Fermilab is developing a 2-in-1, 11 T block-type common coil dipole magnet for a future Very Large Hadron Collider. The common coil design concept allows a large bending radius at the coil ends and therefore is well suited for use of the react-and-wind technique with brittle superconductors. The magnet features one-layer flat Nb/sub 3/Sn coil wound using prereacted cable. A novel mechanical design has been developed to provide effective coil support against Lorentz forces, minimize conductor displacement during excitation, reduce coil pre-load at room temperature, and prevent force accumulation. The details of the design concept and results of the mechanical analysis are presented in this paper.