WT Design analysis with stem in Compression

[buster73]

Checking a as-built WT18X80 in a vertical position that spans 10'-0", laterally loaded at center (5'-0") with a 7k concentrated load. The load is applied through the stem with a pin that connects through a 6" diameter hole centered @ 13" below the flange. Conservatively designing the tee as having a depth of 10" is what I have decided. Scratching my head ... Anybody with a suggestion or opinion to raise my comfort level?
Buster

 

[buster73]

Attached is a sketch for the WT18

 

[WARose]

I'm not sure what you mean when you say "laterally loaded". Do you mean in the plane of the paper, or out of the plane of the paper (if it's the latter, we'd be talking about torsion too). Assuming you mean in the plane of the paper (creating compression in the stem of the WT if its to the left), I ran that section and saw a low utilization ratio [about 0.17] and low deflection.....so I'd assume you are ok as far as the flexural load goes. However, if there is any axial load in the WT, you'll want to superimpose that on this too.

 

[buster73]

See sketch in my second post. The load is acting lateral in lateral (global) or normal to the stem causing compression in the stem and tension in the flange. The concern is the 6" loss of stem d from the 6" diameter hole located 13" from the top of flange. I can't find any code information concerning holes in the stem only holes in the flange. Suggestions? Thanks for your previous post.

 

[KootK]

This is not that unlike a web hole in a wide flange. I'd borrow from principles used in that kind of analysis, either Blodgett or the AISC design guide that deals with web holes. All of the shear will be dealt with in the ten inches of web that remains on the other side of the hole. All you've got to do is prove that the two inch bit can survive as a column across the width of the hole or some portion of it.

Certainly, your ten inch stem assumption should work too if you can make a go of it. How big is the pin that passes through this six inch hole? Does the pin assembly LTB brace the WT?

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[WARose]

I'd just run it with the hole part thrown out (in fact all of it from when the hole begins on down). You would calculate the reduced section properties and run with that.

 

[buster73]

WARose I agree with you and that's what I initially did and will probably go with. I found that the reduced section has the capacity for the load. Actually the pin load is acting 45 degree downward instead of lateral (global). This adds some additional moment along with some axial load, however it still checks. I checked it using the requirements of Specification Section F9 14th edition Steel Construction Manual. I still prefer the ASD since it's what I grew up with.