Evaluation Of Strut And Tie Model For Rc Deep Beams Using Nonlinear Finite Element Analysis

Abstract

This work proposes alternative analytical method for the prediction of ultimate load carrying capacity of reinforced concrete deep beams to that of strut-and-tie method. Three categories each category with five reinforced concrete deep beam specimens of shear span to depth ratio 1.00, 1.25, 1.50, 1.75 and 2.00 are studied. The beams are studied first analytically and then results from analytical method are validated by using nonlinear finite element analysis. It is confirmed that the result from analytical method for ultimate load capacity is in best agreement with nonlinear finite element analysis and this shows that the analytic approach used to predict ultimate load capacity is applicable. In the next session of the work a case study is carried out to determine the influence of some parameters on the predictive capacity of the proposed analytic method. Generally the effect of main reinforcement and web reinforcement ratios are covered in the parametric study part. For all categories the results from parametric study indicates that the increase in main reinforcement ratio has showed significant increase up to ultimate load and further increase will not affect the ultimate load capacity. In the same manner the increase in web reinforcement ratio either vertical or horizontal reinforcement ratio for all categories resulted in a linear load capacity increase especially for deep beams with shear span to depth ratio 1.00, 1.25 and 1.50. But for deep beams with shear span to depth ratios of 1.75 and 2.00 significant increases in load carrying capacity is not recorded. Also the diagrams for ultimate load versus vertical and horizontal reinforcement ratio for all categories indicate that vertical web reinforcement ratio is effective in increase ultimate load carrying capacity than for the same increase in horizontal web reinforcement ratio.