CSP’s barriers in use on the new Kawarau bridge - from start to finish

The new, stylishly curved Kawarau Falls Bridge, on the main route to Southland and Fiordland in Queenstown, officially opened in both directions in May. The new bridge replaces the one-lane, heritage bridge constructed in 1926 which was originally intended as a dam to allow gold prospecting on the Kawarau River bed.

The contract to construct the new 250m bridge was awarded to McConnell Dowell by the NZ Transport Agency, with traffic management, for the duration of the project, undertaken by the Downer team in Queenstown. Both contractors relied on the help of CSP’s products to complete the project - water filled temporary barriers for traffic management - used right from the outset, and road safety barrier on the approaches to the new bridge - once it was completed.

“We programmed work to maintain an open lane for traffic at all times,” says Stavros Kantzidis, Project Manager for McConnell Dowell. “Traffic management was key for our team as we were often operating in confined spaces and had to maintain a safe working environment for our people at all times.”

“Downer were appointed by McConnell Dowell to manage the traffic management throughout the project because of the need to maintain traffic flows on this route,” says Paul Fleet, Central Otago/Southland Construction Manager for Downer. “We use CSP’s hire barriers in projects all around the country so we dealt with Mario Bennett from CSP in the South Island to maintain the required number of TL-1 and TL-2 Water Filled barriers to create a safe work zone for the McConnell Dowell team.”

“Traffic management was an important part of a successful project delivery as traffic volumes were particularly heavy during the peak winter season,” adds Stavros.

As the bridge neared completion CSP’s Thrie-Beam™ Guardrail, transitions and X-350 Terminal Ends were also installed on the approaches to ensure it was ready for its opening in May.

Construction Design and Methodology:

• McConnell Dowell’s designers engineered its iconic two-thirds curvature, including the spiral transition, to ensure the best design speed, safety and road user comfort.
• This unique geometry, piling (up to 9m) into hard green schist and the limited space available for construction were challenges that required a creative approach to design and construction.
• Steel girders form the backbone of the sweeping 250m long curved bridge, comprised of four central spans of 45m and two approach spans of 36m.
• Weathering steel girders, designed to blend in with the surrounding environment, were installed using a launch nose method designed in-house by McConnell Dowell temporary works engineers.
• The launch nose method, which is fairly uncommon in New Zealand, allowed short sections of the bridge (between 16 and 22m long) to be constructed onshore in the limited space available.
• Bridge spans (36 to 45m long) were launched using hydraulic rams from the fabrication pad out to pier columns driven into the riverbed.
• The temporary trestles and the launch nose methodology reduced risk, minimised impacts on the environment and ensured key stakeholders’ safety and access to the river during construction.
• McConnell Dowell also incorporated a substantial variation into the project designing and installing bulk water and wastewater pipelines under the bridge to minimise cost and future disruption to stakeholders.

Fast Facts

• 252m long bridge
• 45m long beam span
• 342 tonne of structural steel
• 758 tonne of reinforcing steel
• 24m launch nose
• 150 tonne crawler crane
• 2000m³ of concrete
• 2.1m dia concrete piles - 7m into the rock