An official report into the collapse of the Christchurch (CTV) building in Christchurch released today found the construction failed to meet key building standards.
The six-storey television building collapsed during last February’s devastating 6.3 magnitude earthquake killing 115 inside the building - nearly two thirds of the total death toll.
New Zealand Department for Building and Housing’s technical report into the collapse found aspects of the construction did not meet relevant building standards in 1986 when the building was constructed.
The report found that intense ground-shaking produced from the earthquake, non-ductile columns supporting the building and the asymmetrical layout of shear walls were the critical factors contributing to the collapse of the CTV building. It also found that concrete in many of the building’s columns were significantly weaker than it should have been.
The ductility of the columns and strength and the asymmetrical layout of the shear walls were found to have not met the building standards of the day (1986), according to the report.
The investigation included eye witness accounts, photographs, site examinations, sampling and testing of materials and structural analysis
Department of Building and Housing chief executive Katrina Bach said copies of the report has been distributed to the Police and Institution of Professional Engineers New Zealand for any further action.
Key findings from the report
Critical factors causing the building collapse
- Intense horizontal ground shaking.
- Lack of ductility in the columns, making them brittle.
- Asymmetrical layout of the shear walls, making the building twist during the earthquake, placing extra strain on the columns.
- The ductility of the columns (and strength) and the asymmetrical layout of the shear walls were found to have not met the building standards of the day (1986).
Other factors that may have contributed
- Low concrete strengths in some of the critical columns.
- Exceptionally high vertical ground movement.
- Separation of floor slabs from the north core of the building.