The SCNZ Excellence in Steel Awards celebrate building projects that use New Zealand-fabricated steelwork. However the judges at the 2022 awards gave special recognition to a project that is focused on the adaptive reuse of existing steel, rather than creating something new.
Designed in the 1950s and completed in 1966, the 18-storey CAB building was one of the earliest high-rise steel structures in New Zealand and is a significant example of post-war ‘international style’ architecture. After serving as the the Civic Administration Building and headquarters of Auckland City Council for many years, the Category A heritage building has now been given a new life as a residential development.
A significant amount of testing was undertaken to confirm the condition of the building’s structural steel moment frame – which was cutting edge in its day. Sophisticated structural analysis was performed to test its seismic strength and resilience against modern seismic requirements.
"It’s a very elegant example of structural engineering," Beca’s General Manager - Structures Neil Horsfield says. "The steel moment frame was well designed, detailed and documented by the original structural engineer John Blume, which helped enormously with our assessment of the building to current seismic standards. Very little intervention was required to improve the earthquake reslience of the building. We did propose some minor modifications to the escape staircases, which are an architectural feature, to avoid them adversely affecting the building’s seismic performance."
New structural steel was required for the three-level basement and podium which wraps around the building. This structure provides carparking and is designed to support the construction of additional multi-storey development in future.
The judges were impressed and recognised the project with a special recognition award for Excellence in Steel Construction. The judges commended the entire project team for a fantastic effort: Structural Steel Contractor and Modeller, D&H Steel Construction; Building Design Engineer and Project Administrator, Beca; Architect, Jasmax; Builder, Naylor Love; Quantity Surveyor, Kingston Partners; Developer, Love & Co.
"Reusing the steel means less energy, less carbon and reduced cost - that’s a win, win, win," Neil says. "Making good use of existing buildings and repurposing them, rather than knocking them down and starting again, is becoming increasingly important to our clients."