In construction, there are two main types of formwork that exist and are used: this is the so-called small-panel formwork of collapsible type, reusable and single use. Reusable formwork is used during construction monolithic structures of various configurations and purposes, often they are monolithic bearing columns and floors.
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With your own hands
Metal formwork and its features
The unified collapsible formwork is a metal formwork or a combination of metal and wood. The metal formwork is made of corners, channels and metal sheets 2 mm thick. This formwork design is more durable, and therefore practical, metal formwork can be reused almost 200 times. The design of metal formwork allows, if it is a unified collapsible formwork, to assemble and install large-size formwork panels. The area of \u200b\u200bthese panels can reach 35 square meters... The use of unified formwork allows you to assemble and erect rigid formwork blocks, reinforcing formwork blocks using a crane. In addition to the unified collapsible formwork, there is another form of metal formwork - the block form.
Block-form is a steel form, all-removable and rigid, intended for concreting foundations of the same type. Installation of formwork block-form by crane. The block-shaped basement metal formwork is installed on concrete preparation... It is economical to use this form of metal foundation formwork for a large number of foundations of the same type. The block-form metal formwork can have a transformed metal formwork structure, then it can be used for several standard sizes of the foundation. Sliding type metal formwork is used for concreting tall structures with a compact perimeter and a plan shape that does not change in height. In the construction of pipes, cores of stiffness of residential buildings, silo cans on an elevator, residential buildings with a high number of storeys, sliding metal formwork is used.
How to make metal formwork? The formwork structure consists of formwork panels, which are suspended from a U-shaped jack frame, jacks and a working platform, suspended scaffolds and oil lines. The height of the metal formwork at this moment is usually 1100 - 1200 mm. The formwork structure encompasses the structure to be concreted along the outer and inner contours. How to make a formwork if the cross section is round? Such a metal formwork consists of two concentrically located walls that are attached to the inner and outer circles. To facilitate lifting, the metal formwork is tapering. The construction of this type of formwork is all-metal, due to this, it is more rigid. This metal formwork is used many times, i.e. inventory. Formwork is erected with the help of jacks, they are supported by jack rods installed inside the formwork of the structure being erected. The jacks rise along the rods and pull the formwork with them. In a metal formwork of the block-form type, the working floor is wooden, it is laid on metal girders (lightweight) and fixed to the racks of the U-shaped frames, and the scaffold is also attached here for other work. The climbing structure of the metal formwork is used to concrete high-rise buildings in the form of a cone or rectangular cross section different sizes... Such metal formwork is made of steel sheets and corners, assembled in the form of panels. The structure of the metal formwork for the construction of reinforced concrete pipes and other conical structures consists of two conical shells. They are suspended from radial guides, which are attached to an annular frame, which is hinged to a mine hoist. The outer shell consists of trapezoidal panels that taper the shape. The panels are rigidly fastened along the top using a special overlay, and between themselves along the side ends using bolted joints. The panels of the inner shell are half the height and are hung in two tiers. The metal formwork is rearranged to a higher tier after reaching the required concrete strength in the lower tier, concreting is performed in tiers.
Specifications
Types of formwork cladding
Formwork-facing is a form assembled from reinforced concrete, reinforced cement slabs; steel or asbestos-cement sheets that are part of the structure and work with it as a whole. 
Formwork cladding performs two functions: formwork during concreting and protective, or decorative, cladding. To increase the durability of reinforced concrete structures, it is necessary to ensure the best adhesion between the formwork-facing and the concrete of the array.
Formwork-facing is produced at the enterprises of the building industry and installed with the help of cranes in concreting blocks. At the same time, labor-intensive formwork removal operations disappear.
Reinforced concrete formwork-facing is used for massive monolithic structures (columnar and strip foundations, walls with a thickness of more than 0.5 mg of sinking pits and caissons, supports for bridges and overpasses, grillages, etc.). Formwork-facing is also widely used for massive foundations for technological equipment, in particular rolling mills, heavy presses, hammers, etc.
Reinforced concrete formwork cladding. In industrial construction, formwork-facing is used in the form of flat and ribbed reinforced concrete slabs. The width of flat formwork slabs is 1 m with a thickness of 5-6 cm. Their length is taken depending on the size of the structures, but not more than 4 m. For better adhesion to concrete, such slabs are given a rough active surface, and in critical "cases, they are supplied with special anchoring release loops
Ribbed formwork plates (3-1, g) have a width of 0.6 or 1.2 m and a length of up to 6 m. In addition to a rough active surface, for better adhesion, through holes with a diameter of 2.5-3 cm are arranged in the ribs with a step of 20-25 cm. When placing concrete, the cement mortar, falling into these holes, forms a kind of anchoring dowels, which contributes to the reliable adhesion of the formwork-facing with the concrete of the massif,
In hydrotechnical construction, reinforced concrete cladding formwork is used from flat slabs with a maximum size of "2.5X5.0 m and a thickness of 8 cm. Such slabs have a rough active surface and anchoring loop-outlets that serve to fasten the cladding formwork."
