Slipform construction technique is an alternative for conventional formwork system which helps in continuous vertical and horizontal construction. The slipform helps to conduct continuous pouring of the concrete to the moving formwork. The procedure stops only when the required length of casting is completed.
The features and advantages of slipform construction technique is explained in the below section.
The property of cement and concrete to gain sufficient strength to stay in shape once cast within the initial setting time of 30 minutes lead to the development of slip form building technique. Engineers took this property to develop a moving formwork system so that the concrete can be poured continuously.
The height of the formwork is designed such a way that, during the pouring of the upper level formwork, the concrete poured in the below formwork would have gained initial setting. The concrete exposed when the formwork moves up will remain firm.
Generally, it consist of yoke legs. The slipform system is designed with varied features. Yoke legs are employed to lift and sustain the weight of the entire structure, so that it behaves as a single unit. Yoke legs are also used to connect with the beams, scaffoldings and working platforms to serve the supporting purpose.
To the yoke legs, walk-away brackets are connected. These walkway brackets will enable proper placement of the concrete.
The whole slipform assembly is lifted by means of strand rods and lifting jacks. These main components are located at equal intervals so that the uniform and good distribution of weight is performed. In some construction, lifting procedure are supported by means of hydraulic pump components.
This helps to achieve huge cost saving. The slipform building method is a rapid and a economic building method compared to the conventional formwork method. The method is best suitable for large building structures and bridges. When small structures are concerned, the undertakings with identical geometry can be easily completed by slipform building.
Continuous movement of formwork in upward direction is performed in slip form approach. The movement is helped by hydraulic jacks and jack rods. In the construction of vertical frameworks, the rate of rising the formwork upwards will be almost in the rate of 300mm per hour. These rise with the help of the supports from other permanent parts of the construction.
The method of slipform construction will vary based on the type of framework constructed. Based on this the frameworks needed to support the system will vary.
The slipform construction method used in high rise construction construction will be performed by vertically extruding the reinforced concrete section. Regular shaped core structures and buildings are easily constructed by this method.
The slipform technique used for the construction of large chimneys, cooling towers and piers are called as tapered slipform. This technique is used for constructing vertical frameworks with varying wall thickness, or shapes or diameters.
Slipform building technique helps to construct the large volume cisterns in industries and factories in a cost effective way.
The slipform method helps to construct the walls of water tanks uniformly with better quality. Tanks of thousands of litres are easily constructed by this method.