Nuances of arranging beams. Beam support unit on an external wall

The beam floor is a multi-element system that carries not only mechanical loads, but is also designed to serve as a heat-insulating and sound-absorbing layer between floors, basement and roof.

All elements of the beam structure are installed and connected in a certain way and form one whole. Today we will talk to you about what such floors can be, give some tips on their construction, and deal with other issues on the topic. Let's get started!

Features of wooden beam floors

All beam floors can be divided according to the type of material used. The most common and easiest to install are wooden elements. In addition to them, reinforced concrete and steel are also used, but this is already in the area of ​​mass and industrial construction, so there is no need to describe them.

• The popularity of the tree primarily depends on its prevalence in our country and its quite reasonable cost. It is also worth noting the ease of installation, in which builders do not need heavy lifting equipment.
• Of course, wood will not last as long as metal, but correct processing the period will be very long. As they say, enough for our lifetime!

• The environmental friendliness of the material can also be a disadvantage - various insects and microorganisms like to live in wood, but all this can be easily eliminated with proper treatment with antiseptics.
• It is immediately worth noting that wood is a flammable material. To avoid this drawback, beams are impregnated with special fire retardant compounds, which impart fire-fighting properties to the wood for a certain period of time.

Interesting to know! The durability of wooden beam floors largely depends on the type of wood used. Let's take, for example, the former apartment buildings of St. Petersburg, which today are more than 200 years old. Among them there are even seven-story buildings, and everywhere wood was used as beams, which, even in the humid northern climate, continues to serve to this day.

The difference between those floors, of course, is the use of logs for beams, and not beams, but all the same, beams in private housing construction will serve for quite a long time.

Parameters of wooden beams

So, today it is mainly used as beams wooden beam- a log of a certain cross-section sawn on four sides. The wood used is mainly coniferous, since the material is naturally “impregnated” with resins, which protects it well from moisture.

• For small spans not exceeding 2 meters, it is allowed to use boards with a thickness of 25, 32 or 40 millimeters, installing them on edge.
• If you need to strengthen the load-bearing elements, you can connect two boards, as shown in the photo above, using nails, screws or bolted connections.

• Logs today are used only in the construction of log houses, and even then beams are often used there too.

• The parameters of the beams directly depend on the width of the span they cover, as well as the step between them.
• When calculating the project, the possible loads that will be exerted are also taken into account. Here is a table that will help you navigate the selection of the cross-section of load-bearing beam elements.

The information given in the table is obtained from GOST 24454-80.

Advice! The calculation of the pitch between the beams includes a potential payload of 200 kgf/m3, as well as the weight of the beams themselves, plus the mass of mineral wool insulation with a density of up to 100 kg/m3. If it is planned to insulate the floor with expanded clay, then the pitch between the beams should be reduced by 20% of the stated value.

The main feature of a wooden beam floor is that when installed on wide spans it can provide sufficient strength, however, due to the characteristics of the material, the floor cannot be rigid, that is, it still bends, especially with increasing load. This property is called floor instability.

How beams are laid out and embedded in the wall

So, the length of the beams is selected according to the opening to be blocked, which is not surprising. Moreover, if the room has rectangular shape, its smaller side is selected. If it is square, then the direction does not matter.

Advice! It is worth remembering that beams can only rest on load-bearing walls, which are designed to withstand increasing loads - light half-brick partitions cannot be used for these purposes under any circumstances.

• Depending on the size of the room, the layout of the beams can be done in different ways. If the spans are too large, you can break them into smaller sections using more massive beams.

• The beams are embedded in brick walls, and at the points of connection with each other they are fixed using special steel fasteners or plywood overlays.