The shuttering boards are transported and stored in special containers in an edge-on position (3-2). Formwork-facing is installed in the concreting blocks with cranes. In this case, slabs with mounting loops are slinging for them (3-3, a). Mounting loops then have to be cut or bent.
In weakly reinforced massifs and thin walls, formwork slabs are fastened using inventory metal or wooden girders, which are removed after concreting (.3-7). After dismantling the girders, the protruding ends of the strands are cut flush with the outer surface of the formwork, and the seams between the plates are sealed with cement mortar.
Formwork-facing made of ribbed reinforced concrete slabs is used for very massive structures (for example, for foundations for rolling equipment). Such slabs are fixed to reinforced concrete racks by welding or using screw clamps (3-8).
Reinforced cement and glass-cement formwork-facing. Armocement is a high-strength, fine-grained concrete, dispersedly reinforced with steel woven mesh.
Reinforced cement formwork slabs have a width of 2.5 - 3.5 cm, a width of 1 m and a maximum length of 3.5 m. Their width is determined by the size of standard woven nets, and their length is determined by the size of the surface to be covered. The slabs have a finely roughened active surface, and in some cases also have anchoring loops.
Reinforced-cement formwork-facing is used for concreting powerful columns and pylons, foundations for industrial buildings and equipment, tunnels, sink wells, etc. Due to the increased water resistance, reinforced cement slabs can simultaneously act as waterproofing underground structures under the burrow groundwater up to 15 m water column.
For the manufacture of reinforced-cement formwork plates, fine-grained (sandy) concrete of grade 300 is used on Portland cement of grade 500. The plates are reinforced with two woven nets with cells of 8-10 mm and a wire diameter of 0.8-1.2 mm. Reinforcement can be applied in the form of a combined armored package consisting of two woven meshes clamped between the rods of a welded mesh with a diameter of 6-8 mm.
Reinforced-cement formwork is transported and stored, as well as reinforced concrete, in the "edge-on" position in special containers (see 3-2). Mount it with cranes. Reinforced cement slabs are fastened in basically the same way as reinforced concrete. However, due to their lower thickness and rigidity, the step between the fasteners is reduced to 0.5-0.7 m. For the same reason, such a formwork is usually fastened using inventory girders (3-9). Glass-cement formwork-facing has the form of slabs 12-20 mm thick, up to 1.2 m wide and up to 2.5 m long. For the manufacture of such formwork, low-base cements are used, in particular alumina. Plates are reinforced with several layers of fiberglass or chopped fiberglass. Glass and cement slabs can be cut with electric saws and holes drilled into them. Due to the increased water resistance of glass cement, the formwork-facing serves as a reliable waterproofing of underground structures.
Metallic formwork cladding. Reinforced concrete structures are clad with steel sheets in particularly severe operating conditions. Steel cladding can serve as a reliable waterproofing, protect concrete from abrasion and from radioactive radiation.
Metallic cladding is usually installed on one side reinforced concrete structure... For its manufacture, steel sheets with a thickness of 5 to 10 mm are used, from which enlarged panels are assembled with an area of \u200b\u200bup to 50 m2. The stiffness of the panels is ensured by welded channels, which remain in the concrete and ensure the connection of the cladding to the concrete. For the same purpose, "whiskers" of round steel with a diameter of 12-16 mm are welded to the sheets.
All welds must be waterproof; they are subjected to density tests. Panels are mounted in design position cranes; fasten them using electric welding.
Mesh formwork. For concreting structures and structures, the lateral surfaces of which may deviate somewhat from the plane, mesh formwork is used. It is used for concreting the walls of basements, sinkholes, tunnels, foundation glasses, etc.
As a formwork, steel woven nets with cells from 5x5 to 12x12 mm and a wire diameter of 0.8-1.2 mm can be used. Mesh formwork can be removable or non-removable. Removable mesh formwork (3-10) is made of mesh with a mesh of 10X10 or 12X12 mm. To exclude the leakage of cement laitance from the concrete, a layer of roofing tar or roofing material is laid in front of the mesh on the concrete side, which is pressed to the mesh with reinforcing pressure rods on twists of knitting wire. Separate mesh panels are sewn together with knitting wire.
Fasten the mesh formwork using vertical "" rods with a diameter of 22-25 mm, which are connected by short ones by welding. The pressure of the concrete mixture on the mesh formwork is perceived by the external vertical rods, through the short ones it is transmitted to the elements of the reinforcing cage. After concreting and curing, the mesh is removed for reuse.
Fixed mesh formwork is made of mesh with smaller cells (5x5 or 8x8 mm) (3-11). The mesh, sewn from individual panels, is attached to the reinforcement frame using twists and vertical rods with a diameter of 22-25 mm. To reduce the leakage of cement laitance, the slump of the concrete mix cone is taken from 0 to 3 "cm. In the process of vibration compaction, the cement laitance fills the mesh cells, which turns out to be in the concrete. After concreting, only the vertical fastening rods are removed, the mesh remains in the concrete.
