In-plane Performance of Concrete Masonry Shear Walls

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Shear walls are essential structural components in structural masonry and other types of buildings that resist lateral loads due to wind or earthquakes. In significant seismic events, shear walls are responsible for maintaining structural integrity and preventing total collapse of a building even if other walls or non-structural components collapse. Thus efficient and safe design of these structural members is very important. The overall aim of the proposed research program is to provide improved guidance for the design and strengthening of masonry shear walls by developing an improved model for in-plane shear which is applicable to various masonry forms. The proposed research is multi-faceted, addressing the efficiency of structural design for shear walls through both experimental and analytical research components. These two components will be carried out concurrently since the results from the experimental work will influence and augment the analytical work and vice versa. The experimental work will be used to explore various influencing factors in shear wall behaviour using already established quasi-static and dynamic test capabilities. The experimental component will also incorporate the use of a new visual measurement system adapted from the Particle Image Velocimetry (PIV) technique. The advantage of using such novel systems in comparison to traditional instruments (e.g. displacement transducers, strain gauges) is the ability to observe movements and strains in an entire area of interest, rather than at a limited number of specific locations where the instruments are attached. Non-contact systems are also crucial for dynamic testing where traditional measurement instruments can be easily damaged. Strengthening of unreinforced concrete block masonry walls using both steel fibre reinforced grout and polyurethane foams as core-fill will also be studied experimentally. Numerical modelling of the experimental results will also be carried out using finite element analysis. The focus of the analytical work is to develop new equations that more effectively capture masonry shear wall behaviour by applying methods from reinforced concrete, such as modified compression field theory (MCFT) and shear friction, to unreinforced and partially grouted masonry for the first time. Shear design methods based on shear-friction or MCFT for reinforced masonry are attractive because, in contrast to traditional, empirically derived models, the approach is based on comprehensive, rational theory that should be more widely applicable. Various existing equations for predicting in-plane shear strength of masonry will be evaluated along with the new equations for their reliability and level of safety by employing stochastic and probabilistic methods. Overall, this ground-breaking research, which combines innovative measurement systems in the experimental work with a novel approach in the analysis, will contribute significantly to the fundamental understanding of the behaviour of masonry shear walls leading to improvement in design standards in Canada and elsewhere, impacting researchers, designers, contractors, and infrastructure owners, including governments.