Monolith 5m wide between floor slabs. Monolithic section between floor slabs

Monolithic plot diagram.

Surface preparation

Structural calculations

Sometimes it is necessary to make wide monolithic sections between the floor slabs. They must be calculated according to the current loads. In the drawing, a monolithic section with a width of 980 mm is developed, supported by two hollow core slabs... The conditions for such a monolithic section (loads, principles of reinforcement, etc.) are detailed in the article.

Monolithic section between two prefabricated slabs

welding of meshes and frames

- Installation of supports and formwork
- Concrete mix and its pouring
- Final recommendations

to form reinforcing mesh
prepare concrete mix
pour concrete correctly.

Required materials and tools

concrete mixer

Stages of work on the formation of a monolithic section between floor slabs

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Installation of supports and formwork

First, we form a formwork for a monolithic section, which must have such mechanical and strength characteristics as to hold a large mass for a long period concrete mortar that will dry long enough.

Sources:

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Monolithic sections between floor slabs

Before you decide to make monolithic sections between floor slabs on your own, soberly assess your capabilities, because this is a serious painstaking work... But if you nevertheless decide to make a monolith between the slabs on your own, then you have to go through the following installation steps.

Monolithic plot diagram.

Surface preparation

At this stage, you have to make sure that in the right moment you had at hand necessary materials and tools. Therefore, oh, availability must be taken care of in advance.

So, to make a monolithic overlap section, you will need the following tools: a hammer drill, self-tapping screws for wood 90 mm long, standard threaded rods 2 m each, nuts, washers, open-end and cap keys, concrete drills, wood drills 90 cm long, screwdriver, cross-shaped bits for a screwdriver of very good quality ( good quality required because the edges of a low-quality cue ball are erased very quickly), a hook, a grinder with discs for metal, a circular saw with diamond dust (for cutting boards along and across the fiber), an 800-gram hammer, a sledgehammer up to 3 kg, steel nails 120 mm in size , tape measure - 2-3 pieces (tape measures are necessary for making accurate measurements, there should be a sufficient number of them, since they often break and get lost), carpenter's pencil, carpenter's corner 50 cm long, joiner's stapler with staples, level.

You will also need building materials: knitting wire with a diameter of 0.3 mm for binding frames, reinforcement with a diameter of 12 mm, wire with a diameter of at least 6 mm, cement, gravel, sand, film 100-120 microns thick, boards 50x150 mm, boards 5x50 mm.

It is also necessary to take care of protective equipment in advance, because you and your assistants will have to work at a high altitude among the nails, fittings and boards sticking out in all directions. For protection, you will need: gloves, closed shoes (construction boots or shoes made of dense fabric such as army ankle boots of the old model), goggles, a cap or helmet.

Structural calculations

Calculation of the prefabricated floor slab.

At this stage, you will need to make accurate measurements and calculations in order to know what and how much you need. First of all, we find out what the floor slabs will be. To do this, we find out the width of the building and divide it in half, into two equal parts. We immediately determine where the stairs to the second floor will be, which side will be the rise flight of stairs, and only after that we calculate the size and number of floor slabs.

Floor slab length is the width of the house divided by 2.

The width of the floor slab is three standard sizes: 80 cm, 1 m 20 cm, 1 m 50 cm.

We calculate the required size and number of floor slabs, taking into account that there should be a gap of 7 cm between the slabs. After everything has been calculated and found out exactly required size and the number of floor slabs, we order them from the manufacturer or from suppliers of building materials.

Attention!

Do not forget to take into account the 7 cm gap between the floor slabs! The absence of a gap between the plates will complicate their installation and subsequently may cause deformation.

Formwork manufacturing

Formwork installation scheme.

For the manufacture of formwork, we take boards of 50x150 mm and sew a shield 40 cm high from them. 3 boards will go to one shield (1 edge of the future formwork). You will get an edge with a height of 45 cm, where 40 cm is the height of the future floor beam and 5 cm is the required margin. They are sewn with transverse pieces of boards 5x50 mm and 40 cm long. These boards, called blazers, are located along the entire length of the shield every 40-50 cm.Remember: the first and last frogs should be no closer than 10 cm from the edge of the edge of the shield. We fasten the bloopers to the boards with self-tapping screws 90 mm long using a screwdriver at the rate of 3-4 self-tapping screws per 1 stitched board. Then align the edges of the flap circular saw with the help of a carpentry corner.

You will need 3 of these prefabricated panels, they will become the ribs of the formwork.

Formwork installation

Formwork installation scheme.

To complete this stage of work, a team of 3-4 people is required.

To facilitate assembly, we put one shield as a base. We install a spacer under each blooper so that nothing sags under load.

We fasten the ribs to the base of the formwork. We fasten the ribs taking into account how wide we need the beam. Beams of three sizes are allowed: 35, 40, 45 cm. With the required width of 35 cm, both side ribs are placed flush. With a required width of 40 cm, only one edge of the two prefabricated panels is flush. If you need a 45 cm wide beam, the ribs are attached without using this technique. All are fastened with self-tapping screws.

As a result, we got a box of three prefabricated panels in the place where the future beam will be located.

Figure 4. Types of attachment of ribs to the base. A - 35 cm, B - 40 cm, B - 45 cm.

Now we harvest the spacers from the reinforcement. They will be needed in order to withstand right size beams and avoid bevels. We simply cut the reinforcement into pieces of the desired length (35, 40 or 45 cm).

After that, we proceed to upholstery the resulting box with a film from the inside, while using a joiner's stapler with staples. This is necessary in order to prevent unnecessary loss of water from the concrete and to avoid the appearance of shells. If this is not done, the concrete will lose a lot of moisture along with the sand and cement. After drying, gravel will show through strongly on the outer edges of the beam. The surface of the beam will be all covered with strong roughness and irregularities, bumps and depressions, the so-called shells. Such a beam will be of poor quality, and it will have to be redone.

Assembly of prefabricated metal structures

Reinforcement cage diagram.

We start knitting the frame on the ground. We make 8 veins of a given length from the reinforcement (the length of one vein is equal to the length of the future beam).

Now we make clamps from M-6 wire, which are bent manually. From a single piece of wire, it is necessary to make a square with a given length of its sides. So, for a beam with a size of 35x35 cm, a clamp with sides of 30 cm is needed, for a beam of 40x40 cm we make a clamp of 35x35 cm, for a beam of 45x45 cm - a clamp of 40x40 cm. ... Remember: the minimum distance between the wall of the formwork and the clamp should be 2.5-3 cm, not less!

This is necessary so that, as a result, the metal parts of the clamp are not visible on the surface of the beam. If the metal appears on the surface of the beam, then it is in this place that metal corrosion and destruction of concrete, and hence the beam itself, will begin.

