Surveying on the Green Point Stadium by Clare Van Zwieten, Positionit
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Surveying technical Surveying on the Green Point Stadium by Clare van Zwieten, PositionIT Construction on Cape Town’s Green Point Stadium got off to a somewhat controversial start, but is now well on the way towards its completion date at the end of 2009. The complexity of the stadium’s design is providing some interesting and challenging work for the surveyors on the project. s hosts of the 2010 FIFA World Green Point Stadium to a stringent environmental impact Cup, South Africa will see 64 assessment which resulted in a record The Green Point Stadium is being football matches played in of decision that influenced the design A built for the City of Cape Town who nine of its cities – Johannesburg, fairly fundamentally in particular the are the contracting party and a 2010 Cape Town, Durban, Port Elizabeth, aesthetics, the profile, the acoustics, World Cup semi-final host city. It Nelspruit, Polokwane, Bloemfontein, traffic and parking. These requirements will be owned by the city and will be Rustenburg and Pretoria. For this have been included in the design of South Africa's second largest stadium. purpose ten stadiums are being built the stadium and have influenced the The new stadium replaces the or upgraded across South Africa. height, the profile, the roof, the façade, 18 000-seater Green Point Stadium, These stadiums are expected to seat parking and traffic impact. more than 570 000 people during the that was demolished in 2007, and will World Cup. be surrounded by a 60 hectare urban The stadium is intended to have a park [2, 3]. capacity of 68 000 spectators and The five stadiums under construction is scheduled to host five first-round The multi-billion rand stadium is are located in the following areas – matches, one second-round, one located in an extremely sensitive Cape Town (Green Point Stadium), quarter-final and one semi-final during Port Elizabeth (Nelson Mandela Bay environment on the Green Point the course of the 2010 FIFA World Cup. Multi-purpose Sports Facility), Durban Common, adjacent to residential After the event the stadium will be (Moses Mabhida Stadium), Nelspruit areas, close to the central business reduced to a 55 000 capacity stadium (Mataffin Stadium) and Polokwane district, adjacent to the Victoria & to comply with stringent environmental (Peter Mokaba Stadium). The five Alfred Waterfront, and being under requirements as stipulated in the stadiums undergoing upgrades Table Mountain it will be a prominent record of decision. are situated in Rustenburg (Royal landmark impacting on the image of Bafokeng Stadium), Bloemfontein the city. Stadium design (Vodacom Park Stadium), Pretoria (Loftus Versfeld Stadium) and The stadium design is in part a The design of the Green Point Johannesburg (Soccer City Stadium response to its situation in this Stadium is the most complex of all and Ellis Park Stadium)[1]. environment. The stadium was subject South Africa’s world cup stadiums. Fig. 1: An artist's impression of the completed Green Point Stadium in its final form at night. PositionIT - July/August 2008 21 SURVEYING technical Fig. 2: Paul Edgecome, Dirk Wolters and Keith Lee of Edgeworks Surveys. Fig. 3: Julian Gray of GNA Geomatics. It will be 55 m at its highest point and positioned on a daily basis using The lead structural design consultants and the construction will involve 250 ton and 450 ton Crawler Cranes. for the stadium are BKS. The lead 130 000 m3 of concrete, 390 000 m2 architectural consortium is made The roof structure will primarily of formwork, 12 000 tons of comprise a 1300 ton perimeter up of GMP (the German architects reinforcing steel, 6-million bricks, a compression ring mounted on the responsible for the concept design) fabric façade and a unique steel cable pylons, an internal cable tension and Louis Karol Associates (the local tensioned glazed roof [4]. More than ring, steel trusses radiating inwards architects of record). The work on the 1800 people are currently involved in towards the pitch, and glass panels roof is being done by Birdair Pfeifer, its construction. installed on top of the steel trusses. a joint venture between US company As the site where the stadium is being The roof’s construction will involve the Birdair and German firm Pfeifer. To constructed is subject to high winds compression ring, being placed on big date the net construction costs for and has been labelled an area of box girder intersections that sit on top the project stand at approximately potential seismic activity, the design of all the 72 raked pylons. Seventy-two R2,75-billion. has needed to accommodate high cable strands with the internal tension wind and seismic loading factors. ring forming a doughnut, will then Surveying teams be strand-jacked into final position The stadium has a specific height Paul Edgecome of Edgeworks Surveys by huge hydraulic jacks. Secondary restriction of 55 m stipulated in the has been contracted to undertake the support in the form of steel trusses