Mesh formwork is in some cases more economical than inventory formwork. It is also used where it is difficult to remove the formwork (for example, to form construction joints in walls and thick slabs)
Firms
Inventory metal climbing formwork
Inventory metal climbing formwork is used for the construction of high-rise reinforced concrete structures of a conical shape with a variable section of walls in height. In this formwork, cylindrical reinforced concrete high-rise structures can also be erected. This formwork - its outer panels - is lifted every 2.5 m in height using a special lifting head supported on a mine hoist, or worm hoists fixed in the nodes of the shaft hoist struts located inside the structure under construction. The panels of the inner formwork are dismantled every 1.25 m in height and installed for concreting the overlying tier of the structure. 
Inventory metal collapsible (panel) formwork is used for the construction of high-rise reinforced concrete structures of various shapes - hyperbolic, conical, biconical, cylindrical, polygonal, etc. - with a constant and variable section of walls in height. The panels of the internal and external formwork are disassembled every 1 m in height and installed for concreting the overlying sections. Relocation of the formwork panels is carried out from the inner steel tubular scaffolding, the outer suspended scaffolding and from the hanging cradles of the unit.
Instructions
Formwork types
The most common are wooden formwork, plywood formwork, metal formwork: steel formwork or aluminum formwork, reinforced concrete formwork, plastic formwork, combined formwork and some others. We would like to offer you plastic formwork. Before setting out the advantages of this type of formwork, consider the disadvantages of others. These do not include formwork Ukraine or Epic Eco.
Wooden formwork 
Wooden formwork is made from conifers wood. This formwork has a low thermal conductivity, which is a positive quality in the conditions of Siberia and the North of Russia, but not the formwork Ukraine. For our region, this factor is not significant. Its main disadvantages are low strength and shape change when exposed to moisture. Same wooden formwork subject to deformation during transportation and shrinkage. As a result, warping, opening of the seams between the boards, cracking appears, which Epic Eco formwork is not subject to.
Plywood formwork
Plywood formwork belongs to the high-turnover types of formwork, but not as durable as Epic Eco. To achieve this effect, this formwork must be water resistant. The best solution is film faced plywood. Film faced plywood sheets are used only for cladding. The supporting frame is made of metal or wood. Plywood formwork has low thermal conductivity, low weight. This formwork is relatively inexpensive. Its main disadvantages are the hygroscopicity of the perimeter of the sheets, the low mechanical strength of the laminate. High cost as a percentage of the cost of restoration work. What the formwork of Ukraine or Epic Eco is not subject to.
Metal formwork
Metal steel formwork is more expensive than wood, which is the main disadvantage. However, when using it, there are practically no deformations regardless of the weather conditions in which the structures are being erected. The disadvantages include high thermal conductivity. Another drawback is the need to use a crane during erection and stripping. The Epic Eco formwork does not require a crane when erecting.
Metal aluminum formwork is much lighter than steel. Namely, three times, while maintaining the same characteristics. This allows the formwork and formwork to be erected manually, without the use of lifting equipment. Disadvantages - high cost, concrete adheres strongly to the aluminum formwork, which requires constant cleaning costs. When connected to the rest of the formwork elements, galvanic couples arise, which leads to the destruction of aluminum components. Epic Eco formwork does not form galvanic couples. If you type in the search engine formwork Ukraine, then the best choice - this is Epic Eco formwork.
Reinforced concrete formwork
The assembly of the formwork can be carried out without the use of special tools, by workers without prior training except for passing the safety exam. What is the formwork made of? - Made of polypropylene and fiberglass, which gives the structure strength, water resistance, wear resistance.
- High quality and dimensional accuracy of elements
- The strength of the plastic formwork. Sixty to twelve kN per square meter.
- High tightness of the butt gap allows not even water to pass through.
- The weight of the beam is seven and a half kilograms. Size 1.4 meters.
- The strength of the structure allows you to fill the floor up to seventy centimeters.
- High speed of assembly and demoulding.
- High degree of standardization.
- The cost of filling the floor is reduced by fifty percent due to the durability.
- Operating temperature of the formwork from minus thirty degrees to plus sixty.
Equipment
The advantages of plastic formwork
The best that exists on this moment from plastic formwork, so that the price-quality ratio is optimal - these are the products of Epic Eco. The products of this company are of European quality - this is the number one formwork Ukraine! The main office is located in Slovenia. If metal formwork, despite its advantages, involves up to 50 revolutions, then plastic formwork up to 500 times. This is a construction set for builders. In other words, a prefabricated modular structure of plastic, fiberglass-reinforced shields of seven different standard sizes, plastic fasteners and a plastic beam. 
The assembly of Epic Eco formwork can be done without the use of special tools, by workers without prior training, except for passing the safety exam. What is Epic Eco formwork made of? - Made of polypropylene and fiberglass, which gives the structure strength, water resistance, wear resistance.
What are the advantages of Epic Eco plastic formwork?
- Relatively low price. One square meter from two hundred euros.
- Not subject to corrosion, warpage, swelling. Moisture resistant.
- Easy. One square meter weighs no more than twenty-two kilograms.
- Formwork elements can be used for both horizontal and vertical surfaces.
- No crane is required to erect the formwork.
