Salah Sarhat and Edward G. Sherwood
i Assistant Professor, Civil and Architectural Engineering and Construction Management Engineering Department, Milwaukee School of Engineering, Milwaukee, Wisconsin, USA, sarhat@msoe.edu
ii Associate Professor, Department of Civil and Environmental Engineering, Carleton University, Ottawa, Ontario, Canada, ted.sherwood@carleton.ca
ABSTRACT
Shear failures of reinforced concrete masonry (RCM) beams without stirrups can be brittle and sudden, with little to no warning of impending failure. Since it is difficult to provide web reinforcement in masonry, RCM beams are often constructed without stirrups. As such, the design provisions used to determine shear strength of RCM beams without web reinforcement must be accurate, safe, and rational. The objective of this paper is to assess the reliability and predictive capability of the shear design provisions of RCM beams in the TMS 402 code. A database of 133 shear tests reported in the literature on RCM beams without stirrups was used to conduct the evaluation process. The failure shear stresses of the beams covered in the assembled database were predicted using two North American masonry design standards (i.e. TMS 402-2022 and CSA S304-2024) and one reinforced concrete code (ACI 318-2019). The study showed that the TMS 402 predictions were associated with the highest coefficient of variation of the three analyzed codes along with the larger number of unsafe predictions. Although the recently revised shear design provisions of ACI 318- 2019 produced a smaller number of unsafe predictions and smaller ratios of experimental to predicted shear strengths, there was only marginal improvement in the coefficient of variation. The CSA S304, on the other hand, had the lowest coefficient of variation with a small number of unsafe predictions. Further analysis indicated that CSA S304 can account accurately for all factors affecting the shear strength of RCM beams. These results highlight the need to revise the shear design provisions for RCM beams in the TMS 402 code and suggest that CSA S304-2024 provisions serve as a base for the needed revisions.
KEYWORDS: Beams, reinforced concrete masonry, size effect, shear strength, design codes.
009-Sarhat.pdf
