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

Sealing of joints should be performed after checking the correct installation of the plates, accepting the welded joints of the elements in the junctions and performing anti-corrosion coating welded joints and damaged areas of coating of embedded products. Concrete mixtures used for sealing joints must meet the requirements of GOST 7473-94 and the project.

After installing and welding the anchors, the loop nests in the slabs must be monolithic with M 100 mortar.

The horizontal shtraba in the walls must be laid with bricks with a careful wedging of the masonry.

The device of monolithic sections in the ceilings

Base normative documentation: www.complexdoc.ru

and in height, the reliability of their fixation.

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

Database of normative documentation: 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: employees of the quality service, foreman (foreman), representatives of the technical supervision of the customer.

Technical requirements

SNiP 3.03.01-87 p. 2.14, tab. 2

Permissible deviations:

- in the distance between:

- separately installed working rods - ± 20 mm;

- mesh rows - ±10 mm;

- from the design thickness of the protective layer of concrete with its thickness up to 15 mm and the linear dimensions of the cross-section of the structure:

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 dropping of the concrete mixture into the formwork of the slabs should not exceed 1.0 m.

Database of normative documentation: www.complexdoc.ru

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

Not allowed:

Add water at the place of laying the concrete mixture to increase its mobility.

Reinforcement of monolithic sections should be documented by an act of examination of hidden works.

Requirements for the quality of the materials used

GOST 7473-94. Concrete mixes. Specifications.

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

GOST 10922-90. Welded reinforcing and embedded products, welded joints of reinforcing and embedded products of reinforced concrete structures. General specifications.

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

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

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

Deck boards must have a width of no more than 150 mm.

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 boards, more than 3 mm on the deck of wood in the amount of not 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, and the protective coloring of surfaces that do not come into contact with concrete.

Limit deviations for reinforcing meshes, mm:

Database of normative documentation: www.complexdoc.ru

- width, cell sizes, difference in the length of the diagonals of flat meshes, free ends of the rods - ± 10;

- lengths of flat grids - ±15.

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

Concrete mixtures should be characterized by the following indicators:

- strength class;

- workability;

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

- size of fillers.

By agreement with the design organization exercising architectural supervision, it is allowed not to take samples of the concrete mix at the place of their laying in a monolithic structure, but to evaluate the strength of concrete according to the control data of the concrete mix manufacturer.

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 laying.

Work instructions

SNiP 3.03.01-87 paragraphs. 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 laying the concrete mixture, the cleaned surfaces must be washed with water and dried with a jet of air.

Concrete mixtures should be laid in concrete structures in horizontal layers of the same thickness without gaps, with sequential laying in one direction in all layers. Reinforcing steel (bar, wire) and rolled products, reinforcing products and embedded elements must comply with the project and the requirements of the relevant standards. The replacement of the reinforcing steel provided for by the project must be agreed with the customer and the design organization. Installation of reinforcing structures should be carried out mainly from large-sized blocks or unified prefabricated meshes.

Scheme of a monolithic section.

Surface preparation

Structural calculations

Sometimes you have to make wide monolithic sections between floor slabs. They must be calculated according to the current loads. In the drawing, a monolithic section 980 mm wide is developed, based on two hollow-core slabs. The conditions for such a monolithic section (loads, reinforcement principles, etc.) are detailed in the article.

Monolithic section between two prefabricated slabs

• mesh and frame welding

• • Installation of supports and formwork
  • Concrete mix and pouring
  • Final Recommendations

• form a reinforcing mesh
• prepare concrete mix
• pour concrete correctly.

Necessary materials and tools

• concrete mixer

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

Back to index

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 which will take a long time to dry.

Sources:

www.sferatd.ru

Monolithic sections between floor slabs

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

Scheme of a monolithic section.

Surface preparation

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

So, to make a monolithic floor area, you will need the following tools: perforator, wood screws 90 mm long, threaded studs standard 2 m each, nuts, washers, open-end and cap wrenches, concrete drills, wood drills 90 cm long, screwdriver, cruciform cue balls for a very good quality screwdriver ( good quality required because the edges of low-quality cue balls are erased very quickly), a hook, a grinder with metal discs, a circular saw with diamond-coated(for cutting boards along and across the fiber), an 800-gram hammer, a sledgehammer up to 3 kg, steel nails 120 mm in size, a tape measure - 2-3 pieces (tape measures are necessary for 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, carpenter's stapler with staples, level.

Building materials will also be required: knitting wire with a diameter of 0.3 mm for tying 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 the means of protection in advance, because you and your assistants will have to work at a height of injury among nails, rebar and boards sticking out in all directions. For protection you will need: gloves, closed shoes (construction boots or shoes made of thick fabric like army berets of the old sample), goggles, 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 will 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, from which side the rise will be flight of stairs, and only after that we calculate the dimensions and number of floor slabs.

The length of the floor slab 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 the fact that there should be a gap of 7 cm between the slabs. After everyone has calculated and exactly found out 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 gap of 7 cm 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 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 a rib 45 cm high, where 40 cm is the height of the future floor beam and 5 cm is the necessary margin. They are sewn together with transverse pieces of boards 5x50 mm and 40 cm long. These boards, called slippers, are located along the entire length of the shield every 40-50 cm. Remember: the first and last slippers should be no closer than 10 cm from the edge of the shield edge. We fasten the slippers with boards with self-tapping screws 90 mm long using a screwdriver at the rate of 3-4 self-tapping screws per 1 board to be sewn. Then align the edges of the shield circular saw using a carpenter's corner.

It will take 3 of these prefabricated shields, they will become formwork ribs.

Formwork installation

Formwork mounting scheme.

