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Folded plate structures |
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As you saw previously, plate-like structures have significant strength in resisting shear |
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stresses. Therefore they are used extensively to strengthen building frameworks against |
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wind and seismic shear loads. Plates are also used on their own to build stable structures |
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like the plate girders shown before. Such plate structures may be comprised of relatively |
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thin, lightweight material such as plywood, fiberglass, aluminum plate, thin plastic sheet, |
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reinforced concrete, and even glass. This is due to the fact that plate action dissipates the |
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load over the entire surface of the plate, which is then concentrated at the shear line joints |
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where the plates meet. |
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However, an unsupported thin plate has relatively weak compressive strength. It tends to |
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buckle easily when subjected to a load parallel to its plane (i.e. edge on), or bend easily |
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when loaded perpendicular to its surface. This weakness can be partially overcome by |
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simply folding the plate in an accordion-like, or corrugated, fashion. This causes the plate |
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to be triangulated thereby increasing its effective thickness, or height. The corrugated |
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plate can now resist buckling and bending by plate-like action which resists the tendency |
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of the individual folds of the plate to shear past each other. Each fold also acts like an |
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| 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 | |||||||||
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stabilized by bracing the ends of the V-shaped channels so that the plate does not flatten |
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out under a perpendicular load. |
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Back to Knowhere |
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