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Wimbledon 1958
An article from the 1958 edition of the 'Expamet News'.
Important part played by Expanded Metal in construction of new covered courts. Wimbledon is more than just a part of the great metropolis of London, it is the mecca of all the world’s great amateur lawn tennis players.
The All England Lawn Tennis Club dates back to 1868 when it was founded on a ground on Worple Road, Wimbledon, as the All England Crocquet Club. By 1922 it had expanded to such an extent that new grounds had to be taken over (the present site of Church Road) and the Worple Road Ground closed.
This year a new landmark has arisen on the Wimbledon horizon in the shape of a huge dome roof covering two hard tennis courts to be used by ‘possibles’ for the Davis and Wightman cups and for winter training by promising young players.
The shape of the Reinforced Concrete shell was formed on expanded metal shuttering.There is no other material that so readily shapes the contours of a shell roof. It is so easily fixed into position and is so economical to use.
The type of structure required at Wimbledon was one with a maximum of natural lighting and with its sides made in some form of folding or sliding doors. Preference was given to a roof that had no internal supports. It was felt that the most satisfactory solution would be a concrete ‘handkerchief’ dome, supported only on four columns at the corners, and forming in effect a permanent umbrella. The area to be covered by the dome was 15,200 sq.ft.
Before embarking on the present scheme, three possibilities were investigated: (1) steel roof trusses and framework; (2) twin cylindrical concrete shells; (3) a doubly curved concrete shell. The third scheme was chosen on the basis of cost, architectural and functional merits.
The 3 in. thick shell forms a paraboloid with a span of 175 ft. and a rise of 24 ft. 3 in. were cut off the circular projection, giving a square base and segmental openings on all sides.
It would appear at first that the formwork for a doubly curved shell would considerably increase the cost of the structure; in fact, the opposite is true.
Since the curvature of the shell is quite small, the ‘generating’ scaffold tubes were bent to only three different radii, and the varying curvature was obtained by ‘springing’ the tubes during fixing. The vertical scaffold tubes were placed on a 6 ft. grid covering the whole base. The heights were first measured from a ‘fixed’ horizontal plane, and then checked using carefully made parabolic jigs to ensure correct continuous surface. By this procedure the major labour problems were eliminated, with a considerable saving in cost.
