An experimental study on the effectiveness of externally bonded corrugated GFRP laminates for flexural cracks of RC beams

In recent years, the most important challenges in the field of structural engineering are the repair and rehabilitation of structural members of existing buildings and bridges. Strengthening of existing structures may become necessary to cater for the latest codal provisions and to meet the expected life span. Many researches have carried out on shear and flexural strengthening of reinforced concrete beams using plain Glass Fibre Reinforced Polymer (GFRP) sheets. Usage of plain GFRP composites is a traditional method for strengthening reinforced concrete (RC) beams. So in the present work, the author is intended to check the possibility/suitability of using GFRP corrugated laminates for the purpose of strengthening the RC beams. With GFRP chopped strand mat, corrugated profile was fabricated in the industry and used as a new technique of strengthening system with a view to improve sectional properties and hence flexural strength of RC beams. It is observed that cracks are formed in existing structural members due to excessive deflections as a result of uncertainty in loading conditions. To simulate this condition, the test beams were pre-cracked up to 0.3 mm width at tension zone. Fourteen beams were tested to study the load carrying capacity of beams strengthened with plain sheets and corrugated laminates and those results were compared with control specimens. The novelty of using GFRP rectangular corrugated laminates to enhance the load carrying capacity of pre-cracked beams has been carefully studied experimentally. Also mathematical models were developed for the prediction of load carrying capacity of pre-cracked strengthened beams. Furthermore theoretical analysis for control and beams strengthened with plain sheets and corrugated laminates were done and the results were compared with experimental results. The experimental results indicate that RC beams strengthened with GFRP corrugated laminates may provide an attractive rehabilitation technique for repair as well as strengthening.