• In order to wall up beams into the wall, it is necessary to prepare special niches for them during the laying process, which will correspond to the dimensions of the beams used.
• In order for the connection to be sufficiently reliable and withstand all the necessary loads, the landing depth of the end of the beam must be at least 15 centimeters. This applies to any brick, stone or block wall.
• In this case, the depth of the niche itself should be 20-30 millimeters greater to provide an air gap to the rear wall.
• If the wall has a heat-insulating layer on the outside, then the inside of the niche need not be filled with anything.
• If there is no such layer, then due to the remaining small thickness of the wall, the niche can turn into a cold bridge that will freeze when the outside air temperature drops. As a result, condensation will begin to form on the wooden beam, which, as you understand, is very bad and will lead to accelerated aging of the material. To prevent this from happening, the niche is filled with heat-insulating material, for example, polystyrene, which itself does not allow moisture to pass through and will perfectly protect the beam.

The diagram above shows how beams are installed in different types of walls.

Advice! The insulation placed inside does not need to be wrapped plastic film, since condensation may form in closed space, as a result of which the niche may still freeze.

• Before laying in a niche, the ends of the beams must be sawed off at an angle of 60-70 degrees.
• The saw cuts and the entire immersed part are treated with an antiseptic composition.
• You will also need to create a moisture-proof layer - the edge of the beam is wrapped with roofing felt or roofing felt (the second option is better). In this case, the end is left open to ensure air flow

• If you wish, you can not wrap the edges, but this is less reliable. In this case, it is necessary to put pads under the beams - the same roofing felt, roofing felt or a piece of board soaked in an antiseptic to prevent the wood from coming into contact with the stone. If this is not done, the process of wood rotting will begin soon enough.
• The most reliable way to do this would be to combine these two methods, that is, place the wrapped beam on a substrate, which, in principle, is shown in the previous diagram.

• The gaps that remain around the beam must be sealed with polyurethane foam. Such a coating will reliably protect the wood from moisture that can get inside from the room, but at the same time the whole thing will be ventilated through microscopic pores.
• The remaining space is filled with cement mortar.
• If a backing made of boards treated with an antiseptic is placed not only at the bottom, but also on all sides of the niche, the beam will last even longer, almost like those found in the already mentioned ancient buildings. True, back then tar was used as an antiseptic, but modern impregnations are also perfect.

Advice! Also, ancient beams were additionally treated with soot - a natural antiseptic, which coped with the task no worse modern compositions prepared by the chemical industry.

• If you support the beams on the inside load-bearing wall, then all measures to isolate the element from moisture must also be taken.
• When building a house, it is very important to remember that beams, in addition to their main load-bearing function, strengthen the walls of the building, which, as we know, are connected to each other only at the corners. Even in two-story house the height of the walls reaches 6-7 meters, so without the proper connection, unpredictable consequences can occur.
• That is, the beams should not just lie in prepared niches, but be rigidly connected to the walls of the building. For this purpose, anchoring of these elements is used.

• Anchoring is performed using prepared metal plates T-shape, one edge of which is nailed to the beam, and the remaining blades are embedded in the masonry.
• Anchors can be placed on each beam, or through one - in both cases the bundle will be strong enough.

• When connecting to wooden walls, special fasteners with perforations are used, through which everything is secured with self-tapping screws. In this case, the edges of the beams should also rest on the cut niches, as in the photo.

• In some cases, hinged joining is also allowed, but then perimeter boards must be screwed to the walls.

• If two beams are supported on interior wall, then they must be connected to each other with steel strips, which are stuffed on both sides.

We should also talk about supporting floor beams on walls made of aerated concrete blocks. This material does not have high density and is not able to fully support the weight of the floor and roof.

• Therefore, a monolithic reinforced concrete belt is poured, which will greatly strengthen the structure and fix the beams themselves. It is also possible to lean on the belt itself - this will be even more reliable.
• For this purpose special aerated concrete blocks“U”-shaped, in which recesses are cut along the edges of the beams.
• You can see a similar connection in the photo above.
• Anchoring in this case is performed using metal plates that are connected to the armored belt itself.

Supporting beams on vertical elements

If we're talking about Regarding the frame structure, the beams are often additionally supported by a system of free-standing supports, such as columns, pillars, racks.

• If it is necessary to connect elements above a vertical support, then the joint should be located strictly above it.

