Construction World December 2016

Winner

B

Specialist Contractors or Suppliers

129 RIVONIA ROAD (VILLAGE WALK), SANDTON

method. 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. Blasting of hard rock, constituting a third of the overall basement excavation volume, was undertaken with precision and each blast design individually prepared with its own parameters and restrictions. Overall, in excess of 80 blasts were set off without a single problem. The lateral support structure installed had to provide a safe environment during the earthworks and lateral support contract as well as for the duration that the building contractor would take to construct the basement structure. This period would be in the region of 30 months. A strict environmental plan was adhered to in order to have as little impact on the daily activities around the site as possible. Being a highly traffic congested area, strict traffic control measures were implemented and maintained throughout the construction phase. Dust control was continuously enforced with the use of water bowsers. The fine balance between time, cost and safety was respected to ensure that the client benefited from the optimum solution. Multi disciplines were running in parallel with the lateral support activities, these including bulk earthworks, blasting, the surgery precision saw cutting of existing beams and slabs as well as the bulk demolition of the existing four basement structure. All disciplines were planned to a micro level to ensure all contractors could work simultaneously in a crowded and space restricted environment. The introduction of the building contractor halfway into the lateral support contract further complicated the site logistical challenges. Almost half of the site footprint was handed over to the building contractor, in early November 2015 with six months still left to run on the bulk earthworks and lateral support contract. Working works were strictly adhered to as the three surrounding hotels with 80% occupancy had an obligation to their guests. Activities were carried out during working hours and Saturdays

The second and final phase would encompass the excavation and lateral support to the new proposed basement layout, including the demolition and removal of the existing four-basement parking garage. Challenges were numerous, including but not limited to unknown location of services, concrete obstructions covered by soil, a diabase dyke running through the site with the unknown position and extent, retaining neighbouring property structures and basements and the most difficult of all, the time constraints. Due to the nature of the complex goestrata in the location of the site, the lateral support design had to cater for the constantly varying soil conditions. In addition, the neighbouring property structures comprising the Balalaika, Protea and Holiday Inn Hotels, the Bull Run Pub and Restaurant, Nedbank Building and the highly traffic-congested Maude Street and Rivonia Road, all depended upon the absolute effectiveness of the lateral support design and installation. The proximity of the neighbouring property basements provided a further challenge as the required anchor lengths would clash with the existing basement positions. Accurate surveys had to be undertaken to determine the location and depth of these and anchor designs were adjusted accordingly. Exceptionally long strand anchors were installed along the Maude Street and Rivonia Road faces while exercising extreme care not to drill into neighbouring basements. A grout design capable of complying with strict quality requirements, but still allowing the tight programme to be met, was implemented and maintained throughout the project execution. The lateral support was designed using the observational In June 2014 the decision was taken by Eris Property Group to redevelop the old Village Walk site. The primary phase would support the existing boundary walls with the Balalaika and Protea Hotels, this paving the way for the second phase.

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until 14:00 only, further restricting the overtime facility to catch up on the lost time. Therefore, from both a technical and management aspect, Franki showcased the optimum solution, bringing the ultimate goal of a successful project to the client that entrusted Franki Africa with this responsibility.

Project information • Company entering: Franki Africa • Client: Eris Property Group • Main contractor: Franki Africa • Architect: Boogertman + Partners • Principal agent: SIP • Project manager: SIP • Quantity surveyor: Aecom • Consulting engineer: Aurecon • Subcontractor: Zero Azani • Subcontractor: Phoenecian Demotlition • Contract value: R140 000 000

Construction WORLD

DECEMBER • 2016