Multiplex contracted Delta Group to complete civil construction works for the $800m, 39 storey ’80 Collins’ office, hospitality and retail complex in the heart of CBD Melbourne.

A complex scope of works involved the combination of demolition and civil construction works due to a joined existing basement:

  • Demolition of joined existing basement structure.
  • Bulk/detailed excavation works allowing for the construction of reinforced concrete foundations.
  • Propping of the existing structure.
  • Concrete infrastructure – slab preparation and construction, retention systems, lift core rafts and car stacking pit slabs.
  • Construction of crane and mast bases.
  • Emissions, noise and vibration controls.
  • Transport logistics, including traffic management and supervision.
  • Site dewatering.
  • Recycling of construction waste materials.
  • Removal of asbestos and hazardous waste.

In order to overcome the unique challenges posed by the joined basement structure, it was filled with rubble which was battered back from the wall. Our piling rig was then positioned against the wall to complete the necessary retention works. As in previous CBD projects, we were operating within an extremely confined site footprint and we called upon our experience in designing and constructing a loading platform using temporary piles that acted as columns for the slab and which would eventually become part of the future structure. Other key achievements included:

  • Removal and recycling of waste/HAZMAT materials and services spoil to support the developer’s aim to achieve a 6 Green Star environmental rating.
  • Excavation of more than 25,000 cubic metres of siltstone.
  • 90 lineal metres of capping beam.
  • Spraying 1,000 sqm of shotcrete.

Our integrated works programme is ongoing.