- Four builders will assemble one hundred square meters of formwork in one and a half to two hours.
- Convenient transportation due to low weight. One hundred square meters weighs a little over two tons.
- You can use shields up to five hundred times.
Reusable formwork is traditionally made of steel or aluminum panels. Formwork metal reusable
, in comparison with aluminum, is subject to corrosion, but it is more resistant to mechanical damage. Monolithic structures allow to erect buildings in a shorter time, their strength characteristics are much higher than, say, panel or brick structures. The increased strength characteristics of monolithic structures allow constructions to be made less voluminous, which reduces the consumption of concrete. All types of formwork do not require any special conditions for storage and transportation, all these operations can be carried out in the open air and under any weather conditions. 
Reusable formwork is an advanced technology in the construction of not only multi-apartment residential buildings and public buildings, but also in the construction of private facilities, swimming pools and other structures. On order, it is possible to manufacture formwork of any design, with any dimensions, which allows you to build any object at the request of the customer. The process of assembling and disassembling the formwork does not take much time and does not require high qualifications and skills from the working personnel, which makes it possible to attract cheaper labor during the construction process.
The installation of the formwork is, perhaps, the most crucial stage in the process of manufacturing a reinforced concrete bath. It depends on the quality of the installation and fastening of the formwork how the concrete will go. The most common defects in poor formwork are: pressure bulging of the concrete mass, collapse of walls, violation of the pool geometry.
We use 21 mm plywood as formwork. Of course, the use of reusable metal formwork will simplify the formwork installation procedure, but since almost every pool has its own unique shape, different bottom profile and depth, rounding, it is often easier to get by with a one-time formwork.
A few tips from experience
1. Do not install the embedded elements before pouring the concrete. It is better to leave the niches and put them out after removing the formwork and leveling the walls.
2. Do not spare spacers and ties. It is better to install them every 50 cm.
3. You can use the wall of the house to which the pool adjoins as an external formwork, only through the laid divider. Styrofoam 5 cm thick is enough.
Foundations and its structure
The foundation is the main bearing part, foundation, support of any building, any structure. It is necessary to start laying the foundation after the location of the house has been chosen, its project, appearance, internal distribution to premises, type of foundation and materials have been approved. The operational qualities of the building, its capital and durability largely depend on the reliable operation of the foundations. The cost of building foundations is 15-20% of the value of the house.
It is necessary to start with engineering and geological surveys at the place where the building will stand, since many factors influence the choice of foundation, including the condition and type of soil in the allotted area, the level of freezing, the presence of groundwater, the structure of the building itself, the load on the foundation, use of basements, etc.
By their design (and, accordingly, the method of pressure on the ground), foundations are divided into strip, slab, columnar and pile foundations.
Strip foundations
Strip foundations are the most fashionable among builders. Today they are used in the construction of houses of any type, including those with heavy walls, basements and basements. Strip foundations are laid in a solid line under all external and internal capital walls. Actually, the strip foundation itself is a wall - high or not very (depending on the depth of the foundation). For device strip foundation first, the pit is dug. Inside it, the foundation line is marked. Formwork is installed along this line - hollow temporary walls for pouring concrete. Reusable metal formwork is commonly used to obtain a neat foundation. 
After the formwork is mounted, reinforcing metal reinforcement is placed in it, and then poured with concrete. The remaining voids between the walls of the constructed foundation are filled with the same soil that was removed when digging the foundation pit. Then the soil is rammed, and, if necessary, a concrete basement or basement floor is arranged on it. The foundation walls in this case become the walls of the basement or basement. Horizontal ceilings are installed on the walls of the foundation - solid or in the form of beams, after which they begin to erect the walls of the house.
Prefabricated strip foundations consist of individual blocks, they are made in factories building structures... They are installed in the pit using a crane, and then connected to each other with cement mortar.
In heaving and deeply freezing soils, shallow strip foundations are used. For their construction, they do not dig pits - they manage with shallow trenches. Moreover, such strip foundations are made not only of concrete (monolithic or prefabricated), but also - as thousands of years ago! - made of stone or brick. This is especially practiced in the construction of lightweight panel board and chopped wooden houses... Moreover, it is brick that turns out to be the least preferable, since it actively absorbs water and begins to quickly collapse.
Slab foundations
Foundations Slab foundations are also quite popular and widespread. Thanks to the rigid structure - a monolithic slab made under the entire area of \u200b\u200bthe building, they are not afraid of any movement of the soil: the slab moves with it, protecting it from destruction of the house structure. A solid slab of such foundations is made of reinforced concrete and has rigid reinforcement along the entire bearing plane. This further increases their resistance to loads arising from freezing, thawing and soil subsidence.
Slab foundations are built mainly on problem soils - heaving and subsiding. Their use is especially justified on moist soils with a high level of groundwater standing. Slab foundations are ideal for waterproofing basements and basements.
For building slab foundation first, a pit is dug, then it is tamped down and a pillow is made at the bottom of a layer of sand and a layer of gravel. Lay on top of them waterproofing material... A thin layer of concrete is poured over the waterproofing. And then the reinforcement is laid and concrete solution is pumped into the pit. On the slab constructed in this way, a tape is arranged monolithic foundation under the load-bearing walls of the house. Further foundation slab can become a basement floor.
