Encyclopedia of fire safety

Do-it-yourself installation of concrete columns. How to make formwork and the correct form: column pouring technology. Making concrete columns with your own hands. Work on pouring concrete columns How to make concrete columns with your own hands

Concrete load-bearing structures are used in construction to provide buildings with vertical stiffness. They transfer the entire load of the building to the ground and are very important element during construction.

There are several types of such structures. Each type has a certain load capacity, flexibility coefficient, advantages and disadvantages. Typically, columns are used in the construction of multi-storey buildings, strengthening balconies and terraces. Designs can be made in an original way and give the building a richer, more interesting appearance. Also, concrete columns can be round, square or rectangular.

Varieties of concrete structures

There are monolithic and prefabricated concrete columns. Prefabricated structures attract with their cost and speed of assembly, this is due to the fact that the blocks are manufactured in factories, delivered to the construction site and only then assembled. are poured right at the construction site, which means that you have to spend a lot of time waiting for the mixture to dry. Also for monolithic structures needs to be prepared in advance quality frame and formwork.

Advantages of concrete columns

Concrete columns are highly durable. Such structures are durable, fire resistant and perfectly cope with atmospheric influences. Due to the prevalence of materials, the price for them is quite low.

Disadvantages of concrete columns

In spite of a large number of advantages, it also has disadvantages.
If the calculations of the expected load were made with errors, then cracks in the structure and even its destruction are possible in the future.

Selecting the type of concrete column

When choosing a type concrete columns several important factors. These factors include:

  • climate type;
  • soil features at the construction site;
  • the expected level of load on the structure;
  • number of storeys and size of the building.

To select a design, it is recommended to contact several specialists for advice. It is better to calculate a concrete column together with professionals in construction companies, because, by making calculations on your own, you can allow serious mistakes. If you are unable to seek help from construction company, the calculations can be made online. Remember that this is a very important and responsible stage of construction. The strength and reliability of iron depends on the correct choice and calculations. concrete structure and the building as a whole.

When calculating a concrete column, it is necessary to take into account:

  • Column type.
  • Quantity and
  • Estimated load (it is worth noting that this indicator also takes into account the weight of the column itself).
  • Quality and class of concrete.
  • Column size.

Concrete column design and pouring process

To assemble precast concrete structures, you will need equipment and labor, it will not take much time, so we will not consider such a process.

It is much more difficult to pour monolithic concrete columns. Installation must be carried out at the construction site.

After choosing a monolithic type of construction and calculating the required amount of material, it is necessary to start preparing the process of pouring the columns. It is necessary to choose a metal for fittings that has strength and weldability. It must also have good adhesion to concrete.

Before proceeding with the assembly of the formwork, you need to clear the area around. It is desirable to make the formwork in the form of a cylinder, the diameter of which coincides with the diameter of the future column. Around the cylinder is covered with earth, and a concrete mixture is poured inside it. The frame of the column should be mounted from a strong, thick one should be as long as possible and fastened with wire to the rods protruding from a pre-prepared foundation. When the frame is fully assembled, the reinforcement should be wrapped with a sheet of galvanized steel. Galvanized steel must be fixed as best as possible, as at the time of pouring, a large load is expected on them. After preparing the structure, you can start pouring concrete mix, the choice of which must also be taken with full responsibility. Filling should be done in equal layers. The solution must be periodically compacted so that air bubbles do not appear in the structure. If necessary, the formwork and the reinforcement frame should be corrected.

After pouring the concrete structure, it is necessary to dismantle the formwork. Dismantling should begin only after the concrete mixture has completely solidified, when the structure has fully acquired the necessary characteristics. Dismantling is not an easy process, so it is advisable to entrust this to specialists who know in what sequence the formwork structure should be dismantled. It is important during the dismantling process not to damage the column and keep it intact, therefore, before starting, you need to make sure that the concrete is strong.

Features of the installation of reinforced concrete structures

The installation of columns is a very time-consuming process and it is quite difficult to cope with it on your own, so we recommend that you seek help from specialist builders.

If desired, this design can be replaced with a small wall made of bricks. You can make such a wall yourself, and it will cost less. Its disadvantage is that it will not withstand too much load.

