Numerical predictions for the ultimate torque capacity of FRP strengthened reinforced concrete beams

![CDATA[Despite years of theoretical work on the ultimate torque capacity of reinforced concrete beams, the current models do not produce convincingly accurate results. The prediction of ultimate torque by the current code recommendations is rather conservative and there is no model that accurately predicts the ultimate torque capacity of strengthened beams. The study here is looking at these models in a comparative scenario measuring them against ANSYS and experimental results. For the numerical solution with ANSYS, a three-dimensional model is created in which the concrete is modeled by an eight-node solid element specifically designed for concrete material. This element is capable of handling plasticity, cracking in tension and crushing in compression and requires an iterative solution. Experimental benchmarking contains the results of a series of experiments on plain and FRP strengthened reinforced concrete beams subjected to torsion for which the torque-twist curves are extracted. The results of the study provide a good insight to the weaknesses and strengths of the torsion models and the accuracy of the numerical model.]]