Adrien Sparling and Dan Palermo
Adrien Sparling, PhD Candidate, Department of Civil Engineering, York University, 4700 Keele St., Toronto, ON, Canada, adriensp@yorku.ca
Dan Palermo, Professor, Department of Civil Engineering, York University, 4700 Keele St., Toronto, ON, Canada, dan.palermo@lassonde.yorku.ca
ABSTRACT
Modern reinforced concrete masonry unit construction allows for the efficient use of resilient materials for the construction of large buildings. In Canada, the CSA S304 Design of Masonry
Structures standard governs all aspects of practical design. The current standard was developed based on pioneering research and testing of masonry assemblies; however, the legacy of traditional assumptions and rules of thumb is still evident in certain sections. The clauses related to the design of slender reinforced masonry (RM) walls contain seemingly arbitrary prescriptive constraints.
This paper is focused to inform the current understanding of the response of slender RM walls under service loading conditions including axial and out-of-plane loading. Simply supported 8mhigh hollow RM walls are subjected to out-of-plane 4-point bending, while a sustained axial load is applied. Through cyclic out-of-plane loading under increasing axial load, the flexural response is characterized under axial load increments up to 150kN. The test series will compare the behaviour of walls with conventional embedded reinforcement to those reinforced with vertically oriented Near-Surface Mounted (NSM) steel reinforcement. Conventionally reinforced slender concrete unit masonry walls have limited out-of-plane stiffness due to the location of the reinforcing steel near the centre of the wall’s cross-section; conversely, NSM reinforcement is located near the extreme tension fibres of the wall, thereby greatly improving stiffness. The benefits of the NSM reinforcement system (i.e.: reduced cracking and reduced moment magnification through improved stiffness) will become apparent through this full-scale test series on slender RM walls.
KEYWORDS: reinforced masonry; slender wall; out-of-plane flexure; near-surface mounted reinforcement; moment magnification
