Whangarei's second harbour crossing is on track, with several of the pile caps already installed, and design work proceeding on the bridge deck and the hydraulic rams that will lift it, to allow vessels to pass through.
The majority of the steel for the 265-metre bridge will be sourced from New Zealand, fabricated by Napier firm, Eastbridge.
However, three factors have caused Council to begin negotiating to source the fabrication of the lifting span, including J beams (that form the 'hook' like structure of the lifting platform) and the lifting deck from China, to be delivered in large pieces ready for assembly on site, through contract JV partners McConnell Dowell.
Council Group Manager Infrastructure Services Simon Weston said New Zealand steel mills did not make steel plates wide enough to be used in the manufacture of the J beams.
"New Zealand fabricators would have to import the wide plates to assemble with New Zealand sourced components, and this option had a 10 month delivery time."
Mr Weston said the time factor is critical in a project like this because every week's delay incurs considerable costs.
"China can deliver the project in five months, enabling existing timelines to be met, whereas New Zealand suppliers estimate 10 months. A compounding benefit is that sourcing the entire unit from China will cost $700,000 less than the New Zealand option."
Mr Weston said Council and the joint venture partners were confident of the quality of the steel and the fabrication of the lifting span.
"McConnell Dowell has recently sourced 20,000 tonnes of steel from the same Chinese mill for a Western Australian marine project. The total size of our order is under 400 tonnes, so we have full confidence in the ability of the Chinese mill to meet the required standards and delivery timeframes," said Mr Weston.
"McConnell Dowell has an office in China that will undertake quality assurance while the steelwork is being produced and the span is being fabricated."
Other key suppliers and subcontractors appointed for the project to date include locally-based companies GHK Piling, Northpower, Allied Concrete, Winstones Aggregates, Hynds Pipe Systems, Cates Transport, Hirepool and Cowleys Hire. With locally based joint venture partners Transfield Services constructing the roading and earthworks, it is expected that 45% of the project works will be completed by local companies.
Progress on the bridge to date includes pre-loading* of the Riverside Drive roundabout and Port Road bridge approach, construction has commenced on the Port Road and Okara Drive roundabouts, piles have been driven and piers are being constructed on the Pohe Island side of the bridge. The base of the road across Pohe Island has been prepared, and pavement metal is due to be laid on it in the next two weeks.
* pre-load: a heavy load of fill that is spread over an area to speed settling and improve the bearing capacity of the subsoil and is later removed to enable work to proceed on the hardened ground.
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