Grant: Discovery Grants Program - Individual

Post-earthquake reconnaissance has highlighted the importance of residual drift (permanent displaced shape) as an indicator of damage and a measure to quantify structural performance. The residual drift, therefore, determines whether a structure can be serviceable, requires repair, or must be demolished. The long-term objective is to develop resilient and sustainable structural systems to address the disruption to community and business continuity following an extreme event (i.e., earthquake). The short-term goal focuses on mitigating two phenomena that are critical to develop concrete structures that are structurally resilient: permanent displacements and concrete damage, which will be investigated through the implementation of novel and emerging materials, such as Shape Memory Alloy (SMA) to limit residual displacements and Engineered Cementitious Composite (ECC) to control concrete damage and improve ductility. SMAs can sustain large strains, but with the capacity to return to its original shape after removal of stress (SE-SMA). This is the main behavioural characteristic that makes the material attractive in seismic applications. ECC is a high-performance concrete that incorporates synthetic fibers with the ability to bridge and control the width of cracks in concrete. This leads to improved strength retention and improved ductility in tension. Each of these materials plays an important role to improve the resiliency of structures. Specifically, through this proposal nonlinear modelling capabilities will be developed for performance assessment of concrete structures incorporating SMAs and ECCs; self-centering (SMA) and low damage (ECC) slender shear walls (new construction) including planar and C-shaped walls will be developed and investigated before and after repair; and a self-centering retrofitting strategy in the form of a SE-SMA buckling restraint brace for existing seismically deficient reinforced concrete frame structures will be developed. Impact: While it is accepted that concrete is a major contributor to carbon dioxide emissions, concrete structures still dominate the global infrastructure stock. This is compounded by the demands to continually build new infrastructure in urban centres for growing populations. Nationally, a significant percentage of the building stock in Canada is vulnerable to current estimates of seismic demand. Demolishing and rebuilding are not economically practical. This research will develop design strategies that improve the resiliency of new and existing structures by enhancing seismic performance and that mitigate the need to rebuild and extends service life, all of which improve the life-cycle sustainability. This research will equip researchers and engineers with the necessary numerical tools. Furthermore, the experimental testing will provide benchmarks and data for future provisions to enable the design of structures incorporating these materials that currently are not considered in building codes.