Distributed strain sensing to assess corroded RC beams

Abstract

Corrosion of reinforcing steel reduces the capacity of reinforced concrete structures by reducing the reinforcement area and decreasing the bond between the reinforcement and the surrounding concrete. Currently the assessment of reinforced concrete structures is based largely on visual inspections, which do not provide quantitative data about structural behaviour. This research program investigates the use of distributed fibre optic strain sensors to measure the effects of corrosion on reinforced concrete beam behaviour. Six beams with varying levels of corrosion are instrumented with fibre optic sensors and tested in three point bending. The percentage of reinforcement area lost due to corrosion has a disproportionate impact on the percentage reduction in beam capacity, however these results are a function of the testing parameters and may not be applicable to structures in the field. The fibre optic measurements are used to identify regions of reinforcement-concrete bond loss and the effect of that bond loss on beam behaviour.