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Seismic restraint for equipment

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RayJay33

Structural
Feb 12, 2015
2
Is calculations needed for equip at any weight, 4 ft above floor ht. or 72" high, i have provided anchors plates.
Thank you
 
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The words in your subject suggest a thorough analysis is required. How would you know your anchor plate, and anchor bolts are correct size?
 
This is a city plan check comment & they specified the 48" mounted above floor, & not wanting to do any more work on this project that
has been dragging on, I have a typical detail L3x3x1/4x4" wide pl (4) total with (2) #8 tek screws & (1) 3/8" dia hilti TZ Anchor with 2" emb. This cabinet is less than 400 LBS but is under 72" high
The 48" above floor only makes sense if the equip is mounted on wall . just don't want this to bounce back.


 
Thats a pretty common connection for a merchandise cabinet or even storage racks. I've used light gauge angles like a L2x2x14 gauge, and argued that it is a "ductile" steel element. I've used 3/8" hilti Kwik HUS EZ for slab on grade. You can probably go to a 3" embed. Sometimes expansion anchors like the TZ will pop the top of the slab off if it's not deep enough when they torque it. Just make sure you go through the proper calc of Fp=0.4*ap*Sds*Ie*W/Rp. Floor mounted you don't have to worry about the (1+2z/h) as it goes to 1.
 
Its good practice to check it and its likely you can do a quick and dirty calc. Do your non structural component calc, lets say it 1g (which is high) at cg (say 48"). then your uplift and shear is 400lbs. likely 2 Hilti TZ's can resist the force. Check the base your fixing too can resist the 400lbs uplift. 0.1m3 of concrete is more than 400lbs.
 
What Code are you subject to? The ASCE 7 Code allows for exceptions for equipment less than 400 pounds and with a center of gravity less than 48" above the slab. If you exceed either of these the piece will need to be anchored and the AHJ probably will want proof via calculations.

If your equipment is too tall or heavy it could jump around or topple over and injure or kill somebody during a seismic event. It all seems pretty logical and straightforward for a high-seismic area.
 
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