Long road to city’s newest motorway
It doesn’t usually take 60 years to build a motorway.
The people of Christchurch have faced a long wait for a motorway running from the north into the heart of the city, with plans bandied about since the 1960s.
But now the wait is almost over. The $290 million Christchurch Northern Corridor will partially open on Monday, so cars can start bedding in the chip seal surface before all four lanes open in midDecember.
The 10km corridor extends the Christchurch Northern Motorway through to QEII Drive and Cranford St, and is designed to make travel times in and out of the city shorter.
Construction only got under way in late 2016, after congestion on Main North Rd and Marshlands Rd started to reach frustratingly high levels for locals.
In 2015, 35,000 vehicles were travelling down Main North Rd through Redwood every day. NZ Transport Agency (NZTA) projections showed that reaching 42,000 a day by 2026 if nothing changed.
With the Northern Corridor put in, that number is expected to drop to 24,000 cars each day.
Principal project manager Brendon French said a major push factor behind the corridor was giving people who live in North Canterbury, from Waimakariri and beyond, easy access to the city without using local roads.
It is estimated by 2026, 42,000 vehicles a day will be using the Waimakariri to QEII stretch of the motorway.
But French said it will also support the city’s economic development.
‘‘[It is] to provide more freeflowing access through to Lyttelton... Belfast’s heavy industrial area is on the rise. French has been involved in the project for five years now, through the design process, the tendering phase, forming the Christchurch Northern Corridor alliance with Christchurch City Council and contractors, and construction.
‘‘It’s been a challenge at times, but we’re now getting very, very close to opening. It’s been a great success for everyone involved.’’
He said it is great to see the ideas talked about nearly five years ago become a reality.
‘‘I remember talking five years ago about a shared user path running the entire length, it was just an idea at that stage, and now it’s basically built.’’
The biggest issue crews faced was settlement, or sinking of the ground.
‘‘It goes through Marshlands, which is obviously a marsh, but there were big issues around Cranford St too.’’
French said they knew it was going to happen to some extent, so they tried to mitigate the issue with lots of preloading.
‘‘It’s basically squashing down the soil by putting something heavy on it. It can take years, and we have to constantly monitor the rate of settlement.
‘‘Then when we take the load off, it can rebound.’’
Soil around Cranford St took the longest, he said, at over a year.
In total, crews brought in 1.3 million cubic metres of rocks and dirt from quarries to pack it down.
‘‘It takes a lot of time to put it on and take it off again, and then you’ve still got to build the actual road.’’
The Northern Corridor’s original opening date in mid-2020 was pushed back because of the ground conditions. NZTA blamed the delays on extra work that had been added, and longer than expected settlement times.
Slumping foundations on a bridge over QEII Drive also had to be rebuilt, which included removing ramps that lead up to the bridge so that 445 steel piles could be put in to stabilise the soft ground.
The project has also faced community opposition from its inception, particularly from members of the St Albans Residents Association.
Locals feared a sudden influx of cars from the nearby motorway down Cranford St, with ‘‘rat runners’’ cutting through small local roads to try and beat the traffic.
NZTA regional relationships director Jim Harland said even though many of the streets residents were concerned about where under Council jurisdiction, his team still held regular meetings to hear their concerns and keep them in the loop.
St Albans Residents Association chairman Jason Harvey said once construction began in 2016, they accepted there was no stopping the motorway.
Harland said NZTA has been engaged in consultation for this project for the last decade, and these concerns have shaped what the Northern Corridor has become.
‘‘There’s been a change from the original thinking, of just having a third road. It gave us the opportunity to put in a walking cycleway, and there is a high occupancy vehicle lane too.’’
The lane is a Christchurch first, and will open on January 11 to line up with Environment Canterbury’s new express bus from Rangiora.
There is still a little more work to be done before the Northern Corridor is finally complete.
Brendon French said about this time next year, the road will need a final surfacing, which will mostly take place at night to avoid disruption.
Monday’s opening could be pushed back too if there is too much rain over the weekend, which could see cars damage the new road.
But French said if all goes to plan, Monday won’t be much different than driving through a normal roadworks site.
One traffic lane in each direction on the Northern Corridor will be open from Monday, November 30 to December 11. It will be open to northbound traffic between 7am and 4pm, and to southbound traffic between 10am and 6pm. NZTA is planning an open day for walkers and cyclists on December 12, and the motorway will be fully open to all traffic from December 17.