Motorway construction picks up pace after Covid lockdown

A giant girder is gently manoeuvred into place for the Puhoi viaduct section of the Puhoi to Warkworth motorway. Work on the motorway has picked up pace since the end of lockdown

A 200 tonne girder is gently manoeuvred into position.A 200 tonne girder is gently manoeuvred into position.

Members of the viaduct construction team, from left, Paco Alonso, Kelvin Ng, Steve Perry, Alberto Torres, David Couto, Mikel Ledesma

Motorists travelling south just before the Johnstones Hill Tunnels late last month were treated to stunning views of giant cranes lifting girders into place to construct the Puhoi Viaduct – part of the Puhoi to Warkworth motorway.

On Saturday, June 20, four inter-connected girders with a combined weight of around 200 tonnes were lifted in to place, using two caterpillar-tracked cranes to complete one of seven segments of the 320-metre-long span.   

The girders were trucked up from Napier. Where possible, girders running in parallel are connected with bracing on the ground, which is more efficient. Though sometimes due to restricted movements in tricky locations, it is necessary to connect them when installed on their supporting columns.

It is anticipated the viaduct will be complete by the end of August. Engineers say restrictions on construction imposed by Covid-19 have delayed completion of the viaduct by about two months.

Moreover, construction is more difficult in winter, as it’s impossible to lift girders during high winds and more troublesome to complete work during heavy rain.

Project delays following the Covid-19 lockdown has forced the NZ Transport Agency (NZTA) and contractor Northern Express Group (NX2) into discussions over the completion date of the Puhoi to Warkworth motorway.

NZTA spokesperson Darryl Walker says the motorway is currently scheduled to open by the end of 2021, but the lockdown will likely have an impact on the opening date and the overall project cost.  

Mr Walker said the motorway project was a public-private partnership, subject to commercial terms.

“We will provide further information when our discussions with NX2 have been completed. No further comment will be provided until these discussions have been concluded,” he said.

During Alert Level 4, the majority of the motorway project was shut down apart from essential environmental, safety and traffic management works. Work resumed on April 28 under Alert Lever 3, though activities remained restricted until lockdown restrictions were progressively relaxed.  

NX2 says it’s now “full steam ahead” on activities planned over winter. These include enabling works for the southern connection of the motorway, including the connection to the Johnstones Hill Tunnels and the Puhoi on and off ramps. Further enabling works will take place at the northern connection, where the motorway will join SH1, north of Warkworth.

This winter NX2 also plans to create 12 wetlands to encourage aquatic and bird life and aims to be halfway through planting around 1 million trees, plants and shrubs.