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

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

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

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

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

Now we prepare spacers from reinforcement. They are needed to survive right size beams and prevent bevels. We simply cut the reinforcement into pieces of the desired length (35, 40 or 45 cm).

After that, we proceed to upholstery of the resulting box with a film from the inside, while using a carpentry stapler with staples. This is necessary in order to prevent excessive 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 sand and cement. After drying, gravel will show strongly on the outer edges of the beam. The entire surface of the beam will be 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.

Installation of prefabricated metal structures

Scheme of the reinforcing cage.

We start knitting a frame on the ground. We make 8 veins of a given length from 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 by hand. From a single piece of wire, it is necessary to make a square with a given length of its sides. So, for a beam measuring 35x35 cm, you need a collar with sides of 30 cm, for a beam of 40x40 cm we make a collar 35x35 cm, for a beam 45x45 cm - a collar 40x40 cm. Such dimensions of the collars are necessary so that after it is installed in the formwork, it does not touch its walls . Remember: the minimum distance between the formwork wall and the clamp should be 2.5-3 cm, no less!

This is necessary so that in the end it is not visible on the surface of the beam. metal parts collar. If the metal will show through on the surface of the beam, then it is in this place that corrosion of the metal and the destruction of concrete will begin, and hence the beam itself.

The ends of the clamp are overlapped, that is, there must 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, getting a double knitting wire. It is with such a wire that the ends of the clamp must be connected.

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 their required number.

Assembling the frame. To do this, we tie 2 wires to each side of the clamp with a double knitting wire. equal distance from the folds and between each other. Clamps are placed on the cores 40-50 cm apart. The distance between the clamps must be maintained.

We lay the finished frame in mounted 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 fix it with a stapler.

Sometimes by different reasons you have 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 rebar and tie it with an overlap with double tie wire over the junction of the two pieces of vein, with an overlap of 60 cm in each direction. This immediately explains why builders prefer to make veins from solid pieces of rebar, rather than assembling 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 with your own hands.

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

The length is calculated as follows: the width of the support beam + two board thicknesses + two slipper thicknesses + two threads for screwing nuts with washers. The resulting studs are inserted into the box.

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

We take the 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 with the help of side struts. The installation of studs and the installation of spacers is one of the important prefabricated stages of construction.

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

Now let's start hanging the frame. To hang the frame, it must be tied to the studs. The easiest way to do this is with a height template - a small board measuring 2.5x2.5x30 cm. It's simple: put a height template under each collar and fasten it to the hairpin at the points of contact 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 breaks in the film or contact of the clamps with the walls of the box. Then we fill the transverse rails for stitching the formwork boards. From the bottom of the base we measure the height of the beam and drive in 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 lower and side struts, they should be free to withstand a decent weight. If in doubt, add more supports. Remember: concrete has high density. The slightest oversight - 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 grade M300 or M350 is used, which is best bought ready-made, since the beam must be poured at a time without interruption. If this is not possible, hire a large concrete mixer to mix all the required volume of concrete on site in one step.

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

After the concrete has completely dried, you can proceed to dismantle wooden formwork and installation of the floor slabs themselves.

o-cemente.info

Monolithic section between two prefabricated slabs

Such a monolithic section operates as a slab resting on adjacent prefabricated slabs. To do this, it has a working reinforcement curved by a trough, the diameter of which depends on the width of the section ( effective length slabs of this section) and floor loads. Longitudinal reinforcement is constructive, it creates a reinforcing mesh, but does not carry a load. An anti-shrink mesh made of smooth small-diameter reinforcement is also laid on top of a wide monolithic section.

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

We divided by two, because. a monolithic section rests on two plates, and each of them accounts for 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 section, the width of the slab and the loads acting on it.

Beam monolithic section.

class="eliadunit">

Add a comment

svoydom.net.ua

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 on the spot you have to change design solution, and as a result - a 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 plates provide for their laying with seams of 15 mm, that is, almost end-to-end. The regulatory literature prescribes the installation of monolithic sections with reinforcement at a distance between the plates of 300 mm.
To seal the joints between the floor slabs, it is necessary to use concrete on quick-hardening Portland cement or Portland cement grade M400 or higher on fine aggregate. The grain size of the filler should not be more than a third of the interslab gap and three quarters of the clear size between the reinforcing bars. Plasticizers and setting accelerators must be introduced into the concrete mixture.

If a standard seam between plates 10-15 mm wide is obtained, then usually a reinforcement bar is laid on the bottom of the seam, which is arranged in the form of a “cone”, and poured with a solution.

We seal off-design joints up to 300 mm

In the event that the width of the joints between adjacent plates does not exceed 300 mm, it is relatively easy to seal such a joint, there are several ways to fill the joints to choose from.

Method 1

• From the bottom of the adjacent slabs, using spacers, we install a board or a sheet of plywood that bridges the gap - this is the formwork;
• A piece of roofing material or film can be laid on top of the formwork, then there will be no traces of concrete on the formwork, and it can be used further;
• The gap between the plates is filled 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 fixed formwork from galvanized roofing steel with a thickness of 0.8-1 mm according to the size of the gap between the plates, resting on the upper edge of the plate (trough). The profile of the side surface of the plates will provide additional spacer and rigidity to the monolithic section.

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. At the bottom (in the plane of the lower edge of the plates) we put a strip of galvanized roofing steel, plywood or plastic, concrete. This method provides reliable adhesion of the monolithic section to the plates.

Method 4

If you come across a pair 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 sections with a width of more than 300 mm

If the gap between the plates is from 100 to 300 mm, we perform a monolith with reinforcement. There are also options here.

Option 1

It is used in cases where formwork from below is not possible.