Slab foundations are quite expensive due to the high costs of excavation, concrete and metal fittings. Therefore, to save money, designers sometimes propose to do with a monolithic strip foundation, and make the floor in the basement or basement separately. Unfortunately, this design does not provide reliable waterproofing, and is more prone to drawdowns. Monolithic slab turns out to be preferable in many cases.
Foundations Columnar foundations are placed under wooden houses with light walls and without basements - chopped, frame, panel board. Pillars are erected at all corners and at the intersection of the walls. Pillars can be made of various materials - concrete, natural stone, brick. The distance between the posts usually does not exceed 2.5-3.0 m. To create a rigid, stable structure, strapping beams (metal or wooden) are laid on the top of the posts. The use of such foundations on sites with a height difference is impossible: there is a danger of their overturning due to lateral soil pressure.
To insulate the underground space and protect against the ingress of snow, moisture and dust between the poles, a so-called zabirka is made - a wall connecting them. For this, brick, concrete or rubble masonry with a thickness of 10-20 cm is used. The filling is buried in the ground by 20-30 cm.If the soil is heaving, then they also arrange it under the filling. sand pillow 15-20 cm thick. It is very important not to forget that the filling needs ventilation holes on each side of the house. They are closed for the winter.
Columnar foundations in terms of material consumption and labor costs are 1.5-2 times, and with a deep foundation, even 3-5 times more economical than tape foundations. Unfortunately, not all houses can be built on such simple and inexpensive foundations.
Pile foundations are used where the top layer of soil cannot withstand greater weight, and it is too expensive to remove it to denser layers and put a foundation on them - for the reason that they start too deep. They are also used at high groundwater levels and on quicksands. Pile foundations are typical, for example, in Venice and St. Petersburg. Piles are pillars with a sharpened bottom end. They are driven or driven into the ground. For obvious reasons screw piles more resistant. They are like giant screws, but they are screwed in using small equipment. This technology contributes to the preservation of the pristine landscape and has a minimal man-made impact on the construction site and around it. Kinds: driven piles, piles-piles, screw piles, shell piles, rammed piles... Passing through the weak layers of the soil, the pile rests on the harder ones and transfers the load from the building to them. Load bearing capacity a single pile usually ranges from 2 to 5 tons, that is, it is a suitable option for large-scale construction. To create a rigid structure, the tops of all piles are connected by beams. But sometimes the piles are not driven in or screwed in, but are made directly in the ground. In this case, a well is drilled, a reinforcing cage or hollow pipes are inserted into it, after which the well is poured with concrete. The concrete is then compacted by compaction or vibration. How do such piles differ from the pillars that form the foundations.
Formwork types and their application
The most common are wooden formwork, plywood formwork, metal formwork: steel formwork or aluminum formwork, reinforced concrete formwork, plastic formwork, combined formwork and some others. We would like to offer you plastic formwork. Before setting out the advantages of this type of formwork, consider the disadvantages of others.
Wooden formwork
Wooden formwork is made of softwood. This formwork has a low thermal conductivity, which is a positive quality in the conditions of Siberia and the North of Russia, but not the formwork Ukraine. For our region, this factor is not significant. Its main disadvantages are low strength and shape change when exposed to moisture. Also, wooden formwork is prone to cracking.
Wooden formwork elements absorb moisture from the concrete. At the same time, the shape changes, the formwork bends. The formwork is designed for a specific object, which does not allow it to be reused. Formwork Ukraine or Epic Eco allows you to use it repeatedly.
Plywood formwork 
Plywood formwork belongs to the high-turnover types of formwork, but not as durable as Epic Eco. To achieve this effect, this formwork must be water resistant. The best solution is film faced plywood. Film faced plywood sheets are used only for cladding. The supporting frame is made of metal or wood. Plywood formwork has low thermal conductivity, low weight. This formwork is relatively inexpensive. Its main disadvantages are the hygroscopicity of the perimeter of the sheets, the low resistance to mechanical stress of the laminate. High cost as a percentage of the cost of restoration work.
Metal formwork
Metal steel formwork is more expensive than wood, which is the main disadvantage. However, when using it, deformations are practically absent regardless of the weather conditions in which the structures are being erected. The disadvantages include high thermal conductivity. Another drawback is the need to use a crane during erection and stripping.
Metal aluminum formwork is much lighter than steel. Namely, three times, while maintaining the same characteristics. This allows the formwork and formwork to be erected manually, without the use of lifting equipment. Disadvantages - high cost, concrete adheres strongly to the aluminum formwork, which requires constant cleaning costs. When connected to the rest of the formwork elements, galvanic couples are generated, which leads to the destruction of aluminum components. The formwork does not form galvanic couples.
Reinforced concrete formwork
Reinforced concrete formwork in the process of concreting is a formwork, and later this formwork remains as a separate element of the structure. The disadvantages include the difficulty of transportation and installation. For the construction of buildings, reinforced concrete formwork is practically not used.
