Sustainability requires ethical practices

tapered columns, as well as 20 front-end and 20 top raker beams was completed in mid-January 2022. This is in addition to the more than 340 seating benches, 19 back benches, 34 side panels and 76 steps, as well as the structural steel bracing for the structure.

The principal contractor began constructing the foundations and the cast-in-situ bases in mid-October 2021 in preparation for Corestruc to start erecting the structure in January 2022. This preliminary work included excavation, placement of the stabilised fill, and construction of the in situ 10 MPa concrete bases.

Concrete bases

Constructed in sound founding material, the concrete bases for the front raker beams and front columns are 3 200 mm in width and length and 500 mm thick. For the back columns, the concrete bases are 3 900 mm in width and length and 600 mm deep. The chemical anchors that are used to connect the precast concrete columns extend between 300 mm and 400 mm into the concrete bases and have a pull-out resistance of more than 150 kN.

The back columns were braced vertically with structural steel. By bracing the first and second, third and fourth, fifth and sixth, seventh and eighth, and ninth and tenth columns, five frames spaced 5.5 m apart were created. This provided the critical stability that was required at this stage of the erection process, considering the slenderness of the columns.

The top raker beams were then installed in the same way that the front elements were placed. Afterwards, they were braced horizontally in a similar sequence to that used for the back columns.

This was followed by the placement of the seating benches. They were lined up with the raker beams and then grouted into position and, in doing so, formed a single monolithic structure. The process was followed by the installation of the side panels and steps.

Research and development

Infinite Consulting Engineers and Corestruc have been refining and perfecting this modular system adopted on stadium projects since 2016. The focus has been on designing an ‘off-the-shelf system’ that reduces erection time and requires only minor design modifications – if necessary.

This has been achieved by standardising and reducing the number of prestressed precast concrete elements. The use of curved columns and flat surfaces for the rakers, benches and side panels has also facilitated quick and efficient installation.

Infinite Consulting Engineers has also refined the method of connecting the various precast concrete elements over the years. The columns are connected to the in situ bases by components that have been cast into the precast concrete elements and secured using hold-down bolts in the base.

Furthermore, the raker beams, seating benches and side panels are secured with dowels that fit seamlessly into sleeves that have been cast into the various precast concrete elements and into which the grout is then poured. The dowels have also been strategically positioned to facilitate ease of installation.

These and other innovations have ensured that clients derive maximum benefit from the latest advances in precast concrete technology.

*Director, Infinite Consulting Engineers **Managing Director, Corestruc

According to surface mining industry association ASPASA, sustainability is not the exclusive sphere of environmentalists, but rather the whole supply chain within the infrastructure development process, including the quarrying sector. To achieve this requires strict adherence to ethical practices and quality standards that promote local communities and economies.

The latter are among ASPASA’s key objectives in ensuring the longerterm viability of the South African sand and aggregates industry, and to align it with quality labour and social requirements, as well as legal and environmental compliance.

“The building industry can increase its standards by simply dealing with accredited, sustainably operated suppliers of building materials and therefore discredit unethical and illegal suppliers,” says Anthony Bowen, environmental auditor, ASPASA.

Bowen says that key points for industry to adhere to include: • sustainable and energy-efficient designs • environmentally friendly practices • sustainable maintenance practices • materials produced in a sustainable way • material quality • surrounding communities should derive maximum benefit from all building and construction activities • skills development and job creation should leave a sustainable legacy.

Governmental cooperation

“In addition, role players need to be identified to drive development and act in a leadership role to ensure sustainability,” explains Bowen. “Our first most important role player is our government, focusing on the development of infrastructure, which all needs to be well mapped out and developed into the community in a sustainable manner.

“The government’s duty is to legislate the quarrying industry and create equal opportunity by cutting out illegal mining and preventing imports of low-grade building materials,” Bowen continues.

“We also need to deal with suppliers and contractors that are focused on true sustainability in terms of social, environmental and economic upliftment of the region and the country,” Bowen concludes.

Anthony Bowen, environmental auditor, ASPASA