Anchoring into SOG using expansion anchors
Anchoring into SOG using expansion anchors
(OP)
So, I am trying to make sure that I have all of my bases covered. I am verifying the anchorage of some elevated mechanical equipment to an interior 6" SOG reinforced with #3 @ 18"oc. I calced the T/C force to be 974# per base plate and the contractor used 4- 1/2" x 6" Redheads and an 8"sq base plate. I checked the bolts for combined shear and tension and get a ratio of 0.57. So the anchors work. My question is: Can the reinforced SOG take the uplift? The area of concrete required to hold down 974# with 0.6DL factored in is about 4'-9". Can I assume that the rebar will engage the reqd concrete? Is there a calculation that that determines the maximum area of SOG that can be engaged?
Thanks in advance for any help.
Thanks in advance for any help.






RE: Anchoring into SOG using expansion anchors
RE: Anchoring into SOG using expansion anchors
RE: Anchoring into SOG using expansion anchors
I have used Simpson's.
Redhead does not have a program.
If the lateral loads to the equipment are governed by seismic loads, you have to be sure that the anchors you use are qualified to resist seismic loads. Most are not.
Mike McCann
MMC Engineering
RE: Anchoring into SOG using expansion anchors
RE: Anchoring into SOG using expansion anchors
Three checks you could do:
1. Punching shear like it was column load on slab.
2. One way shear check at face of anchorage.
3. One way flexure check assuming cantilever at face of anchorage.
RE: Anchoring into SOG using expansion anchors
RE: Anchoring into SOG using expansion anchors
RE: Anchoring into SOG using expansion anchors
Brian C Potter, PE
http://simplesupports.wordpress.com
RE: Anchoring into SOG using expansion anchors
Briancpotter: I also checked for 1 way and 2 way shear of the SOG.
Thanks for the responses, they really help out.
RE: Anchoring into SOG using expansion anchors
On a piece of equipment like you’re dealing with, fixed to a SOG, you might consider the following: use a skid connecting the two legs on each side of the machine, that is two skids; this would allow you to distribute the gravity loads better, w.r.t. punching shear; and it would allow you to install more A.B’s. (expansion bolts) and distribute them better; and finally it would allow you to bring more of the slab into play w.r.t. the overturning moments, and the slab DL brought into play.
RE: Anchoring into SOG using expansion anchors