Wamberal Basement Package

Architect: White Dickson Architects

Builder: Tecorp

Engineer: Northrop Consulting Engineers

This project was a true complete package of works, which included:

- design involvement;

- demolition assistance;

- cfa piling; 

- screw piling; 

- temporary sleeper walls; 

- capping beams; 

- temporary steel propping; 

- bulk excavation; and 

- shotcreting

The residence, which is situated directly on the shoreline of Wamberal beach is designed to withstand coastal erosion. In a large storm event, the house will be able to remain suspended on its pile foundations with 9m of sand missing beneath it.

The house also a large garage, constructed using a contiguous flight auger (CFA) pile wall with a capping beam over and shotcrete on the front face. The structural and coastal engineers considered the relationship between these underground retaining walls and a major erosion event, and the pile layout and embedment depth were specifically designed to absorb and diffuse wave action, rather than rebounding it onto neighboring properties. 

Complications:

The 16m foundation pile depth required Heavy Foundations to hire a 70ton drilling rig from the Gold Coast, Queensland. 

Temporary propping was opted for to provide lateral stability to the CFA basement walls, while reducing the underground volume of the structure and it's impacts on the path of wave run-up in a storm event. The propping and whaler beams meant that a lot more work and careful planning was required surrounding the completion of the nearby building elements, including piles, the above ground structure, and the propping's eventual removal from the completed building. 

507.4m3 of concrete was used in the buildings piles and retaining walls.