Metal formwork is an effective structure for arranging the foundation and walls of buildings. Thanks to its use, the appearance of defects at the joints is excluded. Which is almost impossible to avoid when installing wooden formwork.
Shields are the main structural element. Slopes, racks and struts are used for their fastening. The deck is the main part of the structure. It comes into contact with a concrete surface. The type of structure being built and the design load are the main factors affecting the strength of the formwork.
Formwork is subdivided into:
- removable;
- non-removable.
Removable structure removed after pouring and hardening concrete mortar... This formwork can be used several times. Its inner surface, which is in contact with concrete, must be as smooth as possible. The area of \u200b\u200bapplication is the construction of several monolithic structures with different configurations.
Permanent formwork is constructed in combination with thermal insulation material... In most cases this design is a hollow block with grooves that connect adjacent elements. The main area of \u200b\u200buse of non-removable products is wall construction.
For the production of metal formwork for the foundation, materials such as steel or aluminum are used. The steel structure is more resistant to mechanical stress. But it corrodes. The aluminum frame is lightweight and will last much longer. But his device is more expensive.
Construction characteristics
To create metal formwork, sheets with a thickness of 1-2 mm are used. Despite the high cost, the use of this material has its advantages. These include:
- foundation device of any configuration;
- additional waterproofing;
- versatility;
- creating a completely smooth surface;
- ideal for monolithic and strip foundations (due to reinforcement welded to the formwork);
- simplicity of facing (with a significant elevation of the base of the house above the ground);
- maximum rigidity;
- ease of implementation installation works.
Steel formwork has the following technical characteristics:
- shield height - 0.6-3 m;
- their width is 0.25-1.2 m;
- frame turnover - up to 300 cycles, deck turnover - up to 80 cycles;
- deflection - no more than 1/400 span;
- concrete pressure - 75-80 kPa.
The frame of the panels is a closed loop, for the manufacture of which 2 types of profiles are used: rectangular (for stiffeners) and edge (located along the perimeter of the panels). To create the deck, plywood is used, which has a thickness of up to 2 cm.
Preparatory work
When laying the foundation, it is necessary to take into account the depth of freezing of the soil. For this reason, the steel formwork must be laid to a depth of at least 0.7-0.8 m.
For high-quality work, you will need the following materials and tools:
- ready-made shields;
- wooden pegs;
- paint;
- hammer;
- brush;
- spanners;
- screwdriver;
- pliers;
- assembly grip;
- struts;
- leveling beams;
- building level;
- plumb line;
- roulette;
- wire;
- special locks (elongated and wedge);
- brackets;
- kingpin;
- clamping screws;
- plastic tubes and cones;
- nuts and washers;
- traffic jams.
At the preliminary stage, the surface is marked. The correct alignment of the foundation axes is checked with a tensioned wire. And formwork - using plumb lines, which are lowered from the wire.
Before the aluminum formwork is installed, beacons must be set up. They are wooden stakes that are driven flush with the base. On the lighthouses, marks are made with paint, which should be guided by when installing shields and supporting elements.
The following requirements are imposed on the place of installation work:
- it must be free of debris and dirt;
- the surface is leveled with a cut of protruding tubercles;
- installation of shields is carried out without adding earth;
- the supporting elements of the structure are installed only on a fixed base (without seasonal ground movements).
The part of the formwork that will be in contact with the concrete surface is coated with a special grease. This improves the adhesive properties of the coating and provides reliable protection formwork from environmental influences (corrosion, frost).
Stages of installation work
The assembly of the structure can be done independently. But rental aluminum formwork is also a good option. Installation can be carried out both using separate panels and pre-assembled panels (but no more than 5-6 panels measuring 3 × 1.2 m).
The connection of the elements is carried out with the help of tie screws (with washers and nuts), which are threaded into the tapered holes in the frame of the panels. It is recommended that the clamping screws be placed in a plastic tube. This ensures their reliable protection against the influence of concrete. The length of the plastic tube must match the thickness of the wall to be erected.
When installing wall formwork with one tier using boards with a height of 1.2-2.5 m, 2 clamping screws in height are sufficient. If the structure is erected from 2 tiers with shields over 2.5 m in height, then on each side there should be 3 tension screws. Unused openings are closed with plugs or plastic cones.
Adjacent shields are connected using locks. Their number depends on the height of the elements and the proximity of the joint to the outer corner. When the outer shield is attached, pivots are used instead of locks. The horizontal parts are fixed with tie screws.
To connect the additional elements with the main shields, 2 wedge locks are mounted. If the structure is too high (over 2.5 m), the connection to the main shields is carried out using wedge locks and leveling beams with pivots. Their number depends on the width of the additional shield.
Often, when erecting wall formwork, the panels are connected by additional inserts. If the size of the additional insert is less than 0.2 m, then universal locks are used to fasten them. When installing inserts longer than 0.2 m, use locks and leveling beams. The use of additional inserts guarantees maximum strength tensile structures.
Construction formwork is an auxiliary structure used in monolithic construction architectural structures to retain building mixtures in a given geometric shape until they are sufficiently solidified.