Also don't forget about supporting structures in the center of the building, as they are a very important structural element. The installation of such supports practically does not differ from the installation of supports located along the edges of the structure. The only difference is that the reinforcement must be used with a metal section.

Replacement of concrete columns

Depending on the purpose of using the columns, they can be replaced with the following materials:

  • square steel pipes(can be used in the construction of a one-story or two-story house, at the corners of the building).
  • Brick columns (it is undesirable to use if a large load is planned, since the material is less durable and may not withstand the weight of the structure).
  • Wooden structures that can be made of timber or logs (it is possible to use in structures similar to a veranda, gazebo).

For almost all of these structures, as well as for mounting concrete slabs, it is necessary to use and attract several specialists.

It is worth noting once again that the process of pouring columns with a concrete mixture is very time-consuming, which means that it is difficult to do it yourself. It requires great responsibility, skills and abilities to work with these materials. In the process of concreting, it is necessary to follow many rules that were listed above.

Column formwork is designed to form a square or rectangular area, which will allow you to properly mount the column. Exist different types formwork, which are intended for certain types construction works. In this article, we will consider the features and parameters of mounting formwork for columns with detailed step-by-step instructions.

Types of columns

The main purpose of creating formwork is to form a certain shape for columns of the desired height and parameters. There are two types of work, the first of which involves the installation of universal columns, and the second is the formation of formwork for columns with a fixed section. When carrying out installation, you need to remember the features of installing additional shields.

Previously, columns were used as decorative element buildings. However, in modern world this type of product is intended as supporting elements for different types of buildings. There are several types of columns that differ in geometric shape:

  • round or cylindrical;
  • square;
  • multifaceted;
  • rectangular.

It should be noted that the universal formwork of columns is carried out for different types of columns and provides for the installation of standard shields with special holes for the kingpin, the pitch for which is 5 cm. For a fixed installation scheme, it is necessary to fasten the column using four corner elements and some formwork locks.

Formwork purpose and product requirements

The formwork of walls and columns is carried out for pouring concrete base under the supporting elements. This is necessary so that the mixture does not spread and, after hardening, has a square or other shape. Without carrying out this stage of work, it is almost impossible to carry out the installation of the column. Experts identify some requirements for formwork:

  • compliance with the dimensions of the structure;
  • stability and strength of the installed product;
  • the formation of a form through which the solution will not flow;
  • smooth inner side;
  • dismantling is not difficult.

Formwork for columns: disposable, reusable, non-removable

The most simple and convenient option work is the construction of a one-time formwork. This design is made up of cardboard, which is wound in a spiral. The formwork product has water repellency that do not allow the solution to soak into the structure of the cardboard. Thicker-walled PVC film can be placed inside the cardboard column formwork.

The approximate diameter of such formwork can be from 20 to 115 cm, and maximum length products can be 12 meters. Depending on the parameters of the column, the height of the formwork may vary, as well as the thickness of the walls. For example, in the lower part of the structure, the wall thickness may be greater, which is determined by the maximum load. concrete mortar. The technology of work is not complicated, with large volumes of installation, you can use lifting mechanisms. Only two people may be required to carry out the installation.

Another option for column formwork is the construction of a reusable structure. As a rule, the formwork can be used several times for the installation of several columns. The following features of the work are distinguished:

  • the need to build formwork at the construction site;
  • pouring concrete mortar into the structure;
  • keeping for several days until the concrete dries completely;
  • removal of the formwork structure and its installation in another place.

When performing such work, you must remember to follow the rules for installing the column. When choosing a reusable formwork for columns and ceilings, it is necessary to calculate the height of the product, which should not be higher than the indicated forms. When choosing this form of formwork, the filling will no longer be monolithic. Therefore, you should carefully read the requirements and characteristics of the implementation of this type of formwork in compliance with the height of the column.

Reusable formwork is more expensive than disposable formwork, which is determined by the following parameters:

  • Necessary costs for storage of the structure.
  • Formwork transportation for the installation of other types of columns and maintenance.
  • Additional expenses for the use of lifting equipment services.

