| Slipforming is an important technique developed for high-rise construction. It involves using a circular set of formwork that is slowly lifted as the concrete placed into it hardens. It is then refilled and the process repeated until the final height of the structure is reached. It has been used to build a number of very tall structures, including several industrial chimneys 1200 feet high and the world's tallest freestanding structure, the CN Tower in Toronto, which has a total height of 553 meters, or 1,815 feet. The inner core of the forner IBM building in Atlanta was constructed using the slipform method. |