Assembly for lifting a payload of an offshore platform, said offshore platform further comprises at least one support structure supporting the payload, said payload comprising at least a main deck and at least one column directly connected to said support structure, said at least one column supporting at least said main deck; said assembly comprising: - at least one lower lifting device, having at least one welding surface weldable to a welding portion of said at least one column of said payload; - at least one upper lifting device having a coupling interface adapted to couple to a coupling portion of said payload; - a plurality of tension rods, connecting said lower lifting device and said at least one upper lifting device; wherein said welding portion of said column being located at a lower level in respect of said main deck of said payload and said coupling portion of said payload being located at a higher level in respect of said welding portion so that, when said assembly is in operative condition, said at least one upper lifting device is located at a higher level in respect of said lower lifting device; and wherein: - at least some tension rods of said plurality of tension rods extending for a rod length along a rod direction (X-X) between said lower lifting device and said at least one upper lifting device; - at least some tension rods of said plurality of tension rods are pre-tensioned, in such way to exert a compressive action to said payload; characterized in that said assembly comprises at least one rigging device connected to said at least one upper lifting device and designed to be lifted by at least one crane for the purpose of lifting the payload after having separated said at least one column from said support structure; and that because of the provision of said pre-tensioned tension rods, said assembly avoids to exert a traction action on said at least one column, loading said at least one column with a compressive action substantially equal to or less than the compressive stress acting on said columns during normal use of the offshore platform. said assembly comprising: - at least one lower lifting device, having at least one welding surface weldable to a welding portion of said at least one column of said payload; - at least one upper lifting device having a coupling interface adapted to couple to a coupling portion of said payload; - a plurality of tension rods, connecting said lower lifting device and said at least one upper lifting device; - at least one lower lifting device, having at least one welding surface weldable to a welding portion of said at least one column of said payload; - at least one upper lifting device having a coupling interface adapted to couple to a coupling portion of said payload; - a plurality of tension rods, connecting said lower lifting device and said at least one upper lifting device; wherein said welding portion of said column being located at a lower level in respect of said main deck of said payload and said coupling portion of said payload being located at a higher level in respect of said welding portion so that, when said assembly is in operative condition, said at least one upper lifting device is located at a higher level in respect of said lower lifting device; and wherein: - at least some tension rods of said plurality of tension rods extending for a rod length along a rod direction (X-X) between said lower lifting device and said at least one upper lifting device; - at least some tension rods of said plurality of tension rods are pre-tensioned, in such way to exert a compressive action to said payload; - at least some tension rods of said plurality of tension rods extending for a rod length along a rod direction (X-X) between said lower lifting device and said at least one upper lifting device; - at least some tension rods of said plurality of tension rods are pre-tensioned, in such way to exert a compressive action to said payload; characterized in that said assembly comprises at least one rigging device connected to said at least one upper lifting device and designed to be lifted by at least one crane for the purpose of lifting the payload after having separated said at least one column from said support structure; and that because of the provision of said pre-tensioned tension rods, said assembly avoids to exert a traction action on said at least one column, loading said at least one column with a compressive action substantially equal to or less than the compressive stress acting on said columns during normal use of the offshore platform.