ON SITE dhk
The ground floor façade is set back, so that the three office levels above appear to float.
Basson informs that treated effluent is used to flush toilets, as well as for irrigation and cooling of the HVAC. The engineer says that the civils scope for the project was“ fairly minimal” but nevertheless, he describes what it entailed:“ It involved bulk earthworks and subsoils, and we are also building an access road for this site and the site alongside it, and a ramp into the basement.” The entire Century City development is built on what was once a wetland, with very wet underfoot conditions owing to the high water table. This posed a challenge when it came to the earthworks.“ The two buildings are at different levels,” the expert explains and adds that this difference was about a metre in depth. This variance created water seepage in the lower basement excavation, which then required dewatering.“ What we did was make a pioneer layer of large rocks and stones, with the maximum diameter measuring 100mm. Franki’ s piling rigs were able to move on that surface, putting in the piles and lateral support for the building,” he explains. Franki’ s geotechnical works started at the end of November 2016 with the installation of a three-metre cantilever lateral support wall that consisted of 215 No. 500mm diameter CFA soldier
16- CEC April 2018
piles and a gross 788m 2 of gunnite. The foundation piling commenced in mid-January 2017 and consisted of 513 No. 520mm diameter pre-drilled Franki piles, which were completed on 17 March 2017. The end of January 2017 saw the completion of the lateral support piles, with gunnite completed on 24 February 2017.“ All stormwater from the site are diverted back into the Century City canal system as per the Century City: Sustainable Urban Drainage System Evaluation & Master Plan,” Basson explains.“ The water goes into a settling tank where the silt settles. The water then flows into another tank before being pumped back into the stormwater system. The good thing about this system is that only the overflow goes back into the municipal grid / network. It’ s all contained within the canal system and doesn’ t run out to sea.”
Architecture
The buildings are each split into two wings, with a central core and full height atrium bringing light into the centre of the expansive floorplates. Discovery’ s new regional offices will be in the one building, while the other building, which is ideally suited for a large corporate, is being designed to be flexible and if necessary, could be subdivided to accommodate smaller users, says Rabie director, Colin Anderson.
Each building is set on a green podium with a sunken amphitheatre, creating an active public space, with shared basement parking below. The buildings actively engage with both Sable Road and Bridgeways, as well as with each other and the new developments planned for either side of the site. Both enjoy high visibility as well as panoramic views towards Table Mountain and Table Bay. The twin buildings are designed as a series of shifting volumes along the linear site. The ground floor façade is set back, so that the three office levels above appear to float. Two office levels are enclosed in a vertically articulated façade with recessed glazing, creating a delicate veil that serves as passive solar control. Within this layered envelope, protected walkways and terraces have been created to the north and south, capitalising on the differing views and seasonal changes. A further office floor takes the form of a fully glazed crystalline white box that floats on a shifted axis. This building form is reversed on each wing of each building, creating dynamic arrangement along the length of the site. dhk is responsible for the full architectural services, having previously designed the Bridge Park office building for Rabie in the same precinct in Century City. In addition