Limit analysis on RC-structures by a multi-yield-criteria numerical approach

The present study proposes a multi-yield-criteria limit analysis numerical procedure for the prediction of peak loads and failure modes of reinforced concrete (RC) elements. The proposed procedure, which is a generalization of a previous one recently presented by the authors, is hereafter applied to structural elements reinforced either with traditional steel bars and stirrups or with fiber reinforced polymer (FRP) sheets used as strengthening system. The procedure allows to take into account the actual behaviour, at a state of incipient collapse, of steel, FRP and concrete by a finite element (FE) based plasticity approach where concrete is governed by a Menétrey-Willam-type yield criterion, FRP reinforcement obey to a Tsai-Wutype yield criterion and steel reinforcement follow the von Mises yield criterion. To check the effectiveness and reliability of the numerically detected peak loads and failure modes a comparison with experimental laboratory findings, available in literature for large-scale specimens, is presented.