Use of French expertise has helped Keller’s South Africa-based business Franki Africa deliver ground improvement work for a major new port development.
Ground conditions at a former race course meant that piled foundations were not suited to development of the 37ha Clairwood Logistics Park in Durban.
Franki worked with its parent company to solve the problem columns with mixed moduli (CMM) and has now successfully installed more than 46,000 columns to depths of up to 38m at the site.
“Working closely with the client, we started our investigations. We initially looked at traditional piling, but this wasn’t financially feasible due to the depths required,” said Franki business development manager Victor Ferreira. “You have to go quite deep to find a competent soil layer and under those soft, compressible clays we would have had to use casings, which would have made the production slow and expensive.
“We spoke to our Keller colleagues in Germany to explore other options, such as stone columns and deep-soil mixing, before deciding on CMM. With this technique, you can vibrate the tube in very quickly, pour in the concrete and then lift the tube out – it’s around three times quicker than traditional piling methods.”
Equipment was brought in from France and Poland and supervision expertise from France to deliver the scheme.