Quay Quarter Tower – Australia 

BG&E, now part of SYSTRA, delivered structural, construction, materials and sustainability engineering for Quay Quarter Tower — the conversion of a 50-year-old, 45-storey commercial building in Sydney’s CBD into a 54-storey vertical village while retaining two thirds of the original structure — one of the largest adaptive reuse projects of its kind internationally.

The tower forms part of Quay Quarter Sydney, a new neighbourhood spanning two city blocks close to Sydney Harbour, combining commercial and residential spaces with retail, green spaces and cafés.

One of the first global applications of this construction methodology 

One side of the tower was demolished and rebuilt while the other was retained and refurbished simultaneously — one of the earliest applications of this methodology anywhere in the world.

Approximately two-thirds of the original structure was retained, conserving around 12,000 tonnes of embodied carbon. Usable area doubled from 45,000 sq m to 102,000 sq m, and the building’s capacity increased from 2,500 to 9,000 occupants.

Designed by 3XN around the concept of a “vertical village”, the tower is composed of five shifting glass volumes stacked on top of one another, contributing to the complexity of the structural solution.

Structural engineering for a complex existing asset

Working closely with builder Multiplex and developer AMP Capital, BG&E provided construction engineering for both permanent and temporary works, alongside materials testing supported by complex modelling and analysis.

Design and construction progressed in parallel as Multiplex undertook demolition and reconstruction in several areas of the tower and connected new floor plates to the existing structure.

The structural solution addressed irregular floor plates varying across the full height of the building with no typical floors, extension and strengthening of the existing core for lateral stability, raking columns forming complex transfer structures with elements hung from the roof across more than 20 floors, and a unique crown structure at the top of the tower. Composite columns — concrete-filled steel tubes — and a continuous composite beam and slab system were used to minimise additional load on the core.

An accelerated programme required floor plate extensions to be constructed independently and ahead of the new core to the structural tie-in point.

RECOGNITION

Quay Quarter Tower was selected from 161 shortlisted global projects to receive World Building of the Year at the 2022 World Architecture Festival in Lisbon. Additional awards include the 2022/23 International High-Rise Award; Development of the Year, awarded by Urban Taskforce; Project of the Year, awarded by Engineers Australia; and four Master Builders Association NSW awards — Best Adaptive Re-use, Best Innovation, Best Use of Steel and Outstanding Construction.

In 2025, Quay Quarter Tower was also named a finalist in The Earthshot Prize’s “Build a Waste-Free World” category.