There are different types of reusable formwork:

  • shield structure;
  • beam-transom;
  • steel formwork;
  • plastic construction;

Formwork using shields is intended for columns square shape. Shields made of metal must be fastened together using different fixation items. It is important to place laminated plywood in the middle of the boards. Next, a concrete solution is poured after hardening, which the formwork can be removed and moved to another work site.

A similar type of work has a beam-and-beam formwork of columns, for which you need to use the following products:

  • shields;
  • crossbars made of steel;
  • beams.

This type of construction will allow you to form a reliable formwork different heights. As a rule, such a scheme is used to build round walls, columns, bridges, as well as to form large vertical surfaces. Formwork execution technology resembles an assembly scheme children's constructor, and all parts are fixed with struts.

Steel column formwork is designed for square and round products. Main characteristic design lies in the fact that after its use it is necessary to clean and lubricate the sections. This type of formwork is heavy, as well as panel formwork, so it is necessary to use the services of lifting machines to move it.

A more affordable and lighter option is plastic formwork for columns. The main disadvantage of the product is the unreliability of the design, and for the implementation of work it will be necessary to seek the help of specialists. It is advised to work with this type of formwork carefully and with special tools so as not to damage the walls. All elements plastic construction connected to each other using different parts.

There is another type of formwork that is non-removable. The use of this type of construction is rare, however, such a construction scheme is quite popular among builders. All blocks and blanks for formwork assembly are made on special machines. Thus, products with thin walls are created, which are quite strong and reliable.

Formwork elements are made from high-strength concrete. The technology for preparing the solution involves the use of cement, sand and water. A feature of the preparation of concrete is the compaction of pores using rolled products. Thus, all liquid is displaced from the solution, which increases the properties of frost resistance and strength of concrete. Formwork products made in this way have increased resistance to temperature and humidity changes.

Installation of column formwork: features of installation and dismantling

Before considering the installation technology for a particular type of formwork, it is necessary to study standard specifications performance of work. Before installing the formwork on the concrete surface, it is necessary to mark the parameters of the column. As a rule, the column should be installed around a pre-prepared reinforcement frame. All work must be carried out using project documentation. Formwork panels must be assembled in l-shaped, which are fixed with nuts and a kingpin or through a corner, then it is determined by the type of column. The second and other tiers of the structure assembly must be assembled using a mobile tower or scaffolding.

If the height of the formwork of round columns is higher than 4.2, then it is important to mount a special crossbar on the column, which will level the structure. The installed column must be checked for a vertical position, which is carried out using braces or tolpers. The brace consists of the lower and upper areas of the product, as well as a special connector. The latter must be mounted on a concrete surface, then the upper part is attached to highest point fixing the column, and the bottom to the bottom. Using special tools and nuts, the column should be leveled and fixed in a vertical position.

The feature of dismantling the formwork can be done when the concrete is completely dry. First of all, it is necessary to remove the formwork braces, after which the locks are dismantled from the upper part and the shields are removed.

It's important to know! If the height of the mounted column is more than three meters, then the concrete solution must be supplied through a special window. In the next tier, one of the shields must be removed, which forms a window required sizes. Further, the shield is installed in its original place, after which the concrete solution enters through the upper part of the column formwork.

Do-it-yourself step-by-step instructions for installing panel formwork for columns

The installation process must begin with the layout of the workspace. It is important that it coincides with the parameters of the previously erected frame and reinforcement:

2. After that, the formwork is assembled from the panels on one side, and it is important to fix all the details of the structure using locks.

4. Having determined the thickness of the pouring of the concrete wall, it is necessary to install the next formwork wall using the same technology.

5. It is important to mount the running console at the top of the formwork.

6. After leveling all the walls of the structure, you can proceed to further work on installing the column and pouring the base.

It's important to know! To properly install the panels on one side, it is necessary to use crossbars that will allow you to level the formwork.

The dismantling method consists in carrying out the work in the reverse order: first, the running consoles and tolper braces are removed. After that, the locks are dismantled from the upper area of ​​\u200b\u200bthe structure, and the formwork panels are removed.

Instructions for installation of beam-transom formwork

Beam-transom formwork is a structure that consists of beams and crossbars. All parts are fastened with clamps. The main material used in the work is wood, so all work is not laborious. This material has a low thermal conductivity, in contrast to the aluminum formwork of the columns.

