Drift or Horizontal deflection limits of rigid frames
Drift or Horizontal deflection limits of rigid frames
(OP)
Folks-
Hopefully you all can settle a disagreement. The subject is a steel rigid frame--roof only, and the discussion is whether the drift limit is H/60, or as the Designer quotes from the UFC-3-301-01 Structural Engineering Chapter 2 Modifications to IBC, 2-1.2.1 1604.3 Serviceability (Supplement)"in the wind design of a building or a non-building structure, the lateral drift shall not exceed H/480......."
Need this settled kind of quickly as the costs to provide for the H/480 are significantly higher than H/60, and may not be necessary at all for this situation.
I Appreciate any and all help with this one.......
Respectfully,
Qwikone
Hopefully you all can settle a disagreement. The subject is a steel rigid frame--roof only, and the discussion is whether the drift limit is H/60, or as the Designer quotes from the UFC-3-301-01 Structural Engineering Chapter 2 Modifications to IBC, 2-1.2.1 1604.3 Serviceability (Supplement)"in the wind design of a building or a non-building structure, the lateral drift shall not exceed H/480......."
Need this settled kind of quickly as the costs to provide for the H/480 are significantly higher than H/60, and may not be necessary at all for this situation.
I Appreciate any and all help with this one.......
Respectfully,
Qwikone






RE: Drift or Horizontal deflection limits of rigid frames
http://www.nceng.com.au/
"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning."
RE: Drift or Horizontal deflection limits of rigid frames
RE: Drift or Horizontal deflection limits of rigid frames
RE: Drift or Horizontal deflection limits of rigid frames
In ASCE they have inter-story drift limits for seismic, which allows for inelastic behavior (something that you don't have for wind, and probably wouldn't want) which are all around the H/50 and up.
Another point is that the P-Delta effects with H/60 would be very significant, both for the rigid frame and the gravity only system.
RE: Drift or Horizontal deflection limits of rigid frames
RE: Drift or Horizontal deflection limits of rigid frames
Some additional details I left out. StructSU10 is close--this will be a military structure. It is actually an open "sun-shield" with no siding. Basically a steel frame 24' high open sides and a 4/12 pitch standing seamless metal roof.
We are submitting a proposal for a less stringent drift requirement than H/480 as the serviceability doesn't warrant stricter requirements in this case. We have proposed H/250 to the Base as a compromise solution.
I'll let you guys know what happens....................
Qwik
RE: Drift or Horizontal deflection limits of rigid frames
RE: Drift or Horizontal deflection limits of rigid frames
http://www.nceng.com.au/
"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning."
RE: Drift or Horizontal deflection limits of rigid frames
The Base accepted the H/250 for this case.
Thank you for all your help and suggestions!!
Qwik
RE: Drift or Horizontal deflection limits of rigid frames