Title:
Maximum Shear Strength Limits for Reinforced Concrete Walls
Author(s):
Jung-Yoon Lee and Min Jae Kang
Publication:
Structural Journal
Volume:
122
Issue:
4
Appears on pages(s):
173-188
Keywords:
maximum shear strength limit; over-reinforcement; reinforced concrete (RC) walls; shear failure
DOI:
10.14359/51745490
Date:
7/1/2025
Abstract:
Reinforced concrete (RC) structure design codes stipulate various
design limits to prevent the brittle failure of members, as well as
ensure serviceability. In the structural design of RC walls, the
maximum shear strength is limited to prevent sudden shear failure
due to concrete crushing before the yielding of shear reinforcement
due to over-reinforcement. Despite the increase in wall shear
strength provided by a compression strut, the maximum shear
strength limit for walls in the ACI 318-19 Code is the same as the
maximum torsional strength. Consequently, the shear strength
of large-sized walls with high-strength concrete is limited to an
excessively low level. The ACI 318-19, Eurocode 2, CSA-19, and
JSCE-17 standards provide similar equations for estimating wall
strength, but their maximum shear strength limits for walls are all
different. In this study, experimental tests were conducted on nine
RC wall specimens to evaluate the maximum shear strength. The
main variables of the specimens were shear reinforcement ratio,
compressive strength of concrete, and failure mode. The experimental results showed that the maximum load was reached after yielding of shear reinforcement, even when the shear reinforcement ratio was 1.5 times higher than the maximum shear reinforcement ratio specified in the ACI 318-19 code. In addition, the measured shear crack width of all specimens at the service load level was less than 0.42 mm (0.017 in.). The shear strength limits for walls
in the current codes were compared using 109 experimental results
failing in shear before flexural yielding or shear friction failure,
assembled from the literature. The comparison indicated that the
ACI 318-19 Code limit underestimates the maximum shear strength
of walls, and it particularly underestimates the maximum shear
strength of walls with high-strength concrete or barbell-shaped
cross sections. Additionally, this study proposes an equation for
estimating the maximum shear strength limit of walls based on the
truss model. The proposed equation predicted the maximum shear
strength of RC walls with reasonable accuracy.