Making Karori Tunnel Stronger

2 July 2012

Essential quake-strengthening work on Karori tunnel is going well and in the coming weeks, tunnel users will see the new retaining wall on Glenmore Street taking shape.

New retaining wall on Glenmore Street, at the entrance to Karori Tunnel

New retaining wall on Glenmore Street, at the entrance to Karori Tunnel

The bank is being stabilised, secured to the hillside with 160 12-metre-long steel rods and covered with concrete.  Project Manager Faiz Tawfeek says the work is part of the Council's programme to  strengthen and protect important city transport routes.

"While the tunnel itself is likely to withstand a reasonably large earthquake, major work was needed on the portals and Glenmore Street hillside to make this route safer," he says.

More scaffolding is going up on the city side of the tunnel so that workers can begin anchoring the portal to the hill with long rods or rock anchors. On the Karori side, all the anchors are now in and the next step is to demolish the old buttresses on either side of the entrance and replace these with stronger ones.

Work is a few weeks behind schedule but we are working to address this by bringing in more construction workers and equipment.

All going well, the work should be finished towards the end of the year. The tunnel is open as usual at peak times but is down to one lane Mondays to Fridays between 9.30am to 3.00pm and 7.00pm to 12 midnight, and sometimes on Saturday mornings from 7.00am to 9.00am. There will continue to be occasional night closures.