Title: Two-Way Shear in Nonprestressed Slabs: Flexural Reinforcement Ratio Effects

Author(s): Madhura Sanjay Chavan, Mary Beth D. Hueste, and Aikaterini S. Genikomsou

Publication: Structural Journal

Volume:

Issue:

Appears on pages(s):

Keywords: design provisions; flexural reinforcement ratio; nonprestressed slabs; punching shear strength; reinforced concrete; two-way shear

DOI: 10.14359/51742137

Date: 7/30/2024

Abstract:
A detailed investigation of the ACI 445-fib punching shear database studied the effect of flexural reinforcement ratio on the punching shear strength of nonprestressed slabs. The ACI 318-19 expressions for the two-way shear strength of nonprestressed slabs do not directly include the flexural reinforcement ratio. The experimental data shows that this simplification can lead to unconservative predictions of shear strength for slabs with low flexural reinforcement ratios. ACI 318-19 introduced a minimum flexural reinforcement area requirement for two-way slabs to address this concern. Based on a review of the data, this study proposes modified expressions to directly incorporate the flexural reinforcement ratio ρ in the design of two-way shear strength of nonprestressed slabs. This approach provides safer strength predictions for slabs with low reinforcement ratios, which can be critically important when evaluating existing structures. The proposed equations, in conjunction with the ACI 318-19 minimum flexural reinforcement requirement, can also promote safer designs for two-way slabs.