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Base plate design

Base plate design

Base plate design

(OP)
i have a base plate with 4 M24 anchor rods, the pull out strength of the rod in ram connection is calculated assuming a headed anchor rod, in reality the rod doesn't have a head and is replaced with 2 nuts and a plate between them, assuming that the nut is a high strength nut do i have to check the plate for any limit states, i mean i designed the anchor rod assuming it is a headed rod and it is ok and the plate is added as general practise in my company, shouldn't that be enough???

RE: Base plate design

You should be fine as long as your plates exceed the dimensions of a standard washer. With 36 ksi bolts, I believe that double nuts and a standard washer are sufficient to develop the strength of the bolts. You know, so long as all the appendix D stuff checks out.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

RE: Base plate design

(OP)
Thanks you Kootk but the thing as i am using Gr55, and it is loaded to a stress ratio of 0.9 of it is steel strength in tension , my main concern is that the pull out strength will govern because of the high grade of the anchor.

RE: Base plate design

I assume that this load is an applied load and not just a pre-tension.

In my view, the bolt should not be as strong as the pullout value because pullout is, or can be, a sudden failure. Yes you should check the anchorage. The size of the plate is governed by the pullout cone and the depth; having sized the plate for the base of the cone, logically, you must follow through. I would do a simple conservative bending check across one centerline, through the hole.

In a case with a highly stressed anchor bolt, I try to make sure I have reinforcing bars running up into the cone to further anchor it

Michael.
"Science adjusts its views based on what's observed. Faith is the denial of observation so that belief can be preserved." ~ Tim Minchin

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