Such a formwork assembly scheme has many advantages, which is indicated by the reliability, strength and simplicity of the structure used. The work does not require significant costs, while the formwork is considered universal. Using this type of construction construction, it is possible to concrete columns different sizes. Also, using the beam-and-beam formwork scheme, it is possible to erect concrete walls different settings. To strengthen and form the formwork, it is recommended to use only a screwdriver and a hammer.

Formwork advantages:

  • it is used to install columns and walls of different heights and sizes;
  • intended for building formwork different forms, for example, radius, round and inclined without unnecessary waste;
  • allows you to get good quality concrete on the surface of the formwork;
  • using this type of assembly of the structure, it will be possible to reduce the number of gaps and ties;
  • the formwork is able to withstand a large concrete load, up to about 10 t/sq. m.

Detailed instructions for assembling the beam-transom formwork have the following sequence:

1. We prepare the work site for the installation of formwork.

3. Beams for formwork of the required length are laid perpendicularly on the crossbars.

4. These beams must be attached to the ledger using special clamps.

5. The approximate distance between the beams should be from 20 to 40 cm, which is determined by the project documentation.

It's important to know! When laying the beams, make sure that they do not coincide with the fixing points for the tie screws. Laminated plywood sheets should be placed on the installed beams, while the joints should be in the middle of the beam. Plywood is fixed to the beams using self-tapping screws, which are screwed in every 35-40 cm. The length of the fastener should be 50 or 60 mm. The area for the installation of self-tapping screws can be puttied, which will extend the shelf life of plywood for further use.

Exist different variants formwork installation, however, not all work can be done by hand. The installation technology for each type of structure is determined by the height and section of the columns. To better understand the formwork scheme, we recommend watching the video presented at the end of the article.

The composition of the process, preparation for concreting

When concreting, the mixture fills all the gaps between the reinforcement bars, forms protective layer of the required thickness and is subjected to compaction of the appropriate given density and grade of concrete.

Concreting consists of preparatory and verification operations, the laying process, which includes operations for receiving, distributing and compacting the concrete mix, as well as auxiliary operations carried out during concreting.

Immediately before concreting, the formwork is cleaned with a jet of water or compressed air from debris and dirt. The surfaces of wooden formwork are moistened. Slots in wooden formwork with a width of more than 3 mm are sealed to prevent leakage of cement laitance. The surfaces of steel and plastic formwork are coated with a lubricant, such as used oil, and the reinforced concrete reinforced cement or asbestos-cement formwork-cladding is washed with a stream of water. The fittings are cleaned of dirt and rust. At the same time, they perform work on setting up mechanisms, machines and devices used in all interrelated concreting operations. The necessary equipment is installed at the workplace, fencing, safety and protective devices provided by the safety regulations. If necessary, equip telephone, light or sound signal communication between the workplaces for supplying, receiving and laying the concrete mix.

Concrete compaction

The task of the concrete mixture compaction process is to limit the packing of particles of various shapes and sizes that make up a multicomponent conglomerate - a concrete mixture. The density of concrete in comparison with the concrete mixture with its good compaction increases from 2.2 to 2.4...2.5 t/m 3 .

The concrete mixture is compacted by tamping, bayoneting and vibrating.

Rammers- manual or pneumatic - used when laying rigid mixtures in concrete and low-reinforced structures, when vibrators cannot be used (for example, for fear of vibration exposure to operating equipment).

For bayonet(pushing pieces of crushed stone hanging between the reinforcement bars) when laying and vibrating mixtures with a cone draft of 4 ...

Vibration- the main method of compacting concrete mixtures with a cone draft from 0 to 9 cm. The essence of the process is that with the help of vibrators installed on the surface or lowered into the laid layer of concrete mixture to a certain depth, nearby components of the mixture are involved in oscillatory horizontal and vertical movements developed by the vibrator with a certain frequency and amplitude inherent in it

Vibration is a short process. After 30 ... 100 s (depending on vibration conditions), the concrete mixture stops settling and cement laitance and air bubbles appear on the surface of the compacted concrete, which indicates the end of vibration exposure. Further vibrating can lead to separation of the mixture due to the sinking of large particles.

