Following observations of out-of-plane instability in slender ductile structural walls in some recent earthquakes, this mode of wall failure has been and is being investigated by several research groups. Analytical, numerical and experimental investigations have been conducted to study this failure mechanism as well as its controlling parameters. Both singly reinforced and doubly reinforced concrete walls have been studied under uni-directional and bi-directional loading. A simplified approach making use of concrete columns representing boundary zones of rectangular walls has also been used to reduce the computational and experimental costs of the research programs. This presentation provides a state-of-the-art on the research conducted on this failure mechanism and elaborates on the sequence of events resulting in its development in structural walls, including the effect of governing parameters such as wall section thickness, length, axial load, and longitudinal reinforcement ratio. Suitability of the existing requirements in the New Zealand Concrete Design Standard (NZS 3101:2006-A3) for prevention of this failure mechanism is also evaluated and several key design recommendations are discussed in light of the numerical and experimental studies conducted at the University of Canterbury.
September 26, 2022 from 5:00pm to 6:00pm