MOSES MABHIDA S TA D I U M
The Moses Mabhida Stadium, designed by Gerhard le Roux is a multifunctional world class stadium that was built to host soccer matches for the 2010 FIFA World Cup. It is located in Durban, South Africa, named after Moses Mabhida, a former General Secretary of the South African Communist Party. The 85,000 capacity stadium sits on an elevated platform in the central sports park on the shore of the Indian Ocean and is accessible from the city and station via a broad flight of steps. The iconic arch which rises high over the stadium has become one of the world’s first tourist attraction featuring a high-tech cable car.
MAT E R IA L IT Y
Roof : Polytetrafluoroethylene (PTFE) coated fiberglass The roof is made of Teflon-coated glass fibre membranes and is attached to the arch by 95mm diameter steel cables. The membrane admits 50% of sunlight into the arena while shades against glare and rain. It also produces a translucent glow when the stadium is lit up.
CO N S TRU C TIO N PRO CESS
Foundation
Arch
Compression Ring and Facade
The stadium sits on saturated swamp-land blanketed with sea-sand. Thus, foundations were piled down to the bedrock 20m below ground level. Diaphragm walls were chosen due to its practicality and least time consuming. Foundations are elongated rectangular boxes with 800mm thick reinforced concrete walls. A reinforced concrete plinth is used to connect the arch to its foundation.
The arch consists of 56 elements, each having 8 reference points bolted into the arch. The first 4 elements on each side were adjusted using hydraulic jacking systems before grouted onto the foundation. Each stage had a set of coordinated points to define the arch geometry. Before placing an element, the arch was lifted to a position, after the element was installed, re-measured to check that all criterias were achieved.
The compression ring and facade are carried on steel columns connected to precast columns by welding a steel lug to the cast-in plate on the columns. The columns were adjusted using a temporary push-pull system. This also adjusted the compression ring once placed onto the columns. Measurements were done at night as heat affected the steel structure and adjustments were made prior in the morning.
Facade : Perforated metal sheeting The facade membrane of perforated metal sheeting rises to the outer edge of the roof, providing protection against rain, wind and direct sunlight. The facade forms a lively pattern of light and shadow, offering glimpses of the interior thus creating a light and airy feel.
Pre-stressing Cables
PTFE coated roof membrane
The cable net links the compression ring to the arch and suspends an inner ring made up of six cables. The network was laid out on the ground and connected to the compression ring before being lifted by hydraulic jacks to connect to the arch. The cables are connected by a steel cast item. The positions was carefully monitored during the lift to ensure the cable net was lifted evenly and none had been installed wrongly.
After the cable net was installed and prestressed, the membrane installation started by pulling the large PTFE panels off a roll supported at the horizontal arch. The roof consists of a 46000 sqm of PTFE membranes. After securing the panels in position, the membrane is tensioned towards the ridge and valley cable.
O RTH O G R A PHIC DRAWINGS
The Bowl : Precast concrete Precast concrete is chosen as the main material for the structures of stadium’s bowl, such as the seating panels, columns, ranking beams and also the retaining walls.
Floor Plan
Roof Plan
Elevation
Section
Scale 1:5000
Scale 1:5000
Arch : Steel hollow boxes The expansive 350m steel arch, consisting of a 5x5m steel hollow box rises 105 meter and carries the weight of the roof ’s inner membrane. The arch is connected by cable system to the external edges of the roof.
Scale 1:5000
Scale 1:5000
S T R UCT UR A L AN ALY S I S
LOA D DISTRIB U TIO N
The shear cores provide lateral stability for each section of the stadium bowl (expansion joint to expansion joint). The thickness of the walls varies from 250 mm to 300 mm. The main reason for this variation in wall thickness is to obtain compatible deflections in the concrete structure at the interfaces with the roof structure at Level 6.
Arch The expansive 350 meter arch rises 105 meter and carries the weight of the roof ’s inner membrane. The main forces are transferred through the arch onto the reinforced concrete foundations.
Load Distribution Diagram
The loads transferred from the steel roof columns onto the concrete structure at Level 6 vary vastly around the circumference of the bowl. The concrete structure provides lateral support to the arch at the north and south sides, whereas the reactions on the east and west sides are mainly axial loads. The main forces transferred through the arch onto the reinforced concrete foundations are in excess of 100 MN applied at an inclination of approximately 38˚ to the horizontal.
Cable System The arch is connected by cable system to the external edges of the roof. Fifty main ridge cables are supported from the arch which defines the shape for the roof membrane. Compression Ring (Horizontal Arch) And Façade The ridge cables and valley cables, are connected to the compression ring that in turn is supported on steel facade columns . Over 100 columns surround the stadium.
S T R UCT UR A L S Y S TE M
The arch is connected by cable system to the external edges of the roof, carrying the weight of the roof 's inner membrane. The arch is above all of these and helps suspend the cable network. All the components when connected to each other form the full roof structure. Without any one of these components, the others would not stay erected as they all hold each other up.
Tensile Stress Diagram Plan View
Tensile Structure Arch and perimeter compression ring Three Arch System This system does not rely on the same geometrical constrains. The horizontal arches are pinned against the vertical arch. The horizontal thrust at this position is balanced by the tension ring ties, which creates a fundamentally different structural behaviour, leading to minimised deflections of the horizontal arches and therefore to a greater efficiency.
Tensile Stress Diagram Sectional View
The Three Arch System does not rely on the standard geometrical principles and, therefore, achieves a much better cover while matching the surface area in plan. Furthermore, the system also spans a great roof depth of 78m.
Cable System
CON S T R UCT IO N D E TAI L S Cable to Cable and Fabric Connection
Cable to Compression Ring Connection
Arch Installation and Cable to Arch Connection Pre-installed hook
Bolts and nuts Anchor pin 95mm thick cable
Tension cable clamp
PTFE membrane
Steel cable
Edge cable with clamps
Radial steel cables span from the horizontal compression ring alternately to the vertical arch and to the inner tension ring.
Anchor plate Re f e r e n c e points
The Moses Mabhida Stadium required custom designed & built stainless steel cable clamps and rigging to complete part of the tensile roof structure.
Customized stainless steel cable
Arch Element
56 arch elements each with 8 reference points bolted together punched into the arch.
Corner plate with keder
M OD E L L ING PRO G RE S S
Laying out and fixing the structural base of the model onto an A3 board. The model is built to a scale of 1:1200.
Elements of the outer ring and inner compression ring are laid out and fixed together before adjusted onto the base on columns.
The columns are installed into position to support the two layers of rings resting above and as the facade system of the stadium.
The arch is measured and adjusted accordingly before installed. The compression ring and this serve as the structural system.
Strings are used to represent pre-stressed tension cables. They are connected from the arch to the compression ring then to the outer ring.
Model representing the structural system comprising of arch, compression ring and column support.
R E F E R EN CES
Building Construction II
http://faculty.arch.tamu.edu/media/cms_page_media/4433/MosesMabhida.pdf https://riunet.upv.es/bitstream/handle/10251/7068/PAP_BALZ_1230.pdf http://www.ee.co.za/wp-content/uploads/legacy/PositionIT%202009/PositionIT%202010/moses%20madhida%20stadium_3.pdf https://www.civildesigner.com/press/moses.pdf
Tutor: Dr. Sujatavani Gunasagaran
Project 2 - Understanding Forces in Building Construction
Model showing part of the roofing system and how it is linked to the structural system.
Group Members:
Esther Wong Jia En Priscilla Huong Yunn Wendy Lau Jia Yee Yong Ping Ping
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