Embodiments of the invention relate to support arrangements for semi-membrane tank walls and, more particularly, to a universal support assembly for tanks that experience thermal expansion and contraction. One embodiment of the invention may include a tank assembly having at least one tank wall, a support structure at least partially adjacent to the wall, and a link member coupling the tank to the support structure. The link member may be configured to accommodate relative movement between the tank and the support structure through rotation. The link member may be coupled to the tank wall by a ball and socket joint and coupled to the support structure with another ball and socket joint, allowing substantially unlimited in-plane movement of the tank wall relative to the support structure.