Continuous or Discontinuous diaphragm help
Continuous or Discontinuous diaphragm help
(OP)
I'm trying to determine if I can make a "continuous diaphragm" out of a second floor that has 1/3 of the square footage is concrete on metal deck and 2/3 is wood sheathing on wood joists. A little more background: it is a three story building that is framed out of all wood members except for approximately 1/3 of the second floor required the concrete deck framing system (due to architectural reasons). I'm concerned that a separation joint would cause undue complications. Is there a way that I can satisfy ASCE 7 section 12.10.1 by connecting the two different diaphragm materials? Thank you for any help you can provide to me.






RE: Continuous or Discontinuous diaphragm help
The inherent problem that strikes me is two structurally different diaphragms - one flexible and one rigid. I would have to think how to do this, and would also have to consider the shearwall/frame locations as to whether this would be feasible.
Can you post a sketch with the shear walls shown and the diaphragms dilineated. Itr would help immensely.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Continuous or Discontinuous diaphragm help
I was hoping to make the wood diaphragm on the second floor blocked and therfore at least semi rigid to work better with the rigid concrete diaphragm....?
Yes, this is very challenging! Again I appreciate your help!
RE: Continuous or Discontinuous diaphragm help
You'll need drag struts extending out from your return walls, and then you will essentially have two diaphragms divided into two sections. Rigid diaph on the left side and flexible on the right side, though you may model the wood diaph as rigid. The interior CMU wall will take a small amount of shear from the left conc diaph. and then 1/2 of the right side wood diaph. shear (between the CMU wall and the drag strut to the right).
Dig in a little more and post your prelim analysis if you want...
RE: Continuous or Discontinuous diaphragm help
RE: Continuous or Discontinuous diaphragm help