LIMIT ANALYSIS OF REINFORCED-CONCRETE BEAMS SUBJECTED TO PURE TORSION

A limit analysis method for predicting the torsional strength of reinf orced concrete beams is introduced in this paper. This method uses the modified Coulomb-Mohr failure criterion as the constitutive law of co ncrete, and assumes the plastic dow of concrete after yielding to be a ssociated with its failure surface. A generalized formulation for ener gy dissipation rate along a yield line in accordance with the failure criterion as well as the upper-bound method are employed in this resea rch. The ultimate strength of reinforced concrete beams subjected to p ure torsion is then predicted by the work equation based upon the ener gy dissipation rate and the permissible failure mechanism at the ultim ate state. The theoretical torsional strengths are compared with the e xisting experimental results and they appear to be in good agreement.