The slipform technique of construction allows for the continuous pouring of concrete into walls of a structure and only stops when the full required height of the structure has been reached.
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Development of the Slipform Technique
Cement, and concrete by its association with it, has an initial setting time of just about thirty minutes, after which the cement and the concrete have gained sufficient strength to remain in the shape into which it has been poured. It is this property that led to the development of slipform building that allows a non-stop method of construction. It is this property of early setting that inspired engineers to develop means of moving the formwork so that the concrete can be poured continuously. The height of the formwork is designed in such a way that while the top of the formwork is being filled by concrete the lowest layer of concrete poured earlier has already gained an initial set. When the formwork is moved upwards the concrete that is then exposed remains firm. Image Source : Wikimedia
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Advantages of Slipform Building A major cost of concrete structure construction comes in the form of the required formwork to retain the concrete while it retains it necessary shape and gains the necessary strength till it can be safely de-shuttered and be able to support itself and other imposed loads. It also requires the formwork to be continually removed to newer locations and then re-erected. All this requires the continuous use of manpower and lifting equipment like cranes. In the case of slipform building, the formwork is erected only once and remains intact until the entire structure is completed. This greatly reduces the cost of the formwork as well as any time that may be required to erect and move it for re-erection, which can result in huge savings in time as well as money.