Hoist support scaffold
The façade of the building is clad in pre-panels and therefore, non-load bearing, so the scaffold had to be designed to transfer the horizontal loads from the hoist back into the building at each floor where structural concrete ring beams were located.
Due the shopping centre not wanting to surrender car parking spaces, the only remaining space to locate the site cabins was on the existing roof. Due to the existing roof structure not being able to support the weight of the cabins, the scaffold was required to span between the main structural roof beams with the support legs of the cabins located in these positions. Using this method, the main contractor was able to have 3 offices, a canteen and facilities cabins.
To enable the existing roof covering to be removed and some small single storey buildings be demolished, it was required to provide weatherproofing in the form of a temporary roof. Due to the layout of the existing buildings at roof level and the extents of the new build, the smaller temporary roof was designed to span across the 10m void spanning from the same side as where the cabin gantry was built across and sitting on the existing roof on the other side. On the far side, the scaffold was designed to span between the existing roof trusses, sitting on the purlin lines, where timber packing was required so as not to crush the purlins. The main roof was initially programmed to be a system roof but due to the span being in the region of some 44m, the vertical and horizontal loads were deemed too great to be sustained by the narrow support scaffold which would be located within 1800mm inside of the parapet. Therefore it was decided to design a spine beam, which was linked into the smaller temporary roof support scaffold, spanning 90° to the trusses, across to the support scaffold, and then the roof trusses were to span from each support scaffold, spanning across to the spine beam, forming, in essence, a pitched roof, but with the spine beam in place, the horizontal loads were greatly reduced. The support scaffolds to the three sides all had to be bridged between the main structural roof beams.