الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Various techniques are available for strengthening and rehabilitating the reinforced concrete members, among which, the application of fiber-reinforced polymers (FRP) is the best method for improving the overall performance of reinforced concrete members. In this research, an experimental program consists of eleven reinforced concrete beams was prepared and carried out to evaluate the effectiveness of using different materials and methods in the strengthening of RC beams subjected to combined bending and torsion. One beam was kept without strengthening as a control beam, while the other ten beams were strengthened by using externally bonded carbon or glass fiber-reinforced polymers (CFRP/GFRP) with different strengthening methods. In addition, a new technique was used as external strengthening called ”polyuria coating”, which is a high strength synthetic elastomeric coating that can be
sprayed over existing concrete structures instead of the traditional manual installation method. All tested beams were loaded until failure under combined bending and torsion. The behaviors of the tested beams were described using recorded data based on the measured values of the cracking and ultimate loads, the behavioral curves and the failure modes. The test results demonstrated the effectiveness of using fiberreinforced polymer systems, as well as, polyurea coating in improving the behavior of
RC beams subjected to combined bending and torsion. In order to get a more in-depth understanding of the behaviors of reinforced concrete beams subjected to combined bending and torsion, a three dimensional FE model was developed by using computer program ”Abaqus/CAE” to simulate the reinforced concrete beams with their longitudinal and transverse steel bars as well as with the additional strengthening for different strengthening materials used in this study. The FE model results were verified and compared with the experimental test results, where the FEM results showed good agreement and harmony with the experimental results.