Architect and Builder Magazine South Africa Dec 2017 / Jan 2018 - Page 72

with a gas fired hob). Leak detection and fire signal interfaces were provided to automatically shut-down either the specific leg of the system, or if a fire occured in the garage where the main gas pipe runs, to lock down the whole system at its main incoming valve. • There are two emergency power generator plantrooms on this site that are dedicated to 1 Silo with its 5 generators and the other (located in the parking garage) belonging to the V & A Waterfront and serving only the residential block and the large parking garage. Where required, to maintain the integrity of the emergency power to life safety equipment, these cables were fire proofed as they cross spaces not protected from the effects of fire on them. CIVIL & STRUCTURAL ENGINEER’S COMMENT Basement Parking Component For the development parking, Sutherland were tasked with the enormous challenge of engineering a solution to accommodate a 2 level basement whose excavations were not only within 15m of the operating V & A harbour jetties (in historically re-claimed land) but, more importantly, were up to 5.45m below MSL. The solution to support the excavations in both the temporary and permanent phases of the project was a key aspect, coupled with the critical issue of solving the substantial drainage requirements in both phases being so close to and so deep below sea level. Heritage buildings constructed in the 1920s, together with operational basements, were underpinned to allow the construction of basements beneath them, thus maximising income generating area. During the operation, the neighbouring Nedbank office block, as well as the Clock Tower Precinct, continued to operate despite the heavy machinery and complex operation which was underway literally within metres. Office Block Component The incredible attention to detail that was effected by the architects to achieve a clean uncomplicated light structure called for some avant garde structural design. ‘Floating’ glass box breakaway rooms were cantilevered 6m off the main structure and very slender 16m structural steel bridges, together with cantilever staircases, provided linkages between levels within the huge volume central atrium. The external glass façades were supported by a 1,000m 2 space truss matrix. 72 No 1 Silo