Exxaro head office showcases geotechnical expertise

Challenging dolomitic ground conditions at the site of the new Exxaro head offices for Growthpoint Properties in Centurion, Pretoria, resulted in infrastructure company AECOM collaborating closely with AMA Architects to optimise the building design.

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AECOM was responsible for the structural, civil, geotechnical and quantity surveying aspects of the project. The earthworks contract was completed by Stefanutti Stocks Geotechnical, while the raft and first suspended floors were cast by main contractor WBHO.

‘In terms of the architecture, we had to reshape the building design to account for the ground conditions. We ended up with 16 different variations of the initial format of the building shape compared to the underlying ground conditions. The challenge was to mitigate the risk in the most cost-effective manner possible,’ AECOM executive for Structures, Buildings and Places. Kim Timm (PrEng) explains.

Award-winning design

AECOM’s involvement with the project resulted in it being awarded the AfriSam Innovation Award for Sustainable Construction at the Construction World Best Projects Awards 2019, at a gala banquet at the Rand Club in Johannesburg on 6 November.

It also won the >R250 million project award category at the CESA Excellence Awards 2019.

Sites underlain by dolomite rock are prone to sinkhole formation. The Lakeside site was specified as a D4 site with Inherent Hazard Class 8 Dolomite. The site had four known cavity locations that could potentially produce 15-metre-wide sinkholes. Hence, an expert reviewer was required by the Council for Geoscience to verify AECOM’s geotechnical solution.