Title: Effect of Axial Compression on Shear Behavior of High-Strength Reinforced Concrete Columns

Author(s): Yu-Chen Ou and Dimas P. Kurniawan

Publication: Structural Journal

Volume: 112

Issue: 2

Appears on pages(s): 209-220

Keywords: axial compression; columns; cyclic loading; diagonal cracking; double curvature; high-strength concrete; high-strength reinforcement; reinforced concrete; shear

DOI: 10.14359/51687300

Date: 3/1/2015

Abstract:
To observe the effect of axial compression on the shear behavior of high-strength reinforced concrete columns, eight shear-critical high-strength columns were tested under cyclic shear with an axial compressive stress of 0.3fc' to 0.4fc' and compared to eight columns tested in a previous study with an axial compressive stress of 0.1fc' to 0.2fc'. Test results showed that the increase rate of concrete shear strength tended to decrease with increasing axial compression and reached an upper limit at high axial compression. Most columns under axial compressive stress of 0.3fc' to 0.4fc' failed at the same drift as diagonal cracking. This suggests the minimum shear reinforcement equations of the ACI Building Code need to include the effect of axial compression. Based on a test database of 77 high-strength columns and the biaxial behavior of high-strength concrete, this study proposes concrete shear-strength equations incorporating the weakening effect of axial compression.