Title: Where is Shear Reinforcement Required? Review of Research Results and Design Procedures

Author(s): Michael P. Collins, Evan C. Bentz, and Edward G. Sherwood

Publication: Structural Journal

Volume: 105

Issue: 5

Appears on pages(s): 590-600

Keywords: aggregate interlock; safety; shear; size effect; strain effect; strut-and-tie

DOI: 10.14359/19942

Date: 9/1/2008

Abstract:
This paper reviews the past 60 years of research on shear behavior with attention paid to the behavior of beams ranging from shortspan deep beams to members controlled by flexure. A database of 1849 tests is included and conclusions based on these tests are made concerning the safety of the shear provisions currently in use in North America. The paper concludes that using the current ACI shear provisions to decide where shear reinforcement is required can be unconservative for members with larger effective depths, or higher stresses in the longitudinal reinforcement. Improvements to the ACI Code are proposed to mitigate these weaknesses. The paper also demonstrates that the AASHTO-LRFD and Canadian CSA sectional and strut-and-tie provisions provide a more uniform level of safety for all member types.