Article published in the June 2020 edition of the SA Builder Magazine
Franki Africa recently called on its experience to prevail over an array of challenges to deliver a two-level basement with depth of up to 10 m at Growthpoint Properties’ famed Longkloof Precinct project in Cape Town, on time and within budget.
Specialist geotechnical contractor Franki Africa was recently contracted to deliver a two-level basement for the construction of the Canopy by Hilton Cape Town Longkloof hotel developed by Growthpoint Properties, South Africa’s largest real estate investment trust. The 150 guestroom building will be the Canopy by Hilton brand’s first property in Africa.
The Canopy by Hilton Cape Town Longkloof is expected to become a South African landmark, which will welcome guests from all over the country and the world. Located right close to Cape Town’s historical epicentre, the Gardens Suburb, the project – which forms part of Growthpoint’s precinct redevelopment – gives new shine to the 112-year-old heritage site, Longkloof Studios.
Scope of project
Franki Africa’s scope of project, explains Contracts Engineer Daryn Cloete, entailed the construction of a two-level basement with depth up to 10 m, as well as relocating services – most notably a 250 mm diameter sewer pipe and 1 050 mm diameter stormwater pipe, among others.
“There was also a façade of a 100-year old heritage building close by that needed to be protected with a steel structure that was supported on piles,” says Cloete, adding that there were also items to be salvaged before demolition of the back half of the heritage building could take place.
In a nutshell, the project included rock breaking, façade protection, demolishing of the building, salvage of items, the relocation of services and the construction of the lateral support works. The basement comprised 2 130 m² of lateral support, had 23 corners within it and was surrounded by some notable heritage buildings, which meant that it was not your typical rectangular or square-shaped basement.
Not without challenges
The project had its fair share of challenges. Firstly, Cloete explains that the services had to be relocated in close proximity to a busy road, which made the execution of that particular task challenging. This was exacerbated by having to relocate and deal with live electrical cables in the process.
With the prime Longkloof redevelopment project located right in the middle of a historic urban quarter with existing neighbourhoods, Cloete admits that managing noise and dust pollution from breaking rock was a major challenge.
Below the clayey silt sand – approximately 1,5 m below ground level – was the Malmesbury bedrock, which turned out to be slightly weathered to unweathered. A total of 24 000 m³ of material was ultimately removed from the site.
Breaking the 70 MPa rock on site also made it difficult to stick to production targets. Despite the raft of challenges, the five-month project – which commenced on 16 August 2019 – was completed on time and within budget.
A big factor contributing to the success of the project, says Cloete, was the way in which the Franki team ‘juggled’ the constant challenges, while keeping their focus on the main task at hand, which was to create enough area for the subcontractor, Ross Demolition, to break and remove rock.
To prevail over these challenges, Cloete says “we kept tackling the challenges as they arose and continued to push forward as a team”. “Due to great teamwork of the crew, led by Fikile Tshetsha, the contract was completed well within the stipulated timeframe. A big ‘THANKS’ to DHK Architects, Atvantage Project Managers, MLC Quantity Surveyors and LH Consulting Engineers, whose input and expertise contributed hugely to the success of this project.”