Experimental and analytical study on reinforced concrete deep beams

A new simple strut-and-tie model was presented in this paper to study the behaviour of reinforced concrete deep beams. This model was obtained based on bottle-shaped struts that can predict flexural, bearing and shear modes of the failure. Also, the effect of web reinforcements was considered. The proposed model was verified by laboratory test results that obtained from five deep beams with a shear span-to-depth ratio of two and some other experimental results existing in the literature. Comparison of the results of the proposed model with relations from ACI 318 and AASHTO-LRFD codes and some other relations showed that the proposed model is efficiently capable of accurately predicting the ultimate load of simply supported deep beams. Also, comparison of experimental results demonstrated that the flexural capacity of deep beams obtained from the strut-and-tie model is conservative.