Construction World December 2021

BUILDING CONTRACTORS

OLD CAPE QUARTER D e Waterkant, situated on the slopes of Signal Hill and overlooking Table Bay, has a history that dates to the 1 700s and today is one of Cape Town’s most fashionable districts. The project consisted of three levels of basement parking, ground floor retail , first floor offices and the addition of four floors of residential units on the existing heritage structure. The strengthening of the existing structure with three additional l ift shafts and staircase shafts were constructed to carry and support the new structure. In addition the tender specification included specific instruction on various elements to achieve green star rating. GVK-Siya Zama took site in May 2019 and the first priority was to hoard the building on Dixon and Waterkant Streets. Due to the location and historic nature of the structure, a geotechnical evaluation commissioned at the outset provided insights to conditions on site. The team knew that the site was underlaid by stiff residual soil that graded through soft to hard rock and that the expected water table varied from 18 m to 21 m. Strengthening of the basement foundations and columns became extremely difficult because of the confined space. As the excavation and exploratory works proceeded, it became clear that the design had to be adapted due to conditions underground. Provision at the

outset allowed for 4 000 dowels and in the end, 11 000 dowels were used during this process. Back-propping throughout the existing structure was immense with certain strategic foundations requiring pil ing, new foundational bases, and column replacement within and under a structural steel supporting framework. Strengthening of columns and beams included the use of special ised concrete mortars, reinforcing and structural steel wrapped columns. In order to accommodate the delayed access to various retail areas GVK-Siya Zama adopted an out of sequence construction approach whereby the l ift core was built ground up and top down to minimise delays to the programme. The construction team proposed to create a crash deck on level 0 to allow them to work on the shaft in two halves. Once the demol ished shaft reached level 0 at ground floor level , they proceeded to cast the new shaft on steel beams, back-propped all the way down to basement level. This allowed the team to halve the expected delay and work on the shaft in two halves. Lockdown in 2020 brought about a particular set of challenges to progress on the project. The level 2 slab, for which decking was already in place, had to be dismantled as it posed a safety risk with winter approaching, along with the uncertainty about how long the decking would need to stand before the actual cast date. Easing of lockdown restrictions and the return to site around June 2020 required specific safety protocols in place to enable the safe return of subcontractors to site and the ramping up to full production. The original structures on the lower level blend well into the historic look of the Bo-Kaap neighbourhood and make a bold statement with colourfully painted facades. The new section comprising luxury apartments over four floors has a modern appeal with a play on contrasting colours between l ight and dark shades. External balconies are clad with Siberian larch which provides a l ight timber finish with a Scandinavian feel. At the time of going to press GVK-Siya Zama had achieved practical completion of this challenging project of bringing a classy lady back to l ife. This milestone stands alongside the team attaining 1 000 000 LTIF hours, a proud achievement indeed. 

• Company entering: GVK-Siya Zama Building Contractors • Project start date: May 2019 • Project end date: September 2021 • Client: The Cape Quarter Property Company • Main Contractor: GVK-Siya Zama Building Contractors • Architect: dhk Architects • Principal Agent: Igual Project Managers • Quantity Surveyor: Smith and Co Quantity Surveyors • Consulting Engineer: Sutherland Engineers PROJECT INFORMATION

34 20 th Best Project Awards 2021