Evaluation of lower damage concepts for enhanced reparability of reinforced concrete walls
AuthorBlount, Stephen W
AdvisorRyan, Keri L
Civil and Environmental Engineering
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As a consequence of recent earthquakes in New Zealand, many concrete buildings have been demolished due to structural damage. Researchers have assessed the unsatisfactory performance of concrete walls and improved current design standards to result in a more ductile response. However, despite meeting the current performance objectives of the design standards, reinforced concrete walls may still require extensive or costly post-earthquake repairs. The objective of this project was to develop simple modifications to conventional reinforced concrete walls to increase their reparability. Four modified walls were constructed and subjected to cyclic lateral loading until failure, and compared to a previously tested conventional ductile reinforced concrete benchmark wall that failed at 2.5% drift. The modifications considered included debonding of reinforcement at the wall base, substituting fiber-reinforced concrete (FRC) for conventional concrete, and substituting engineered cementitious composite (ECC) for conventional concrete in the ends of the plastic hinge region (applied in two walls). Debonding delayed vertical reinforcement buckling, but failure occurred shortly thereafter (2.5% drift) due to constricted movement of the buckled bars within the debonding sleeves. The FRC and both ECC walls had increased crack propagation up to a drift demand of 0.5%, but then the cracks localized to a single dominant crack and the walls failed at lower drifts (about 1.5%) than the benchmark wall.