Complete Urban Transformation
Auckland, New Zealand
The Commercial Bay project involves the major redevelopment of the entire city block in the Auckland CBD. The project involves the construction of a 33 storey steel framed building on top of a retail podium and over two underground rail tunnels. The structural system of the tower consists of a diagrid structure, featuring composite concrete filled hollow section steel tube columns and braces and long span beams.
Holmes Fire provided fire engineering advice for the entire development, including master-planning to allow for future subdivision of the entire block into four discrete separate properties. The fire engineering allows for separate phased evacuation and independent commissioning and ownership of fire protection systems serving the retail centre and the office tower. Holmes Fire was also engaged to provided advice to almost all of the retail and office tenants, to integrate their specific tenancy fitout design with the overall base building fire engineering strategy.
Holmes Fire was also engaged to provide specialist structural fire engineering services to rationalise the passive fire protection requirements of the entire tower. Advanced finite element modelling was undertaken to analyse the response of the whole floor and megaframe in fire. The analysis demonstrated the robustness of the whole structural frame in resisting a full burnout fire. The resulting analysis showed the composite columns and secondary beams did not require passive protection and a reduced FRL could be applied for the primary beams. The analysis was peer reviewed by Professor Jose Torero who is a renowned international expert in structural fire engineering.
This resulted in major savings on site with regard to project timeframes, labour and material costs, and the improved aesthetic and air quality within the space. The costs savings in fire proofing alone was estimated to be approximately $4M.