The ends of the clamp are overlapped, that is, there should be an overlap of the ends of the clamp, which are fastened to each other with a double knitting wire with a diameter of 0.3 mm.

The wire is folded in half to form a double knitting wire. It is with such a wire that the ends of the clamp should be tied.

Knowing that the clamps should be located along the entire length of the beam at a distance of 40-50 cm from each other, it is easy to calculate the required number.

Putting the frame together. To do this, we tie to each side of the clamp with a double knitting wire, 2 cores at an equal distance from the folds and between each other. Place the clamps on the veins 40-50 cm apart. The distance between the clamps must be maintained.

We put the finished frame in the installed box, being careful not to damage the film. If suddenly the film is damaged, then it's okay, just close the hole with another piece of film and secure it with a stapler.

Sometimes, for various reasons, it is necessary to make veins from pieces of reinforcement of different lengths. There is nothing wrong with that, the construction technology allows it. Simply take another piece of reinforcement and overlap it with a double knitting wire over the junction of the two pieces of vein, making sure that the overlap is 60 cm on each side. This immediately explains why builders prefer to make veins from whole pieces fittings, rather than collecting them from pieces. After all, if you collect from pieces of different lengths, you get a strong overrun building material... Moreover, this work is carried out when the frame is already inside the box.

Scheme monolithic floor do it yourself.

Then we take a drill for wood and, taking into account the fact that the concrete pressure comes from below, we make holes equal to the diameter of the stud, 15-20 cm from the bottom of the box. We make 1 through hole at the bottom of each blooper. We cut the hairpins to the length we need.

The length is calculated as follows: the width of the support beam + two thicknesses of the board + two thicknesses of the frog + two reserves of thread for tightening nuts with washers. We insert the resulting pins into the box.

Now we take pre-prepared pieces of reinforcement - spacers. We install them on top of each stud. We twist the studs to the light stop of the spacers so that they hold.

We take a level and level the formwork vertically to the ground so that it does not lead after compression. All deviations in one direction or another are eliminated using side struts. The installation of studs and the installation of spacers is one of the important prefabricated stages of the design.

After installing the spacers, check everything again with a level, only then attach all the support boards to the formwork with nails or self-tapping screws.

Now we start hanging the frame. To hang the frame, it must be tied to the studs. The easiest way to do this is using a height template - a small board measuring 2.5x2.5x30 cm. It's simple: place a height template under each clamp and tie it to the hairpin where it touches with a double knitting wire. After fixing the last clamp, the frame will be suspended in the air.

After that, check and inspect everything. Do not allow film breaks or clamps to touch the box walls. Then we stuff the transverse slats for sewing together the formwork boards. We measure the height of the beam from the bottom of the base and drive nails along the entire length of the box at this height. These nails are beacons, concrete will be poured over them.

Now we check the strength of the bottom and side struts, they should freely support a decent weight. If in doubt, add more props. Remember: concrete has a high density. The slightest mistake - and the structure will collapse under the weight of concrete.

We made sure that everything was done correctly - then feel free to pour concrete.

For the manufacture of beams, cement of the M300 or M350 brand is used, which is best bought ready-made, since the beam must be poured at one time without interruption. If this is not possible, hire a large concrete mixer to mix the entire required volume of concrete in one go.

After 3-5 days, in good weather, the concrete will dry out, in bad weather, it will take longer.

After the concrete is completely dry, you can start dismantling the wooden formwork and installing the floor slabs themselves.

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Monolithic section between two prefabricated slabs

This monolithic section acts as a slab resting on adjacent precast slabs. To do this, it has a working reinforcement curved with a trough, the diameter of which depends on the width of the section (the estimated length of the slab of this section) and the load on the floor. Longitudinal reinforcement is structural, it creates a reinforcing mesh, but does not bear any load. On the top of the wide monolithic section, an anti-shrink mesh made of smooth reinforcement of small diameter is also laid.

The figure shows examples of reinforcement of two monolithic sections in housing (without any additional loads in the form of warm floors and brick partitions).

We divided by two, because the monolithic section rests on two slabs, and each of them carries half the load.

1.3 * 140 * (1.2 + 0.58 * / 2) + 1.1 * 50 * (1.2 + 0.58 * / 2) + 1.3 * 150 * (1.2 + 0 , 58 * / 2) + 199 = 929 kg / m> 480 kg / m.

Thus, one should always check bearing capacity slabs, depending on the dimensions of the monolithic area, the width of the slab and the loads acting on it.

Monolithic girder section.

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Sealing joints between floor slabs after installation and on the ceiling

Installation of floor slabs is a responsible business that requires knowledge and experience. Unfortunately, there are situations when you have to change the design solution on the spot, and as a result - non-standard situation when the width of the slabs brought to the construction site is not enough for the installation of the ceiling. We will answer the age-old Russian question "What to do?"

Regulatory requirements for the size and filling of assembly joints

Typical dimensions slabs provide for their laying with seams of 15 mm, that is, almost end-to-end. The regulatory literature prescribes the device of monolithic sections with reinforcement with a distance between the plates of 300 mm.
To seal the joints between floor slabs, it is necessary to use concrete on fast-hardening Portland cement or Portland cement M400 or higher on a fine aggregate. The grain size of the aggregate should not be more than a third of the inter-slab gap and three-quarters of the clear size between the reinforcing rods. Plasticizers and setting accelerators must be added to the concrete mixture.

If you get a standard seam between the plates 10-15 mm wide, then usually a bar of reinforcement is placed on the bottom of the seam, which is arranged in the form of a "cone", and poured with mortar.

We close non-design joints up to 300 mm

If the width of the seams between adjacent slabs does not exceed 300 mm, it is relatively easy to seal such a seam; there are several ways of filling seams to choose from.

Method 1

From the bottom of the adjacent slabs, using spacers, we install a board or plywood sheet, bridging the gap - this is the formwork;
On top of the formwork, a piece of roofing material or film can be laid, then there will be no traces of concrete on the formwork, and it can be used further;
Fill the gap between the plates with mortar;
We are waiting for the concrete to gain strength within 3-4 weeks, we remove the formwork.

Method 2

If it is not possible to bring the formwork from below, it is possible to make a permanent formwork of galvanized roofing steel 0.8-1 mm thick according to the size of the gap between the slabs, with support on the upper edge of the slab (trough). The profile of the side surface of the slabs will provide additional space and rigidity to the monolithic area.

Method 3

Another way to seal seams fixed formwork- from steel strips with a thickness of 4 mm and a width of 5 cm, make mounting parts along the gap profile, as in the previous case, resting on the front surface of the plates, lay these mounting parts every 0.5 m along the length of the plate. On the bottom (in the plane of the lower edge of the slabs) we put a strip of galvanized roofing steel, plywood or plastic, and concreting. This method ensures reliable adhesion of the monolithic area to the slabs.

