This building consisted of two basement carparks, a retail level at ground floor, eight residential levels, and a recreational roof deck. The original building design was inherited from the previous approval of the site, and initial cost estimates indicated the project was not feasible.
From an initial review, we identified potential savings in the project and prepared an alternative sketch design to the lower floors (B2, B1, Gr, & L1). A detailed cost estimate review indicated the savings were significant (10% of the build cost), making the project feasible. The project then proceeded and was completed in 2013.
Advantages of RMA’s Re-design
Basement size: A reduction in the plan area of the basement of more than 15% with increasing parking numbers and all the tandem carparks deleted.
Reduction in shoring: A substantially reduction in the amount of shoring. That also allowed the majority of the basement walls to be constructed using precast shoring walls with temporary prestressed ground anchors.
Reduction in transfer structure: An increase in the efficiency of the transfer structure arrangement. Originally, the main transfer structures in the building were split over three levels, reducing the efficiency of the structure and increasing the complexity.
The alternative layout incorporated a single transfer floor higher up the building at level 2 supported on a regular grid of columns at a more economical spacing for flat plate post-tensioned floor. This greatly improved the structural efficiency and reduced the construction time.
Simplification of lower floors: Simplifying the structure reduced construction costs and time. Originally, the lower floors (B2, B1, Gr & L1) where split-level, divided along the centre of the building. With that arrangement, the efficiency of the suspended slabs was not ideal and a high number of columns where required.
Our alternative layout changed the floors to single levels, which was much more efficient, required fewer columns, was less complex and much simpler and faster to construct.
Columns: A simplification of the column layout on a regular shaped grid with spacings optimised for the floor spans greatly improved structural efficiency and reduced costs. The arrangement aligned the columns from the footings (B2) to the transfer floor (L2), eliminating all transfer on intermediate floors and reducing the number of columns required by 20%.