Abstract: A collar assembly of or for a tower being formed by progressively higher concrete composition pours into reinforcement including formwork defined cavities, the assembly comprising or including; a higher subassembly adapted as a collar to selectively index to a zone of the tower being formed, a lower subassembly adapted as a collar to selectively index to a zone of the tower being formed, and a jacking arrangement whereby (I), when the lower subassembly is zone indexed and the higher subassembly is not, the higher subassembly can be raised relative to the lower subassembly and the zone to a fresh indexing height and (II), when the higher subassembly is zone indexed and the lower subassembly is not, the lower subassembly can be raised to a fresh indexing height.

Abstract: A collar assembly of or for a tower being formed by progressively higher concrete composition pours into reinforcement including formwork defined cavities, the assembly comprising or including; a higher subassembly adapted as a collar to selectively index to a zone of the tower being formed, a lower subassembly adapted as a collar to selectively index to a zone of the tower being formed, and a jacking arrangement whereby (I), when the lower subassembly is zone indexed and the higher subassembly is not, the higher subassembly can be raised relative to the lower subassembly and the zone to a fresh indexing height and (II), when the higher subassembly is zone indexed and the lower subassembly is not, the lower subassembly can be raised to a fresh indexing height.

Abstract: A method and apparatus for constructing a multi-storey building. A first slab (22) is formed directly on top of a second slab (21). The slab (22) is formed with a plurality of apertures spread about the slab area. A plurality of extendible prop means (10) are positioned in the respective apertures, the head portion (12) of each prop means being connected to the first slab (22), the foot portion (13) of each prop means being supported by a slab below the first slab (22). The prop means (10) is extended such that the first slab (22) is lifted to its desired position. Once in that desired position, the foot portion (13) of each extended prop means is retracted through its respective aperture to engage the upper surface of the first slab (22) and the process is repeated according to the number of storeys required in the building.