Method 4

If you come across a couple of defective slabs with the wrong location of the side locks, when the recess is at the bottom, they can be installed next to a gap of 2-3 cm. From below, bring the formwork according to method 1 and pour concrete through the provided gap.

Monolithic areas with a width of more than 300 mm

If the gap between the slabs is from 100 to 300 mm, we perform a monolith with reinforcement. Variants are also possible here.

Option 1

Used when formwork from below is not possible.

We install load-bearing beams with a section of 40x100 mm on an edge, with a step of 1 m, resting on adjacent slabs;
We fasten the formwork panels to the supporting beams with wire twists;
We close the formwork roofing material or film;
We install the reinforcement cage on the glasses so that the reinforcement is 30 ... 50 mm higher than the formwork;
We are concreting.

Option 2

If it is possible to fix the formwork from below, it can be used for the device supporting structure fittings.

We build the formwork;
We make mounting parts from reinforcement A1Ø8… 12 (depending on the width of the gap to be overlapped), taking into account that there must be a distance of at least 30 mm between the bottom of the formwork and the reinforcement;
We put protective material at the bottom of the formwork;
We install mounting parts;
We lay the reinforcement or reinforcement cage;
We are concreting.

Do not settle for filling the gap between the wall and the slab with lightweight concrete honeycomb blocks(foam concrete, expanded clay concrete, etc.) - they do not have the required bearing capacity. Taking into account the arrangement of furniture along the walls, this section of the floor has a large load, this will lead to the destruction of blocks and the need for costly repair of the floor.

Areas between the wall and the slab are sealed in the same way.

This story tells not only about sealing joints, but also about anchoring the plates to each other:

Ceiling seam from the underside

Inter-tile seams - the rusty walls are filled with concrete at the installation, then the ceiling is primed, putty and painted, if no other finish is provided.

Sequence of embedding of rusticates

Before concreting, the seams are thoroughly cleaned of dust and mortar residues with a metal brush, for better adhesion mortar can be primed to the stove lateral surfaces.

The prepared fresh concrete solution is unloaded into a container and delivered to the place of work;
With a small width of the rusticum, the filling is performed at one time, with a large width of the site - in several layers, but not more than after 2 ... 3 hours;
A small-width concreting site is bayonetted, with a large one - compacted with a vibrator;
For the first week, the surface of the monolith is moistened with water daily;
After 28 days, the formwork is removed.

Uneven shrinkage at home

It's unpleasant when cracks appear on the ceiling. This often happens due to:

Uneven building settlement;
Incorrectly selected grade of concrete;
Poor quality concrete.

Let us dwell on the reasons for the uneven precipitation. It can occur if:

Constructive flaws - incorrectly designed foundation;
Foundation devices without taking into account geology, the depth of soil freezing and the depth of occurrence groundwater;
Poorly performed work on the construction of the foundation and masonry of the walls;
Low-quality building materials.

To understand the reason for the appearance of cracks, sometimes you have to order a construction expertise.

Decorative ceilings

Protective layer concrete with a thickness of 30-50 mm should guarantee the absence of rust stains from the reinforcement on the ceiling, but sometimes this layer is ineffective. From contemplating stains on the ceiling, traces of leaks and cracks in rustic best remedy- installation of a suspended, hemmed or stretch ceiling.

Decorative ceiling – the best solution if necessary, leveling the ceiling surface. It will close all construction flaws and complement the interior. If you want to reduce the height of the room, arrange multi-level or dropped ceilings from plasterboard, acoustic panels or combined from various materials.

In rooms of small height, they are made of hemmed or stretch ceilings. Here is the champion - stretch ceiling, which "eats" only 3-5 cm of the height of the room.

Any problem finds its solution. Sealing joints between slabs in aerated concrete house, even with a large width, does not constitute a large constructive or technical problem... From the options offered, it is easy to choose the one that suits a particular case.

We tried to write the best article... If you liked it, please share it with your friends or leave your comment below. Thanks!

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Monolithic section between two prefabricated slabs

The figure shows examples of reinforcement of two monolithic sections in housing (without any additional loads in the form of warm floors and brick partitions).

As you can see, plots are different widths, but when setting the goal of making a wide monolithic section based on the slabs, you should always check whether the floor slabs will withstand it. This is the most important point in the design of monolithic sections. The load-bearing capacity of floor slabs is different (from 400 to 800 kg / m2 - excluding the weight of the slab).

Suppose we have two prefabricated slabs with a width of 1.2 m, between which there is a monolithic section with a width of 0.58 m. The load-bearing capacity of the slabs is 400 kg / m2, i.e. one running meter such a plate can withstand 1.2 * 400 = 480 kg / m.

Let's calculate the load per 1 running meter of the slab from a monolithic section with a thickness of 220 + 30 = 250 mm = 0.25 m. The weight of reinforced concrete is 2500 kg / m3, the load safety factor is 1.1.

0.25 * 1.1 * 2500 * 0.58 / 2 = 199 kg / m.

We divided by two, because the monolithic section rests on two slabs, and each of them carries half the load.

In addition to the weight of the monolithic area, we have a load on the slabs from the floor structure (140 kg / m2), from partitions (50 kg / m2) and a live load from the weight of people, furniture, etc. (150 kg / m2). Multiplying all this by the coefficients and the width of the precast slab plus half the width of the monolithic section, and adding the load from the self-weight of the monolithic section, we get the final load on each precast slab:

1.3 * 140 * (1.2 + 0.58 * / 2) + 1.1 * 50 * (1.2 + 0.58 * / 2) + 1.3 * 150 * (1.2 + 0 , 58 * / 2) + 199 = 929 kg / m> 480 kg / m.

We see that the load is greater than the plate can withstand. But if you take a slab with a bearing capacity of 800 kg / m2, then one running meter of such a slab can withstand 1.2 * 800 = 960 kg / m2 - the reliability of the structure will be ensured.

Thus, it is always necessary to check the bearing capacity of the slabs depending on the dimensions of the monolithic area, the width of the slab and the loads acting on it.

Types of monolithic sections in precast floors.

Monolithic section between two prefabricated slabs.

Monolithic section between precast slab and wall.

Monolithic girder section.

Monolithic plots by metal beams with a stove on top.

Monolithic sections on metal beams with a slab underneath.

Calculation of monolithic sections on metal beams.

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Monolithic sections between floor slabs

Before you decide to independently make monolithic sections between the floor slabs, soberly assess your capabilities, because this is a serious painstaking work. But if you nevertheless decide to make a monolith between the slabs on your own, then you have to go through the following installation steps.

Monolithic plot diagram.

