D + 0.75 Lr + 0.75W loading

m1208 · Feb 22, 2014

When designing the roof beam, one of the load combination is D + 0.75 Lr + 0.75W .

To design the post under the beam, I always use the reaction from the beam (assuming the above equation governs).
Is there any California Building Code requirement that we have to use the D + 1.00 Lr + 1.00 W loading for the post design to support the beam (instead of D + 0.75 Lr + 0.75W)?

EngineeringEric · Feb 24, 2014

CBC, i do not know. But I would look at as what will the beam see of possible load combinations... and one of the combos is 1D +1L So the design shall be based on:

maximums( D+L , D+0.75L+0.75W, 0.6D+W, ...)

Do whatever you can easily argue in a courtroom

jeffhed · Mar 9, 2014

m1208,
Our beam spreadsheets always provide unfactored reactions for all entered load types. We then enter those loads into our column spreadsheets and run through all the load combinations again and take the governing load combination. You may be able to guess the governing load combination, but the governing load combination for the beam may not always be the governing load combination for the column, especially if it is an exterior wall column or if it has floor loading on it also.

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D + 0.75 Lr + 0.75W loading

m1208

Structural

EngineeringEric

Structural

jeffhed

Structural

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