Q-system & support calculator

Inputs in the worked example

The live calculator starts with these values; change any of them and every result, check and diagram updates instantly.

Worked example — results

• ✗ Span unsupported OK

Method, formulas and assumptions

• Q = MAX(10,65)/9*1.5/1*1/1 = 10.833
• De = span/ESR = 10/1 = 10 m
• RMR ≈ 9 ln Q + 44 = 9*LN(10.833)+44 = 65.444
• Max unsupported span 2 ESR Q^0.4 = 2*1*10.833^0.4 = 5.1872 m

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