Surface preparation

At this stage, you have to make sure that at the right time you have the right materials and tools at your fingertips. Therefore, oh, availability must be taken care of in advance.

So, to make a monolithic overlap section, you will need the following tools: a hammer drill, self-tapping screws for wood 90 mm long, standard threaded rods 2 m each, nuts, washers, open-end and cap keys, concrete drills, wood drills 90 cm long, screwdriver. cross-shaped cues for a screwdriver of very good quality (good quality is required because the edges of low-quality cue balls are erased very quickly), a hook, a grinder with discs for metal, a circular saw with diamond dust (for cutting boards along and across the fiber), an 800-gram hammer, sledgehammer up to 3 kg, steel nails 120 mm in size, tape measure # 8211 2-3 pieces (tape measures are necessary for making accurate measurements, there should be a sufficient number of them, as they often break and get lost), carpenter's pencil, carpenter's corner 50 cm long, joinery stapler with staples, level.

Structural calculations

Calculation of the prefabricated floor slab.

At this stage, you will need to make accurate measurements and calculations in order to know what and how much you need. First of all, we find out what the floor slabs will be. To do this, we find out the width of the building and divide it in half, into two equal parts. We immediately determine where the stairs to the second floor will be, on which side the staircase will rise, and only after that we calculate the size and number of floor slabs.

The length of Floor Slab # 8211 is the width of the house divided by 2.

The width of the floor slab comes in three standard sizes: 80 cm, 1 m 20 cm, 1 m 50 cm.

Do not forget to take into account the 7 cm gap between the floor slabs! The absence of a gap between the plates will complicate their installation and subsequently may cause deformation.

Monolithic section between two slabs 980 mm wide (download drawing in dwg format)

Monolithic section between two prefabricated slabs

The figure shows examples of reinforcement of two monolithic sections in housing (without any additional loads in the form of warm floors and brick partitions).

As you can see, the sections are of different widths, but with the goal of making a wide monolithic section based on the slabs, you should always check whether the floor slabs will withstand it. This is the most important point in the construction of monolithic sections. The bearing capacity of floor slabs is different (from 400 to 800 kg / m 2 - excluding the weight of the slab).

Let's say we have two prefabricated slabs with a width of 1.2 m, between which there is a monolithic section with a width of 0.98 m. The bearing capacity of the slabs is 400 kg / m 2. one running meter of such a plate can withstand 1.2 * 400 = 480 kg / m.

Let's calculate the load per 1 running meter of the slab from a monolithic section with a thickness of 220 + 30 = 250 mm = 0.25 m. The weight of reinforced concrete is 2500 kg / m 3. The load safety factor is 1.1.

0.25 * 1.1 * 2500 * 0.98 / 2 = 337 kg / m.

We divided by two, because the monolithic section rests on two slabs, and each of them carries half the load.

In addition to the weight of the monolithic area, we have a load on the slabs from the floor structure (140 kg / m 2), from partitions (50 kg / m 2) and a live load from the weight of people, furniture, etc. (150 kg / m 2). Multiplying this by the coefficients and the width of the precast plate, and adding the load from the monolithic section, we get the final load on each precast plate:

1.3 * 140 * 1.2 / 2 + 1.1 * 50 * 1.2 / 2 + 1.3 * 150 * 1.2 / 2 + 337 = 596 kg / m 480 kg / m.

We see that the load is greater than the plate can withstand. But if you take a slab with a bearing capacity of 600 kg / m 2. then one running meter of such a slab can withstand 1.2 * 600 = 720 kg / m - the reliability of the structure will be ensured.

Thus, it is always necessary to check the bearing capacity of the slabs depending on the dimensions of the monolithic area, the width of the slab and the loads acting on it.

Monolithic slab with an oblique corner. Reinforcing frame for beveled slabs. Concrete work for a monolithic bevel slab. Concrete curing and maintenance.

Reinforcement work should be performed in accordance with the requirements and recommendations of SNiP 3.03.01-87 Bearing and enclosing structures, GOST 19292-73. Instructions for welding joints of reinforcement and embedded parts of reinforced concrete structures СН 393-78. Manufacturing manuals reinforcement works... And other acting regulatory documents.

Concrete works should be carried out in accordance with the requirements and recommendations of SNiP 3.03.01-87 Bearing and enclosing structures.

The composition of the concrete mix. preparation, acceptance rules, control methods and transportation must comply with GOST 7473-85.

When performing work on the construction of reinforced concrete monolithic structures one should be guided by the requirements of SNiP 3.03.01-87 Bearing and enclosing structures and the relevant sections of the safety rules given in SNiP III-4-80. working drawings and instructions of the PPR - the project for the production of work.

1. Monolithic overlap section with oblique angle (UM-1).

In houses. where the plan provides for construction with an angular transition of walls at an angle not 90 °, as usual, but, for example, 45 ° - the floors are performed in a monolithic version.

You can, of course, take an ordinary reinforced concrete slab and use a jackhammer to knock out the desired bevel of the slab, and cut off the reinforcement.

But this is fraught with the fact that if a reinforced concrete slab is made with a stressed reinforcing cage (and this is most often done in reinforced concrete factories - such a frame requires less reinforcement consumption), then in such a truncated form the slab will lose its bearing capacity. And it may burst immediately during such a circumcision.

NOTE: A stressed cage is a cage whose bars were clamped in special form... and then, heating, stretched to the desired size.

Then it was welded with transverse frames. poured with concrete and dried in a steaming chamber. Trimming of the rods from the fixed form was carried out when the slab was in finished form... Those. reinforcing bars in concrete are stretched like guitar strings. Well, if the string breaks, you yourself know what happens.

Therefore, everything that does not fit into the standard dimensions of industrial reinforced concrete products and structures is performed in a monolithic version at the construction site of the house. In our version, a monolithic slab is a continuation of prefabricated reinforced concrete slabs.

2. Reinforcing frame for beveled slab (UM-1).

The fabrication of the reinforcing cage and mesh should be carried out according to the drawings and have the exact location of the elements to be welded. Replacement of the reinforcing steel provided for by the project by class, brand and range is agreed with the design organization.

Technological process the manufacture of a reinforcing cage provides for:

straightening and cutting of steel reinforcement, wire. supplied in coils with a diameter of 3 ... 14 mm and in rods with a diameter of 12 ... 40 mm on rods of measured length
straightening (bending) and butt welding of rods to the desired size
welding of meshes and frames
enlarged assembly (welding and wire tying) of bulk reinforcement blocks
transportation and installation of frames at a construction site.

The reinforcement frame of the UM-1 monolithic section is made according to the dimensions indicated in the diagram (see Fig.). And it consists of a C-2 grid and two reinforcement cages K-1. interconnected by reinforcing bars made of the same steel A-III.

