For Balwin Properties, developer of the 24-block Strelitzia apartment complex in Greenstone, Johannesburg, using the Echo hollow-core prestressed concrete flooring panel system enabled the completion of this huge project six months earlier than would have been the case had a conventional flooring construction method been employed.The prestressed panels provided the logical solution to the architectural design and the logistical challenges presented by the large site and the magnitude of the project. “In fact, Echo Prestress was the only solution,” says Balwin director Ulrich Gschnaidtner.
Strelitzia comprises 376 two-bedroom apartments in four-storey buildings and the extensive residential complex includes a clubhouse and gym.
A total of 22 900m² of 120mm and 150mm prestressed slabs were used to construct the first, second and third floors as well as walkways and balconies. The top floor has a conventional roof. Construction time was slashed: the conventional slab method would have required a forest of back-propping at each level, delaying finishes and slowing completion of the project, but with the prestressed concrete panel system, no props were required and finishes could continue unhindered at lower levels.
The chosen construction method also easily accommodated architectural features such as corner windows by using a nominal size load-bearing steel corner mullion.