Distributed Optical Fibre Sensor for Strain Measurement of Reinforced Concrete Beams

This work aims to prove the capabilities of the distributed optical fibre acoustic sensor (DAS) to detect early damage in reinforced concrete structures. Two small-scale reinforced concretes were designed and manufactured to simulate beams in a real structure. Two types of optical fibre were integrated into the structures and attached on the surface of the reinforced concrete beams respectively. Four-point bending test was employed to demonstrate the effectiveness of DAS in dynamic strain measuring.

I. Introduction

Structural Health Monitoring (SHM) employs various types of sensors to monitor and assess the health condition of structures for safety purposes, and optimize the regime of structural inspection. The structure of modern buildings tends to be more and more structurally versatile and functionally complex [1]. For large-scale concrete structures, the influence of external environments and humans are difficult to measure in the laboratory or simulated. On site monitoring is essential to evaluate the performance of structures. Conventional assessment method relies on a series of sensors attached at different areas of a structure to measure different parameters of the structure [2]. However, these sensors can only provide information at limited points, which provides very limited information of the structure as a whole. Techniques which can provide real-time distributed data of the structure on-site, would have a positive effect on the SHM in civil engineering to assess the structure more accurately and provide maintenance in a timely manner.