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residential steel design
i am designing a residential steel and composite concrete slab structure? does anyone have any information on what an acceptable initial deflection for steel beams would be? i know that in commercial applications, it you does not matter due to a higher tolerance allowed by finishings i.e suspended ceilings. a house however could be unforgiving with a much more strict allowable deflection criteria. i was trying to keep the initial deflection to 0.75 in. i know that the the floor will be poured flat, but i wanted to know if anyone just had a reference on construction deflections. thanks.
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when i design beams for custom homes, i look at deflection but i also consider vibration due to walking. a typical criteria i use to design steel beams is that the depth should be at least l/20. this, i believe, comes from one of aiscs steel tips booklets. for deflection, i will try to keep it around l/360 to l/480 for total loading (dl + ll).
don't forget to take into account that load bearing walls below will be framed to the bottom of the floor/roof system. there is nothing worse than a falling cieling line or crushed dry wall at the tops of walls!
this house is a full steel frame with a composite concrete floor system. i am looking for the allowable initial deflection (construction deflection). do you know any publications or articles that disuss allowable construction delflections. thanks.
i would think that construction deflections would be an osha thing.
final ll and dl deflections would be local code i.e: frc, ibc, ubc, etc. and of course, these are all minimums. discuss with the contractor the materials and systems going below the steel and the order of their installation and make a "judgement" based on your research. you can also discuss with the owner/contractor the cost increase of increasing sections to limit deflections vs. the possiblity of falling cieling lines etc. document everything! cya
thanks. i think that is the best solution. make an agreement with the architect and contractor on an allowable deflection. |
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