amount of deflection?
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: amount of deflection?
: amount of deflection? -- HeathB	Post Reply	Top of thread	Engineering Forum

Posted by: jboggs ® 01/04/2010, 07:50:52 Author Profile eMail author Edit

You didn't mention the loading conditions. 31' is an extremely long unsupported span for such thin plates. I don't think they would support their own weight over that distance, assuming they are oriented with the wide dimension horizontal. The calculators to which Kelly referred you apply to any cross section (I-beam, flat plates, round tube, etc.). You must calculate the moment of inertia (based on the beam cross section) and then use that in the deflection equations.

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: : amount of deflection?
: : amount of deflection? -- jboggs	Post Reply	Top of thread	Engineering Forum

Posted by: HeathB ® 01/04/2010, 13:23:07 Author Profile eMail author Edit

Well,,,, My thought is to sandwich the steel between two 2x8 or 2x10 yellow pine wood and bolt together to make a beam. The load conditions are minimal, Texas hill country, we don't hardly ever see snow and ice. We are do a house addition and the living room is 18' wide x 31' long with cathedral ceiling. The roof material is 24 gauge tin. Rafters 2x6 yellow pine 16" centers. Ceiling 1/2" sheetrock. I could step up the rafter size to span the 18' but just thought boxing in the beam would look good in the room. Thanks for the answers!!!!

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: : : amount of deflection?
: : : amount of deflection? -- HeathB	Post Reply	Top of thread	Engineering Forum

Posted by: jboggs ® 01/04/2010, 15:08:11 Author Profile eMail author Edit

If you browse through this site you will see that this type question pops up regularly. You will also see our common response. Most users will recommend that you contact a structural engineer familiar with the building codes in your jurisdiction. Sorry for the inconvenience but the reasons for this are numerous and valid.

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: : : : amount of deflection?
: : : : amount of deflection? -- jboggs	Post Reply	Top of thread	Engineering Forum

Posted by: HeathB ® 01/05/2010, 13:51:14 Author Profile eMail author Edit

I figured that would be the "answer". I would not be holding anybody responsible for any comments giving. Hey, now you have that in writing. As for the building codes we live in a small town and they have not implied codes "yet". I can promise you that I would not build something that would be a safety issue for my family and I. I do have building experience, just wanted to know the answer to a simple question.

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: amount of deflection?
: amount of deflection? -- HeathB	Post Reply	Top of thread	Engineering Forum

Posted by: Kelly Bramble ® 01/03/2010, 11:58:14 Author Profile eMail author Edit

Welcome to Engineers Edge!! See /beam-deflection-menu.htm

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: : amount of deflection?
: : amount of deflection? -- Kelly Bramble	Post Reply	Top of thread	Engineering Forum

Posted by: HeathB ® 01/03/2010, 20:22:32 Author Profile eMail author Edit

Thank you for the welcome and the info. I have looked at the "beam-deflection menu" but correct me if I am wrong, doesn't that mean an I-beam? If that menu is what I need to use I am going to have to get my son to explain the formula to me as that is greek to me!!!! Ha Ha!

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