Hutt athletes and spectators may be stuck with a minimally safe Petone Rec grandstand, after a report suggested full seismic strengthening could be a waste of time.
Liquefaction was highly likely at Petone Recreation Ground after a strong earthquake, and the area was also in the tsunami zone, the report from Sawrey Consulting Engineers said.
Hutt City Council should carefully consider the value of the 1939 grandstand before it began an expensive process of strengthening to the ideal 67 per cent minimum.
"We would expect the building would be unusable and need demolition following an earthquake liquefaction event," engineer Graeme Silcock wrote.
"If the ground was to liquefy, support to foundations would be lost and the building is likely to sink or tilt and it is possible that structural damage may occur. The extent of this damage is difficult to predict."
Christchurch's 2011 quake showed deaths were rare in buildings damaged by liquefaction, Silcock noted.
While investigating the now-defunct Petone Arena concept in April, the council discovered the grandstand and changing rooms complex met just 5 per cent of the building code. Anything below 34 per cent is considered earthquake-prone.
Sawrey's report, made public yesterday, upgraded the grandstand to 11 per cent of code.
Many parts of the building were in poor condition. Concrete and steel reinforcing was cracked and corroded, and concrete walls were beginning to disintegrate.
Parts of walls were built from brick rather than reinforced concrete as original plans detailed, and the interior wall layout had been changed over the years.
The council will spend $120,000 bringing the grandstand to 34 per cent of code, starting work when the rugby season finishes in late August. Rear and end walls will be strengthened, and a brick chimney and one internal brick wall removed.
The ultimate fate of the grandstand would be decided over the next year, said Bruce Hodgins, the council's divisional manager of parks and gardens.
Risk-reducing options detailed in the Sawrey report included limiting the 1000-seat grandstand to just 300 spectators, or removing the grandstand seating, leaving just the changing rooms underneath.
While its changing rooms were the best in the Hutt, the grandstand was not dear to the hearts of the Petone Rugby Club, its chairman, Gus McMillan, said.
The council was planning a broad review of its sports assets in coming months, and the best option for Petone Rec could be a purpose-built facility for rugby and cricket combined, McMillan said.
- The Dominion Post
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