Alexander Forbes: 115 West Street, Sandton
115 West Street in Sandton was developed by Zenprop Property Holdings for tenants, Alexander Forbes. The project has achieved 4-Star Green Star SA Office v1 Design and As-Built certifications. The client needed to consolidate its offices, previously located in two buildings on Katherine and Rivonia Roads, with a more efficient use of space for 2500 people. This involved creating state of the art work facilities and upgrading technology services, with added security.
The building incorporates a variety of staff facilities including a crèche, a gym and health studio, prayer rooms, a beauty parlour, physiotherapist rooms, a 200-seat auditorium, state of the art AV meeting rooms, staff training rooms, a fully integrated caterers kitchen and canteen, coffee shop, bar and wine cellar.
The design warranted a flexible building hence the large floor plates, punctuated by two atria to maximise the natural daylight into the office spaces. The north-west orientation of the site also influenced the design with the powerful scalloped elements to capture north and south light and protect the building occupants from east and west light.
The atrium space was designed as a park-like environment, with 6m high Ficus Benjamina trees sunken into the floor, and natural materials such as bamboo veneer and wafer thin slate stone. The skylights are made up of 12 giant cones, 8.4m in diameter each, which were generated through Revit to maximise their performance balanced with cost. These cones were required to introduce vertical light into the spaces below, and float above the atrium space like giant clouds.
8.5m high, raked off-shutter concrete columns are one of the architectural features of the atrium. These were moulded in a single cast using specialised formwork that was generated in Revit and Structures. Sizes were specified by the engineer and then sculpted by the architects.
Internal circulation incorporates escalators, effectively deterring users from using the lifts when moving up a single floor; while the splayed bridge across the atria reduces dedicated circulation around the floor plates.
Steel bridge links shaped liked wishbones link the north and south blocks across the atrium. Spanning 22m across the atria, they are suspended by 16mm diameter solid steel rods from the roof trusses. Due to the tight construction programme, the bridges were suspended temporarily from steel columns until the roof structure was in place and the columns could be removed.
The building’s Green Star rating had a profound impact on the architectural design. Approximately 22,000sqm of glazing was used, specified in various combinations to achieve a balance between light and heat loading; with all facades being double-glazed. Shading devices were incorporated to control the internal environment, with internal motorised blinds operated by remote control; and external vertical fabric blinds controlled by sun and wind sensors.
Other sustainability features include the use of renewable materials such as bamboo; the extensive use of low VOC paint; grey water collection; the integration of passive heating and cooling systems; waste recycling; and planter walls constructed from off shutter concrete.
1,800 parking bays are provided over 6 basement levels, with preferential bays for fuel efficient, hybrid and carpooled vehicles. 140 bicycle bays, as well as shower facilities, have been provided to encourage the use of non-motorised transport.
Photo credits: Andrew Bell