It's a while since I have looked at this but I don't think you should have vertical expansion / contraction joints in the wall. However it's certainly an option top place an expansion / contaction joint between the base and wall
I'm calculating hot-spot stresses at a tubular connection for input to a fatigue analysis. The Efthymiou parametric equations provide SCFs relating nominal stress in the brace to hot-spot stress in the chord.
However there is also a large axial force in the chord. The stresses in the brace are...
