The COVA re-development on the Isle of Capri near Surfers Paradise is a modern commercial complex offering boutique shopping, gourmet food and beverages to local residents and tourists. The project has revitalised a once thriving retail hub that became run down and tired with age.
To maximise the land use and to comply with modern town planning requirements, basement parking was required beneath the entire site which provided challenges to the designers and builders due to the sandy soils and proximity to the Nerang River.
The depth of the basement was required to be below the water table which regularly rises and falls due to tidal influences from the adjacent river. During major flood events, the sandy soil can also become fully saturated which induces major uplift forces on the foundations as the waterproof basement begins to act like the hull of a ship when the basement is submerged.
In addition to the uplift forces from the buoyancy effects of the water table, the soft ground conditions required that the foundations handle the significant vertical forces from the weight of the structure. The challenge for the designer was to come up with a foundation solution that worked equally well in both tension and compression.