CTICC East is an extension to the very successful Cape Town International Convention Centre. It comprises two convention halls of approximately 5 000m2 each, a larger concourse area as well as smaller meeting rooms.
Three distinct areas can be described:
a) The support structure for the second-floor hall, which is provided with only 4 internal support points for the 5 000m2 floor. In addition to dead loads, this steelwork carries a design live load of 750kg/m2 above as well as exhibition hanging loads and movable wall elements below. A system of deep primary and secondary girders, and tertiary beams supporting Bond-Dek cladding was selected.
b) The roof structure over the upper hall, comprising a column-free space of 5 000m2. Due to architectural requirements, only two girders were permitted to span the short direction, with secondary girders spanning the
long direction of the hall, and rafters above. The depth of the secondary structure was limited to gain as much headroom as possible. The roof structure is also designed to carry significant hanging loads as well as
suspended movable walls.
c) The concourse and meeting pod structure, comprising a vertical structure for the support of the 22m-high curtain wall, a composite roof structure over the meeting pods and part of the concourse, and a saw-tooth roof structure supporting insulated panels and glazing orientated towards the South.
Steelwork was the only practical solution for the large spans carrying very heavy loads on this project, although numerous other options were considered. Universal column sections were used for many of the primary and secondary girders to benefit from the heavy profiles available, while tubular sections were used to achieve the most slender possible sections for the support of glazing elements as well as the saw-tooth roof.
There are numerous unusual elements to the steelwork on this project. A few are mentioned below.
a) Triple-ply girders, 3.5m-deep with universal column chords up to 167kg/m per ply supporting the second-floor hall, and carrying a live load of almost 300kN/m. Connection design, pre-cambering, transport, and
erection were all a challenge due to the size and weight of the sections.
b) A 23m-high curtain wall supported by external steel wind girders to keep the internal spaces as clear as possible.
c) A saw-tooth structure rotated 45 degrees relative to the supporting structure and lifted 2.6m above that supporting structure, with a minimum of vertical members. The saw-tooth structure was also kept as light as
possible using tubular sections to keep the roof space as uncluttered as possible.
Due to space constraints, the mobile mill had to be hoisted by crane onto a scaffold tower built next to the roof so that sheets could be rolled directly onto the roof.
The connection between steel and concrete elements was particularly challenging, especially where forces were very high. Cast-in plates were used as much as possible, some weighing as much as 1 000kg.
Steel connections in girders were also carefully workshopped to result in something that could transfer the massive internal forces while not being too difficult to assemble on site.
Careful planning was also required to plan the erection methodology of the hall floor and roof, as girders had to be temporarily supported due to the distance between supports and the weight of the sections.
Architect: Convention Architects – A joint venture between Makeka Design Lab, SVA International and Van Der Merwe Miszewski Architects
Structural Engineer: Sutherland
Main Contractor: Aveng Grinaker-LTA
Project Manager: Target Projects
Steelwork Contractor: Anchor Steel Projects
Quantity Surveyor: Mbatha, Walters & Simpson
Cladding Manufacturer: Bluescope Steel
Cladding Supplier: Macsteel
Cladding Contractor: Scheltema and Company