Round HSS to round HSS connection? 2

[WWTEng]

Is there a good detail to connect a 23' long (tall) 12.75" OD (11.75 ID) column to a 10' long 10.75" OD (9.75" ID)? The column is transitioning from larger to smaller diameter. The lower columns is encased in an exterior masry pier, the pier stops at around 26' due to architectural/aesthetic reasons and the arch wants a column a smaller column above the masonry where its exposed to the view. The axial load is low, only 10 k and the wind in each direction is 100 plf.

I can't think of any good detail. Putting a cruciform (or plus shaped) plates within he columns to is the only thing I can think of.

 

[BAretired]

Why not a cap plate on top of the larger column with smaller column welded on top?

BA

 

[KootK]

BA's suggestion is best if it can be made to work. Even a 2" thick plate will be cheaper than stiffeners. If your level of moment transfer is very high, or you're worried about flexibility in the connection, you can sleeve the smaller column inside of the larger one for a short distance. I've seen details of this type used on tall sign structures. They're not all that fabricator / contractor friendly however.