It took only four seconds and 783 non-electronic detonators to bring about the successful implosion of the Kaserne building in downtown Johannesburg in May, bringing to a close the former administrative nerve centre of South Africa’s vast rail network.
The building had served South African Railways and Harbours and then its successor, Transnet, for more than a century.
Its demolition is in line with the Johannesburg authorities’ efforts to rejuvenate the country’s financial nerve centre to its former glory after decades of deterioration.
Transnet donated the building to the City of Johannesburg (CoJ) in about 1999. The city’s Metropolitan Municipality Department of Housing condemned the building last year because of structural damage caused by a fire.
The implosion was undertaken by Phoenecian Group, appointed by Johannesburg Social Housing Company, an entity of the CoJ.
It worked under Mbongiseni General Services to implode the five-storey building and prepare the site for its proposed redevelopment.
“We have carried out work for the CoJ before. Implosion is a demolition technique especially well-suited for this type of pre-existing structure,” says Phoenecian contracts manager, Sne’ Khanyile.
The demolition experts had to conduct minimal ‘soft’ work within the building from a structural perspective. This included pre-weakening certain structural elements such as the lift shafts and stairwells to ensure the successful implosion on the day.
“It took three months of detailed preparation and careful planning to achieve this,” reports Kyle Perkin, explosives engineer for Phoenician’s Demolition and Earthworks Division.
“There is a huge amount of planning involved as you only have a single attempt to implode such a structure successfully.”
After the implosion, the Phoenecian bulk earthworks division broke the rubble down further so that it can be reused as a platform substrate for the next stage of the overall development of the site for affordable housing and commercial development.