The maximum shear plate thickness is checked via AISC 360-10 chapter 10 under the "Extended Configuration" checks (page 10-104) to ensure that the moment strength of the plate does not exceed that of the bolt group (to help ensure ductility).
There are a couple exceptions to this, but I don't think the program is considering them. Can you confirm this?
- For a single vertical row the plate thickness is less than d.b/2 + 1/16" and L.eh>= 2*d.b
- For a double vertical row.... (same as above)
Also if the eccentricity "a" (from weld to center line of bolts) is less than 3.5" then the connection really isn't an "extended" plate. so this would be another exception (however the check is same)/
The program help indicates that those provisions still apply in the extended case, but the in the output for a connection with 2 columns of bolts, I see the max thickness increase based on gage and bolt diameter well beyond the d.b/2 + 1/16" limit, which confirms what you are saying.
Answer Verified By: RFreund
Just to confirm we are on the same page....
What I'm saying is that if you are using one row of 3/4" diameter bolts the maximum plate thickness is 7/16" thick unless the moment capacity of your bolts exceeds the moment capacity of your plate (in which case you can go thicker). However, if I create a single plate connection with 5-3/4" diameter bolts and 3/8" thick plate, the maximum plate thickness warning is thrown.
I ran that test in version 13.06.00.213, with a = e= 4", and I can get the plate thickness warning when Leh = 1.5" (exactly 2d.b), but when I make the Leh a tiny bit larger, then the Thickness max limit goes away. See if that's the same for you.
I think I set this up wrong. It needs to be 6 - 3/4" bolts. So the template is SP_BCF_3/8PL_6B3/4. I created a custom template. Here are the files:
1drv.ms/.../s!AuriOnmsjYYyv8oSYZGL2HJC9fLoqg
Thanks for the files, this clear up a lot.
In this case the connection is not extended or even non-standard. Thus the plate thickness limit is taken directly from Table 10-9. When n <= 5, the limit is d.b/2 + 1/16" as you noted, but when N>=6, the limit is reduced to d.b/2 - 1/16" (in standard holes).
Ah, yep, sorry. I was looking at the wrong code addition. I set the design code to the 14th addition in the program, but I was reading the 13th edition. The 13th edition doesn't have the table (it only uses the d.b/2+1/16" requirement). They seem to change this section a little bit every addition. Probably easiest solution in my case is to make the holes SSLT.