Fertiliser company Westfert required a massive warehouse to take advantage of favourable global conditions in the market. The large-scale dome in Hoopstad that was built is described as the biggest in the southern hemisphere.
The main objective of the structure was to create an inland fertiliser storage facility where various basic granular fertilisers can be blended and bagged for the specific needs of farmers. The structure is 116 metres wide and 152.25 metres in length and covers approximately two hectares.
There are no supporting pillars within the structure, which creates enough space for two Airbus 380s to fit inside the building. A triangular pipe frame structure was used for the trusses. A single 194mm diameter bottom cord pipe and two 140mm diameter pipes were used as top sections. The bracing is 76mm pipe and all the sections are 3mm thick.
Creating a structure of this scale wasn’t without its challenges, says project engineer Hentie Park. One of the main challenges was to ensure that all the trusses were rolled on a 96m radius. Secondly, all the welded connections were profiled with a CNC plasma cutter to ensure exact fit. Each truss consisted of 10 sections that were joined by specialised welding on site. Articulating joints were designed where the truss connected to the concrete plinth. Two halves of the trusses were lifted by two 25ton cranes and the centres were connected with three pins – one for each cord. The latter reduced the election time and costs significantly.
The unsupported span of this building is 116m. Global Roofing Solutions supplied approximately +-27 000m2 of Klip-Tite and Nu-Rib for the product and 127m long sheets were rolled on site and clipped into position.
The dome is the fourth largest such structure in the world and it will be able to house approximately 200 000 tons of fertiliser. Thanks to the new dome warehouse, Westfert will now be able to buy input ingredients such as urea in bulk when exchange rates and prices are at their most favourable.