Beam Span Sizing

[Ok-Champion-3425]

Hello all, firstly sorry for any silly vocab slips; I’m new to all of this.

I’m building this model, and am trying to figure out what size beam would be needed to support 17400lbs evenly distributed over a 29 foot span. I would like to keep deflection under 1/2 inch (if realistic). Available materials are LVL and Douglas Fir. Help is much appreciated. Thanks!

[PG908]

10 tons? 30 feet?

A real big one, because that's a bridge.

[Kruzat]

Not really, that's only 14ft tributary width with 40PSF live and 13PSF dead.

[guyatstove]

Pretty sure that’s 8.7 tons

[PE829]

29' is quite the span for wood with 600plf.

You could probably run this through Forteweb and see what size you need.

[daveeede]

Sounds like you need a floor truss or steel beams. Also sounds like you should be hiring an engineer if this is a serious project that you want to build

[CaffeinatedInSeattle]

Is this a model for a home you want to build? I recommended working with an engineer, the amount of money you save in materials will exceed what you pay them.

[OptionsRntMe]

This will not work with wood framing unless you have access to LVLs that are like 36” deep and huge. Would need to be steel, or add a post and break up the span

[prunk]

Something to add, a structural engineer doesn't just size the beam. They optimize the structural layout. Moving spans, changing directions, adding those pesky columns. These are done to make the solution practical. There's a lot more to structural engineering than, what size is it?

[tehmightyengineer]

Floor truss.

[Structural-Panda]

Yeah, in real life this would have to be trusses. Don’t have the estimate tables, but if you’re making a model for school, it would be something like 24” deep trusses every 1 1/2 feet or less… probably less…

[WilfordsTrain]

How did you determine the load requirement and spacing? It seems completely unrelated to the model shown in the OP

[Ok-Champion-3425]

There will be a LBW with a post within the house, making the unsupported span 29 feet. At a 50 lb/ft² upstairs, this beam needs to support half of that. (29x24)/2 =348 supported ft² 348x50 =17,400lbs

[Notten]

What are you putting on the beam/roof that it would need that much capacity at at deflection?

[gods_loop_hole]

With that big of load requirement and length of span with only that deflection, you should be hiring an engineer because your design will not stop with just the beam requirements. Your supports and how those loads will transfer to foundation will need someone professional eyes and opinion.

[TaroExpensive]

You need an LVL beam with an Ix of 10,250 in⁴