Cape Town Stadium

Edgeworks Surveys was contracted by the Murray & Robert / WBHO Joint Venture, to undertake all the survey work for the contractors. This involved the establishment of the survey control, the setting out of the structure and as built surveys of all elements. Later in the contract a survey team was provided to HIGHTEX / MOSTOSTAL Joint Venture for the setting out of the façade. All the streetlights were set out for Adenco and all the balustrades for the entrance stairs. Towards the end of the project, all the setting out and as built survey requirements of Groenvlei Gras for the construction of the pitch were also undertaken.

Finding a practical solution to setting the pylons was the first challenge. One could calculate the position of each corner of the pylon at the elevation of each pour, but this would mean that the formwork had to be positioned to an exact elevation.Practically this wasn’t going to be achieved. If any movement occurred a new co-ordinates would have to be calculated.

It was decided to calculate a co-ordinate for the top outside centre and the bottom outside centre of the pylon.These two co-ordinates established the orientation as well as the slope or rake of the pylon.

The surveyors were required to position the formwork in the correct position before the concrete is poured and then recheck and adjust it after the concrete has been poured. Considering that the wet concrete weighed about eighteen tons and the formwork about three tons, it was a huge weight to try and push around. Obviously it was essential to have the formwork in the precise position and to be well secured, in order to minimize the movement. Fortunately, the survey control was very stable and it enabled the required accurately to be achieved.

A sixteen metre high tower was erected in the centre of the pitch, on top of which a survey instrument was set up. This enabled a cast in plate to be positioned on top of each pylon, from one point. The cast in plate was required to accommodate the roof structure. The cast in plate was positioned in wet concrete after the formwork had been positioned. After the concrete had set and the formwork was stripped, the cast in plate position had to be resurveyed to record the as built. In order to achieve this, the survey assistances were required to hold a prism pole, on top of each plate. Considering that the pylons are forty to fifty metres high, 800mm wide and 3 metres long and were only accessible by crane and man-cage, the survey assistants had to have a good head for heights, be sure footed and have very steady hands.

Although we all feel a lot older after the project is was a fantastic experience and one that will be talked about for years to come.

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Contact Paul for more information:

Email: paul@edgeworks.co.za

Tel: 021 7891223

Cell: 082 457 1789

Downloads:

Download Cape Town Stadium article from PositionIT Magazine

Download Cape Town Stadium Presentation by Paul Edgecome


9 Brook Cres. Noordhoek • P.O. Box 1459 Sun Valley 7985 • Tel: 021 789 1223 • Fax: 086 545 4093 • Cell: 082 457 1789 • email: paul@edgeworks.co.za