United Civil was contracted by KiwiRail to rebuild Bridge 217 on the Palmerston North to Gisborne line (PNGL), which had been washed away during Cyclone Gabrielle. Within just four months of construction works starting, the bridge was reopened and trains were again hauling freight into and out of Napier Port along the economically vital transport link that is the PNGL.
In mid February of 2023, Cyclone Gabrielle smashed New Zealand, leaving a trail of destruction in its wake. The Hawkes Bay region was hit hardest by the cyclone, with loss of life and massive damage to property all across the region.
Bridge 217, which crosses the Tūtaekurī River just to the south of Napier and is part of the economically important rail link between Napier port and the rest of the country, was destroyed, with floodwaters washing away the 6-span bridge and severely damaging its approach embankments.
United Civil was selected by KiwiRail to rebuild Bridge 217, based on the company’s record of successfully working with customers to deliver complex civil projects works in often challenging circumstances, and for its proposed construction methodology which would allow for the safe completion of the bridge in time to meet what was a very ambitious programme.
The design of the 75 m long replacement bridge provided for 760mm diameter steel tube piles bottom driven to a depth of around 34m. The upper 20m of the pile was filled with reinforced concrete with pile sets connected by 2*610mm UB crossheads and cross-bracing. 1000mm deep bridge girders completed the main structure before the placement of sleepers, handrailing and new track.
As construction started in late May 2023, the Kiwirail team and United Civil worked to optimize the design, looking for ways to simplify construction and further speed up the building of the replacement bridge. Our site teams, along with those of our subcontract partners and the Kiwirail field crews worked long weeks and often in trying conditions to complete the works safely and on time, with the bridge being completed and the rail line reopened 17 weeks later, on 15 September 2023.
KEY FEATURES AND INNOVATIONS INCLUDED:
- Using the finished permanent bridge piles as a foundation for temporary staging as the works continued, allowing for constant progress and efficiency to completion of the bridge.
- Welding casings offsite to the maximum length the site crane could pitch, so that casings could be spliced together at specified depths onsite more efficiently.
- Collaborating with bridge designers to improve constructability and efficiency, by combining two separate structural steel components into a single element almost halving the installation time onsite.
- Using a Duramesh retaining system to construct crane platforms on the edge of the river embankments that can withstand future extreme weather events.