An Investigation of the Use of Embedded FBG Sensors to Measure Temperature and Strain Inside a Concrete Beam During the Curing Period and Strain Measurements under Operational Loading

Abstract

This paper covers detailed investigation on the use of a FBG sensor for temperature and strain measurement in a reinforced concrete beam within first 28 days after pouring and structural response after 28 days curing period. A Fiber Bragg grating (FBG) sensor and a few thermo-couples (TC) have been embedded in the concrete beam at the casting stage. After curing the beam was laterally loaded on a three-point bending arrangement until a crack formed on the beam and subsequently heated to 200 0C with a 5kN lateral load at mid-span. A detailed analysis was performed on the data obtained from FBG sensor, thermo-couples and surface mounted electrical strain gauges (SG). Further, the cracked surface was continuously monitored with an Infrared Red (IR) camera during the heating to establish the temperature profile of the cracked surface of the concrete beam. A detailed Finite Element Analysis (FEA) of the concrete beam (structural and thermal) was performed using ABAQUS and compared with the experimental results.