This is not generally calculated; it is usually looked up in manufacturers' catalog data. Some corners may be rounded and some surfaces tapered, so exact calculation would be awkward.
(In the U.S., the final number in standard designations such as S10x24 gives the pounds per foot directly.)
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• From any structural steel handbook properties and dimensions like this Structural_Steel_Properties, it is very easily to find the weight of unit length.
• And to find the total weight of the specified structural steel section, multiply the weight of unit length with the total length of that section.
• For example, for I Beam type IPN 100x50, from table at page 16, the weight of unit meter is 8.32 Kg/m. And the total beam weight = 42 m x 8.32 Kg/m = 349.44 Kg.
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• Additional structural steel properties and dimensions in French, English and German, free download: Structural__Steel_Properties.
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