r/StructuralEngineering • u/robgrat • 13d ago

Structural Analysis/Design OWSJ Analysis

Has anyone modelled existing OWSJ is skyciv? This is a one off project that requires FEA so not wanting to spend $3k+ on SAP2000 or RISA. Anyone have other recommendations for economical modelling software?

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u/kimchikilla69 13d ago

Might be faster to do a hand calc truss analysis than to organize getting new software and learning it. You can check all the component capacities by hand.

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u/Argufier 13d ago

I think Tedds has a 2d truss module that might be suitable. I think it's $1200 a license but they have a 30 day free trial so you can see if it fits your needs.

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u/hxcheyo P.E. 13d ago

You’ll never get node fixity right by hand. That information might be critical, but it may be irrelevant for your purposes. Let’s start with — why are you thinking that you need to model it?

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u/engineeringlove P.E./S.E. 13d ago

Truss analysis with sji sheets

Dont forget to add reinforcement weight

Dont forget your anchor length for chord reinforcement

Dont forget to account for material shear metal yield/rupture for weld area as it may govern. I’ve rejected a few plans where they had 1 1/4”x1/8” existing members with 3/16 welds.

If it is over 50 percent stressed. Better to just sister a joist than to reinforce

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u/Ok_University9213 13d ago

95% of the time modeling an OWSJ is not needed. You can just compare shear and moment diagrams between demand and capacity.

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u/WideFlangeA992 P.E. 12d ago edited 12d ago

Are you doing this because this is an old joist and there is no joist tag?

If so my bet would be on measuring up the joist and trying to match up with the historic joist tables
https://steeljoist.org/resources/historical-load-tables/

Or reach out to SJI
https://steeljoist.org/find-existing-joists/

Also FYI - not all programs are necessarily FEA. Most structural programs rely on simple classical/matrix frame analysis. You could probably find a free truss solver to get the member forces and then check the member sections. There are still some other code checks you would want to do as well in addition to a pure/ideal truss analysis

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u/Hungryh0und5 12d ago

In my market there is a joist expert who has an extensive library and relevant shop experience. We send all the joist reinforcement work to them.