Concrete Folded Plate Roofs
C B Wilby
Preference :
Folded plates have been used on various buildings, for instance storage buildings, swimming
pools, gymnasia, offices, centres, entrances to buildings and tunnels - for examples see Plates
1-18. Sometimes industrialists like to have the facility to hang unpredicted miscellaneous light
loads from anywhere under a roof and regard the structural steelwork as inherently providing this
facility. Because of this requirement the author designed the shells shown in Plate 10 to have a
network of numerous cadmium-plated steel bolts placed through holes in the shells and through
steel anchorage plates of 152 mm (6 in) square on the top surface of the shells. Each bolt protruded
out of the soffit of the shell so that just about anything could be screwed on to it at some
future date. The nuts and plates were covered with a 50 mm (2 in) layer of vermiculite insulation
on the top of the shell, waterproofed with three layers of built-up roofing felt. This facility can
similarly be applied to the plates of folded plate roofs.
Because they are of concrete, such roofs have inherent resistance to fire, deterioration and to
atmospheric corrosion. They allow large spans to be achieved in structural concrete. This allows
flexibility of planning and mobility beneath. Where ground conditions require expensive piled
foundations the reduced number of supporting columns can be an economic advantage. For large
spans in structural concrete folded plates compete with barrel vault roofs. The plates are required
to be thicker than the shells, and there are more firms who will tackle constructing them without
excessive prices, increasing competition and sometimes making the cost more competitive than
for cylindrical shells.
pools, gymnasia, offices, centres, entrances to buildings and tunnels - for examples see Plates
1-18. Sometimes industrialists like to have the facility to hang unpredicted miscellaneous light
loads from anywhere under a roof and regard the structural steelwork as inherently providing this
facility. Because of this requirement the author designed the shells shown in Plate 10 to have a
network of numerous cadmium-plated steel bolts placed through holes in the shells and through
steel anchorage plates of 152 mm (6 in) square on the top surface of the shells. Each bolt protruded
out of the soffit of the shell so that just about anything could be screwed on to it at some
future date. The nuts and plates were covered with a 50 mm (2 in) layer of vermiculite insulation
on the top of the shell, waterproofed with three layers of built-up roofing felt. This facility can
similarly be applied to the plates of folded plate roofs.
Because they are of concrete, such roofs have inherent resistance to fire, deterioration and to
atmospheric corrosion. They allow large spans to be achieved in structural concrete. This allows
flexibility of planning and mobility beneath. Where ground conditions require expensive piled
foundations the reduced number of supporting columns can be an economic advantage. For large
spans in structural concrete folded plates compete with barrel vault roofs. The plates are required
to be thicker than the shells, and there are more firms who will tackle constructing them without
excessive prices, increasing competition and sometimes making the cost more competitive than
for cylindrical shells.
Content :
- Practicalities
- Analysis used for the design tables
- Factors used in the design tables
- Construction
- Appendices: Design tables for concrete folded plate roofs
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