Reinforcing mesh must be cooked spot welding... For the frame and mesh, the reinforcement according to the indicated table 1 is used.

Table 1: Specification of reinforcement for the framework of a monolithic floor slab.

Creating a monolithic section between the slabs with your own hands

Necessary materials and tools
Stages of work on the formation of a monolithic section between floor slabs
- Installation of supports and formwork
- Reinforcement mesh formation
- Concrete mix and its pouring
- Final recommendations

The construction of a private house # 8211 is a complex and time-consuming task, within the framework of which it is necessary to perform various types of work. For example, it may be necessary to fill in a monolithic area between floors due to the fact that it is not possible to form a floor completely from slabs according to the project. This happens very often in cases of the formation of flights of stairs or when it is necessary to lay various communication elements between the plates. It is quite possible to form a monolithic section between the slabs with your own hands. Although this work is laborious, it is quite doable if you adhere to all building codes and rules.

If you need to lay various communication elements between the plates, you can form a monolithic section between the plates with your own hands.

In the process of forming a section of a monolith between floor slabs, it is important to correctly perform following works:

install props and form the formwork
form reinforcement mesh
prepare concrete mix
pour concrete correctly.

Correct implementation of these types of work will allow you to create a solid and reliable section of the monolith between the floor slabs in the required place.

Required materials and tools

Considering that the work on the device concrete area floors consist of different stages, for each of them it is necessary to prepare a number of materials. The list of such materials may vary due to various factors, including the distance between the plates to be poured. The standard list looks like this:

On the wooden beams the horizontal formwork support is laid.

plywood or boards for creating a direct surface for pouring mortar and side formwork, construction film
wooden beams or metal channels to create a horizontal support on which plywood or a wooden pallet will be laid
timber (120-150 mm), wooden beams or channels to create load-bearing supports for the formwork platform
reinforcing rods (15-25 mm), wire for tying, metal chairs for installing reinforcing rods at the required height (you can use and reinforced mesh)
cement M400, sand, crushed stone, water for mixing concrete mortar
concrete mixer
circular for cutting beams, boards, plywood, as well as metal reinforcing bars
a shovel, a bayonet tool, a trowel or a rule for leveling the surface of the overlap between the slabs, protective film to cover this area.

The amount of all materials depends directly on the distance between concrete slabs you need to overlap and what area as a whole the monolithic overlap area occupies. Usually, in private houses, such an overlap area is not very large, so its formation is not too challenging task... However, in this case, all the same, one should adhere to a clear phasing and rules for working with building materials and structures.

Stages of work on the formation of a monolithic section between floor slabs

A monolithic overlap area between slabs is formed in approximately the same way as any monolithic overlap. Given the small area of such a site, the work, of course, is simplified, but it is necessary to adhere to all building codes and regulations. Therefore, no matter what distance between the concrete slabs is poured, all stages of work must be carried out carefully, on which the reliability of the monolithic structure created independently will depend.

The grade of the solution is adopted according to the project. The mobility of the solution should be 5-7 cm along the immersion depth of the cone.

The grouting of the joints should be performed after checking the correct installation of the plates, accepting the welded joints of the elements at the interface units and making an anticorrosive coating of the welded joints and damaged areas of the coating of embedded products. Concrete mixtures used for embedding joints must meet the requirements of GOST 7473-94 and the project.

After installation and welding of the anchors, the hinge nests in the slabs must be cast with M 100 mortar.

A horizontal wall in the walls must be laid with bricks with careful laying of the masonry.

Installation of monolithic sections in ceilings

	Scope of operations and controls
Stages of work	Controlled operations	Control	Documentation
Stages of work	Controlled operations	(method, volume)	Documentation
Preparatory	Check:		Passports
			(certificates),
	Availability of documents on	Visual	general journal
	Availability of documents on	Visual
	quality for elements
	formwork and reinforcement
	products, concrete mix;
	Installation accuracy and	Visual,
	connection of individual	measuring
	elements, quality
	mountings and internal
	formwork surfaces;
	Installation accuracy	Technical
	reinforcement products in plan	inspection of all
		elements

Base regulatory documents: www.complexdoc.ru

and in height, the reliability of their fixation.

Device	Control:	General Journal
monolithic
plots	The quality of the concrete mix;	Laboratory
	The quality of the concrete mix;	Laboratory
	Formwork condition;	Technical

	The procedure for laying concrete
	mixtures, sinus filling,
	sufficient sealing;
	Temperature Humidity Measuring
	concrete hardening regime
	according to the requirements of the PPR;
	Concrete strength and timing
	stripping.
	Check:	Acceptance certificate
completed		completed

	Actual strength	Laboratory

	Surface quality	Visual,
	designs, measuring compliance,
	design position
	holes, channels, openings,
	embedded parts.

Control and measuring tool: plumb line, two-meter rail, tape measure, metal ruler.

Base of regulatory documents: www.complexdoc.ru

Operational control is carried out by: foreman (foreman), laboratory engineer - in the process of performing work.

Acceptance control is carried out by: quality service workers, foreman (foreman), representatives of the customer's technical supervision.

Technical requirements

SNiP 3.03.01-87 clause 2.14, tab. 2

Permissible deviations:

- in the distance between:

- separately installed working rods - ± 20 mm;

- rows of mesh - ± 10 mm;

- from the design thickness of the concrete cover with its thickness up to 15 mm and linear dimensions cross section constructions:

Up to 100 mm - +4 mm;

- from 101 mm to 200 mm - +5 mm;

- local irregularities of the concrete surface when checking with a two-meter rail - 5 mm.

The height of the free throwing of the concrete mixture into the slab formwork should not exceed 1.0 m.

Base of regulatory documents: www.complexdoc.ru

The strength of concrete (at the time of stripping of structures) must be at least 70% of the design strength.

Not allowed:

Add water at the place where the concrete is placed to increase its mobility.

Reinforcement of monolithic sections must be formalized with an act of survey of hidden works.

Requirements for the quality of the materials used

GOST 7473-94. Concrete mixes. Technical conditions.

GOST 23279-85. Welded reinforcing meshes for reinforced concrete structures and products. General technical conditions.

GOST 10922-90. Reinforcement and embedded products are welded, welded joints of reinforcement and embedded products of reinforced concrete structures. General technical conditions.

GOST R 52086-2003. Formwork. Terms and Definitions.

The formwork must have strength, rigidity, shape invariability and stability in the working position, as well as in the conditions of installation and transportation.

The moisture content of the wood used for the deck should be no more than 18%, for supporting elements - no more than 22%.

Deck planks shall be no more than 150 mm wide.

The formwork elements must fit snugly against each other during assembly. Slots in butt joints should not be more than 2 mm.

