Effect of Unit Bonding Patterns on the Structural Performance of Loadbearing Concrete Block Masonry Beams
Publication: Journal of Structural Engineering
Volume 145, Issue 1
Abstract
Loadbearing concrete block masonry construction in North America is generally designed by engineers as a 50% running bond pattern. However, in some situations an architect opts for a stack pattern (or stack bond) unit coursing, not realizing that there are structural implications to this choice. The lack of research in the area of the structural effects of a unit bonding pattern has led to inconsistent and sometimes very punitive requirements for loadbearing masonry design in North America. This paper presents the results of an experimental study on 12 concrete block masonry beams with depths of two, three, and four courses to study the structural effects of a unit bonding pattern. Beam stiffness, crack patterns, deflection profiles, and ultimate strengths are presented and discussed. Using a stretcher unit with approximately 50% of the web height removed to permit grout continuity demonstrated no significant difference between running bond and stack pattern unit coursing. This evidence supports changes to current Canadian design requirements to include stack pattern masonry beams with this unit configuration. This evidence may also be considered to support the adoption of more stringent recommendations in current American design requirements.
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Acknowledgments
This work was completed with financial assistance from the Natural Sciences and Engineering Research Council (NSERC) and Canada Masonry Design Centre (CMDC). The authors sincerely thank Con-Tact Masonry Ltd., located in Oldcastle, ON, for their support and help. Special thanks to Kyle Gerard, many graduate students, Lucian Pop, and Matthew St. Louis for their help in the lab work.
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Information & Authors
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Published In
Journal of Structural Engineering
Volume 145 • Issue 1 • January 2019
Copyright
©2018 American Society of Civil Engineers.
History
Received: Jul 1, 2017
Accepted: Jun 27, 2018
Published online: Oct 31, 2018
Published in print: Jan 1, 2019
Discussion open until: Mar 31, 2019
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