Title:
Shear Strength of Reinforced High-Strength Concrete Deep Beams
Author(s):
Jung-Keun Oh and Sung-Woo Shin
Publication:
Structural Journal
Volume:
98
Issue:
2
Appears on pages(s):
164-173
Keywords:
beam; high-strength concrete; shear strength; span
DOI:
10.14359/10184
Date:
3/1/2001
Abstract:
Fifty-three reinforced concrete deep beams with compressive strengths in the range of 23 MPa £ fc¢ £ 74 MPa (3335 psi £ fc¢ £ 10,730 psi) were tested to determine their diagonal cracking and ultimate shear capacities symmetrically under two-point loading. The effective span-depth ratio le/d was varied from 3.0 to 5.0, and the shear span-effective depth ratio a/d from 0.5 to 2.0. All the beams were singly reinforced with ratio rt of 0.0129, 0.0156 and ratio of rv from 0 to 0.0034, and rh from 0 to 0.0094, respectively. The ultimate shear failure mode of deep beams was governed by a/d regardless of concrete strength. At a lower a/d, deep beams with high-strength concrete failed abruptly without any caution, which could be seen in deep beams with normal-strength concrete. Test results indicate that the ultimate shear strength of deep beams was determined predominantly by a/d. For all tested beams, ACI Code Eq. (11-29) and (11-30) are conservative and underestimate the effect of concrete compressive strength fc¢ and that of longitudinal steel reinforcement rt in deep beams using high-strength concrete. Addition of horizontal shear reinforcement does not improve the ultimate shear strength with decreasing a/d in deep beams with high-strength concrete