Nonlinear nite element analysis of RC beams under combined shear and torsion to extract linear and curvilinear ranges of interaction curves

The use of non-linear nite elements to assess the eect of transverse reinforcement amount on the shape of shear-torsion interaction curve for RC beams is addressed. At rst, FEM results for specimens under pure torsion and combined shear and torsion were validated with previous outcomes. Secondly, reference specimens were made with the minimum required transverse reinforcement at rst. Each specimen was analyzed with the nite element method and tested under similar conditions in the laboratory, and the results, including the cracking pattern, cracking and ultimate loads, and shear-torsion interaction curves, were found to be in very good agreement. Finally, the transverse reinforcement amount was increased to certain extents and similar results were determined. FEM interaction curve stood below the experimental curve. It was also deduced that, from a certain increase in the transverse reinforcement, the shear-torsion interaction curve transforms from linear to elliptical.