Construction World December 2023

BUILDING CONTRACTORS

PROJECT INFORMATION

• Company entering: Concor Construction • Client: Intaprop Investments • Main Contractor: Concor Construction • Architect: GLH Architects • Principal Agent: Duncan Clark • Quantity Surveyor: Agora Africa • Consulting Engineer: Pure Consulting

T he design and construction of 5 Parks Boulevard – which is Concor’s seventh contract at Intaprop’s Oxford Parks Mixed-Use Development in Rosebank, Johannesburg – achieved a high Green Star rating from the Green Buildings Council South Africa (GBCSA). Built on four platforms with 80 piles, the elegant building comprises four basement levels and five office levels – providing about 7 300 m 2 of gross leasable area (GLA). The stylish office block features a façade combining glazing and stone which enhances the use of natural light. Constructed at a fast-track pace, the Concor team accomplished a safe and on-specification result between July 2022 and Beneficial Occupation in February 2023 with final handover in August 2023. The elegant structure of 5 Parks Boulevard comprises conventional reinforced concrete slabs from the basements to the roof, with a lift core to accommodate three lifts down to the lowest basement. An innovative method of lift construction was implemented using an hydraulic formwork system, which allowed the vertical shafts to be constructed ahead of the slab pours to optimise the cycle time between slabs. Each level of slab consumed between 150 m 3 and 250 m 3 of 25 MPa readymix concrete, with the bulk supply of all readymix concrete provided by AfriSam. The slab on each level was placed in four pours, with the schedule requiring on average two pours per week. Higher strength concrete – ranging from 35 MPa to 60 MPa – was used for the columns and verticals. The roof and levels three and four were designed and constructed using higher strength readymix concrete with additional steel reinforcement to enable early strip to be achieved. This, in turn, allowed early access to complete façade elements and services on the top two floors. The façade of the building was constructed using prefabricated facade panels which were lifted into position and bolted onto the structure between the slabs. This process was facilitated through the accurate detailing of the façade panels during the early stages of construction which allowed these to be manufactured 5 PARKS BOULEVARD, OXFORD PARKS, ROSEBANK

ahead of time, again speeding up the construction programme. As part of its qualification as a Green Star rated building, the concrete mix designs used in the construction of 5 Parks Boulevard contributed to reducing the overall carbon footprint of the structure. This was achieved by using more fly ash in the mixes reducing cement levels by 30%. Less cement means less clinker, which consumes considerable energy in its manufacture. The green design includes photovoltaic panels on the roof, which will generate renewable energy for up to 90% of the tenants’ needs. To further support the energy efficiency requirements of the Green Star rating, the building makes extensive use of glass windows – about half of which are double-glazed. Thin-glazed glass will be mainly used on the atrium side, with punch windows being installed for the rest of the building. In compliance with the Green Star rating criteria, the building process is conducted within the confines of an environmental management plan and waste management plan. All waste is separated into wood, steel, cementitious and general waste on site, and placed into the appropriate skip containers before being removed and disposed of responsibly by certified waste removal subcontractors. Concor’s ISO 14001 environmental certification also required that the project’s suppliers and subcontractors were sourced within 40 km of the site, where possible, to reduce the CO 2 footprint. The design of 5 Parks Boulevard combines functionality and aesthetics, with a triple-volume atrium in the reception area that makes the most of natural light and reduces energy consumption. This feature extends from the ground floor through to the second floor. Further utilising the natural light is a double-volume area on the third and fourth floors of this five storey building. The façade encompasses various elements including double-glazed glass and large tiles, and a Versus paint application which gives a durable textured finish that does not require extensive maintenance. 

40 22 nd Best Projects Awards 2023