Computer-aided analysis of reinforced concrete using a refined nonlinear strut and tie model approach

This paper presents a computer program for implementing a refined nonlinear strut and tie model approach for the practical design and analysis of disturbed regions in structural concrete. Nonlinear techniques in the selection, analysis and verification processes of a strut and tie model are incorporated in this program to eliminate the limitations of the conventional strut and tie model relating to the behavior and strength prediction of reinforced concrete. For the verification of the proposed model, the model results are compared to the experimental results of one-quarter-scale simply supported bottom-loaded deep beams. Analytical results showed a lower bound solution that agreed well with the experimental results. It was concluded that the nonlinear strut and tie model allows more economical design than the conventional strut and tie model. It was also concluded that for higher strength concrete, the strength of struts and nodal zones given by the ACI-318 02 code is unconservative and needs refinement to account for the brittleness of high-strength concrete. Copyright ©2006 Japan Concrete Institute.