Seatoun tunnel strengthening

Wellington City Council plans to undertake earthquake strengthening work on the Seatoun Tunnel in 2019.

Seatoun tunnel entrance.

This is part of an ongoing programme to improve the safety and accessibility of Wellington’s earthquake prone structures. 

Alongside the essential strengthening work, there are plans in place to extend the existing pedestrian handrail on both sides of the tunnel and to replace the sodium lights with new more efficient LED fixtures.

The 112-year-old tunnel is a heritage structure so it will be a priority to ensure it maintains its current charm. However, the inside will be painted to make it brighter and safer for residents to walk to through.

Updates

November 2019

The Seatoun tunnel will be closed Sunday to Thursday nights from 10 November 2019 for six weeks, to allow contractors to install new state-of-the-art LED interior lighting and emergency lighting.

Traffic will be detoured between 11pm and 5am via Tio Tio Road. Trucks and heavy vehicles should use Ira Street, Para Street and Awa Roads. Please note there will be no work on Friday and Saturday nights, so the tunnel will be open as per usual. Pedestrians and cyclists wanting to travel through the tunnel while crews are working will be escorted through by one of the crew on site. Buses will still be able to travel through the tunnel after 11pm as they are unable to use either detour route.

The lighting work is part of a larger project to upgrade and earthquake-strengthen the tunnel, part of an ongoing programme to improve the safety and accessibility of Wellington's earthquake prone structures.

Daytime earthquake strengthening work continues between 9am and 4pm each week day, with traffic controlled by the traffic signals at either end of the tunnel.

We apologise for any inconvenience this project may cause.

July 2019

Seatoun tunnel's new traffic signals will be tested during the week of 9-12 July to check they work correctly. The new signals are at each end of the Seatoun tunnel and will be used to control traffic during maintenance and improvement works and in the event of a major incident. 

The new signals are a permanent fixture at both ends of the tunnel. When there are no works taking place in or near the tunnel, the signals will be turned off. 

Once the signals are operational work can start on the installation of state-of-the-art LED interior lighting and emergency lighting. The quake-strengthening work will also start. 

Work starts in earnest in August and is expected to be complete by mid-2020. 

While crews are working the tunnel will be down to one lane and all traffic (including cyclists) controlled by the traffic signals. Pedestrians and cyclists will be able to use the tunnel throughout the project but at times they will have to wait and be guided through. 

Installing the new interior lights will require the tunnel to be closed and traffic detoured. We'll do this work at night when the number of people needing to travel through the tunnel is significantly less than during the day.

May 2019

From Monday 6 May contractors will begin work to install traffic signals at both entrances to the Seatoun tunnel.

Installing the signals will take approximately four to six weeks, with crews working between 9am and 4pm. In the latter half of the project there will be approximately one week of night works, with any noisy work finishing by 10.30pm. During night works traffic will be controlled by stop/go paddles while the tunnel is reduced to one lane. 

Once operational, the signals will be used to manage traffic during earthquake strengthening work, scheduled to start in August. Beyond this the signals will remain in place to manage traffic during any future maintenance or upgrade works, or in the event of a major incident, as happens with the Karori tunnel.

When there are no works taking place in or near the tunnel the signals will be turned off.

Contractor contact: HTS Group, 027 432 1059

About the project

The project includes:

  • building new buttress overlay beams in front of the existing ones of both sides of the tunnel
  • constructing ground beams behind the parapets of both portal walls
  • installing 20 rock anchors (10 either side of tunnel)
  • repairing defective areas of portal and painting both walls
  • constructing new ground beam in front of retaining wall - held in place with four rock anchors
  • extending the pedestrian handrail along the ramp on both sides of the tunnel
  • replacing lighting in the tunnel with LED lights.

Vehicle and pedestrian access to the tunnel will be affected at times while the work is underway, and diversions will be in place. More information will be available nearer the time.

Background

Originally constructed in 1907, the tunnel comprises of an arched brick liner with concrete portal walls. It is 2.5 m in height, 8.1m wide at road level and has a 6.2m wide carriageway. There is a 1.2m wide footpath with a steel handrail that sits approximately 0.6m above the carriageway surface.

More information

Faiz Tawfeek, Team Leader Structures
Phone: 04 499 4444