Seatoun tunnel strengthening

We completed essential earthquake strengthening work on the Seatoun Tunnel in May 2020.

The opening of the Seatoun Tunnel with construction workers standing on either side of it.

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

Maintaining the charm of the 112-year-old heritage structure has been a priority during the works.

Alongside the essential strengthening work, we replaced the sodium lights with new more efficient LED fixtures and we painted the inside to make it brighter and safer for residents to walk through.

Updates

June 2020

The transition to the new LED lighting system has been delayed as some of the equipment needs replacing. The replacement equipment has been ordered from overseas and works to do the replacement will happen in August.

It will take two days to install the new equipment. During the installation one lane will be closed and traffic managed with a stop/go sign.

May 2020

We will complete the earthquake strengthening work on the Seatoun Tunnel this month.

Seatoun Tunnel is the last vehicle tunnel, maintained by Wellington City Council, to complete earthquake strengthening work. Despite construction halting in April 2020 when New Zealand went into Alert Level 4, we will complete the work on Friday 22 May 2020 ahead of schedule.

The new LED lighting system, installed in November 2019, will be tested following the completion of construction. The tunnel will be closed to one lane for a day in early June to take light measurements.

Due to COVID-19 related delays around the delivery of goods, the pedestrian handrail extension will be installed once it is delivered.

The site office will be removed and the traffic lights will remain in place for any future maintenance works on the Seatoun Tunnel.

November 2019

The Seatoun tunnel was 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.

The lighting work was 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.

July 2019

Seatoun tunnel's new traffic signals were 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. 

May 2019

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

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.

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.

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