Title: Evaluation of Shear Reinforcement Design Limits in High- Strength Concrete Beams

Author(s): Gerardo Aguilar, Sandra Villamizar, and Julio A. Ramirez

Publication: Structural Journal

Volume: 115

Issue: 2

Appears on pages(s): 401-414

Keywords: beams; high-strength concrete; minimum shear reinforcement; shear strength

DOI: 10.14359/51701132

Date: 3/1/2018

Abstract:
Twelve reinforced concrete beams with compressive strengths from 7000 to 15,000 psi (48 to 105 MPa) were tested: eight specimens without stirrups and four with shear reinforcement. Additional test parameters were amount of longitudinal reinforcement and concrete strength. Test results supported by relevant tests available in the literature indicate that the minimum amount of shear reinforcement required by ACI 318-14 and AASHTO LRFD 2014 provide sufficient reserve strength after formation of first diagonal cracking up to 15,000 psi (105 MPa). An increase to the upper limit of the nominal shear strength to 12√fc′ is proposed for the ACI 318-14 Code. This limit is deemed appropriate to prevent failures where crushing of the concrete web occurs prior to yielding of stirrups.