The David Malcolm Justice Centre is an iconic 33-level office development on the corner of Barrack and Hay Street in Perth. WGE provided Mirvac with structural construction-phase engineering services, featuring the following structural components:
- A single level basement car park
- Reinforced concrete core
- Post-tensioned-flat slabs
- An adjoining 5-level hotel annex
The constricted site layout and the surrounding heritage-listed Town Hall and Old Treasury Building presented some unique technical and logistical challenges which necessitated some out-of-the-box thinking by the design and construction team.
A key complexity associated with basement excavation was the presence of foundation remnants of a 1960’s mid-rise building which previously occupied the site. These large, buried concrete obstructions which included rafts, footings and basement walls, precluded the use of a conventional piled boundary retention system in most places. To address this, the design team opted to make use of the original 1960’s basement walls in conjunction with ground anchors and micro-fine injection as a means of providing temporary boundary retention along the Old Town Hall. WGE undertook a rigorous verification of the existing wall’s ability to support the Town Hall and ensured that the structural integrity of the wall would perform adequately as a means of temporary retention.
Part of the basement works also included the construction of a vehicular access tunnel under the State Buildings to link the Tower basement car-park to the existing Law-Chamber car-park. This tunnel was constructed using a top-down construction method working within the ground-floor confines of the State Buildings.
Careful sequencing of the temporary works, jacked propping and micro-fine injection work was required to enable the heritage building foundations to be demolished and replaced with a new concrete foundation raft.
The project won the Hassell Commercial Architecture Award and the Sustainable Architecture Award at the 2016 WA Architecture Awards.