nIn SpaceClaim, you only need to draw the concrete. Make a solid with the correct ID and OD of the concrete. Then with the Select Tool, click on the ID face, Ctrl-C and Ctrl-V. Do the same on the OD face. Now you have geometry with two surfaces and one solid. Finally, click on the Workbench tab and then the Share button. This makes it so the mesh on the solid will align with the mesh on the surfaces. Close SpaceClaim.nIn Mechanical, assign a thickness to the surface on the ID, assign a material and configure the offset type. Repeat this for the OD.nWhen you turn on Thick Shells and Beams, you can see that the skin thickness shows up outside the concrete, not inside.nThe apply a Fixed support to the bottom face and a Displacement in -y to the top face and you are ready to solve.nThis is a good way to build the model for operational loads on a column. If you want to load it past that and see things like slippage between the steel tube and the concrete material, you can't see that with this model because of the Share button back in SpaceClaim, which effectively bonded these two materials. Advanced simulation methods can show the relative displacement between the concrete and steel on a model built without using the Share button.n