• We install load-bearing bars with a section of 40x100 mm on the edge, in increments of 1 m, resting on adjacent plates;
• We fasten the formwork panels to the load-bearing 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 concrete.

Option 2

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

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

Do not settle for sealing the gap between the wall and the slab with lightweight concrete cellular 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 the blocks and the need for costly repairs to the floor.

The areas between the wall and the slab are sealed in the same way.

This story tells not only about the sealing of the seams, but also about the anchoring of the plates among themselves:

Ceiling seam from the underside

Intertile seams - rustication at installation is filled with concrete, then the ceiling is primed, puttied and painted, if no other finish is provided.

The sequence of sealing rusts

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

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

Uneven house shrinkage

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

• Uneven settlement of the building;
• Wrong brand of concrete;
• Poor quality concrete.

Let us dwell on the causes of uneven precipitation. It may occur if:

• Structural flaws - incorrectly designed foundation;
• Foundation devices without regard to geology, depth of soil freezing and depth of occurrence ground water;
• Poorly executed work on the construction of the foundation and masonry walls;
• Poor quality building materials.

To understand the cause of the appearance of cracks, it is sometimes necessary to order a construction expertise.

Decorative ceilings

A protective layer of concrete 30-50 mm thick should ensure that there are no rust stains on the ceiling from reinforcement, but sometimes this layer is ineffective. From seeing stains on the ceiling, traces of leaks and rust cracks the best remedy- the device of a suspended, hemmed or stretch ceiling.

Decorative ceiling - The best decision alignment if needed ceiling surface. It will close all construction flaws and give completeness to the interior. If you want to reduce the height of the room, arrange multi-level or dropped ceilings drywall, acoustic boards or a combination of various materials.

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

Every problem has its solution. Sealing joints between boards aerated concrete house, even with a large width, does not constitute a large constructive or technical problem. From the proposed options, it is easy to choose the appropriate one for a particular case.

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

Excellent article 2

izbloka.com

Monolithic section between two prefabricated slabs

Such a monolithic section operates as a slab resting on adjacent prefabricated 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 ceiling. Longitudinal reinforcement is constructive, it creates a reinforcing mesh, but does not carry a load. An anti-shrink mesh made of smooth small-diameter reinforcement is also laid on top of a wide monolithic section.

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

As you can see, the sections are of different widths, but when setting out to make a wide monolithic section based on slabs, you must always check whether the floor slabs can withstand it. This is the most important point in the design of monolithic sections. The bearing capacity of floor slabs is different (from 400 to 800 kg / m2 - without taking into account the weight of the slab).

Suppose we have two prefabricated slabs 1.2 m wide, between which there is a monolithic section 0.58 m wide. The bearing capacity of the slabs is 400 kg/m2, i.e. one linear meter of such a plate can withstand 1.2 * 400 \u003d 480 kg / m.

We calculate the load per 1 linear 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. a monolithic section rests on two plates, and each of them accounts for half the load.

In addition to the weight of the monolithic section, we have the load on the slabs from the floor structure (140 kg/m2), from the partitions (50 kg/m2) and the live load from the weight of people, furniture, etc. (150 kg/m2). Multiplying all this by the coefficients and by the width of the precast slab plus half the width of the monolithic section, and adding the load from the own 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 turned out to be more than the plate can withstand. But if we 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/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 section, the width of the slab and the loads acting on it.

Types of monolithic sections in a prefabricated floor.

Monolithic section between two prefabricated slabs.

Monolithic section between prefabricated slab and wall.

Beam monolithic section.

Monolithic sections on metal beams with a slab on top.

Monolithic sections on metal beams with a slab from below.

Calculation of monolithic sections on metal beams.

class="eliadunit">

Add a comment

svoydom.net.ua

Monolithic sections between floor slabs

Monolithic sections between floor slabs

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

Scheme of a monolithic section.

Surface preparation

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

So, in order to make a monolithic section of the floor, you will need the following tools: a puncher, wood screws 90 mm long, standard threaded studs 2 m each, nuts, washers, open-end and cap wrenches, concrete drill bits, wood drill bits 90 cm long, screwdriver cruciform cue balls 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 metal discs, a diamond-coated circular saw (for cutting boards along and across the fiber), an 800-gram hammer, sledgehammer up to 3 kg, steel nails 120 mm in size, tape #8211 2-3 pieces (tapes are necessary for accurate measurements, there should be a sufficient number of them, as they often break and get lost), carpenter's pencil, carpenter's angle 50 cm long, joiner's stapler with staples, level.

Building materials will also be required: knitting wire with a diameter of 0.3 mm for tying 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 the means of protection in advance, because you and your assistants will have to work at a height of injury among nails, rebar and boards sticking out in all directions. For protection, you will need: gloves, closed shoes (construction boots or shoes made of thick fabric such as old-style army berets), 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 will 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, from which side the flight of stairs 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 gap of 7 cm 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

Such a monolithic section operates as a slab resting on adjacent prefabricated 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 ceiling. Longitudinal reinforcement is constructive, it creates a reinforcing mesh, but does not carry a load. An anti-shrink mesh made of smooth small-diameter reinforcement is also laid on top of a wide monolithic section.

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

As you can see, the sections are of different widths, but when setting out to make a wide monolithic section based on slabs, you must always check whether the floor slabs can withstand it. This is the most important point in the design of monolithic sections. The bearing capacity of floor slabs is different (from 400 to 800 kg / m 2 - without taking into account the weight of the slab).

Suppose we have two prefabricated slabs 1.2 m wide, between which there is a monolithic section 0.98 m wide. The bearing capacity of the slabs is 400 kg / m 2. i.e. one linear meter of such a plate can withstand 1.2 * 400 \u003d 480 kg / m.

