Brian Rudman: Let's hope dyslexia explains $73m repair bill

As a member of a trade which often has difficulty getting the decimal point in the right place, I'm hoping Auckland City's advisers are suffering a bout of journalistic arithmetic dyslexia in the case of the cost of Civic Carpark repairs.

The $15 million guesstimate of two months ago was worrying enough. But now we're told the bill for replacing the collapsing roof of the carpark and the associated redevelopment of Aotea Square above will cost $73.2 million.

The first thing Mayor Dick Hubbard's crisis committee should do is hot-foot down to the waterfront and get a quote from the Aussies who are building us a swish new indoor arena. If they can build a 12,000-seat stadium for $80 million, then it's worth asking them what's their best price for repairing the leaking roof of a 970-car garage.

One solution would be to seal up the entrance and leave it to the archaeologists of the future to contemplate its significance. The trouble with that solution is the structure is so shonky there's every likelihood if we just walked away from it that, in five years' time, some portly concert-goer rushing across the square to his seat could be swallowed up by its sudden collapse.

Over the last year, Auckland City has begun paying compensation to victims of the leaky homes scandal because of shortcomings in the building inspectorate.

The Civic report by engineering consultants Murray Jacobs suggests the council has been pretty slack as far as its own buildings are concerned as well. We read that since the carpark was built in the mid-1970s, basic rules relating to weight loading, for example, were ignored.

The reinforcing in the top concrete roof slab "is too light to carry the concentrated loads from the wheel of a heavy vehicle. The reinforcing is also too light to carry the weight of the 600mm of soil presently on parts of the slab as well as live loads from crowds."

The report adds later: "The capacity of the slab is under one half that specified in the code for crowd loadings."

And: "The steel in the roof slab is highly stressed and any loss of strength due to corrosion would further weaken the load-carrying capacity of the slabs."

In layman's terms, the roof wasn't up to the job expected of it. The weight of the dirt and trees loaded on to the underground carpark was too heavy. To add to the stresses, when the Aotea Centre and the adjacent entertainment centre were built, overweight entrance stairways to both complexes sat atop the carpark, adding to the loads.

To top off the nightmare, poor waterproofing resulted in a history of water leaking into the structure.

Without calling for a witch-hunt, the city should be seriously considering a parallel "please explain" inquiry running alongside Mr Hubbard's "what to do next" committee, probing into the cumulative errors over 30 years that have resulted in this disaster. We also need some reassurance that similar timebombs are not lurking in other council-built or designed structures.

Not only is this a financial bombshell for ratepayers, it is also a threat to the livelihood of the city's arts organisations. Getting to concerts across mucky temporary ramps while the rebuilding of the carpark roof takes place will be a minor inconvenience compared with the sudden removal of nearly a 1000 adjacent carparks.

The financial viability of music and theatre groups is shaky at the best of times, without patrons being told to catch a bus or walk after years of being able to park alongside the venue. Surrounding businesses and professional firms will be concerned as well.

My solution would be to rip off the earth on the carpark roof and relieve the stress on the structure as soon as possible. If necessary, replace the heavy Aotea stairway with a temporary lighter structure.

That would provide breathing space in order to fast-track the additional parking building that the council has long been contemplating in the area.

Two sites are being mooted: a $48 million southern extension to the existing underground park, or a $35.5 million standalone underground park west of the Bledisloe Building. Both of these would provide about 500 parks, giving some relief for when the main park closes for 14 months of repairs.