Overloading was to blame for the collapse of a balcony in North Dunedin last week which injured 18 people, a structural engineer investigating for the Dunedin City Council says.
Chartered professional engineer Dave Charters said there was no use in pointing fingers following the collapse, which seriously injured two students, but there were lessons to be learned.
He expected to hand his report to the council next week and did not want to speculate on its conclusions.
He had reviewed footage of the collapse several times, inspected the structure in Castle St, including other balconies at the address in question, and had spoken to witnesses.
Eighteen people were injured when the deck collapsed at a Six60 concert in Castle St on the Friday.
University of Otago student Bailley Unahi (19) is in Burwood Hospital with serious spinal injuries and Otago Polytechnic student George Karamaena (18) is in Dunedin Hospital with two broken legs and a broken back.
‘‘The conclusion that is out there was that it was overloaded,'' Mr Charters said.
‘‘I have watched the Animation Research video over and over again and that not only supports the conclusion that it was overloaded, but there were a number of students moving up and down.
‘‘They weren't jumping and they weren't acting irresponsibly, but that appears to be the final straw [causing the collapse].''
He emphasised that the behaviour he witnessed on the video was not reckless and the party-goers were dancing, not jumping, on the balcony.
He did not want to comment on the number of people on the balcony at the time of collapse, but it is understood it could have been as many as 16.
Mr Charters expressed his sympathy for the students involved and their families and said they were blameless.
The Otago Daily Times understands the structure was compliant with building codes when the structure was built and similar codes remain in place. However, it was designed to take the weight of about 12 80kg people who were completely still, but a limit of eight was imposed on such structures.
Council services and development general manager Simon Pickford said the remaining balconies at the address remained closed while the investigation into the collapse continued and the council had recommended the owner undertake some strengthening work.
‘‘If that work had been done before the collapse, it wouldn't have prevented it,'' he said.
‘‘The collapse was caused by overloading beyond design specifications.
‘‘There's nothing wrong with them but it would be prudent to strengthen them considering they are 16 years old.''
Neither measure was enforceable, but council had requested them as ‘‘prudent measures''.
The building code could require balconies be built to twice the strength if they were to be used as areas likely to be used for congregation.
When asked if it would be appropriate for future permits to require student accommodation to be considered as areas likely to be used for congregation, Mr Pickford said: ‘‘We haven't gone that far into that because it has significant implications for all these balconies.''
‘‘We will look at these things and consider if we need to strengthen it, but at this stage we are looking at whether it was built to design and what was the cause of the failure.''
