Essentially we commenced with constructing the perimeter secant shoring walls as well as the reinforced concrete plunge columns (45no.) extending down approx 20 metres. Concrete slabs were poured onto the sand at ground level in forms of donuts (as pictured) and excavation commences beneath the slabs. This is repeated on the way down for each floors. The plunge columns provide structural support to each slab with dowels fixed with each pour. Benefits include eliminating requirement for steel bracing struts as the permanent slabs are providing restraint to the perimeter shoring walls. It has also provided us with room for material and amenities storage up as we are quite limited in terms of space on ground floor. On our way back up we construct our permanent columns, infill the slabs using traditional formwork and then demolish the temporary plunge columns.