Built-up steel column

[ecomarazamy]

I am trying to strengthen the base of a steel column only about 1.5' from the base. I have added WT connection plates to the HSS column on the top and bottom (required).
I found aashto section 6.9.4.3 which provides compressive strength but I can't find anything on the flexural resistance. Any advice on this?

 

[BridgeSmith]

See section 6.9.2.2 for columns with combined axial compression and flexure.

The definition for the moment capacity (Mrx & Mry) will direct you to 6.10, 6.11, or 6.12 to calculate the capacity.

You can use equation 6.9.2.2.1-3 to check the combined demand to capacity ratio, whether the elements are compact or not, but if you want to use the less conservative equations for combined effects (Equations -1 or -2), you'll have to go through applicable provisions listed in the first bullet point to check if the elements are compact.