Study of stress distribution in deep reinforced concrete beams

Abstract

A total of ten brick aggregate reinforced concrete beamsin two series have been tested in this study in order to investigate the effect of span/depth ratio and variation of web reinforcement on the stress distribution in deep beams and also on the shear strength of such beams. The deep beams were subjected to uniformly distributed loading. The first beam of each series was designed and detailed as per the recommendations of ACI Building Code (ACI-318-77). In the other four beams of each of the series, the amount of both vertical and horizontal web reinforcements were either increased or decreased in relation to those of first beam of the corresponding series. Results are presented in tabular and graphical form. It is observed in the study that amount of web reinforcements influences to some extent both the diagonal cracking load and the ultimate shear capacity of deep beams. It is also found that for-such beams the available theories,--for-stresscomputation=--_cc.,.,- do not predict the stress in concrete, in flexural steel and in web reinforcement properly. -Regarding the prediction of ultimate load capacity of deep beams, it is found that some of the available methods including the recommendations of the ACI code are conservative, whereas the others are unconservative. Some tentative suggestions regarding modifications of the aforementioned available methodsfor estimation of ultimate load capacity of deep beams are presented in this thesis. It is expected that these suggestions will help any future attempt to adapt the ACI Code provisions regarding deep beams when such beams are made from brick aggregate concrete.