The Chifley South Tower demolition is located in the heart of Sydney’s CBD. It was a project that exemplified industry-leading collaboration under uniquely complex conditions. With the adjoined 43-storey Chifley North Tower remaining fully live and operational throughout the entirety of the project. Mann Group was engaged by Built to lead the demolition in a high-risk, service-congested environment where failure to coordinate would have had major commercial and operational consequences.

At the time of contract award, no geotechnical investigations had yet been undertaken, which posed a critical challenge, as the five basement levels could not be demolished until a retention system was designed and installed around the 4,000m² site footprint. MANN had to coordinate closely with both permanent and temporary geotechnical and structural engineers to address not only the immediate temporary works but also the long-term structural requirements. The design process was expedited through strong collaboration and over 100 exploratory pockets excavated around the perimeter to inform engineering decisions. A significant milestone emerged when the retention system, initially scoped as a short-term temporary measure, had to be adapted mid-project to incorporate the client’s permanent retention needs. MANN led intensive design reviews and working groups, enabling transparent decision-making among Built, engineers, and subcontractors. The outcome was a hybrid system that satisfied both temporary and permanent structural demands without impacting critical milestones or slowing the demolition program.

Structurally, the North Tower(43 Stories) which was to remain, relied on the South Tower for lateral support, this determined that significant design, fabrication and installation works were required such that the South Tower could be demolished without affecting the North Towers ability to be self supporting. MANN worked with Built’s Design Team, our in house temp engineer team, Built’s permanent structure engineering team and third party to certify that the loads would be transfered back into the North Tower.

From the outset, MANN worked hand-in-hand with Built, multiple service trades, and multiple independent engineering consultants to navigate overlapping structural, services, and program challenges. Thousands of live services—running through the South Tower and feeding into the North Tower’s main server room—had to be carefully identified, isolated, and rerouted without a single outage to the North Tower. This required meticulous sequencing and constant interface between trades, Mann Group, and our client Built. Because full zone shutdowns weren’t possible, MANN led the manual hand strip-out of approximately 18,000m², enabling service contractors to follow behind and surgically dissect service lines. Demolition crews and service trades worked in real-time collaboration, adjusting crew sizes and workfronts daily to mitigate any program delays and ensure continuity and safety.

Despite a compressed program, overlapping works proceeded safely and efficiently. As excavation neared completion, the Client’s FRP subcontractors began constructing the new jump form core directly within the live demolition zone. MANN led daily coordination between all stakeholders to ensure safe shared use of space, maintained access routes, and upheld strict environmental and safety controls, which allowed the structural works to commence whilst MANN were still undertaking their Scope of Works. This project’s success was not due to any one innovation—but to the strength of collaboration and a CAN DO attitude at every level. MANN’s open communication, technical leadership, and ability to bring together diverse project partners under intense pressure enabled the safe, seamless, and incident-free delivery of one of Sydney’s most complex demolition undertakings.