Sumner Road from Evans Pass to Lyttelton was badly damaged in the earthquakes, with numerous rockfalls along the 3km stretch of road and many of the 30 odd retaining walls beneath it damaged or collapsed.
Contractors McConnell Dowell and teams of sub-contractors have been working for the Council and NZ Transport Agency for the past 15 months on the first stage of work to reopen Sumner Road - mitigating the rockfall risk. This work is extremely complex, identifying rock features that are high-risk or unstable and removing them. The rock is removed by ‘scaling’ which involves abseiling down the bluff face to find the unstable and high-risk rock and removing them by levering, air-bagging or blasting.
The bluffs from Evans Pass down to Battery Point have all been scaled and cleared and work has begun creating the rockfall protection features. The rockfall protection features include a catchbench which is being excavated and a rockfall interception bund which has just been completed. The catchbench and interception bund will literally catch falling rock and contain it to reduce the risk of it falling or rolling onto the road.
Extra material has also been removed from around Windy Point bringing the alignment of the road closer to the hill, away from the damaged outer edges of the corner.
Check out this video about progress towards re-opening this key route.
The rockfall interception bund
The second stage is to repair the damaged retaining walls, and reinstate the road itself. The start date for the work, and the complexity of it (much of which only became apparent when contractors were able to access and clear parts of the road), mean we have had to revise the date for re-opening the road. It is now expected that the road will reopen and the roading corridor will be reinstated early to mid-2019, not early 2018 as previously thought.
To reduce the timeframe for the re-opening, and reduce cost, the Council agreed to award the contract for the second stage of the works to McConnell Dowell.
Having the same head contractor for both stages means that some of the first and second stage work can be done at the same time, therefore avoiding having to push the open date out further still. It also means the work can be done for less cost than having a new contractor come into the work for the later stage.
Christchurch City Council General Manager David Adamson understands that many people may be disappointed with the later opening date.
“This project is about making an important roading link safe, resilient and fit for purpose. It is important therefore that work is done to the appropriate standards that will serve the community for decades to come," he said.