A formwork system is a set of structural elements (formwork panels, brackets, special locks, shelves, etc.) sufficient for carrying out work on the monolithic construction of a building.
Construction formwork can be removable and non-removable.
The removable formwork keeps the mortar in the required form until it gains sufficient strength to dismantle the formwork. Once the mortar is sufficiently strong, the formwork is dismantled and can be used on a new construction site or on a new facility. The removable construction formwork is reusable.
Fixed formwork also serves to hold the concrete mixture in a given shape, but is not dismantled after it has set. Permanent formwork is one-time and after pouring concrete remains as a constituent element of the floors.
Materials
Traditionally, construction formwork has been made from wood for centuries. The easy-to-handle material was mainly used as formwork for foundations. Today wooden formwork is used mainly in private small-scale construction and is not used in the construction of large objects. Significant disadvantages of timber formwork are low bearing capacity and the inability to reuse it.
Metal formwork is widely used in modern construction. Low-carbon steel (oxidized, galvanized, painted) or aluminum is used as a material for the production of formwork. Today metal formwork is the most convenient and technologically advanced for the construction of any, even the largest and most complex architectural objects.
The expanded polystyrene formwork is not removable. It is mainly used in private and small-scale construction. Fixed formwork made of expanded polystyrene partially insulates and insulates the building. The disadvantages include the complexity of the work, the price and the impossibility of repeated use.
Design features of metal formwork
The main element of the metal formwork system is the shield, which consists of the frame and the deck itself.
The frame is a rectangular frame with internal ribs for increased rigidity. A sheet of construction film faced plywood is installed inside the frame. The ends of the plywood sheet are recessed in a metal profile, the gaps are sealed with a sealant (to prevent moisture ingress). The formwork panels are assembled into a single system using auxiliary equipment: to install the formwork in the vertical plane, support brackets (one- or two-level) are used, and the panels are pulled together with special locks (both for horizontal and vertical assembly). In the upper part of the formwork system, platforms are attached to the boards for the convenience and safety of personnel.
Versatility
Metal formwork can be used for the construction of architectural objects of any complexity, including multi-storey buildings. At the same time, the same sets of formwork equipment can be used to fill various surfaces (for example, both walls and columns).
Economic benefit
Metal formwork is more expensive than wood, but unlike it, it can be used many times (dozens of times before repair and hundreds of times throughout its entire service life), which significantly reduces the unit cost construction works... Hundreds of objects can be erected using the same formwork kits. Moreover, today it is not at all necessary to buy construction formwork. Many companies specializing in the production of formwork systems offer their customers services such as formwork rental and leasing (finance lease). That is, even with a one-time construction, you can profitably use metal formwork.
Convenience of work and quality of poured surfaces
Thanks to the well thought-out design, the shuttering panels are easily, quickly and accurately assembled into a single system. In this case, the concrete surfaces are of high quality - they are even, flat and smooth.
High strength characteristics
The metal formwork has high strength and rigidity, perfectly withstands the pressure of building mixtures. The load-bearing capacity of steel formwork is significantly higher than that of a similar wooden form, therefore, such a structure allows much larger volumes of concrete to be poured. Aluminum formwork in terms of rigidity and strength is slightly inferior to steel, but has less specific gravity, which facilitates its transportation and installation work.
Maintainability
The main elements of the removable formwork are laminated sheet plywood and metal carcass... The weaker link is the plywood sheet. Usually, construction plywood can withstand several tens of casting cycles, after which it is simply replaced with a new one. Small local defects on the surface of the plywood sheet can be repaired directly at the construction site (defect cutting, filling, cleaning and painting).
The metal frame is also subject to repair. Minor damage can be repaired directly on site. If the frame is severely deformed, its individual elements are out of order, or the welds have burst, the formwork can be repaired in a workshop or a small machine shop.
Metal formwork is a set of panels with fasteners. It is designed for construction operations where liquid mortars are used. Most popular in monolithic construction. Formwork is used for pouring liquid concrete in the manufacture of piles, foundations, walls, floors. Inside, the structure is reinforced with reinforcement. The concrete hardens, the formwork is removed and transferred to the next site.
Varieties of metal formwork
Among the huge variety of metal structures most widespread received two types of formwork: steel and aluminum. Each of them is appreciated by builders in its own way. Aluminum formwork has significant advantages - due to its low weight, no special lifting mechanisms are required during its installation. Lightweight, reliable shields can be assembled, disassembled, moved by one person.
Aluminum is not subject to corrosion, therefore the metal formwork panels are durable and can be rearranged several times on the construction site. The main advantage of steel formwork is the accuracy of the profile geometry and a high degree of rigidity. Due to this, the steel shields at the joints with a maximum tightness fit one to one. Deformations, dents, the slightest gaps are excluded. The result is perfectly flat wall planes.
Formwork panels made of steel are able to hold a much higher load than aluminum ones. Thanks to this, walls of any thickness can be poured into it without observing the stops for concrete setting. When erecting thin walls, aluminum formwork is poured in several layers with technological breaks. At a wall height of 3 m, the deformation of the steel shield is allowed no more than 1 mm. The steel profile is much stiffer than aluminum, which makes it easier to assemble and disassemble the kit.