• If both elements are made of wood, then the joining is quite simple - nails are driven in at an angle and the whole thing is additionally fastened with staples.
• The connection can also be made using wooden or plywood overlays installed on both sides. Fastening is performed perpendicularly using nails or self-tapping screws.
• Having examined the diagram above, you can see that various metal connectors are also used, which can be purchased ready-made in the store. They are usually made of galvanized steel to prevent corrosion of the element.

Inter-beam filling of the floor

The filling between the beams is essentially a set of enclosing elements, each with its own purpose. Let's see what device options there are here.

This type of construction can only be used if the distance between load-bearing beams does not exceed 60 centimeters. If this rule is neglected, the floor will be “unsteady”. The layout of such an overlap is shown in the following diagram.

Let's break this cake down layer by layer:

• So, in this case, our floor beams become the basis for holding the sheathing, a subfloor will be laid on top of them, and inside there will be layers of vapor, heat and sound insulation - the last two, often in the form of one material.
• Let's go from bottom to top. The lowest layer is finishing material ceiling, which can be plastic, wooden lining, drywall, MDF and more. The trim is installed last if you do not plan to lay the insulation directly on top of it. This solution is extremely unreliable, so we will skip its description.

• To keep everything firmly, especially if a fairly heavy heat insulator such as expanded clay is used, it is mounted below wood flooring(12), which will be held by cranial bars (10), wound parallel to the beams along their lower edge. For cranial bars, a rail with a cross section of 30*40 and higher is perfect. Everything is attached with self-tapping screws.

• Next, a layer of vapor barrier is placed on top of the flooring, which will prevent debris from spilling down, plus it will protect the beams themselves and the insulation between them from the penetration of moisture from the air.
• Next is a layer of thermal insulation - usually it is either foamed polystyrene or mineral wool, although there are a great many other options on the market. Moreover, mineral wool would be preferable, since it is not a flammable material and is not afraid of rodents.

Advice! Mineral wool greatly loses its thermal insulation properties when wet, so it is necessary to take care of its high-quality insulation.

• The next layer is again film, but this time waterproofing. Water can seep out from above if something is spilled on the floor or the roof leaks. It is also recommended to use membrane films that do not interfere with gas exchange.
• The distance from the film to the insulation is usually left at 50 millimeters to ensure air circulation, although sometimes this rule can be neglected

But what about sound insulation, since today’s popular insulation materials are not so effective in this regard? Still - the weight of the same mineral wool is 1 square meter will be some 5-6 kilograms, and sound in such a loose environment will propagate practically without interference!

In this case, before laying the insulation, it is worth installing a separate layer of sound insulation, for example, installing a soundproofing panel, or pouring sand or clay, if we are talking about a very budget construction project. At the same time, do not forget that the load-bearing capacity of the floor must withstand increased loads.

It is also necessary to place a separating membrane film between the layers of sound and thermal insulation.

Sound insulation will not be complete if vibrations are transmitted through the beams themselves when walking on the floor top floor. To eliminate this unpleasant effect, an elastic material, for example, the same roofing felt, is laid over the beams.

Next, a rough flooring is installed, which will serve as the basis for finishing flooring, for example, laminate. For flooring, boards with a thickness of 32 millimeters are used - thinner is possible, but provided that the step between the beams is small and the floor will not sag.

Floors with joists

During the course of the article, we analyzed the table, from which it became clear that the cross-section of the beams and the step between them are interrelated quantities. The pattern here is directly proportional - the more powerful the bars, the greater the distance between them it is allowed to leave.

• The approach with a large indentation is good for reducing labor costs in terms of arranging niches for beams, but the strength of the floor itself may suffer.
• Logs help solve the problem - transverse boards or beams that are placed on an edge or laid flat. Lumber is taken with the following section - 50x75 or 50x100 millimeters.
• The step between them is chosen to be acceptable for the future flooring. End connection elements is performed over the logs. The fastening element in this case is a wooden, metal or plywood overlay.

The inter-beam filling of the floor will be the same as in the previous case, however, due to the increased thickness of the floor, you can add another layer of insulation to make the insulation more effective. You also need to remember that, unlike beams, logs are not embedded in the wall, but simply adjacent to them.

