Architect and Builder August 2017 | Page 90

Two great developments … … two great geotechnical solutions Two new buildings - the SASOL head office in Sandton and the Ballito Junction Mall in KZN - have certainly caught the imagination of both professionals and the public alike. M agnificent designs, both prac- tically and aesthetically - and great buildings require great geotechnical solutions. To this end, Franki Africa, the leading geotechnical solu- tions provider in South Africa, developed technically robust and cost-effective solutions for both buildings. SASOL “This was not just another building,” says Franki Africa’s Paulo Alves of the SASOL premises. “It has a massive footprint of about 6,500m² and is 67,000m² in total.” “Our main challenge on this job was to excavate the 170,000m³ - of which 100,000m³ was decomposed granite rock - to a depth ranging between 14m and 18m and still complete the job in seven months, which is extremely tight from a time perspective” Alves says. Alves adds that this was a two-phase contract, which meant that Franki Africa did not have immediate access to the entire site. “It is fairly difficult to work under partial-access circumstances, which were exacerbated by the fact that there were also five large buildings on the site that had to be demolished. We had to work while the demolition was taking place and on only half the site at a time.” Alves says. But ultimately this project went off very smoothly starting with the fact Final touches being applied to the Sasol project 90 that the original soil investigations were, according to Alves, pretty accurate. “There were no surprises,” he said. T he scope of works included : 170,000m³ excavation; 6,600m² of lateral support; 169 (no) 600-diameter soldier piles, 550 strand anchors, 400 rock-bolts and a 6,600m² gunite face area. It also included ±85 (no) structural piles and the diversion of existing storm-water and sewerage lines that ran through the site. Ballito Junction Mall This contract was on the 5,000m² exten- sion to the existing mall and one of the challenges was on a very fast-track programme to meet the handover dates demanded by the prospective new tenants. Franki was appointed for the piling works directly by Ballito Junction Mall developers, Menlyn Maine and Flanagan & Gerard consortium, in January 2015. Franki’s scope of work comprised ±1,650 foundation piles made up mostly of 520mm and 610mm diameter Zwidi DCIS piles, and 4,600m² of anchored CFA piles for the lateral support – all to be completed within 6 months! The lateral support works entailed retained heights of up to 14m with nearly 600 anchors in four rows up to 23m long to support the heavily trafficked Ballito Drive. The variable sands – some dangerously The Ballito Junction Mall sprouts from the ground close behind Franki’s piling works collapsible – meant that excavation had to be carefully controlled. The added burden of dealing with storm water runoff from the adjacent parking area and road increased risk and lead to flooding and difficult working conditions. Staged access for the foundation piling was required with critical areas being those where key clients had requested early access. The main contractor for the building works, WBHO, followed closely behind piling works meaning detailed planning and co-ordination of the works was essential. Franki’s work was on the critical path and handover of the various zones was achieved on time, with zero lost time due to injury. All the clients’ stringent specifications were met laying the foundation for a successful new development for Franki’s client. Franki Africa, part of the Keller group (the largest independent geotechnical solutions provider in the world) is the largest, oldest and most established specialist geotechnical contractor in Sub -Saharan Africa. Franki offers a comprehensive range of services which ensures that its customers benefit from the most cost-effective solutions. Franki operates in sub-Saharan Africa and the Indian Ocean Islands and, together with Keller, has the experience, capability and capacity to undertake projects of all sizes. Advertorial