We calculate the load per 1 linear 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. a monolithic section rests on two plates, and each of them accounts for half the load.

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

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 turned out to be more than the plate can withstand. But if you take a plate with a bearing capacity of 600 kg / m 2. then one linear meter of such a plate can withstand 1.2 * 600 \u003d 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 section, the width of the slab and the loads acting on it.

Monolithic section of the overlap with an oblique corner. Reinforcing cage for a slab with a bevel. Concrete work for a monolithic slab with a bevel. Curing and maintenance of concrete.

Reinforcing work should be carried out in accordance with the requirements and recommendations of SNiP 3.03.01-87 Bearing and enclosing structures, GOST 19292-73. Instructions for welding reinforcement joints and embedded parts of reinforced concrete structures SN 393-78. Guidelines for the production of reinforcing work. and other applicable regulations.

Concrete work 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 regulations given in SNiP III-4-80. working drawings and instructions for PPR - a project for the production of works.

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

In houses. where the plan provides for construction with an angular transition of the walls at an angle not of 90 °, as usual, but, for example, 45 ° - the ceilings are made 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 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 at reinforced concrete factories - such a frame requires less reinforcement consumption), then in such a truncated form the slab will lose its bearing capacity. And then it can immediately burst during such a circumcision.

NOTE: A stressed reinforcing cage is a cage whose bars have been clamped into special form. and then, by heating, stretched to the desired size.

Then it was welded with transverse frames. poured with concrete and dried in a curing chamber. The cutting of the rods from the fixed shape was already carried out when the slab was in ready-made. Those. the rebars in the 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 carried out 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 cage for a beveled slab (UM-1).

The manufacture of the reinforcing cage and mesh must be carried out according to the drawings and have the exact location of the elements to be welded. The replacement of the reinforcing steel provided for by the project by class, grade and assortment is agreed with the design organization.

Technological process the manufacture of a reinforcing cage provides for:

• straightening and cutting steel reinforcement, wire. supplied in coils with a diameter of 3 ... 14 mm and in bars with a diameter of 12 ... 40 mm on rods of a specific length
• straightening (bending) and butt welding of rods to the desired size
• mesh and frame welding
• pre-assembly (welding and wire tying) of volumetric reinforcing blocks
• transportation and installation of frames at the construction site.

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

Reinforcing mesh must be welded by spot welding. For the frame and mesh, reinforcement is used according to the specified table.1.

Table 1: Reinforcement specification for frame monolithic slab overlap.

Do-it-yourself creation of a monolithic section between the plates

• Necessary materials and tools
• Stages of work on the formation of a monolithic section between floor slabs
  • Installation of supports and formwork
  • Formation of a reinforcing lattice
  • Concrete mix and pouring
  • Final Recommendations

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

If it is necessary 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 monolith section between floor slabs, it is important to correctly perform following works:

• install supports and form formwork
• form a reinforcing mesh
• prepare concrete mix
• pour concrete correctly.

Correct execution of these types of work will create a solid and reliable section of the monolith between the floor slabs in the right place.

Necessary materials and tools

Considering that the work on the installation of a concrete section of the floor consists 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 how much distance between the plates needs to be filled. The default list looks like this:

On the wooden beams a horizontal formwork support is laid.

• plywood or boards to create a direct surface for pouring mortar and side formwork, building foil
• wooden beams or metal channels to create a horizontal support on which plywood or a plank pallet will be laid
• timber (120-150 mm), wooden beams or channel to create load-bearing supports for the formwork platform
• reinforcing bars (15-25 mm), wire for tying, metal chairs for installing reinforcing bars on required height(you can also use reinforced mesh)
• cement M400, sand, gravel, water for mixing concrete
• concrete mixer
• circular saw 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 overlapping area between the slabs, a protective film for covering this area.

The amount of all materials depends directly on the distance between concrete slabs need to be covered and what area as a whole is occupied by a monolithic section of the overlap. Usually, in private houses, such an overlapping area is not very large, so its formation is not too challenging task. However, at the same time, all the same, one should adhere to a clear phased approach and rules for working with building materials and structures.

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

The monolithic section of the floor between the slabs is formed in approximately the same way as any monolithic floor. Given the small area of ​​\u200b\u200bsuch a site, the work, of course, is simplified, but it is necessary to adhere to all building codes and rules. 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.

Any building, regardless of the number of storeys, has floors. They can be wood or concrete. The most reliable is a monolithic floor slab. Consider its advantages and construction rules.

1. Types of plates, schemes
2. Self-laying technology
3. Price

Types and features of the device

The most popular flooring today, both in cottage and industrial construction, is, of course, a monolithic slab.

Those who have the opportunity to order construction equipment (crane) prefer ready-made reinforced concrete products (quickly and fairly cheaply). Many pour the monolith themselves, creating a system of removable or fixed formwork.

Prefabricated monolithic ceilings are also very convenient and available (Marco, TERIVA, NPP, YTONG).

Since a monolithic floor slab is one of the load-bearing structures, heavy grade concrete, lightweight structural concrete of a dense structure, as well as dense silicate concrete can be used for their manufacture.

To install a monolithic floor, it is worthwhile to determine its type in advance, since they also differ in technical parameters, and for the price.

Advantages of floor slabs and their types

According to the structure, the panels are solid and hollow, and according to the method of installation, they are prefabricated, prefabricated-monolithic and monolithic. All of them fall under the concept of monolithic floors; at the finishing stage, all layers are monolithic. Such structures are not only high rates strength, but also fire safety, moisture resistance and extremely durable.

