Observations of the performance of earth buildings following the September 2010 Darfield earthquake
A reconnaissance survey of earth walled buildings in the Canterbury area was carried out in mid October 2010 following the Darfield Earthquake. Fifteen earth walled buildings were inspected during the survey including historic earthbuildings and recently constructed reinforced earthbuildings.
Reinforced earth houses constructed since the 1990s performed well provided the overall wall bracing was adequate and detailing of the reinforcement and connections was generally in accordance with the NZ Earth Building Standards. Several unreinforced earth buildings constructed before 1930 (or reconstructed historic buildings) suffered significant structural damage and will require reconstruction or substantial repair. Unreinforced rammed earth buildings, and reinforced cinva ram brick buildings, constructed between 1930 and 1990 with reinforced concrete foundations and bond beams and adequate overall wall bracing generally performed moderately well given the level of shaking they experienced.
Minor cracking was observed in all but one of modern houses, performance was good where reinforcement and construction complied with the New Zealand Standards. Where buildings did not comply the damage could have been prevented by following the Standards.
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Copyright (c) 2010 Hugh Morris, Richard Walker, Thijs Drupsteen
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