Cracks, burrs and local deviations with a depth of more than 2 mm are not allowed on the deck of plywood panels, on a deck made of wood - more than 3 mm in an amount of no more than 3 per 1 m2.

When accepting the formwork, it is necessary to check the presence of a passport with instructions for the installation and operation of the formwork, check the geometric dimensions, the quality of the working surfaces, the protective paint of the surfaces not in contact with the concrete.

Limit deviations for reinforcing meshes, mm:

Base of regulatory documents: www.complexdoc.ru

- width, mesh size, difference in length of diagonals of flat meshes, free ends of rods - ± 10;

- length of flat meshes - ± 15.

The maximum deviations from the straightness of the mesh rods should not exceed 6 mm per 1 m of the mesh length.

Concrete mixtures must be characterized by the following indicators:

- strength class;

- workability;

- type and quantity raw materials(binders, aggregates, additives);

- the size of the aggregates.

By agreement with the design organization carrying out field supervision, it is allowed not to take samples of the concrete mixture at the place of their placement in the monolithic structure, but to evaluate the strength of concrete according to the control data of the manufacturer of the concrete mixture.

The workability of the concrete mixture is determined for each batch no later than 20 minutes after the delivery of the mixture to the place of placement.

Work instructions

SNiP 3.03.01-87 pp. 2.8-2.11, 2.16, 2.100, 2.109

Before concreting, horizontal and inclined concrete and brick surfaces of working joints must be cleaned of debris, dirt, oils, snow and ice, cement film, etc. Immediately before placing the concrete mixture, the cleaned surfaces must be rinsed with water and dried with an air stream.

Concrete mixtures should be placed in concrete structures in horizontal layers of the same thickness without breaks, with successive laying in one direction in all layers. Reinforcing steel (rods, wire) and bars, reinforcing products and embedded elements must comply with the project and the requirements of the relevant standards. Replacement of the reinforcing steel envisaged by the project must be agreed with the customer and the design organization. The installation of reinforcing structures should be carried out mainly from large-sized blocks or unified factory-made meshes.

Provide for their laying with seams of 15 mm, that is, almost end-to-end. The regulatory literature prescribes the device of monolithic sections with reinforcement with a distance between the plates of 300 mm.

To seal the seams between floor slabs, it is necessary to use concrete on fast-hardening Portland cement or Portland cement grade M400 or higher on fine aggregate... The grain size of the aggregate should not be more than a third of the inter-slab gap and three-quarters of the clear size between the reinforcing rods. Plasticizers and setting accelerators must be added to the concrete mixture.

We close non-design joints up to 300 mm

If the width of the seams between adjacent slabs does not exceed 300 mm, it is relatively easy to seal such a seam, to choose from - several methods of filling the seams.

Method 1

From the bottom of the adjacent slabs, using spacers, we install a board or plywood sheet, bridging the gap - this is the formwork;
On top of the formwork, a piece of roofing material or film can be laid, then there will be no traces of concrete on the formwork, and it can be used further;
Fill the gap between the plates with mortar;
We are waiting for the concrete to gain strength within 3-4 weeks, we remove the formwork.

Method 2

If it is not possible to bring the formwork from below, you can make permanent formwork made of galvanized roofing steel 0.8-1 mm thick according to the size of the gap between the slabs, with support on the upper edge of the slab (trough). The profile of the side surface of the slabs will provide additional space and rigidity to the monolithic area.

Method 3

Another way of sealing joints with fixed formwork is from steel strips with a thickness of 4 mm and a width of 5 cm, make mounting parts along the gap profile, as in the previous case, resting on the front surface of the slabs, lay these mounting parts every 0.5 m along the length of the slab. On the bottom (in the plane of the lower edge of the slabs) we put a strip of galvanized roofing steel, plywood or plastic, and concreting. This method ensures reliable adhesion of the monolithic area to the slabs.

Method 4

Monolithic areas with a width of more than 300 mm

If the gap between the slabs is from 100 to 300 mm, we perform a monolith with reinforcement. Variants are also possible here.

Option 1

Used when formwork from below is not possible.

We install load-bearing beams with a section of 40x100 mm on an edge, with a step of 1 m, resting on adjacent slabs;
We fasten the formwork panels to the supporting beams with wire twists;
We close the formwork with roofing material or foil;
We install the reinforcement cage on the glasses so that the reinforcement is 30 ... 50 mm higher than the formwork;
We are concreting.

Option 2

If it is possible to fix the formwork from below, reinforcement can be used to construct the supporting structure.

We build the formwork;
We make mounting parts from reinforcement A1Ø8… 12 (depending on the width of the gap to be overlapped), taking into account that there must be a distance of at least 30 mm between the bottom of the formwork and the reinforcement;
We put protective material at the bottom of the formwork;
We install mounting parts;
We lay the reinforcement or reinforcement cage;
We are concreting.

Do not settle for filling the gap between the wall and the slab with lightweight concrete aerated blocks (foam concrete, expanded clay concrete, etc.) - they do not have the required bearing capacity. Taking into account the arrangement of furniture along the walls, this section of the floor has a large load, this will lead to the destruction of blocks and the need for costly repair of the floor.

Areas between the wall and the slab are sealed in the same way.

This story tells not only about sealing joints, but also about anchoring the plates to each other:

Ceiling seam from the underside

Inter-tile seams - the rusty walls are filled with concrete at the installation, then the ceiling is primed, putty and painted, if no other finish is provided.

Sequence of embedding of rusticates

Before concreting the seams are thoroughly cleaned of dust and mortar residues with a metal brush, for better adhesion of the mortar to the board, the side surfaces can be primed.

The prepared fresh concrete solution is unloaded into a container and delivered to the place of work;
With a small width of the rusticum, the filling is performed at one time, with a large width of the site - in several layers, but not more than after 2 ... 3 hours;
A small-width concreting site is bayonetted, with a large one - compacted with a vibrator;
For the first week, the surface of the monolith is moistened with water daily;
After 28 days, the formwork is removed.

Uneven shrinkage at home

It's unpleasant when cracks appear on the ceiling. This often happens due to:

Uneven building settlement;
Incorrectly selected grade of concrete;
Poor quality concrete.

Let us dwell on the reasons for the uneven precipitation. It can occur if:

Constructive flaws - incorrectly designed foundation;
Foundation devices without taking into account geology, the depth of soil freezing and the depth of groundwater;
Poorly performed work on the construction of the foundation and masonry of the walls;
Low-quality building materials.

To understand the reason for the appearance of cracks, sometimes you have to order a construction expertise.

Decorative ceilings

A protective layer of concrete with a thickness of 30-50 mm should ensure that the ceiling is free of rust stains from reinforcement, but sometimes this layer is ineffective. From contemplating stains on the ceiling, traces of leaks and cracks in rustic stones, the best remedy is to install a suspended, hemmed or stretch ceiling.

