Award-winning bridge faces expensive repairs

Heat prevented the Te Matau O Pohe bridge from closing

The cost of a third round of heat-related repairs to Whangarei's $32 million Te Matau A Pohe bridge may fall to the ratepayer.

The bascule (moveable) bridge was stuck open for two hours on Saturday due to a fault caused by expansion in high temperatures, though Whangarei District Council said the multi-award-winning structure is still to be celebrated, despite the "teething problems".

WDC group manager infrastructure and services Simon Weston said it appeared more concrete would need to shaved off the bridge, though he expected the repair bill to be less than the $25,000 WDC split 50/50 with the contractor during similar repairs in 2014. The bridge contract's 24-month defect liability period had now expired, but further investigation into the problem would determine who footed the bill.

The glitch meant the mid-section was unable to close after a yacht passed through about 6pm on Saturday, with traffic diverted for two hours. This was the first time the bridge had been "stuck open", though over the past two summers the bridge had been unable to open when temperatures exceeded 26C.

Although the official temperature recorded by MetService at Whangarei Airport on Saturday was 28.6C, unofficial readings were up to 32C around the city.

Mr Weston said it appeared the bridge had risen while at an appropriate temperature on Saturday, then heated and expanded during the five minutes it was in the air.

Normally, sensors stopped it lifting when it was too hot.

WDC roading manager Jeff Devine said there was "no damage apart from some scraped paint and concrete". Cooling the bridge with water on hot days was one option, though Mr Devine said this could prove more expensive than trimming the concrete facade. He stayed positive about the bridge, which had won a number of infrastructure and design awards.