Folded plate structures


As you saw previously, plate-like structures have significant strength in resisting shear

stresses.  Therefore they are used extensively to strengthen building frameworks against

wind and seismic shear loads.  Plates are also used on their own to build stable structures

like the plate girders shown before.  Such plate structures may be comprised of relatively

thin, lightweight material such as plywood, fiberglass, aluminum plate, thin plastic sheet,

reinforced concrete, and even glass.  This is due to the fact that plate action dissipates the

load over the entire surface of the plate, which is then concentrated at the shear line joints

where the plates meet.


However, an unsupported thin plate has relatively weak compressive strength.  It tends to

buckle easily when subjected to a load parallel to its plane (i.e. edge on), or bend easily

when loaded perpendicular to its surface.   This weakness can be partially overcome by

simply folding the plate in an accordion-like, or corrugated, fashion.   This causes the plate



Fig. 293 - Plate corrugation


◄  buckling of

a thin plate

corrugating the plate

for rigidity  ►

(training aid model)

click mage to enlarge


to be triangulated thereby increasing its effective thickness, or height.  The corrugated

plate can now resist buckling and bending by plate-like action which resists the tendency

of the individual folds of the plate to shear past each other.  Each fold also acts like an

A-frame truss whose strength is dependent on the height of the fold's peak versus the width
of the channel between the folds, that is its H/S ratio.  The corrugated plate can be further

stabilized by bracing the ends of the V-shaped channels so that the plate does not flatten

out under a perpendicular load. 


◄ Fig. 294 - Bracing a folded


plate to resist deflection


Fig. 295 - Temple with

corrugated roof  ►

(scale visualization model)

click image to enlarge


Arching the folded plate strengthens it even more so that it


can enclose large spaces without the need for additional

support.  For example, corrugated steel plates are often

used for aircraft hangers and warehouses.


Fig. 296 - Aircraft hanger with corrugated roof  ►

(scale visualization model built with LT (orange) and IT (blue)


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Page 154 - Building stability - Folded plate structures

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