Prefabricated floors from reinforced concrete panels

Most often they are made from round-hollow panels, which are distinguished by an affordable price, lighter weight, increased thermal insulation properties compared to monoliths. Overlappings from them are quickly mounted, and a wide standard range allows you to choose a plate according to the needs of the customer. The only drawback is the mandatory use of a crane.

The length of the produced plates is from 1.8 to 15 meters, the width is from 0.6 to 2.4 m.

The standard thickness of factory PCs is 220 mm, and the calculated bearing capacity (from 350 to 800 kgf / m2) of the panels differs due to the use of different grades of concrete and reinforcement. The weight of the plates depends on the size and ranges from 0.65 to 2.5 tons.

Marking allows you to determine the necessary parameters. The letters indicate the type of product PC (floor panel), PNO (lightweight decking panel), the numbers indicate the length and width in decimeters, as well as the load in kilopascals. By removing the own weight of the slab from the calculated load, the allowable payload is obtained. When laying parts on the wall, the support depth must be observed at least 12 cm.

If the length of the overlapped room exceeds 9 meters, a monolithic ribbed slab will do. It is twice as light (the weight of a square meter is about 270 kg), which reduces the total load on the walls by almost a quarter.

Sometimes there are cracks in the floor slabs. They are shrinkable or deformable. Cracks up to 0.3 mm are not dangerous, but if the panel has large diagonal or longitudinal cracks, it is better to replace it. If cracks appeared during operation, then it is necessary to reinforce the slab by building up an additionally reinforced screed layer on top.

To insulate the ends of the panels in the outer wall, which serve as "cold bridges", lightweight concrete thermal liners are used.

Practice shows that sometimes the dimensions of the room are disproportionate to the width of the panels and it becomes necessary to additionally fill the monolithic sections between the plates. If the expansion of the slabs is up to 5 cm, such seams are poured with concrete without reinforcement, seams over this size require the laying of an additional reinforcement cage.

Before laying the floor bearing walls be sure to arrange reinforced monolithic belt under the plates. This is a continuous closed beam, the reinforcement of which is carried out with high-quality rolled metal.

In order to guarantee the purchase of high-quality reinforced concrete PCs, it is better to buy them directly at the reinforced concrete factories or in construction companies, which have capacities for the production of reinforced concrete products.

The average price of one square meter of a hollow-core floor panel in Moscow and the region ranges from 1,100 to 1,200 rubles. The most popular plates are from 3 to 7 meters, while products of smaller and longer lengths will cost more (in terms of m2). The most popular width is 1.2 - 1.5 m.

Plates up to 1 meter and 1.8 meters wide are not produced by all manufacturers, which also affects their price.

Prefabricated-monolithic

The device of prefabricated monolithic floors has not yet become the most popular method, but has already won its niche in the construction market. The essence of the method: reinforced concrete beams are laid on the walls (step - 60 cm) and hollow blocks between them, the whole structure is monolithic.

Installation is possible without the use of mechanisms, since the weight of a running meter of a beam is 19 kg. Due to large-hollow blocks, it is light in weight and has improved thermal insulation qualities. The only negative is the complexity (the blocks are stacked manually).

Before pouring concrete, the structure should be reinforced (wire mesh with cells 10x10 cm), the minimum thickness of the concrete layer is at least 5 cm.

One square meter the finished floor weighs up to 390 kg (if the blocks are made of expanded clay concrete) and up to 300 kg (if the blocks are made of polystyrene concrete). And this is almost two times less than a monolithic ceiling 2 cm thick (about 500 kg / m2).

GSK Columbus (MARCO) offers an average of 1,100 rubles per square meter of structures that make up prefabricated monolithic floor slabs, and turnkey installation works will cost 3,000 - 3,500 rubles per m2.

Self-assembly

When building a house with your own hands, it is possible to install monolithic interfloor ceilings on site. After forcing the walls of the first floor, they proceed to the construction of the formwork for a monolithic slab. supports the same size and heights are set in increments of 1 meter around the entire perimeter of the slab. The beams connecting them are adjacent to the walls closely.

Boards are laid on the supports, roofing material is on top (without entering the walls). The formwork is placed around the perimeter of the future ceiling so that the monolith is securely supported by the walls. The reinforcement is placed at a distance of at least 50 mm from the insulation layer. The calculation of the required footage of rods is done according to the formula - S (area) x4x2. The most problematic moment is the filling.

To supply concrete to a height, you need to order a concrete pump.

Casting the slab on your own

Benchmarking Costs

A comparison of two types will be very indicative: using ready-made hollow-core reinforced concrete slabs and building a monolithic slab with your own hands for a 6x6 floor (conditional dimensions). The ceiling thickness in both cases is 0.22 m, bearing load is 8 kPa.

Covering with tiles:

• It will take 5 plates PK 62.12 - 8. (Costs - 8,000 x 5 = 40,000 rubles)
• Delivery and rental of a crane will cost approximately 10,000.
• Filling joints and anchoring (0.5 m3 of concrete) - 2,000
• Installation takes place in one day, two workers (s/n) are enough.

Total - about 55,000.

Do-it-yourself monolith:

• The cost of formwork (lumber 2 m3) and fasteners - 8,000.
• Fittings (steel rod diameter 10, mesh according to calculation + wire for tying) about 0.6 tons with delivery can be bought for 20,000 rubles
• Ready-made concrete (M300) 8 m3 and rental of a concrete pump will cost 26,000 - 29,000
• Workers (4 days formwork, reinforcement knitting, pouring) - 20,000.
• Costs for Additional materials and tools - 3,000.
• The period of technological hardening of concrete is 3 days.

The result is about 80,000 rubles and a week of time.

The cost of a square prefabricated floor is slightly more than 1,500, and a monolithic one is 2,200.

