Discontinuous Brillouin Strain Monitoring of Small Concrete Bridges: Comparison Between Near-to-surface and Smart FRP Fiber Installation Techniques


Brillouin fiber optic sensing is a promising technology for Structural Health Monitoring (SHM) whose diffusion is however at present reduced by the unavailability of proper sensor products and established installation techniques specifically aimed at the building industry.Due to its intrinsic distributed sensing capability, Brillouin systems can individually measure the deformation of any single segment of considerable lengths of single-mode fiber. In addition, Brillouin retains all the other typical advantages of Fiber Optic Sensors (FOS), such as harsh environment durability and electro-magnetic interference rejection.These advantages, especially considering that the required sensors are really low cost, make the system particularly attractive for periodical ("discontinuous") strain monitoring of unattended infrastructures that might be exposed to ageing and vandalism damages. Despite the high equipment cost, the technique can become economically convenient when the same initial investment can be amortized over a number of applications that can be monitored periodically using the same device. This work presents a comparison between two different Brillouin sensor installation techniques: Near-to-Surface Fiber (NSF) embedding and smart-FRP sensor bonding. Both systems have been experimented in the field on small Reinforced Concrete (RC) bridges subject to a diagnostic load test. The obtained results clearly highlight the advantages of the smart-FRP system, in terms of performance enhancements, installation cost, and time reduction.


Electrical and Computer Engineering

Second Department

Civil, Architectural and Environmental Engineering

Keywords and Phrases

Bridge Monitoring; Brillouin; Distributed Sensing; Fiber Optic; Load Test; Reinforced Concrete; Smart Material

Document Type

Article - Conference proceedings

Document Version


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© 2005 SPIE -- The International Society for Optical Engineering, All rights reserved.

Publication Date

01 Jun 2005