A decorative ceiling is the best solution when you need to level the ceiling surface. It will close all construction flaws and complement the interior. If you want to reduce the height of the room, arrange multi-level or suspended ceilings made of plasterboard, acoustic panels or combined from various materials.

In rooms of small height, they are made of hemmed or stretch ceilings. Here the champion is a stretch ceiling, which "eats" only 3-5 cm of the height of the room.

Any problem finds its solution. Sealing seams between, even with large widths, does not pose a major structural or technical problem. From the options offered, it is easy to choose the one that suits a particular case.

Monolithic sections between floor slabs

Monolithic plot diagram.

Surface preparation

At this stage, you have to make sure that at the right time you have the right materials and tools at your fingertips. Therefore, oh, availability must be taken care of in advance.

So, to make a monolithic overlap section, you will need the following tools: a hammer drill, self-tapping screws for wood 90 mm long, standard threaded rods 2 m each, nuts, washers, open-end and cap keys, concrete drills, wood drills 90 cm long, screwdriver. cross-shaped cues for a screwdriver of very good quality (good quality is required because the edges of low-quality cue balls are erased very quickly), a hook, a grinder with discs for metal, a circular saw with diamond dust (for cutting boards along and across the fiber), an 800-gram hammer, sledgehammer up to 3 kg, steel nails 120 mm in size, tape measure # 8211 2-3 pieces (tape measures are necessary for making accurate measurements, there should be a sufficient number of them, as they often break and get lost), carpenter's pencil, carpenter's corner 50 cm long, joinery stapler with staples, level.

Structural calculations

Calculation of the prefabricated floor slab.

At this stage, you will need to make accurate measurements and calculations in order to know what and how much you need. First of all, we find out what the floor slabs will be. To do this, we find out the width of the building and divide it in half, into two equal parts. We immediately determine where the stairs to the second floor will be, on which side the staircase will rise, and only after that we calculate the size and number of floor slabs.

The length of Floor Slab # 8211 is the width of the house divided by 2.

The width of the floor slab comes in three standard sizes: 80 cm, 1 m 20 cm, 1 m 50 cm.

Do not forget to take into account the 7 cm gap between the floor slabs! The absence of a gap between the plates will complicate their installation and subsequently may cause deformation.

Monolithic section between two slabs 980 mm wide (download drawing in dwg format)

Sometimes it is necessary to make wide monolithic sections between the floor slabs. They must be calculated according to the current loads. The drawing shows a monolithic section 980 mm wide, supported by two hollow core slabs. The conditions for such a monolithic section (loads, principles of reinforcement, etc.) are detailed in the article Monolithic section between two prefabricated slabs.

Monolithic section between two prefabricated slabs

The figure shows examples of reinforcement of two monolithic sections in housing (without any additional loads in the form of warm floors and brick partitions).

0.25 * 1.1 * 2500 * 0.98 / 2 = 337 kg / m.

We divided by two, because the monolithic section rests on two slabs, and each of them carries half the load.

In addition to the weight of the monolithic area, we have a load on the slabs from the floor structure (140 kg / m 2), from partitions (50 kg / m 2) and a live load from the weight of people, furniture, etc. (150 kg / m 2). Multiplying this by the coefficients and the width of the precast plate, and adding the load from the monolithic section, we get the final load on each precast plate:

1.3 * 140 * 1.2 / 2 + 1.1 * 50 * 1.2 / 2 + 1.3 * 150 * 1.2 / 2 + 337 = 596 kg / m 480 kg / m.

Thus, it is always necessary to check the bearing capacity of the slabs depending on the dimensions of the monolithic area, the width of the slab and the loads acting on it.

Monolithic slab with an oblique corner. Reinforcing frame for beveled slabs. Concrete work for a monolithic bevel slab. Concrete curing and maintenance.

Reinforcement work SNiP 3.03.01-87 Supporting and enclosing structures, GOST 19292-73... Instructions for welding joints of reinforcement and embedded parts of reinforced concrete structures SN 393-78... Reinforcement production manuals. And other applicable regulations.

Concrete works should be performed in accordance with the requirements and recommendations SNiP 3.03.01-87 Bearing and enclosing structures.

Concrete mix composition... preparation, acceptance rules, control methods and transportation must comply with GOST 7473-85 .

When carrying out construction works reinforced concrete monolithic structures should be guided by the requirements SNiP 3.03.01-87 Supporting and fencing structures and the relevant sections of the safety instructions given in SNiP III-4-80... working drawings and instructions of the PPR - the project for the production of work.

1. Monolithic overlap section with oblique angle (UM-1).

In houses... where the construction plan is foreseen with corner transition of walls at an angle not 90 °, as usual, but, for example, 45 ° - overlap are carried out in monolithic version .

You can, of course, take an ordinary reinforced concrete slab and use a jackhammer to knock out the desired bevel of the slab, and cut off the reinforcement.

But this is fraught with the fact that if a reinforced concrete slab is made with a stressed reinforcing cage (and this is most often done in reinforced concrete factories - such a frame requires less reinforcement consumption), then in such a truncated form the slab will lose its bearing capacity... Or maybe right away burst during such a circumcision.

NOTE: Tense reinforcement cage is a frame whose rods clamped in a special shape... and then, heating, pulled to the desired size.

Further it welded with transverse frames... poured with concrete and dried in a steaming chamber. Trimming bars from the fixed form was carried out already when the plate was ready-made... Those. reinforcing bars in concrete taut like guitar strings... Well, if the string breaks, you yourself know what happens.

So everyone which does not fit into standard sizes industrial reinforced concrete products and structures, performed in monolithic version at the construction site of the house. In our version monolithic slab is an continuation of precast concrete slabs .

2. Reinforcing frame for beveled slab (UM-1).

Manufacturing reinforcement cage and mesh must be carried out according to the drawings and have an exact location welded elements. Replacement envisaged by the project reinforcing steel by class, brand and assortment is coordinated with a design organization.

Technological manufacturing process reinforcement cage provides for:

straightening and cutting steel fittings, wires... supplied in coils with a diameter 3 ... 14 mm and in bars diameter 12 ... 40 mm on rods of measured length
edit(flexible) and butt welding rods to the desired size
welding meshes and frames
enlarging assembly(welding and wire tying) volumetric reinforcement blocks
transportation and installation frameworks at a construction site.

Reinforcing frame of a monolithic section UM-1 performed according to the dimensions indicated in the diagram (see fig.). And it consists of mesh C-2 and two reinforcing cages K-1. interconnected reinforcement rods from the same steel A-III .

Reinforcement mesh necessary spot weld. For frame and mesh used by fittings according to the indicated table 1.

Table 1: Specification of reinforcement for the framework of a monolithic floor slab.

