Clyde Quay Wharf Slab Jacking
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Client: LT McGuiness
Sector: Foundations
Location: Wellington
Contract Value: $542,000
Completed: Aug 2013
Main Contractor: Brian Perry Civil

As part of the upgrade of the Overseas Passenger Terminal in Wellington Harbour which Brian Perry Civil carried out the piling works for, an additional contract consisting of lowering 30 cast in-situ concrete slabs using hydraulics is being carried out. These slabs form the base of a under-wharf car park within the tidal zone.

Each slab is poured in-situ by the main contractor weighing approximately 90 tonnes each. Eight 32mm VSL bars at even spacing are connected to threaded bearing plates cast in to each slab and locked off on top of double 310UC beams above the wharf structure. Eight 60t hydraulic jacks are utilised to lift and lower the slab connected to a main synchronised lifting system unit. Occasionally a pre-cast lift pit is incorporated into the works which is required to be lowered independently before being connected to the main slab.

Works commenced in November 2012 with each slab taking approximately 2 days to complete. one day is required to lift each slab 150mm to allow the main contractor to strip their formwork and the other day is required to lower the slab up to a depth of 1200mm.

This is a challenging project with restricted access and multiple trade interfaces occurring whilst working around weather and tide restrictions.

Work Complete – August 2013

Construction was completed with zero defects, LTI’s or MTI’s.