The 129 Rivonia Road modern development consists of two high-rise towers. This site was surrounded by three hotels and two of the busiest and high-end roads in Sandton CBD. Franki Africa was entrusted to laterally support and excavate a super-basement to provide the hollow core for the new building structure. At its deepest point the excavation would reach a depth of 28 meters.
Franki carried out the geotechnical works for this project.
Volume: The scope comprised of 10 800m² Lateral Support, 260 000m³ of bulk earthworks, 80 000m³ of hard rock blasting and 20 000m³ of reinforced concrete demolition
Construction time: December 2014 (Phase 1) April 2015 (Phase 2) – Completion May 2016 for Geotechnical Works
Numerous unforeseen challenges were encountered during the lateral support and excavation phase and these had to be accommodated in the specified programme time. The lateral support was also complicated by diabase intrusions which was encountered as water-bearing and often saturated silt and required additional support. Copious amounts of ground water from approximately 12 meters below original ground level had to be accommodated to maintain access throughout the site.
Meticulous planning and execution in the safe removal of existing slabs and beams, combined with the installation of the new lateral support solution, proved to be one of the secrets to the success of this project. Exceptionally long strand anchors were installed along the Maude Street and Rivonia Road faces while exercising extreme care not to drill into neighbouring basements.
The site posed a multitude of challenges. Sitting snug between existing buildings, with the Balalaika Hotel a mere 20m away, the developments confined workspace posed construction challenges, including having to blast 80 000m³ of rock, over a 17 000m² blasting area.
Primary support provided by Soldier Piles ranging in depth from 16 to 28m, Strand Anchors and Rock Bolts/Hollow Bar Anchors, secondary support provided by 10 800m² of Gunite Walls.