Formwork design principles

Practicality principle: the formwork shall ensure that the shape, size and mutual position of the components are correct, and the structure is simple, the support and disassembly are convenient, the surface is flat, and the joints are tight without mortar leakage

Safety principle: sufficient strength, rigidity and stability shall be provided to ensure no deformation, damage and collapse during construction

Economic principle: on the premise of ensuring the quality and safety of the construction period, try to reduce one-time investment, increase formwork turnover, reduce support and demolition labor, and realize civilized construction

Common formwork on construction site

At present, the types of building templates used in China's construction industry mainly include wood building templates, steel wood building templates, building wood plywood, steel bamboo building templates, plastic building templates, etc. below, we will compare the characteristics of various types of building templates:

The surface of the bamboo plywood formwork is flat and smooth, and the adsorption force of the film coated bamboo plywood formwork surface on the concrete is only one eighth of that of the steel formwork, so it is easy to demould, and the concrete surface is flat and smooth, which can cancel the plastering operation and shorten the construction period of the decoration operation.

Bamboo plywood formwork has good water resistance, and it will not be opened after boiling for 6 hours. It can still maintain high strength after boiling and freezing. The surface water absorption of bamboo plywood formwork is close to that of steel formwork. Pouring and tamping concrete with bamboo plywood formwork can significantly improve the water retention of concrete surface. In the process of concrete curing, it will not deform in case of water, which is convenient for maintenance. The bamboo plywood formwork is anticorrosive and mothproof. The thermal conductivity of bamboo plywood formwork is 0.14-0.16w/m.k, which is far less than that of steel formwork, which is conducive to thermal insulation in winter construction. Bamboo plywood formwork has high turnover times and obvious economic benefits. The board can be used on both sides. The characteristics of frameless wooden building formwork: the tree species used for wooden building formwork can be selected according to the actual situation of each region, and pine and fir are generally used. Wood building formwork has large wood consumption and low reuse efficiency, but it is convenient to use.

Steel wood building formwork: steel wood building formwork is a stereotyped building formwork with angle steel as the frame and wooden building formwork as the panel. Its advantage is that it can make full use of short wood and can be used repeatedly.

Building wood plywood: building wood plywood is a stereotyped building formwork with plywood as the panel and angle steel as the frame. Taking plywood as the panel overcomes the shortcomings of unequal directivity of wood and has good mechanical performance. This kind of building formwork has the advantages of high strength, small self weight, no warping, no cracking, large plate width and less joints.

Steel bamboo building formwork: steel bamboo building formwork is a stereotyped building formwork with angle steel as the frame and bamboo plywood as the panel. This kind of building formwork has large rigidity, is not easy to deform, is light in weight, and is easy to operate.

Steel building formwork: steel building formwork is generally made into stereotyped building formwork, which is assembled into various shapes and sizes with connecting components. It is suitable for various structural forms and is widely used in the construction of cast-in-place reinforced concrete structures. The steel construction formwork has the largest one-time investment, but the turnover rate is high. During the use process, attention should be paid to storage and maintenance to prevent rusting, so as to prolong the service life of the steel construction formwork. Others, such as plastic building formwork, glass fiber reinforced plastic building formwork and aluminum alloy building formwork, have the characteristics of light weight, high rigidity, convenient assembly and high turnover rate. However, due to the high cost, they have not been widely used in construction. Each construction enterprise can choose the appropriate construction template according to their own needs.