Assignment $4/$ Axial Load $($Indeterminate$)$

Steel shaft $AB$ is firmly attached to a rigid cap attached to steel shafts $CD$ and $EF.$ Shafts $AB,CD,$ and $EF$ are made from aluminium $(E=75$

GPa$),$ and has a length and diameter of $1200mm$ and $20mm,$ respectively.

Determine the reactions at $A,D,$ and $F.$