A plastic model for the assessment of reinforced concrete dapped-end beams

This paper presents a method to predict the shear capacity of RC non-prestressed dapped-end beams. The proposed method is based on the lower-bound theorem of plasticity and considers multiple failure surfaces in beams reinforced with horizontal, vertical and diagonal steel rebars. The method considers the effects of the transverse compressive stresses originating from hangers, stirrups and loading plates on the compressed uncracked concrete and limits the diagonal compressive stress of concrete in the case of beams with low strength concrete and high strength transverse rebars. The shear capacity is obtained by means of a nonlinear constrained optimization problem that is built and solved by means of the program Excel by Microsoft. The method has been validated against results of many dapped-end beams that were tested in the past by other researchers. The results of the numerical analyses show that the accuracy of the predictions of the shear strength is high and independent of the geometric and mechanical properties of the dapped-end beams.