Prior to the 2013 Cook Strait and 2016 Kaikōura earthquakes, Tonkin + Taylor undertook geotechnical assessments to understand the performance of CentrePort’s reclaimed land, including its trigger for liquefaction and potential for lateral spread. The assessment also included the performance of the existing buildings and wharf structures, which in all cases were impacted by the performance of the land.
As part of the assessment, we developed several mitigation options to provide resilience to the port and its amenities. The 2013 and 2016 earthquakes hit before any mitigations were completed. Those earthquakes caused severe damage to the CentrePort’s Thorndon Container wharf structure with significant vertical and horizontal movement of the reclaimed ground behind the wharf.
The 2016 shaking triggered liquefaction and lateral spreading of the reclamation in the vicinity of the two 750-tonne gantry ship-to-shore cranes, which were left inoperable and at high risk of collapse. The earthquake performance of the reclaimed land and the wharf aligned with our pre-earthquake predictions.
We collaborated with structural engineers and the constructor to develop the design and construction of works to secure the cranes and put them back into service. Ground improvement, anchor piles and ties and structural strengthening, design and construction were completed within a few months.
