Construction World September 2018

West Abutment excavation for the pile cap, showing the hardpan calcrete from just below surface which required predrilling.

Installing Predrilled DCIS piles on a pier alongside the R27.

Concrete cubes and Spacer block manufacturing on site.

“The fact is there are some limiting considerations to be taken into account with the CFA system reducing its popularity compared with driven piles. The conditions in the Greenfields Link Interchange, how- ever, made the system a very successful choice,” Stoll says. The key to the success of the piling project was the implementa- tion of Franki’s alternative plan. “It took teamwork to get this right,” says Stoll, “and I would like to pay special tribute to Ross Dold, Nabeel Omar and Wilhelm Wessels on site for AECOM, together with Abie Newmark and Alexi Maravelias from the AECOM office, Harry Viljoen and Mish-al Booley from the Department of Transport and Public Works, while Stefan Herbst and Willie Broekman of WBHO Construc- tion assisted us with the implementation. This was indeed a great team effort,” he says. Stoll emphasised that no project is too big, too small, or too com- plex for Franki. "In terms of South Africa and Africa in general we are geared up like no other geotechnical company in the world. We have permanent offices and yards in South Africa, Mauritius, Mozambique, Tanzania, Zambia, Kenya, Ghana and Angola. We are also registered in Uganda, Botswana, Swaziland, Lesotho, Seychelles and Namibia. Our French speaking colleagues are present in Morocco, Cote d’Ivoire and Algeria and our Middle Eastern colleagues are present in Egypt. “Add to this the depth of global experience that the Keller Group has, it becomes clear that Franki’s ability to provide a world-class service in this country and across the continent is second to none,” he concluded. 

W205 Bridge CFA (Continuous Flight Auger) Piles in the background with a Liebherr service crane in the foreground.

Southern Africa for the past 70 years (and is still today one of the most popular pile-types), proved its worth in the solution. The main feature of the Franki Pile is the enlarged base formed at the toe of the pile. In forming this base, the end-bearing area is increased significantly and the displacement achieved when expelling the plug and forming the enlarged base compacts and preloads the soil surrounding the base. So, the end-bearing of a Franki Pile in sands develops at much lower base deflections than that of a bored pile. Other important advantages of the Franki Pile include: it is often a very economical system; it has an extensive range of pile sizes; it has an exceptional load/deflection performance; noise levels are relatively low; and it has excellent tension load capacity. The CFA piling system is also a fast and economical one, which has no vibration and limited noise levels. Some of its other attributes include: high production levels in suitable soil conditions; while they are economical in suitable soil profiles.

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CONSTRUCTION WORLD SEPTEMBER 2018