SHEAR-STRENGTH OF HAUNCHED BEAMS WITHOUT SHEAR REINFORCEMENT

Paper describes a technique for estimating the shear strength of reinforced concrete haunched beams without shear reinforcement. The technique is based on a conventional approach for taking account of the slope of the compression zone in the haunch, but a new method of identifying the section at which shear strength should be calculated is proposed. The method is validated against test results that are also described. The validation covers haunches with slope angles in the range of 5 to 10 deg. A novel form of testing that allows shear failure in the negative moment region of a haunch was used. A total of six full-scale tests were included in the program. The results show that the presence of the haunch improves the shear strength and ducility. This improvement increases with increasing haunch slope. This behavior appears to result from the development of an inclined strut action formed by the compression zone of the haunch.