Entz, Joseph1; Cruz Noguez, Carlos2; Guzmán Sánchez, Odín3 and Banting, Bennett4
1 MSc student, University of Alberta, 116th St. & 85th Ave., Edmonton, AB, Canada, jentz@ualberta.ca
2 Assistant Professor, University of Alberta, 116th St. & 85th Ave., Edmonton, AB, Canada, cruznogu@ualberta.ca
3 PhD student, University of Alberta, 116th St. & 85th Ave., Edmonton, AB, Canada, guzmansa@ualberta.ca
4 Masonry Research and Development Engineer, Canada Masonry Design Centre, 360 Superior Blvd., Mississauga, ON, Canada, bbanting@canadamasonrycentre.com
ABSTRACT
Tall, slender masonry walls are a competitive solution in both low and high-rise structures to resist out-of-plane and gravity loads. The use of taller and thinner walls is appealing due to the use of less material, need for smaller foundations, faster construction, lower seismic forces, and the ability to create more interior space. However, the design of conventional tall walls for out-ofplane bending according to CSA S304-14 for masonry structures tends to have practical limits related to their axial load capacity, buckling stability, and reinforcement details. Most conventional masonry walls rely on a single reinforcement bar placed at the centre of the unit, and designers that opt for multiple layers of reinforcement or non-conventional units seeking to enhance wall strength and stiffness are hindered by empirical limits in the S304 standard. A new type of masonry slender wall based on a similar concept of seismic boundary elements is proposed in this study. These ‘in-line boundary elements’ act as localized regions of strength and stiffness by providing tied reinforcement in two layers close to the surface of the wall. Results of ongoing experimental tests on masonry prisms containing pre-tied steel reinforcement cages and specially designed masonry units to fit around the cages are presented. The results show that the cage has a beneficial effect on the structural integrity of the confined core of reinforced prisms. Plane-section compatibility analysis is used to compare the performance of the reinforcing cage compared to conventional design scenarios with varying amounts of reinforcement placed at the middle of the section. A preliminary finite-element analysis model developed for tall masonry walls is also presented.
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