The advantages of metal formwork:
- High strength;
- Improved functionality;
- Long period of operation;
- A large number of technological revolutions;
- Good maintainability.
Installation of metal formwork
Installation of the structure is carried out using several types of fasteners. These are internal and external corners, hinges, rolling ties, scaffolds, struts. Steel elements are interconnected by two types of fastening. These include the leveling ledge and the universal wedge lock.
These are simple and, most importantly, reliable connectors. To assemble the formwork with a universal wedge lock, you only need a hammer. With this connection, the shields are held together, the desired angle is set, the metal formwork is built up with additional beams.
The leveling crossbar is a tool with many functions: extension along the length, setting indirect catch, assembly of boards with an offset. Repeated assembly and disassembly does not wear out the formwork and does not lead to its deformation at the joints.
How to order?
Our company sells both new and used metal formwork in perfect condition. It is offered to rent a formwork for any period. The enterprise is certified in international quality systems, there are certificates. Experienced designers, at the request of the customer, will develop models of metal formwork according to individual samples.
The presence of our own production and the departmental vehicle fleet for delivering products to construction sites allows keeping the price of metal formwork lower than that of competitors.
The content of the articleRemovable formwork is most often rented. After all, it can be cleaned and returned back by paying relatively small (especially in comparison with the full cost of a one-time option) money for daily use of the structure. Therefore, the removable option, despite its initially high price, will cost you less than any other design.
Varieties of removable formwork
The classification of removable formwork can be built according to the following criteria:
- The type of structural material used to build the building envelope.
- The method of using the form (removable for walls, foundations, and so on);
- Formwork design features.
Advantages and disadvantages of formwork material
By the first sign (structural material), structures are divided into:
Therefore, if you are interested in renting formwork, pay attention to plastic forms or metal shields. Wooden structures are not worth renting.
Scope of formwork
According to the second criterion (scope), structures are divided into:
- Foundations are forms used to fill strip or slab bases.
- Wall structures are forms used for the construction of load-bearing or conventional walls, as well as for the construction of interior partitions.
- Forms for pouring slabs - formwork for pouring basement, interfloor or attic dividing structures.
The most complex system is used to form the structure of the grillage or interfloor overlap... In this case, a thin slab is poured, the plane of which should be perfectly flat, both from below and from above.
Moreover, the floor slab is mounted on supports and this entire system can be poured in one pass into the overall structure. That is, the slab formwork can consist of a horizontal component (under the slab) and a vertical part (under the supports).
Therefore, for the floors, it is worth renting a professional formwork option - a constructor made of polymer shields, from which you can build a form of any configuration.
Metal formworks are rejected due to their significant weight, and wooden ones due to insufficient strength of the boards.
Formwork construction types
According to the third criterion (type of construction), formworks are divided into:
It is best to use as a large-scale form wooden structureconsisting of large-sized sheets of plywood or oriented strand board, reinforced with a wooden beam.
For a small-panel structure, it is best to take a professional polymer formwork with its complex fastening system, which allows the panels to be positioned in any way.
It is best to use a metal formwork for a movable structure, formed in the form of a finished block or a volumetric element. This element has high rigidity due to the natural strength of the metal.
How to make a detachable structure with your own hands
Let's clarify right away: you can make only metal or wooden formwork with your own hands.
Plastic enclosing structures are manufactured in factories using presses that push through a heated sheet of structural polymer.
Wooden formwork
The basis of timber formwork is a shield, which can be made from a finished plywood sheet or oriented strand board.
Moreover, the plywood must be laminated, and the board must be moisture resistant. After all, the absorption of moisture from concrete will slow down, or even disrupt the process of formation of a cement stone.
For the same reason, it is worth refraining from the typical practice of using a thin board (shalevka) as a shield, which does not have sufficient hydrophobicity.
A shield of the desired shape is cut out of the sheet material. The outer side of the shield is reinforced with a 5x5 centimeters bar, which is stuffed or fixed on self-tapping screws from the outside. Moreover, a lattice with cells of 25x25 centimeters is formed from the bar.
The number and shape of the boards is determined based on their area of \u200b\u200bthe edges of the poured architectural element.
Fixation of individual elements (shields) in general design carried out with the help of latches attached to the outer timber of the sheathing of a separate shield. And as a load-bearing frame, piece slopes, stops and cross beams are used.
Metal formwork
The basis of the metal formwork is sheet metal, which is attached to the frame from shaped pipes or corners. Moreover, the minimum thickness of sheet metal is 1-1.5 mm, and minimum section shaped pipe 2x2 centimeters.
Fastening of the sheet to the pipe is carried out for spot welding or self-tapping screws for metal. During the assembly process, a crate is formed with cells from 20x20 to 40x40 centimeters (depending on the thickness of the sheet metal).
The assembly of the block is carried out using spot welding (a standard arc will melt a thin pipe). Moreover, the internal space of the block is determined by the desired shape of the segment of the architectural element.
