The reclaimed land directly behind Z-Berth underwent lateral spreading and caused partial collapse of the concrete retaining wall settlement and rotation of the remainder of the retaining wall leading to significant differential settlement between the retaining wall and piled structure.
The differential settlement of the retaining wall caused the concrete deck to break, the timber capping beams to significantly deform and severe many of the tie toads which connect the capping beams to the retaining wall.
This project was to investigate conceptual remedial options to restore Z-Berth to accommodate fishing vessels, HPMV trucks and forklifts with the possibility of using the wharf to moor smaller cruise vessels.
CLIENT BRIEF/PROJECT CHALLENGES
Conceptual options were developed to remediate the earthquake damaged Z-Berth to enable use as an operational fishing berth. The works would require replacement of several piles, where the new piles would need to be founded at the same depth as the existing piles to achieve similar bearing capacity but more importantly to ensure the new piles would not change the seismic response of the structure.
Based on the current condition of the asset it was recognised that improving the seismic resilience would require significant rebuild of the structure. As such, the performance objectives for the restored wharf was to allow future use of the asset as a fishing berth with no loss of life as a result of a 1 in 500-year seismic event with the understanding that the berth may be unusable or destroyed beyond repair should another significant earthquake occur.
The study included a review of vehicle tracking onto, along and off the wharf, ensuring safe working areas for the forklifts to load the trucks from both sides, mooring arrangements for the proposed range of fishing vessels and smaller cruise ships.
Bollard arrangements for various fishing and cruise vessels were assessed to ensure sensible bollard locations could be achieved.
The enabling works for the new cruise berth incorporated piles with a capping beam behind the damaged concrete retaining wall. The solution considered connecting the timber Z-Berth structure to the cruise berth enabling works to provide a more robust tie in a future seismic event.
The study was put on hold following the concept design works due to lack of interest from the local fishing industry.