The device of working seams

Structures are usually concreted with breaks caused by shift work, technological and organizational reasons. The place where, after a break, a fresh concrete mixture is laid close to the previously laid and already hardening concrete is called working seam.

In bendable structures, working seams are located in places with the lowest shear force. In columns, seams are arranged at the level of the top of the foundation, at the bottom of girders, beams or crane consoles; in columns of beamless ceilings - at the bottom or top of the haunch, in the frames between the post and the crossbar. In high beams, monolithically connected with the slabs, the seam is arranged, not reaching 20 ... 30 mm to the level of the lower surface of the slab.

It is possible to resume concreting after the concrete at the working joint reaches a strength of at least 1.5 MPa. This determines the duration of the breaks (18...24 hours at a temperature of +15 °C), as well as the location of the joints in accordance with the accepted laying pace. The surface of the working joint must be perpendicular to the axis of the element, and in walls and slabs - to their surface. To do this, it is necessary to install shields-limiters with slots for reinforcing bars. , well attaching them to the formwork panels.

Rice. VII .24 . The device of working seams:a B C -location of working joints when concreting columns,d, d- the same, ribbed ceilings;e- details of the device of the working seam; //-/, // - //,III -1 II - places for working seams

Features of concreting structures

columns without cross clamps they are concreted in sections with a height of 5 m. The concrete mixture is fed from above from the bucket through a funnel and compacted with deep vibrators. When concreting columns of great height, a breakdown is made into tiers of concreting. The last tier in height is concreted after the concrete of the previous tier has reached a strength of 1.5 MPa and the construction of the working seam (Fig. VII.24, a, b, in).

Columns with dense reinforcement and crossed collars , and also with cross-sectional sides of less than 0.4 m, they are concreted without interruptions to a height of not more than 2 m. in), arranged in the side walls of the formwork. It is recommended to lay a layer of plastic in the lower part of the column. cement mortar 10 ... 20 cm thick with a 1: 2 (1: 3) composition to ensure better adhesion to the previously laid concrete.

Walls, partitions and stiffening diaphragms more than 15 cm thick is concreted, supplying the concrete mixture from above through funnels and trunks continuously to a height of 3 m. The laying is carried out in layers with a thickness equal to 0.5-0.8 of the length of the working part of the vibrator tip. Walls with a thickness of less than 15 cm are concreted to a height of up to 1.5 m. With a higher wall height, for the convenience of reinforcing and laying the concrete mixture, the formwork is installed on one side to the height of the tier, then the reinforcement is mounted and the second side of the formwork is installed. The concrete mixture is fed from above or through pockets (Fig. VII. 25, e) and evenly distribute it (Fig. VI 1.25, e). The walls of the tanks are recommended to be concreted along the height and perimeter without interruptions. The concrete of the walls and the bottom are joined in the places provided for by the project. Retaining walls can sometimes be concreted by feeding the mixture directly from a concrete truck (Fig. VII.25, a).

To concreting beams and floor slabs , monolithically connected with columns and walls, start 2 hours after concreting vertical structures, so that the concrete laid in them has time to give the initial draft. Beams and girders with a height of less than 800 mm are concreted in layers of 35 ... ... 40 cm simultaneously with the slabs. With a greater height of the beams, they are concreted separately, arranging a working seam along the height.

The concrete mix in the beams is compacted with deep vibrators with a flexible shaft, and in the slabs - with vibrating beams and surface vibrators. The worker sets the surface vibrator to its original position, turns on the engine and moves the vibrator with a hook to the end of the grip, then moves it perpendicular to the track at a distance of 30..40 cm and moves it parallel to the passed strip in the opposite direction, overlapping the previous strip by 3...5 cm The thickness of the layers of the concrete mixture when laying it in slabs with double reinforcement should not exceed 120 mm, and in slabs with single reinforcement or concrete - 250 mm. Floor slabs are concreted in the direction of the secondary or main beams, feeding the mixture in the direction of the previously laid concrete.

In modern monolithic construction, columns are used quite often. In many projects of multi-storey buildings, they are not only decorative architectural elements, but also the main load-bearing structures the entire building. This allows you to build rooms on the next floor without repeating the plan of the previous one. To ensure the strength and durability of such monolithic structures, the formwork of the columns must be made reliably and efficiently.