Creating a monolithic section between the slabs with your own hands

- Installation of supports and formwork
- Reinforcement mesh formation
- Concrete mix and its pouring
- Final recommendations

If you need to lay various communication elements between the plates, you can form a monolithic section between the plates with your own hands.

In the process of forming a section of a monolith between floor slabs, it is important to correctly perform the following work:

install props and form the formwork
form reinforcement mesh
prepare concrete mix
pour concrete correctly.

Correct implementation of these types of work will allow you to create a solid and reliable section of the monolith between the floor slabs in the required place.

Required materials and tools

Considering that work on the construction of a concrete overlap section consists of different stages, a number of materials must be prepared for each of them. The list of such materials may vary due to various factors, including the distance between the plates to be poured. The standard list looks like this:

A horizontal formwork support is laid on wooden beams.

plywood or boards for creating a direct surface for pouring mortar and side formwork, construction film
wooden beams or metal channels to create a horizontal support on which plywood or a wooden pallet will be laid
timber (120-150 mm), wooden beams or channels to create load-bearing supports for the formwork platform
reinforcing bars (15-25 mm), wire for tying, metal chairs for installing reinforcing bars at the required height (you can also use a reinforced mesh)
cement M400, sand, crushed stone, water for mixing concrete mortar
concrete mixer
circular for cutting beams, boards, plywood, as well as metal reinforcing bars
a shovel, a bayonet tool, a trowel or a rule for leveling the surface of the overlap area between the slabs, a protective film to cover this area.

The amount of all materials depends directly on how much distance between the concrete slabs needs to be covered and how much area the whole monolithic floor area occupies. Usually, in private houses, such an overlap area is not very large, so its formation is not too difficult a task. However, in this case, all the same, one should adhere to a clear phasing and rules for working with building materials and structures.

Stages of work on the formation of a monolithic section between floor slabs

Monolithic plot diagram.

At this stage, you have to make sure that at the right time you have the right materials and tools at your fingertips. Therefore, oh, availability must be taken care of in advance.

So, to make a monolithic overlap section, you will need the following tools: a hammer drill, self-tapping screws for wood 90 mm long, standard threaded rods 2 m each, nuts, washers, open-end and cap keys, concrete drills, wood drills 90 cm long, screwdriver, cross-shaped cues for a screwdriver of very good quality (good quality is required because the edges of low-quality cue balls are erased very quickly), hook, grinder with discs for metal, circular saw with diamond dust (for cutting boards along and across the fiber), hammer 800- gram, sledgehammer up to 3 kg, steel nails 120 mm in size, tape measure - 2-3 pieces (tape measures are necessary for making accurate measurements, there should be a sufficient number of them, since they often break and get lost), carpenter's pencil, carpenter's corner 50 cm long , joiner's stapler with staples, level.

Structural calculations

Calculation of the prefabricated floor slab.

At this stage, you will need to make accurate measurements and calculations in order to know what and how much you need. First of all, we find out what the floor slabs will be. To do this, we find out the width of the building and divide it in half, into two equal parts. We immediately determine where the stairs to the second floor will be, on which side the staircase will rise, and only after that we calculate the size and number of floor slabs.

Floor slab length is the width of the house divided by 2.

The width of the floor slab comes in three standard sizes: 80 cm, 1 m 20 cm, 1 m 50 cm.

We calculate the required size and number of floor slabs, taking into account the fact that there should be a gap of 7 cm between the slabs. After everything has been calculated and accurately determined the required size and number of floor slabs, we order them from the manufacturer or from suppliers of building materials.

Attention!

Do not forget to take into account the 7 cm gap between the floor slabs! The absence of a gap between the plates will complicate their installation and subsequently may cause deformation.

Formwork manufacturing

Formwork installation scheme.

For the manufacture of formwork, we take boards of 50x150 mm and sew a shield 40 cm high from them. 3 boards will go to one shield (1 edge of the future formwork). You will get an edge with a height of 45 cm, where 40 cm is the height of the future floor beam and 5 cm is the required margin. They are sewn with transverse pieces of boards 5x50 mm and 40 cm long. These boards, called blazers, are located along the entire length of the shield every 40-50 cm.Remember: the first and last frogs should be no closer than 10 cm from the edge of the edge of the shield. We fasten the bloopers to the boards with self-tapping screws 90 mm long using a screwdriver at the rate of 3-4 self-tapping screws per 1 stitched board. Then we align the edges of the shield with a circular saw using a carpentry corner.

You will need 3 of these prefabricated panels, they will become the ribs of the formwork.

Formwork installation

Formwork installation scheme.

To complete this stage of work, a team of 3-4 people is required.

To facilitate assembly, we put one shield as a base. We install a spacer under each blooper so that nothing sags under load.

As a result, we got a box of three prefabricated panels in the place where the future beam will be located.

Figure 4. Types of attachment of ribs to the base. A - 35 cm, B - 40 cm, B - 45 cm.

Now we harvest the spacers from the reinforcement. They will be needed in order to withstand the desired size of the beam and prevent bevels. We simply cut the reinforcement into pieces of the desired length (35, 40 or 45 cm).

Assembly of prefabricated metal structures

Reinforcement cage diagram.

We start knitting the frame on the ground. We make 8 veins of a given length from the reinforcement (the length of one vein is equal to the length of the future beam).

The ends of the clamp are overlapped, that is, there should be an overlap of the ends of the clamp, which are fastened to each other with a double knitting wire with a diameter of 0.3 mm.

The wire is folded in half to form a double knitting wire. It is with such a wire that the ends of the clamp should be tied.

Knowing that the clamps should be located along the entire length of the beam at a distance of 40-50 cm from each other, it is easy to calculate the required number.

Sometimes, for various reasons, it is necessary to make veins from pieces of reinforcement of different lengths. There is nothing wrong with that, the construction technology allows it. Simply take another piece of reinforcement and overlap it with a double knitting wire over the junction of the two pieces of vein, making sure that the overlap is 60 cm on each side. This immediately explains why builders prefer to make veins from solid pieces of rebar rather than assemble them from pieces. After all, if you collect from pieces of different lengths, you will get a strong overspending of building material. Moreover, this work is carried out when the frame is already inside the box.

Diy monolithic flooring scheme.

Now we take pre-prepared pieces of reinforcement - spacers. We install them on top of each stud. We twist the studs to the light stop of the spacers so that they hold.

After installing the spacers, check everything again with a level, only then attach all the support boards to the formwork with nails or self-tapping screws.

We made sure that everything was done correctly - then feel free to pour concrete.

After 3-5 days, in good weather, the concrete will dry out, in bad weather, it will take longer.

After the concrete is completely dry, you can start dismantling the wooden formwork and installing the floor slabs themselves.