will environmental impact assessment surveying work on the Green Point then be hung all the way around and report and as a result it will not have Stadium. Keith Lee and Dirk Wolters, glass placed on top. the dome-shaped roof typically found along with six surveying assistants, on these structures. The need to The roof’s shape as well as the are assisting Edgecome with all the accommodate the height restriction exterior fabric facade will reduce the setting out for the Murray & Roberts/ and to provide spectators with the noise level of the stadium by about six WBHO joint venture (see Fig. 2). The best possible views of the pitch has decibels, compared to the old Green Edgeworks engineering surveying added to the complexity of the roof Point Stadium. Unsightly structures team also takes measurements for design. To accommodate 68 000 such as flood lighting masts have been planning purposes and checks the spectators the height of the tiers has avoided by incorporating the flood volumes calculated by Martin & East, had to be maximised and, due to the lighting for the pitch in the hub [5]. the subcontractors responsible for the earthworks, roads and services height restriction, the roof will have a This is the first time that a roof of construction. Thaaniyah Abrahams is complex, concave and super elevated this nature has been assembled in the surveyor for Martin & East. roof structure. South Africa and it is scheduled to be installed by September 2009, ahead The stadium structure itself comprises A number of other surveyors of FIFA's scheduled inspection at the an external oval of 72 pylons acting for and on behalf of various end of October 2009 [5]. which vary in height from 30 m to contractors work on the project, all of whom look to the Edgeworks Surveys 50 m, and an internal network of Contractors team for primary survey control and radial concrete columns supporting to ensure conformality between all seven floors, lift shafts, and access Murray & Roberts in joint venture with surveys done on site. stairways. Pitchside, the pylons, floors WBHO are the contractors for the stadium. The project got underway and columns support a series of raked High precision specialist Julian A beams creating three tiers on which in March 2007 and involves a Gray of GNA Geomatics, an MRICS more than 2000 pre-cast horizontal 34-month programme from the date registered geomatics engineer, has elements are mounted to carry the of handover to ensure completion been contracted by the project stadium seating. The 20 ton precast in time for the 2010 Soccer World management team to act as the horizontal elements are manufactured Cup [3]. The project managers are a quality assurance surveyor off-site, delivered in the evenings consortium between BKS and MDA. (see Fig. 3). Acting on behalf of the 22 PositionIT - July/August 2008 SURVEYING technical Fig. 4: The 16 m tower that has been erected in the centre of the Fig. 5: Construction of the pylons is being done in lifts of 3,8 m. For future pitch. each lift the formwork has to be positioned correctly. client, he is managing the various Town survey marks (TSM) were general as well as the setting out for the coordinate systems used by the handed over to Edgeworks Surveys embedded mounting plates for the roof various consultants and relating by the client as the control points. structure. Management accepted the these to the project survey system (The TSM points are maintained by proposal and the tower was erected in as well as undertaking audit and 3D the City of Cape Town and are on January 2008 (see Fig. 4). It has proved verification surveys of all primary the WG Lo19 coordinate system.) to be a great success with good visibility and critical elements during the Although the TSMs were around the from the tower enabling setting out to construction period. perimeter of the golf course, only two be done of all the various decks, slabs, were used in order to establish the raked beams and the pylons relative to Surveying operations site control. Planners for the Murray one point. Surveying work on the Green Point & Robert / WBHO Joint Venture Stadium involves the setting out of initially used a base map provided by An additional high precision control everything. This includes setting out the consultants. comprising a network of permanent the bases and columns, raked beams prisms mounted on columns At first eight 1,5 m high concrete and pylons as well as the grid lines surrounding the pitch, has been pillar beacons with forced centring on the concrete slabs. Basically from established by GNA Geomatics using were constructed around the the start of the job, this involves a Trimble S8 robotic total station to perimeter of the site and, once the setting out the excavation positions enable the positions of the embedded initial stadium excavations had been to enable the construction team to completed, two further pillars were plates on the pylon tops, (upon which dig the holes for the bases in the constructed on the future pitch of the the roof structure is to be mounted), ground, and providing reference stadium.