Varieties of columns and formwork for their arrangement

According to the geometric shape of the section, all columns are divided into:

  • round (cylindrical);
  • square or rectangular;
  • multifaceted;
  • curly.

The columns of the first two types found the greatest distribution. The last two categories are used mainly for the restoration of buildings or decorative purposes.

By the number of cycles of use, formwork for arranging columns is divided into:

  • disposable;
  • reusable.

Depending on the material of manufacture, the formwork can be:

  • wooden;
  • plastic;
  • metal;
  • cardboard;
  • combined.

Formwork for cylindrical columns

Formwork of round columns can be both disposable and reusable.

As a disposable formwork for round columns, cardboard tubes are now quite often used. In their manufacture, paper tape is used, a special adhesive composition and polymer material(to ensure water resistance). Such column formwork is produced with an inner diameter of 150 to 1200 mm. Its installation is quite simple: the pipe is simply put on the reinforcing cage, then the support rings are installed, to which the spacer struts are attached (to give stability and vertical alignment). For quick dismantling of such products during their manufacture, a special metal wire is pressed along the entire length of the pipe, by pulling which the cardboard is cut along its entire length, and then it is easily separated from the hardened concrete.

On a note! It is advisable to dismantle the cardboard pipe just before the end of construction. This will protect the support from technological damage.

Disposable formwork for columns made of cardboard has a number of undoubted advantages:

  • low cost;
  • ease of installation and dismantling;
  • when using it, the surface of the concrete support is of high quality;
  • light weight;
  • high strength.

As non-removable elements round section use pipes (metal, asbestos-cement or plastic). This, after the concrete mortar has hardened, remains an integral part of the column design.

Attention! Using metal pipes their surface must be treated with an anti-corrosion compound.

Reusable round formwork consists of metal or plastic half-pipes, which are mounted around the reinforcement cage of the column using special quick-clamping locks. Plastic formwork of columns has less adhesion to concrete compared to metal formwork (this ensures ease of dismantling), but less strength.

Formwork for square and rectangular columns

This kind of columns is most widely used both in industrial and in individual construction.

The most common type of removable formwork for arranging such columns is a large-panel formwork system. Universal panels (their dimensions: width - 0.4÷1.2 m, height - 1.0÷3.3 m) allow you to quickly mount the formwork for square columns (the cross section of which is from 0.2⨯0.2 m to 1, 0⨯1.0 m).

Longitudinal technological holes for fasteners (pins) allow you to create formwork rectangular section. For one column, you need: shields (4 pieces assembled into a “mill”), kingpins with special tight nuts (for a column about 3 meters high, as a rule, 16 sets are enough) and slopes (at least 2 two-level supporting ones).

The popularity of such a system is due to:

  • simplicity and high speed of installation and dismantling;
  • the possibility of forming a section of the column in accordance with the requirements of the project;
  • durability (from 80 to 200 concreting cycles, depending on the manufacturer and the material of the panels).

Another common in modern construction type of formwork system in the construction of columns - beam-transom. The main elements of this design are formwork plates, steel crossbars, beams different size and fasteners. This type of formwork system can be easily adapted to create square, rectangular and even octagonal columns. Such steel formwork of columns has the greatest strength and durability compared to other materials ( laminated chipboard, plastic or shields made of boards and plywood).

Independent production of formwork during the construction of columns

When making formwork for monolithic columns with your own hands, you can use several methods.

The easiest way (however, quite laborious) for the manufacture of a formwork frame for square or rectangular columns:

  • From boards (25 mm thick and a length equal to the height of the column), using nails and self-tapping screws, we make a U-shaped structure with internal dimensions corresponding to the section of the future column.
  • We make a shield from the same boards, which will later be the fourth side of the formwork frame.
  • We install the U-shaped structure to reinforcing cage and attach a shield of boards to it.
  • We align the formwork vertically using a level, and fix it with stops made of boards or bars.
  • To give the structure additional strength, we tighten it with additional bars and studs with nuts.
  • Now you can start pouring the concrete mixture.

