The Perth Busport development is an underground structure with three above ground entry portals access. The facility will act as structural foundations for the future Perth City Link Project which will provide new roads for vehicular access between the central business district and Northbridge, as well as a new 20-storey residential, retail and commercial development.
BG&E as member of the City Busport Alliance, with Brookfield Multiplex and the Public Transport Authority, was engaged to design and construct the Perth City Link Bus Project which comprises a new underground Bus station with a footprint of approximately 10,000 square metres. The project also includes fit out of a 250-metre long bus entry tunnel, a new bus tunnel connecting the Busport to nearby Wellington Street and the diversion of major in ground services.
The perimeter of the structure is bounded by a diaphragm wall on three sides with an active underground rail tunnel forming the fourth perimeter wall.
The internal columns have been located on a fixed grid to facilitate bus movements and door positions; this same grid will be used for the future development above ground.
The structure was designed as a top-down construction to meet the stringent requirements to limit the movement of the adjacent rail tunnels and the existing infrastructure and heritage building in the vicinity. The design incorporated bored piles extending up to 50 metres below ground level.
The 750-millimetre thick basement slab is seven metres below the water table. BG&E adopted an innovative combined fibre reinforced concrete solution in combination with waterproofing membranes to ensure a watertight solution was achieved.
To achieve the required long spans the roof was design as an 800-millimtre thick in-situ multi strand post-tensioned slab.
Our pro-active team undertook research to assess the risk of an uncontained hydrocarbon fire and additional passive measures were incorporated to minimise the risk of partial collapse of the Busport (due to this type of event).
Busport documentation was completed using Building Information Modelling (BIM), with BG&E assuming the Lead Co-ordination role between the structural, architectural and services consultants.