the past two years, our laboratory has installed hundreds of fiber optic deformation sensors in more than five concrete, composite steel-concrete, refurbished and enlarged bridges (road, highway and railway bridges). The measuring technique relies on low-coherence interferometry and offers a resolution down to a few microns even for long-term measurements. This contribution briefly discusses the measurement technique and then focuses on the development of a reliable sensor for direct concrete embedding and on the experimental results obtained on these bridges.

Citation Download Citation

Daniele Inaudi, Samuel Vurpillot, and Nicoletta Casanova "Bridge monitoring by interferometric deformation sensors", Proc. SPIE 2895, Fiber Optic Sensors V, (24 September 1996); https://doi.org/10.1117/12.252146

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