HIGH STRENGTH CONCRETE DEEP BEAMS SUBJECTED TO COMBINED TOP- AND BOTTOM-LOADING

Twenty high strength concrete deep beams with various top-to-bottom loading ratios were tested to failure. Two types of web reinforcement were investigated: type 'a' web pattern with vertical web reinforcement ratio at 0.48% and type 'b' web pattern with vertical web reinforcement ratio at 1.43%. Detailing of the web reinforcement followed the recommendations given by the UK CIRIA Guide, which would seem to be the only design document for deep beams subjected to combined top-and-bottom loading. It is found that the CIRIA detailing rules help to ensure ductility in the behaviour of the specimens, and this in turn yields consistent ultimate shear strengths irrespective of the loading condition imposed on the beams. Comparisons with test results also show that the CIRIA predictions are both conservative and consistent. (A)