Diagonal Tension Cracking in Concrete Beams with Axial Forces

Study made of available data on diagonal tension cracking in reinforced concrete beams with and without axial load. Increment of shear between calculated flexural cracking and observed diagonal tension cracking was found to be a function of flexural reinforcement ratio, p, and modular ratio, n. In the study, 31 reinforced concrete beams were tested under combined transverse load and axial load, including both tension and compression. Results obtained confirm the conclusions reached as result of study of previously available test data. Two modified forms of Equation 26-12 of the ACI Building Code, AC1 318-63, are proposed as applicable to both prestressed concrete and reinforced concrete with or without axial load.