C&L, Projects

Highest bridge on Hamilton section of Waikato Expressway now open

The highest bridge on the Hamilton section of the Waikato Expressway, the Kay Road Bridge, opened to traffic recently, providing a key connection to Hamilton’s north-east suburbs.

NZ Transport Agency portfolio manager Darryl Coalter said the amount of dirt moved to build the bridge made it the largest single excavation on the project.

“144,000 cubic metres of soil needed to be excavated to cut the expressway route through the Kay Road ridge, which is enough soil to fill four rugby fields piled 5m high,” Coalter said.

“We’d like to thank the local community for their patience throughout this build. Horsham Downs Road will close at 6am on Tuesday, October 9 for construction of another bridge crossing the expressway.”

The road will close just north of Borman Road (near the old chocolate factory) for up to 14 months, re-opening in late 2019. Detours will be signposted via Kay Road and Henderson/Boyd Roads. 1,600 vehicles per day travel on Horsham Downs Road.

The start of the Horsham Downs Bridge had been timed to ensure the alternative route was open.

The Hamilton section will open to traffic in 2020. This summer, a final 1.7 million cubic metres of sand and soil will be moved, and a third of the road pavement will be constructed.

When the Hamilton section of the expressway opens in 2020, it will improve safety, cut journey times and boost economic growth.

The Huntly and Longswamp sections of the expressway are also under construction.

Kay Road Bridge facts:

  • 18.8m high – the highest on the project. Other bridges are typically only 8m high to provide the required 6.1m clearance for vehicles on the expressway.
  • This bridge carries traffic on Kay Road over the expressway.
  • The bridge is two lanes, 90m long.
  • The bridge (above the ground) consists of 3,320 tonnes of concrete and reinforcing steel.

Construction sequence:

Before the building could begin above the ground, the following work needed to be completed:

  • This work began in November 2016.
  • 144,000 cubic metres of soil needed to be excavated to cut the expressway route through the Kay Bridge ridge. This was the biggest single excavation on the project.
  • Piles were driven 20m deep in the ground as foundations for the bridge columns.
  • The ground around the bridge foundations needed to be strengthened to withstand earthquakes and hold the soils in place to prevent liquefaction. 330x8m deep concrete piles were formed into lines and sq1uares to strengthen the ground.

Bridge construction began ‘above the ground’ in August 2017. Construction included:

  • Building four 15m-long concrete columns.
  • Buidling the bridge abutments at each end, along with backwalls and other concrete elements.
  • Building two crossheads weighing 110 tonnes each on the ground and lifting them on top of the beams using a 350-tonne crawler crane.
  • Lifting 21 super-tee bridge beams to site on top of the crossheads. Each beam is 30m-long and weighs 50 tonnes.
  • Pouring the concrete deck, bridge barriers and guardrails.
  • Installing services under the bridge deck, including water mains and ducting for electricity, phone and internet cables.
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