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Re: Dead+Seismic for heavy equipment on roof
- To: seaint(--nospam--at)seaint.org
- Subject: Re: Dead+Seismic for heavy equipment on roof
- From: Mlcse(--nospam--at)aol.com
- Date: Mon, 26 Jun 2006 01:00:06 EDT
I would go along with the 5%, that is what most building departments have
limited me to without looking at the lateral impact on the entire building...in
some cases they might go as high as 10%, but not very often.
Michael Cochran SE SECB
In a message dated 6/25/2006 2:05:07 P.M. Pacific Standard Time,
I believe the number
Sent: Sunday, June 25, 2006 10:16
Dead+Seismic for heavy equipment on roof
points by Neil and Joe.
force, Fp need not be higher than 4x the forces at ground level for
equipment above the roof level, per EQ. (32-3) of section 1632 of the
UBC/CBC. That's a high lateral load for frames above a
overturning of the frame/equipment at the base for dead plus seismic for
lateral forces in all directions and find the downward jamb force on the roof
beams due to overturning. This may govern over dead plus live.
Design equipment connections through the roof framing to the primary frame for
any uplift - dead minus seismic.
overall mass of the building is not increased significantly by the weight of
the equipment, say over 10% to 15% of the total mass, it may not be necessary
to perform a lateral analysis of the entire building. This is listed in
the code for existing buildings. If the building has poor seismic
design, such as older, poorly connected masonry and concrete wall
buildings with wood roofs, unreinforced masonry buildings or older steel
moment frame buildings, it may be advisable though. In that case
you can recommend it be done (in writing) and list it as not included in
your scope of work.
luck getting the project,
Original Message -----
Sent: Saturday, June
24, 2006 6:41 PM
Subject: Re: Heavy
equipment on roof
Redesign the new
roof beams after they give the exact location of the new
vertical loads to ground.
the seismic attachment of the equipment to new beams and roof
new lateral analysis for building for new dead