The video will help you understand the above described square column formwork technology:

Another way for self-manufacturing largely similar to the previous one. Instead of boards for the manufacture of formwork (preferably moisture resistant, 12 mm thick) and wooden bars. We use reinforcing bars and quick-release spring locks (clips) as tightening elements. For vertical alignment, you can use the telescopic racks, rented.

On a note! It is advisable to use the above methods if it is necessary to produce a small number of columns (3÷4 pieces). Otherwise, the cost of materials and hardware for the manufacture of formwork will be quite high. If you need to build 10÷12 columns (for example, for a large glazed terrace or veranda), then the column formwork on universal boards, rented (the cost of renting one set, which includes: 4 boards, 2 two-level telescopic slopes, a set of necessary fasteners, will be about 7500 rubles per month). And since the formwork of the column can be done within 48 hours after pouring the concrete solution, you can easily produce the required number of columns for the paid month.

In custody

The final choice of this or that type of formwork for the manufacture of columns depends on their number, section size and height. Of course, for the construction of bridge supports or flyovers, only high-tech professional formwork systems are used. And for the construction of several not very high columns during individual construction, you can completely get by with a form made from improvised materials. The main thing is that it strictly corresponds to the geometry of the future column and can withstand the pressure of the concrete solution without deformation.

Columns with cross-sectional sides from 0.4 to 0.8 m in the absence of intersecting clamps are concreted without interruption in sections with a height of not more than 5 m, freely dropping the concrete mixture into the formwork directly from the shipping container. When lowering the concrete mixture from a greater height, link trunks are used.

Columns with cross-sectional sides less than 0.4 m and columns of any section having intersecting clamps that cause the concrete mixture to separate when it falls, are concreted without interruption in sections not more than 2 m high. In this case, the concrete mixture is fed through windows arranged in the side walls formwork. The concrete mixture is compacted with deep or external vibrators. The sections following in height are concreted only after the construction of the working seam.

When concreting columns, the lower part of the formwork is filled to a height of 10-20 cm with a cement mortar of composition 1: 2-1: 3 in order to avoid the formation of defective concrete with accumulations of coarse aggregate without mortar. When dropping the concrete mixture, the largest crushed stone wedges into this solution and as a result a mixture of normal composition is formed.

For strict observance of the thickness of the protective layer in the columns, special gaskets are used, made of cement mortar and attached to the reinforcement bars before concreting with a knitting wire embedded in the gaskets during their manufacture.

The formwork of high columns is mounted only on three sides, and on the fourth it is built up during the concreting process. If beams and girders with dense reinforcement are located above the columns, which does not allow the columns to be concreted from above, then it is allowed to concrete them before installing the reinforcement of the beams adjacent to them.

Columns, as a rule, are concreted to the full height of the floor without working joints. Working seams can only be arranged at the level of the top of the foundation A - A or at the bottom of the runs and beams B - B. In columns industrial shops working seams can be arranged at the level of the top of the foundation A - A, at the level of the top of the crane beams B - B or at the level of the bottom of the consoles (ledges) B - B supporting the crane beams. In columns of beamless floors, it is allowed to arrange seams at the level of the top of the foundation A - A and at the bottom of the capitals B - B. The capital should be concreted simultaneously with the floor slab.

At high altitude sections of the column concreted without working joints, it is necessary to arrange breaks in concreting for the concrete mixture to settle. The duration of the break should be at least 40 minutes and not more than 2 hours.

Frames should be concreted without interruption. If it is necessary to arrange a break between the concreting of columns (pillars) and crossbars of frames, it is allowed to arrange working seams at the bottom or top of the bevel G - G.

When concreting paired columns in places where the expansion joints of the structure are installed, it is necessary to ensure that the partitions inserted into the formwork box are not knocked down and that the identical dimensions of the paired elements are ensured.

  1. Manufacturing technology of prefabricated reinforced concrete structures and parts
    • General issues of precast concrete production
    • Preparation of concrete mixtures
    • Mortar production
    • Transportation of concrete mix
    • Rebar stock
    • formwork
    • Preparation of molds, concrete molding and hardening of products
    • Reinforcement and forming of prestressed products
    • Features of the production of various types of concrete and reinforced concrete products
    • Concreting of various structures

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