Originally, this technology was developed for constant cross sections with precise vertical orientations. It was then developed further for variable layout shapes. Specially developed for the construction of conical towers and industrial chimneys at the beginning of the 1970s, conical slipforming offers a monolithic construction of decreasing and increasing layouts without any steps.
For slipforming variable cross-sections, horizontally moveable formwork structures are used. These are mounted on hydraulically adjustable tapering elements. The overhead girder star with its centre piece forms the central point of the tower and connects all main beams to a uniform, closed scaffolding. At the same time it serves as an upper work platform.
Towers & chimneys
Depending on the diameter of the structure and the maximum, high gridshaped lattice girders, welded castellated beams or even simple H-Beams are used. Despite the use of exact geometry lists describing the tapering in theory, building a conical tower requires a great deal of intuition and experience from our slipform specialists. It also proves that men, and not machines, are the measure of all things. Many factors influence the final geometric accuracy of the construction to be slipformed. Despite all technical advances, it is still not possible to precalculate all parameters. This is due to the different material properties of concrete in different parts of the world. This could be the reason why Gleitbau Salzburg is the only company worldwide offering conical slipforming.
The last years saw further developments of slipforming technologies to respond to new geometrical requirements, thus significantly broadening the range of applications. A contribution to this development was the research into new heavy-duty concrete formulations that meet the special requirements of this slipforming technique.
The execution by means of slipforming is always monolithic, this means without cold joints. The infinite adjustment of the slipform even allows for a fluent transition from initially circular cross sections on the base of the structure to a square shape at the final height of the construction.
The erection of tower-like structures with an axis spatially inclined against the vertical is an absolute innovation and quantum leap in modern slipforming. Because of their complex structural circumstances and construction geometry, ferro-concrete for oil and gas platforms require, to a large extent, a flexible formwork. It has to be capable of following an inclined sometimes curved spatial line.
With the help of this advanced conical slipforming technique, complex spatial structures can be precisely replicated.