Source: http://stoneguru.ru/monolitnaya-plita-perekrytiya.html

Monolithic sections between floor slabs

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

Scheme of a monolithic section.

• 1 Surface preparation
• 2 Structural calculations
• 3 Formwork
• 4 Formwork assembly
• 5 Prefabricated installation metal structures

Surface preparation

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

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

Building materials will also be required: knitting wire with a diameter of 0.3 mm for tying 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 the means of protection in advance, because you and your assistants will have to work at a height of injury among nails, rebar and boards sticking out in all directions. For protection, you will need: gloves, closed shoes (construction boots or shoes made of thick fabric such as old-style army berets), 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 will 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, from which side the flight of stairs will rise, and only after that we calculate the size and number of floor slabs.

The length of the floor slab 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 everyone has calculated and exactly found out 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 gap of 7 cm 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 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 a rib 45 cm high, where 40 cm is the height of the future floor beam and 5 cm is the necessary margin. They are sewn together with transverse pieces of boards 5x50 mm and 40 cm long.

These boards, called slippers, are located along the entire length of the shield every 40-50 cm. Remember: the first and last slippers should be no closer than 10 cm from the edge of the shield edge. We fasten the slippers with boards with self-tapping screws 90 mm long using a screwdriver at the rate of 3-4 self-tapping screws per 1 board to be sewn.

Then we align the edges of the shield with a circular saw using a carpenter's corner.

It will take 3 of these prefabricated shields, they will become formwork ribs.

Formwork installation

Formwork mounting scheme.

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

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

We fasten the ribs to the base of the formwork. We fasten the ribs, taking into account the width of the beam we need. Three sizes of beams are allowed: 35, 40, 45 cm.

With the required width of 35 cm, both side ribs are flush. With the required width of 40 cm, only one edge of the two prefabricated shields is flush.

If you need a beam 45 cm wide, the ribs are fixed without using this technique. Everything is fastened with self-tapping screws.

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

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

Now we prepare spacers from 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).

After that, we proceed to upholstery of the resulting box with a film from the inside, while using a carpentry stapler with staples. This is necessary in order to prevent excessive 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 sand and cement. After drying, gravel will show strongly on the outer edges of the beam. The entire surface of the beam will be 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.

Installation of prefabricated metal structures

Scheme of the reinforcing cage.

We start knitting a frame on the ground. We make 8 veins of a given length from 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 by hand. From a single piece of wire, it is necessary to make a square with a given length of its sides.

So, for a beam measuring 35x35 cm, you need a collar with sides of 30 cm, for a beam of 40x40 cm we make a collar 35x35 cm, for a beam 45x45 cm - a collar 40x40 cm. Such dimensions of the collars are necessary so that after it is installed in the formwork, it does not touch its walls .

Remember: the minimum distance between the formwork wall and the clamp should be 2.5-3 cm, no 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 will show through on the surface of the beam, then it is in this place that corrosion of the metal and the destruction of concrete will begin, and hence the beam itself.

The ends of the clamp are overlapped, that is, there must 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, getting a double knitting wire. It is with such a wire that the ends of the clamp must be connected.

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 their required number.

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

We lay the finished frame in the installed box, trying 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 fix 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 rebar and tie it with an overlap with double tie wire over the junction of the two pieces of vein, with an overlap of 60 cm in each direction. This immediately explains why builders prefer to make veins from solid pieces of rebar, rather than assembling them from pieces.

After all, if you assemble from pieces of different lengths, you will get a strong overrun of building material. Moreover, this work is carried out when the frame is already inside the box.

Do-it-yourself monolithic flooring scheme.

After 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 slipper. We cut the studs to the length we need.

The length is calculated as follows: the width of the support beam + two board thicknesses + two slipper thicknesses + two threads for screwing nuts with washers. The resulting studs are inserted into the box.

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

We take the 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 with the help of side struts. The installation of studs and the installation of spacers is one of the important prefabricated stages of construction.

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

Now let's start hanging the frame. To hang the frame, it must be tied to the studs. The easiest way to do this is with a height template - a small board measuring 2.5x2.5x30 cm. It's simple: put a height template under each collar and fasten it to the hairpin at the points of contact 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 breaks in the film or contact of the clamps with the walls of the box. Then we fill the transverse rails for stitching the formwork boards. From the bottom of the base we measure the height of the beam and drive in 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 lower and side struts, they should be free to withstand a decent weight. If in doubt, add more supports. Remember: concrete has a high density. The slightest oversight - 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 grade M300 or M350 is used, which is best bought ready-made, since the beam must be poured at a time without interruption. If this is not possible, hire a large concrete mixer to mix all the required volume of concrete on site in one step.

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

After the concrete has completely dried, you can begin to dismantle the wooden formwork and install the floor slabs themselves.

Even in professional schemes floor layouts often there is a monolithic section between the slabs in buildings of complex configuration. It is much easier to concrete this piece than to cast a solid slab, since the lower, upper levels are set by default, there is no side formwork, the lower shield is sufficient. One option is to use prefabricated monolithic ceiling SMP.

Technology of a monolithic section of overlap

In individual construction, slabs of a standard height of 220 mm are more often used. This must be taken into account when reinforcing a makeshift section, ensuring the minimum possible protective layer 15 - 30 mm. If the monolithic section between the floors protrudes above the neighboring ones, an increase in the thickness of the screed will be required when finishing the floors.

