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(Above): Piling drilling can hit not only unexpected rock strata, but also formidable old foundations. Pictured is a piling excavation which called for drilling through the foundations of an old structure. (Right): Piling rigs’ soil-collecting flights are spun above ground to disperse the excavated soil.
PREDICTABILITY IS SELDOM PART OF PILING By Nico Maas, founder and CEO of Gauteng Piling It has been estimated that piling foundation techniques date back to the 4th century BC, when it was recorded that Paeonians lived in dwellings erected on lofty timber piles driven into a lake bed. The Romans of old took piling techniques further, with Venice, for example, being initially built on wooden piles. Piling has come a long way since those days, but remains a highly specialised – and invariably challenging – facet of construction. Piling operators find it difficult to tender for projects because of uncertainty about what is waiting for their drilling rigs below ground. Geotechnical tests prior to piling usually provide some indication of soil conditions, but this is not always the case and, in the current post-pandemic economic slump, there is in any event strong resistance
OCTOBER 2021 SOUTH AFRICAN BUILDER
(Left): Nico Maas, CEO and founder of Gauteng Piling, on site while providing foundations for extensions to the Fourways Mall, north of Johannesburg.
to spending funds for proper geotechnical investigations which would help ensure timeous and budgetcompliant foundations. Johannesburg-based Gauteng Piling has handled more than 1 800 piling projects in the past 25 years, mainly using the auger piling method. Auger piles are excavations of predetermined numbers and depths which vary according to the depth of the founding strata. The excavating is done by special rigs fitted with soil-collecting flights (“huge drill bits”, in layman’s terms) of various
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