Just after midnight on 14 November 2016, a magnitude 7.8 earthquake struck a mountainous area of New Zealand’s South Island near the township of Kaikōura. It caused over 30 landslides and severe damage to roads and railways, cutting off communities. WSP mobilised expertise to help the New Zealand authorities restore goods, services and public access via the highway network within two weeks – a task that required alternative thinking and geotechnical risk management.
Assessing and mitigating geotechnical risks
Providing the engineering platform for the ongoing earthquake recovery, we:
• Immediately carried out multidisciplinary engineering inspections of the highways
• Recorded asset damage, anticipating future hazards and carrying out a semi-quantitative assessment of risk
• Prioritised what the engineering effort should focus on
• Mitigated risks to the recovery effort
• Coordinated with key stakeholders.
Assessing, clearing, mitigating risks and operating a live highway past massive landslides was a major undertaking. Yet within two weeks we had provided escorted convoy highway access to Kaikōura township via Inland Route 70. Within five weeks, we were able to provide restricted non-convoy access while ongoing work continued.
Allowing vehicles to pass safely through highly hazardous zones relied upon our semi-qualitative assessment of geotechnical risk. Once we had established workable limits, we used a careful management process to ensure the convoys’ safe passage. We provided daily safety advice on slope conditions and enforced 'trigger action levels' relating to seismicity, wind and rain – all factors that could cause further landslides.
We also specified other measures to control risk. Using ballasted shipping containers provided a quick and cost-effective way to protect workers, the public and the highway itself from further damage. Re-channelling the river moved this hazard away from the highway, which was itself in places re-routed through the river using culvert fords to avoid a rockfall zone. Shaping landslide debris to create rockfall bunds added protection, and unstable rock mass was scaled, blasted and sluiced away.
Our ground engineering expertise and careful attention to risks ensured contractors could carry out their work effectively and safely – there were no accidents or incidents during the works.
Collaboration between offices and competitors
We were helped by our previous experience. As the New Zealand Transport Agency’s asset management consultant in the Canterbury region for over 12 years prior to the Kaikōura quake – a timeframe that included the previous 2010-11 earthquakes – we had already built up expertise in disaster recovery.
To complement local expertise, we engaged teams from the UK as soon as news of the earthquake hit, with boots on the ground within a week. They were backed by remote support 12,000 miles away, with teams from Manchester, Cardiff, Doncaster, Nottingham and Bristol working seamlessly together.
"I would strongly support recognising the WSP team for the exceptional service given to the agencies involved in the response, but more so to the people of Kaikōura, Waiau, Hanmer Springs and other isolated communities affected by the earthquake.”
~ Richard Topham, Senior Network Manager, New Zealand Transport Agency
We also collaborated with competitors such as Arup on an unprecedented level. Together we worked for the North Canterbury Transport Infrastructure Recovery (NCTIR), an alliance partnership of government bodies and construction companies. Everyone placed the needs of the community ahead of potential competition.
On 15 December 2017 – one year, one month and one day on from the earthquake – NCTIR was able to fully reopen the repaired main State Highway 1 north and south of Kaikōura.