SKYLIGHT CONSTRUCTION REPORT At the centre of the Mall there is a 4,300m 2 undulating , free-form skylight , running 170m in the north-south direction . Novum Structures was appointed as the design-build specialist sub-contractor for the design and installation of the skylight . Aurecon designed the perimeter concrete support structure .
Design Overview The 3D surface and grid development of the skylight was a multi-stepped iteractive process which aimed to balance the overall architectural intent , the spanning capacity of the cladding , drainage , cost and other structural considerations . To create a single-layer steel structure , the overall skylight was designed as three independent thrusting skylights , separated by two building expansion joints .
The structural design was carried out using the direct design method , considering both local and global imperfections and considering lateral movements in the perimeter concrete upstand beams . Due to the large spans at the central region of the skylight , tree columns were added to ensure that the same overall rectangular tube sizes could be used throughout the skylight .
Logistics A combination of 1,352 unique rectangular steel beams with custom end castings and 577 machined nodes were used to create the free form structural grid . To increase the accuracy and speed of installation , the beams were sitebolted to the disk-shaped nodes using the Novum FF-system .
The cladding consists of 1,352 unique aluminium extrusions which support 846 ETFE pillows . In order to efficiently manage the fabrication , transportation and installation of these components , each part was marked with a unique number and the orientation was stipulated in the installation drawings . The structure and cladding were fabricated by a combination of various in-house Novum entities and local suppliers . Due to site constraints , materials were stored off-site and delivered to site as required to meet the installation sequence .
Steel Installation The steelwork for the skylight was installed using a combination of a self-erecting crane standing on the level three slab and an eight-ton mobile crane on the level five slab . The structure was assembled by lifting pre-bolted three-arm spider
486 Mall of Africa