Carpark cracks will force closure of Aotea Square

Users of Aotea Square and the underground Civic Carpark face more than a year of disruption after new cracks were found yesterday in the carpark roof.

The Auckland City Council quickly fenced off half the grassed area and put a weight limit on vehicles entering the square.

Big events in the premier open public space will be looked at on a case-by-case basis.

Acting finance manager Robert Nelson said there was no immediate risk to the public.

The problem can be fixed only by closing the square and the 930-space Civic Carpark for up to 18 months to replace the roof. The cost will be "significantly more" than an earlier estimate of $15 million.

The council is considering combining fixing the roof of the carpark with other projects, including an upgrade of Aotea Square and an arts precinct behind the Town Hall, and ripping the front off the Aotea Centre for cafes and bistros. The total cost is more than $50 million and could mean two years of disruptive construction. About one million people attend events at the Aotea Centre and Town Hall each year.

Mr Nelson said it was unlikely work would start before the middle of next year. The roof project was also a chance for the council to look at doubling the size of the carpark towards Mayoral Drive but it would have to "stack up as a commercial proposition".

Engineers have installed props at the northern end of the carpark after discovering new cracks in roof beams caused by water seeping into the concrete and eroding steel reinforcing.

Structural engineer Ashley Smith, of Murray Jacobs, said there was evidence that the drainage system had broken down and too much weight was coming on to the roof.

The worst-affected areas were under the grassed area and the raised paved area of the square.

Engineers have begun a full survey of the roof. This will include placing glass strips on existing cracks which break at the slightest movement.

Mr Nelson said there was no need to change the current weight load limit of 250kg (equal to three or four people) a square metre.

Greg Innes, chief executive of The Edge, the Aotea Centre management board, said there was "no doubt" the safety measures had the potential to affect events.The board would meet on Monday to identify which events could be at risk.

"The biggest impact will be vehicle access, and the markets [held on Fridays and Saturdays] are the activity most likely to be affected," Mr Innes said.

In the long term, Mr Innes said he supported the proposed overhaul of the square, including replacing the roof, although he conceded that could mean a complete closure of the square.