Factory floors have voids in which it is convenient to pull the electric cable. In a home-made slab, communications must be walled up before pouring so as not to hammer concrete later. This technique often used to make hatches. If openings for stairs are cut out in industrially manufactured slabs, the reinforcement scheme is violated, the structure loses its load-bearing capacity, and becomes dangerous for operation.

formwork

The monolithic section between the plates is poured onto the shield, which must be supported from below with racks. The simplest calculations of lumber sections - the most budget option for an individual developer, show that boards, timber with minimum dimensions can be used for formwork:

In this case, the structure will withstand the weight of the concrete floor without sagging or changing the geometry.

A monolithic section between floors by default has a side formwork, which is the ends of reinforced concrete products laid in place. It remains to place the boards under the bottom surface, bringing their edges under the existing PC boards, to control the flatness, the absence of deflection in any direction. To do this, follow the steps:

After that, the remaining posts are mounted between the extreme posts, ensuring the horizontality of the beams, girders, deck boards. When choosing wood of the 2nd grade, the bending strength of the lumber is insufficient. In addition to the lower piping of the poles with 25 mm boards, which is necessary to prevent shifting during pouring, a similar piping is additionally used at the level of 1.3 - 1.5 m. All poles are sewn with an "inch" across, along, forming a rigid spatial structure.

Stackable racks are used to facilitate demoulding:

• they are manufactured less than the design height
• are built up in pieces in the upper part, which is enough to unscrew when dismantling

When stripping, the lower bars of the racks are first dismantled, then the beams with the upper pieces of the racks are removed. After that, the deck with the runs screwed to it is dismantled. AT further all lumber is suitable for the construction of a truss system. If you choose wood of grade I, you can reduce the cost of the "inch" board for tying the racks in the middle part.

If it is necessary to fix formwork elements to existing walls, it is better to use anchors with metal sleeves. They are easily removed from the masonry after stripping, unlike dowel-nails, the plastic elements of which are almost impossible to remove from the wall.

Deck

At this stage, the monolithic section between the slabs is equipped with a deck over the girders. The edges of the boards lead under the existing floor slabs, the middle lies on the beams, which ensures the rigidity of the structure.

The gaps between the boards are foamed from the inside of the formwork (top), the boards are covered plastic wrap. This will keep water in the concrete, facilitate stripping, and prevent cracking of the floor slab. Plank construction is convenient for wiring engineering systems- holes of any diameter are drilled with crowns, drills without problems in any area.

When the width of the hollow section is less than 1 m, technology without racks, beams is often used:

The deck is attracted by wire twists through the beam to the lower planes of the laid slabs, reinforced, poured according to standard technology. It is not recommended to punch holes for reinforcement in the ends of the slabs, as they weaken the design of hollow PC products. Wire clamps are cut with angle grinders when stripping flush, part remains inside the monolithic piece.

To increase the overlapping resource, reinforcement not lower than A-III of a periodic section (hot-rolled) with a diameter of 10 - 16 mm is used. The main nuances of reinforcement are:

For knitting the joints of the cells, a wire of 1 - 2 mm is used, the knots are created with manual, mechanical hooks, home-made equipment installed in a screwdriver or with a special knitting gun.

The area between the slabs can be reinforced with a ready-made or locally bonded mesh. In the first case, the dimensions of the longitudinal, transverse rods are taken, taking into account 4 cm of the protective layer on each side. Nets are knitted on flat ground, laid on the deck on top of the film on spacers 15 - 30 mm. More commonly used concrete blocks 10 x 10 cm or plastic stands with cross slots for fittings.

For the top layer, these devices are not suitable due to small size. Clamps, brackets, tables are used here different forms, designs. The main task of these elements is to support the upper grid in the design position (15 - 30 mm below the plate plane).

Used for bending reinforcement homemade devices. For example, a piece of 50 - 70 cm pipe with a mandrel of 10 - 15 cm welded to one of its edges will provide the required radius (5 bar diameters), and will reduce the effort.

The area between the slabs may contain the input nodes of engineering systems. Mortgages, void formers are installed after or before reinforcement, depending on the location, configuration, size. For example, it is better to mount a 11 cm sewer cross before laying the grids; sleeves for water pipes can be installed at any stage.

Void formers complex shape necessary for specific communications. Therefore, they are usually made from Styrofoam, Styrofoam, cutting pieces of the same format to achieve the desired length from a 5 cm sheet.

For rigid fixation, the absence of movement of light polymer fittings, polystyrene foam void formers, the following technology is used when pouring the ceiling:

• plugs are put on the fitting
• fixed with screws from below through the deck
• or the plug is screwed on top with screws
• then a fitting is put on it

These sections, which are self-filled, can be supported by internal flights of stairs. For them it is necessary:

• release reinforcement of the lower grid
• make a step for supporting the reinforced concrete march structure with a reciprocal seat
• install formwork for stairwell/hatch

For the release of reinforcement, it will be necessary to make cuts in wooden shield jumpers with a chain saw. Put the board on the reinforcement, passing it into the cuts, foam the remaining cracks. Steps, recesses are created by screwing narrow strips to the formwork from the inside.

fill

Before placing concrete between floor slabs, it is recommended to prime the ends of existing slabs to improve adhesion. The main recommendations for concrete work are:

Concrete is contraindicated in solar ultraviolet, hot dry weather, frost. Covering with burlap, sawdust, sand allows you to wet the surface without destruction. The film protects against sun rays, in winter it provides the principle of a thermos, keeping the heat that forms during the hydration of cement with water.

The brand of concrete is selected in accordance with the standards of SP 63.13330 for reinforced concrete structures:

• density - 1 800 - 2 500 kg / m 3
• compressive strength - from B7.5

Waterproof, frost resistance for structures operated indoors, special significance does not have. At self-manufacturing concrete, it must be taken into account that the probability of cracking is sharply reduced if a filler of various fractions with a continuous series of grains is used. Sand should not exceed 1/3 of the total aggregate volume.

