huangyhg

maximum building height for type v construction
i have contracted to design a six-story apartment building, in california. this is larger than any of my previous jobs (custom homes). i am trying to determine what materials/structural systems i am permitted to use, but surprise, i can't figure out the 2006 ibc...
the building is a six-story, sixty-five foot tall rectangle.
i want to use steel moment frames at the lowest floor, and wood framing/shearwalls above. will this be permitted?
table 503 of the code seems to say that, no, this is not permitted.
table 12.2-1 of asce 7-05 seems to sat that, yes i am permitted.
can anyone help me sort this out? i realize that i may not be able to build five stories of wood framing, simply for design/strength reasons, but i'll figure that out as i work on it. i just need to know if it is, in general, permitted.
check out our whitepaper library.
amp-imo you can only build an apartment building (r-2) bigger than 5 stories if you only use type ia or ib construction which only allows fire-retardant-treated wood in non-bearing walls & roof construction.
per table 601 the structural frame would need a 2 or 3 hour fire protection; roof beams & joists would need 1 to 1.5 hour fire protection.
see attached. the construction type column tells you want kinds of materials you can use
call the local building official. regardless of what you think - they will only allow what they will allow.
why not looking at the possibility of using cold formed steel studs instead of wood framing. without looking at ibc tables or asking building officials, i would not feel comfortable at doing 5 stories of even protected wood. it sounds like a little too much wood for such a building. in my mind i would want to see more non-combustible bearing and non bearing floors and partitions in that kind of building.
also anything taller than two (elevated) floors and roof requires a shrinkage analysis if made of wood. for that tall i bet the only option would be to ballon frame it to use wood. (ibc 2006 section 2304.3.3 pg. 426)
j
i agree - six story all wood seems a stretch.. you will have a real problem with cracks - wood shrinking and growing with humidity/temp changes.
first of all, asce 7 is a referenced standard in the 2006 ibc so first you go to ibc.
table 503 is pretty clear - r-2 is limited to 2 or 3 stories for type v, and 4 stories for iv, iii, and ii. you can add an additional story if the building is fully sprinklered per nfpa 13, per 504.2. nfpa 13r does not permit the stories to be increased beyond 4.
sprinklered or not, it appears the building must be constructed of type i, which will be a protected structure.
since you are limited to combustible construction, asce 7's allowing combustible materials would not be permitted in a 6 story building.

don phillips

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