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Abstract

A paper presents a numerical analysis using ANSYS finite element program to develop a model for expecting the performance of seven lightweight aggregate reinforced concrete deep beams with 28 days compressive strength 26MPa and density of 1950Kg/m3 strengthened in shear by externally bonded CFRP. All beams have same dimensions (150mm width, 400mm depth and 1400mm length), longitudinal steel reinforcement ratio p=0.0115 and shear steel reinforcing F5@100mm. CFRP strips 50mm width are used for strengthening. The effective variable parameters were: a/d ratio, CFRP spacing, orientation and number of layers. The results obtained from the ANSYS finite element model got good agreement when compared to the experimental results [1] which were done for the same deep beams with the same material properties, internal reinforcement and strengthening schemes. The results show that the ultimate load and deflection predicted by numerical analysis is less than experimental results by 9% and 5.7% in average respectively. By using CFRP strips in shear strengthening, the ultimate load has increased by 18%, 13.6%, 32% and 27.3% for vertical, horizontal, inclined and double vertical layers, respectively for a/d=1. For a/d =0.8 the increase is 10% for vertical strips. It is recommended that the CFRP is placed such that the principal fiber orientation is either normal to the longitudinal beams axis or normal to the line joining the applied load and supports (strut path) to resist higher tensile stresses and strains distributed along it.