After pouring between the floor slabs, sagging may remain with the newly made section. They are polished with diamond equipment for angle grinders ("grinder") of the plate type. If the project includes a bulk, warm floor, screed, alignment of the joints is not necessary. For better adhesion of two adjacent reinforced concrete structures, strobes can be made in the side faces of the factory plates if the appropriate tool is available.

These recesses are filled with a mixture when laying concrete, two slabs are obtained almost monolithic. The quality of the lower edge of the slab is usually inferior to factory counterparts, therefore, finishing with stretch, level ceilings is more often used.

This technology is very convenient in the manufacture of hatches or stairwells. These technological openings can be reinforced with rods located diagonally near them, dramatically increasing the strength of reinforced concrete. If you cut a hatch in the factory slab, the integrity of the reinforcement meshes is violated, which weakens the default design. This is especially true when the opening is moved to the middle of the slab.

The technology of a monolithic section of a self-made floor allows you to fill voids when laying out slabs without reducing structural strength. Even without pretensioning the reinforcement, the plates have a high resource if the specified requirements are met.

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

Surface preparation

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

So, in order to make a monolithic section of the floor, you will need the following tools: a puncher, wood screws 90 mm long, threaded studs standard 2 m each, nuts, washers, open-end and cap wrenches, 90 cm long drills for wood, a screwdriver, cue balls on a very good quality screwdriver (good quality is required because the edges of low-quality cue balls wear out very quickly), a hook, a grinder with metal discs, a diamond-coated circular saw (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 accurate measurements, there should be a sufficient number of them, as they often break and are lost), carpenter's pencil, carpenter's angle 50 cm long, carpenter's stapler with staples, level.

Building materials will also be required: knitting wire with a diameter of 0.3 mm for tying 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 the means of protection in advance, because you and your assistants will have to work at a height of injury among nails, rebar and boards sticking out in all directions. For protection, you will need: gloves, closed shoes (construction boots or shoes made of thick fabric such as old-style army berets), 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 will 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, from which side the flight of stairs will rise, and only after that we calculate the dimensions and quantity.

The length of the floor slab 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 everyone has calculated and exactly found out 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 gap of 7 cm 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 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 a rib 45 cm high, where 40 cm is the height of the future and 5 cm is the necessary margin. They are sewn together with transverse pieces of boards 5x50 mm and 40 cm long. These boards, called slippers, are located along the entire length of the shield every 40-50 cm. Remember: the first and last slippers should be no closer than 10 cm from the edge of the shield edge. We fasten the slippers with boards with self-tapping screws 90 mm long using a screwdriver at the rate of 3-4 self-tapping screws per 1 board to be sewn. Then we align the edges of the shield with a circular saw using a carpenter's corner.

It will take 3 of these prefabricated shields, they will become formwork ribs.

Formwork mounting scheme.

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

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

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

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

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

Now we prepare spacers from 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).

After that, we proceed to upholstery of the resulting box with a film from the inside, while using a carpentry stapler with staples. This is necessary in order to prevent excessive 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 sand and cement. After drying, gravel will show strongly on the outer edges of the beam. The entire surface of the beam will be 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.

Installation of prefabricated metal structures

Scheme of the reinforcing cage.

We start knitting a frame on the ground. We make 8 veins of a given length from 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 by hand. From a single piece of wire, it is necessary to make a square with a given length of its sides. So, for a beam measuring 35x35 cm, you need a collar with sides of 30 cm, for a beam of 40x40 cm we make a collar 35x35 cm, for a beam 45x45 cm - a collar 40x40 cm. Such dimensions of the collars are necessary so that after it is installed in the formwork, it does not touch its walls . Remember: the minimum distance between the formwork wall and the clamp should be 2.5-3 cm, no 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 will show through on the surface of the beam, then it is in this place that corrosion of the metal and the destruction of concrete will begin, and hence the beam itself.

The ends of the clamp are overlapped, that is, there must 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, getting a double knitting wire. It is with such a wire that the ends of the clamp must be connected.

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 their required number.

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

We lay the finished frame in the installed box, trying 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 fix 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 rebar and tie it with an overlap with double tie wire over the junction of the two pieces of vein, with an overlap of 60 cm in each direction. This immediately explains why builders prefer to make veins from solid pieces of rebar, rather than assembling them from pieces. After all, if you collect from pieces of different lengths, you get a strong overrun of building material. Moreover, this work is carried out when the frame is already inside the box.

After 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 slipper. We cut the studs to the length we need.

The length is calculated as follows: the width of the support beam + two board thicknesses + two slipper thicknesses + two threads for screwing nuts with washers. The resulting studs are inserted into the box.

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

We take the 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 with the help of side struts. The installation of studs and the installation of spacers is one of the important prefabricated stages of construction.

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

Now let's start hanging the frame. To hang the frame, it must be tied to the studs. The easiest way to do this is with a height template - a small board measuring 2.5x2.5x30 cm. It's simple: put a height template under each collar and fasten it to the hairpin at the points of contact 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 breaks in the film or contact of the clamps with the walls of the box. Then we fill the transverse rails for stitching the formwork boards. From the bottom of the base we measure the height of the beam and drive in 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 lower and side struts, they should be free to withstand a decent weight. If in doubt, add more supports. Remember: concrete has a high density. The slightest oversight - 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 grade M300 or M350 is used, which is best bought ready-made, since the beam must be poured at a time without interruption. If this is not possible, hire a large concrete mixer to mix all the required volume of concrete on site in one step.

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

After complete, you can proceed to the dismantling of the wooden formwork and the installation of the floor slabs themselves.