Excavation of the Victoria Park motorway tunnel will reach a milestone this afternoon, when diggings north and south of Beaumont Street in central Auckland meet - marking the halfway point of construction of the 'cut and cover' tunnel structure.
The breakthrough, which should be reached around 2pm, will make it
possible to walk 300 metres within the tunnel trench - from the tunnel's northern portal, under Beaumont Street and through Victoria Park to Victoria Street West.
The tunnel is a major component of the $340 million Victoria Park Tunnel project to remove the last remaining traffic bottleneck on the central Auckland motorway network.
The tunnel - which is due to open in mid-2012 - will carry three northbound lanes while the existing Victoria Park viaduct will be reconfigured to carry four southbound lanes.
NZ Transport Agency's state highways manager for Auckland and Northland, Tommy Parker, said it would provide more reliable travel on the country's busiest route for freight and business travel.
"With a very large hole in the ground through Victoria Park and at the Fanshawe Street motorway on ramp, motorists are now able to see what they are getting in terms of increased motorway capacity.
"However, the view will be brief as the hole is being covered over almost as quickly as it appears."
Around 168 of the tunnel's 360 30-tonne roof beams are now in place and last week the first section of tunnel roof was completely closed in. The seventh of the tunnel's 52 floor slabs was also poured last week.
Mr Parker said good progress is being made at the southern end of the 450-metre tunnel where traffic and major drainage, electrical and communications services have had to be relocated away from the path of the tunnel.
This week and next, traffic is being shifted to run over the top of completed sections of tunnel on Victoria Street West and Franklin Road. This will enable tunnel construction to move to a new area in front of the original Rob Roy Hotel site, which will be moved back to its original site next March.
