EVALUATION OF ACI 318-95 SHEAR-FRICTION PROVISIONS. DISCUSSION

A discussion of a paper with the aforementioned title by R. Valluvan, M.E. Kreger, and J.O. Jirsa, published in this journal (Volume 96, Number 4, July-August 1999), is presented. The discusser supports the finding presented in the paper, that the current American Concrete Institute (ACI) Code provisions dealing with shear-friction are overly conservative, and offers several recommendations on the shear-friction provisions of the ACI Code. Any evaluation of the provisions of the ACI Code dealing with shear-friction must clearly distinguish between a shear plane in monolithic concrete, an interface with intentionally roughened surface, and an interface with surface not intentionally roughened. For shear planes subjected to permanent net compression applied externally, there seems to be no merit in combining the effect of shear-friction reinforcement and the surface condition of the shear plane, with the effect of external compressive force that is applied normal to the shear plane.