Contents: Overview of the Viaduct | Why Upgrade? | Newmarket Viaduct Replacement Project | Only 7 Lanes? | Viaduct Replacement Images | Greenlane Fourth Lane & Construction Images | Project Timeline | Southbound Switch | Comments

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The Newmarket Viaduct Overview

The Newmarket Viaduct was completed in 1966 to link the Southern Motorway to the city, the Harbour Bridge and to Spaghetti Junction. Instead of traffic travelling on Great South Road and through Newmarket Village itself. It was the first bridge in New Zealand to use a prestressed continuous box-girder design (method for overcoming concrete's natural weakness in tension), Freyssinet (prestressed) concrete hinges at the base and used cantilever construction techniques.

Recently the bridge has come under criticism about the fact that debris flies off the viaduct to busy Newmarket below, seismic susceptibility, that the bridge has been separating in sections to create wide gaps and there is limited stopping space now the bridge contains the maximum amount of lanes.

In 2009 the Newmarket Viaduct carried 161,490 vehicles per day with the split being; southbound at 83,117 VPD and 78,373 VPD for northbound. More on State Highway Volumes in the Glossary.

Why Does it Need to be Upgraded?

There are many reasons as to why the Newmarket Viaduct needs to be upgraded:

Aged: The Newmarket Viaduct is starting to show its age, complying with earthquake standards, poor barriers on the sides of the bridge, storm water drainage, ability to be widened and not enough stopping space.

Traffic Volume and the Spaghetti Junction Upgrade: Spaghetti Junction, which is on the Northern Side of the bridge recently had its upgrade completed, which has increased the volume of traffic volume it can handle. On the northern side of the Newmarket Viaduct there are four lanes in both directions and only three in both directions on the bridge. Currently 83,117 have to enter three lanes from four in the southbound section, this causes congestion.

Ability to be upgraded: The Newmarket Viaduct does not have the ability to be upgraded (widened) so that means that the bridge has to be demolished. So the present Newmarket Viaduct is not future proof.

Newmarket Viaduct Replacement Project

Under Construction Since June 2009 | $215m | Completion: Southbound September 6th 2010. Full: 2012. Full timeline.

The above graphic is an animated GIF and should play automatically through the five stages.

Only 7 Lanes?

Note: This section has been written by the web sites author Ben Paul, this does not represent the opinions of the government or local government. Click Here for About.

The Newmarket Viaduct replacement addresses southbound issues and not northbound capacity issues. The southbound section will be widened to four lanes and the northbound section will not be widened, it will remain at the present three. The NZTA has chosen not to widen the northbound section due to many justified reasons.

The main reason is not to induce congestion[?] into the recently upgraded Spaghetti Junction (CMJ). When widening or improving capacity through a section of roadway or motorway it will free up congestion at the relative section but it will push that congestion to another section of the motorway, therefore lessening the benefits from the widening.

Another reason is that the northbound section carries less traffic than the southbound, and it is not necessary to widen the section as the bridge itself does not cause congestion - in comparison with the southbound where four lanes go down to three.

Construction Images

Above: Overview shot of the beams and box-girder under construction on the eastern side of the bridge.

Above: Taken from Newmarket, with northern-most sections mostly complete.

Above: Taken from Newmarket, with the southbound bridge section almost complete.

Above: Taken from St Marks on-ramp, with the southern-most section still under construction.

Above: Public open day held on the 29th of August 2010.

Sequential images:

Above: Construction process overview. Click for larger image.

Above: Construction process from Newmarket (northern end). Click for larger image.

The Fourth Lane to Greenlane

Completion: Late 2010; in conjunction when four lanes on the Southbound section of Newmarket Viaduct open. Full timeline.

Part of the Newmarket Viaduct Replacement project is the continuation of the fourth lane from the new viaduct until the Greenlane interchange in the southbound direction. The reason to carry this extra lane is because 16% of traffic on the viaduct exits at Greenlane. The lane will terminate at Greenlane, and three lanes will continue south. The map (left) shows where the lane extends from: Gillies Ave in the North to Greenlane in the South. The lane extends past the St Marks Road on-ramp and Market Road interchange and under the Omahu Road overbridge. Click Here for a larger version of the map. This will require no land purchase or going beyond the original boundary.

Fourth Lane Construction Images

Above: Fourth lane is complete (but not open) around Market Road.

Above: Widening and preparation of new alignment (from new southbound viaduct) next to the St Marks on-ramp.

Above: Construction continues to Greenlane. Taken from Omahu Road overbridge.

Project Timeline

Three southbound lanes will open on the new southbound bridge on the 6th of September 2010. The project is six months ahead of schedule.

Please note that the above timeline is matched from the NZTA timeline which they note is 'an indicative [timeline] and may be subject to change.'

Southbound Switch

Southern motorway closed in southbound direction between Gillies and Greenlane between 17.00 Sat 04/09/2010 to pre AM peak Mon 06/09/2010.

The southern motorway will be closed between Gillies Ave off-ramp and Greenlane off-ramp to allow for the southbound lanes to be transferred to the new viaduct. To allow for this the motorway will be closed for a maximum of 36 hours between 5pm Saturday the 4th of September to early Monday (6th of September) morning in time for the AM commute.

During this time significant delays in a wide proximity are predicted, detours will be in place, but if possible move plans or do not travel during those times via the motorway without expecting lengthy delays and congestion.

To find detours have a look at the NZTA page here.

Let us know what you think
Polling has closed on this project as it is under construction. The results for the poll which ran for three years recorded 53% of people in favour of the project and 47% were not. If you would like to comment on the project or ask a question use the form below.

Comment

Only recent comments have been included.

From: Martin | Instead of demolishing the last existing section of the viaduct in Stage 5 why can't this section be retained with reduced traffic load and maybe pedestrian access.

Answer: The existing Newmarket Viaduct is the least seismically stable structure on the Auckland Motorway network (mainly because of its construction techniques), so it is a risk if the viaduct remained. Also, I cannot see it being a viable pedestrian link as it is a motorway corridor that provides no access for pedestrians or cyclists (unlike a possible connection on the Harbour Bridge).

From: Karel | A great engineering feat. I use the St Marks on ramp daily and have found the work being carried out very interesting. The amount of delays experienced so far is really minimal. Well done and I hope it will be completed on time.

From: Harvey Weake | Absolutely brilliant! This is an incredible engineering challenge and once complete will put Auckland into a very strong position to maintain its world leadership status as a city to live in. We just need to figure out how to get separate cycleways installed across the inner city away from the mass transport system. Well done to the whole team driving this. You should feel very proud that your work is making a difference to all of us.