Washer over long slot hole 1

[civeng]

Hi everyone,

I was wondering if by thickening the plate washer, I would get away from covering the total length of the long slot (3"). If not, this would mean that at a spot where my bolt is totally at one extremity of the long slot, I would need a plate washer of about 5 1/2" long!

Thanks

 

[KootK]

Did you ever figure this out Civeng? I'm quite curious to know the answer myself.

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

 

[ajh1]

The RCSC rule, and by extension the AISC rule, is that the plate washer must cover the slot regardless of thickness.
RCSC Specification Section 6.1.2. Slotted Hole: when a slotted hole occurs in an outer ply, an ASTM F436 washer or 5/16 in. thick common plate washer shall be used as required to completely cover the hole.

The Canadian S16 spec has similar provisions (Clause 22.3.5.2(c)(ii) and 23.4.2(a)) although they seem to be restricting the requirement to pre-tensioned joints only.

 

[civeng]

Hi KootK,

Nope still no scientific explanation as to if we can use thicker washers while not covering the whole slot.
It sounds a little like a thing that can be verified with equations from that Roark And Young book, very tedious checks...haha

 

[wannabeSE]

I don't think RCSC and AISC washer requirements strictly apply to this connection because the slot is longer than the code prescribed long slot (unless it is 1-1/4" bolt; but, if that were the case, the plate would not need to be 5 1/2 long). I am guessing it is a 1/2" bolt and the code "long slot" for a 1/2" bolt is 1-1/4" long.