Span (architecture)

Span is a section between two intermediate supports, e.g. of a beam or a bridge.

Related Topics:
Beam - Bridge

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The span is a significant factor in finding the strength and size of a beam as it determines the maximum bending moment and deflection. The maximum bending moment and deflection in the pictured beam is found using:

Related Topics:
Bending - Moment - Deflection

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:moment:   Mmax = 1/8 · q · L2

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:deflection: fmax = 5/48 · Mmax· L2 / (E · I)

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From this it follows that if the span is doubled, the maximum moment (and with it the stress) will increase four times, and deflection will increase sixteen times.

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