Title:
Shear Behavior of Reinforced Concrete Beams with Variable Thickness of Concrete Side Cover
Author(s):
Khaldoun N. Rahal
Publication:
Structural Journal
Volume:
103
Issue:
2
Appears on pages(s):
171-177
Keywords:
beams; building codes; cover; cracking; shear; stirrups; strength; torsion.
DOI:
10.14359/15174
Date:
3/1/2006
Abstract:
A study was conducted to investigate the effects of increasing the thickness of the concrete side cover on the behavior of reinforced concrete beams tested in shear. Seven test results are reported. The thickness of the concrete side cover ranged from 5 to 75 mm (0.2 to 3 in.) for beams with a target concrete strength of 25 Mpa (3600 psi), and from 25 to 75 mm (1 to 3 in.) for beams with a target concrete strength of 40 MPa (5800 psi). The beams were reinforced in the longitudinal and transverse directions. The specimens with 75 mm (3 in.) side cover developed a sharp increase in diagonal crack width upon cracking and showed a less favorable behavior. At estimated service stresses, however, all specimens either remained uncracked or developed crack widths smaller than a suggested 0.3 mm (0.012 in.) limit. Spalling was observed in the specimens with larger covers near ultimate conditions, but was limited to the corners of the section, leaving a considerable part of the cover on the vertical side intact. The ACI shear method and the general method provided conservative estimates of the strength.