Strength evaluation and retrofit of reinforced concrete beams subjected to pure torsion
Durrani, Ahmad J.
Master of Science
The behavior of reinforced concrete beams under pure torsion was studied. Six reinforced concrete beams were designed with stirrup spacing as the principal variable and tested under monotonic loading up to failure. Loads, angles of twist and reinforcing steel strains were recorded. Based on the experimental results, methods to predict the response of the beams were examined and an equation for torsional capacity was proposed. Three of the predamaged beams were repaired by adding external steel bands bonded to concrete which was proved to be a very practical and efficient way for retrofitting damaged torsion beams. Experimental data on strength, stiffness, steel strain of the repaired beams were obtained, and comparisons between the repaired and the unrepaired control beams were made. Repair by external steel bands is shown to increase torsional capacity, restore the degraded stiffness of the beams and decrease the reinforcement stress levels.