Buckling tests were carried out on 38 slender reinforced concrete deep beams having height:thickness ratios in the range 25 to 67. Observations were made on the ultimate loads and failure modes. The variables studied included the height:thickness ratio (h/b), the clear-shear-span:height ratio (x/h), and the load-eccentricity:thickness ratio (e/b). The observed behaviour and failure modes of the slender deep beams were described and compared with those of stocky deep beams as reported in the literature. The measured ultimate loads were compared with values predicted using CIRIA Guide no.2: The design of deep beams in reinforced concrete. These tests, which for the first time enabled the CIRIA buckling-load predictions to be checked against experimental values, have confirmed the CIRIA guide as a safe design document. For very slender deep beams, the CIRIA buckling predictions tend to be too conservative.
Professor F.K. Kong, R.C. Garcia, J.M. Paine, H.H.A. Wong, C.W.J. Tang and M. Chemrouk