Performance evaluation of High-Performance Fibre-Reinforced Cementitious Composite slab-column connections

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As the growth of global construction keeps accelerating, structural engineers can serve as responsible stewards of the environment by introducing new technologies and materials for sustainable and resilient structures that help to preserve our resources while reducing the carbon foot print of construction. Based on the Canadian National Climate Change Policy, the cost of cement will increase dramatically in the coming years through carbon tax or a system of tradeable carbon emissions permits. In order to reduce cement production, a potential solution is to use High-Performance Fibre-Reinforced Cementitious Composites (HPFRCCs) in structures to increase sustainability through partial replacement of Portland Cement with fly ash. HPFRCCs are relatively new and innovative materials that resist large tensile and shear forces showing strain hardening in direct tension, increased toughness and ductility, crack control, enhanced performance in case of dynamic effects, and high-energy absorption capacity when compared to conventional concrete. Whereas the mechanical properties of HPFRCCs have been studied and are relatively well documented, research is required to develop models and establish design guidelines to enable large scale HPFRCC use in critical infrastructure. Flat slabs are widely used in many multistory buildings because of the many advantages that they provide, however, they are susceptible to punching shear failure. In this research program, a novel HPFRCC will be considered and the punching shear behaviour of slab-column connections will be investigated. The proposed research program will consider HPFRCC at the connections as an alternative for punching shear reinforcement. This work will first evaluate the mechanical properties of HPFRCC and then undertake an experimental investigation of punching shear in novel slab-column connections. In HPFRCC slabs the effect of the flexural reinforcement ratio will be examined considering potential reductions in steel reinforcement leading to benefits due to the reduced risk of corrosion. At the same time, the seismic performance of the proposed HPFRCC slabs will be examined considering the effect of gravity-induced shear on the rotation and drift capacity. Finally, the tested HPFRCC slabs will be analyzed using advanced nonlinear finite element analysis (FEA), where current and newly developed plasticity-damaged models will be considered. Parametric studies on the effects of concrete properties, reinforcement properties and placement, unbalanced moments, and support geometry on the punching shear strength of flat concrete slabs will be undertaken. This research program is designed to foster and inspire the training of highly qualified personnel (HQP) over a five year period through a combination of apprenticeship, mentorship and exposure to an exciting and rigorous research environment.