INITIATION OF SHEAR CRACKING IN REINFORCED-CONCRETE BEAMS WITH NO WEB REINFORCEMENT

An hypothesis is proposed for the shear cracking mechanisms in point-loaded reinforced concrete beams with no web reinforcement. The hypothesis results from an approximate analytical approach based on the observation that flexural-shear cracking results from a severe localization of internal stress after the onset of flexural cracking. This local stress concentration is associated with the nature of bond between concrete and flexural reinforcement, and the development of arch action in the end region (shear span) of the beam. Analytical expressions are developed for predicting the shear cracking load and the corresponding location of the critical shear crack. The adequacy of these expressions is then established by comparison with published test data.