Source: New Zealand Transport Agency
Construction on the Bayfair flyover is underway with four supersized steel cages recently craned into the middle of roundabout, providing the structure for the columns of the flyover’s first pier.
Waka Kotahi NZ Transport Agency Regional Manager Infrastructure Delivery, Jo Wilton, says it’s fantastic to be moving into the next phase of construction at the Bayfair end of the Bay Link project.
“Most of the progress at the northern end of the project has been below ground to date. Now the ground improvements are complete, focus at this end shifts to construction of both the underpass and the flyover.”
The four eight-metre-long steel cages provide the steel structure for the four columns that will form part of the bridge pier.
The Bayfair flyover will be supported by three piers in the middle and two abutments at either end, which is a change from the original design. In order to accommodate a new underpass, the Bayfair flyover required an additional bridge span, taking it from a three-span to a four-span bridge.
At the Bayfair end of the project, the flyover will take Stake Highway 2 traffic over the roundabout, which is being upgraded to a larger version with traffic signals. The Bayfair flyover is one of three bridges to be constructed as part of the Bay Link project. Two bridges are under construction at the Te Maunga end, which are anticipated to open to motorists at the end of 2021.
“The Bay Link project aims to improve safety by grade separating the railway level crossing, as well as splitting up state highway and local road traffic. Separating heavy freight vehicles from local traffic will also help improve overall traffic flow,” says Ms Wilton.
As part of the construction process of the Bayfair flyover pier, the steel cages sit on a concrete and steel footing located on top of the recently completed lattice pile ground improvements. Each vertical cage will be encased in concrete before a pier head is poured on top.
To align with construction sequencing, the next two Bayfair flyover piers are anticipated to get underway early next year.
“In addition to the flyover getting underway at the northern end of the project, construction is also taking place on the eastern and western portals of the new underpass, which will be pleasing news for the local community who strived to retain a crossing under the state highway. We expect to share more information about the underpass in coming weeks,” says Ms Wilton.
Despite being a short section of SH2 (1.7km in length), construction of the project is taking place within a highly constrained environment, with challenging soil conditions on a narrow, urban, arterial corridor catering to approximately 38,000 vehicles each day, says Ms Wilton.
“The project is approximately 60% complete and is anticipated to be finished in late 2023. We know everyone who lives and works alongside, and travels through, the project is looking forward to its completion as much as we are.”
- The four steel cages that will form the four columns of one of the flyover piers are eight metres long and weigh approximately three tonnes each.
- Each cage sits approximately three metres below ground on a footing, which is located on top of the recently completed lattice pile ground improvements.
- Around 30 tonnes of reinforcing steel has been used in the footing. Each vertical cage will then be encased in concrete before a pier head (containing a further 10 tonnes of reinforcing steel) is poured on top.
- This pier, containing approximately 50 tonnes of steel in total, will support the beams for the Bayfair flyover once all other bridge supports are complete.