So, we have learned how a beam ceiling is constructed, which you can now easily build yourself, following the recommendations given in this article. The video in this article will help further clarify the issue - be sure to take a look. And now we say goodbye to you, see you soon!

To support the beam on brick wall, most often use supports made of steel.

When resting the floors on a brick wall, a ventilated air gap must be created between the end and the floor beam.

The fact that a beam is supported on a brick wall implies that the end of the beam can deform quite freely. At the moment of deflection, the beam must rotate, and under the influence temperature conditions it should shift along the axis (longitudinal).

It is in this case that operation will be safe and reliable and will cost without additional stress. To achieve this goal, movable and fixed supports are used.

An important function of a process such as installing beams is to ensure that the existing floor is connected to the structure that supports it, such as a wall(s). The most important factors for the reliability and strength of the erected connection between the floor and the support are: the degree of depth to which the beams are embedded, their anchoring in the wall and, of course, optimal choice support structures.

We embed beams in the wall

In construction, the stage of embedding beams into the wall is the most important and responsible. Floor structures must meet high requirements for reliability and strength, since they are the guarantee of the safety of everyone living in the house.

1. The first thing that needs to be done is to cut the end ends of the beams at an angle of 60 degrees.
2. Treat the end ends of the beams with an antiseptic composition. Another action characteristic of this stage is the resin treatment procedure.
3. Next, you need to wrap the ends of the beams with roofing felt and lay them so that they do not reach the back wall of the nest, by about 40 mm (+- 10 mm).
4. After the beam is laid, its sides (sides and top) are sealed using a solution that includes crushed stone as a component.

Supporting beams on brick walls: a – with embedding in the wall, b – with the help of clamps, c – on the console, d – on pilasters. 1 – clamp, 2 – console, 3 – pilaster.

With the existing wall thickness equal to 2.5 bricks (this is approximately 640 mm) or more, the beams, or rather their ends, are not covered with mortar. Another sealing option is more suitable for this.

Since the beam is supported by its end ends on the walls (usually no more than 150 mm), it is clear that between its end and the wall of the socket (rear) there is a free space of approximately 100 mm.

This distance is suitable to ensure that the air gap is maintained and that thermal insulation is laid. As for the nest, its bottom must be leveled with concrete, then a layer of bitumen and two layers of roofing felt are applied.

The upper part of the nest and its side walls are covered with roofing felt.

Scheme for sealing the ceiling in outer wall: 1 – wall; 2 – lining; 3 – end of the beam to be sealed; 4 – floor slab.

But for the back wall they use tarred felt. This layer of felt is pressed using a board that has undergone antiseptic treatment. Its thickness is usually 25 mm.

Please note that the end of the beam should be laid in such a way that the space between it and the board is approximately 40 mm.

If the walls of your house are smaller than the above-mentioned size, for example, two bricks, then the following method will suit you.

1. Just as in the first case, the back wall of the nest is covered with tarred felt in two layers.
2. Then a box with three walls is made, its surface is tarred, and it is installed in the nest; the previously laid felt is pressed against it.
3. If the beams are sealed during the installation of an attic floor, and the walls are two bricks thick, then Special attention it is necessary to pay attention to nests, or rather to their protection. As in the above example, it is necessary to make a box with three walls, tar its surface and cover it with felt.
4. Beams located near chimney pipes are placed at a distance of no less than 400 mm from its inner surface.

Scheme of embedding a wooden floor beam into a brick wall: 1 – wooden beam; 2 – the end of the beam, coated with resin and wrapped in roofing felt;
3 – waterproofing; 4 – brick wall; 5 – air gap between the wall and the beveled end of the beam.

Of course, it also happens that the beam cannot be positioned at a further distance from the chimney. Under such circumstances, the beam is inserted into the crossbar structure.

And the crossbar itself is already cut into two beams, as a result of which they are weakened. Reducing the weakening is achieved by laying the beams with a thicker end in relation to the chimney pipe.

When building brick, stone and other similar structures, it is necessary to comply with the condition that there is a gap of at least 50 mm between the wall and the outer beams. It is sealed using a lath. Do not forget that the lath and beam are separated from each other using a layer of roofing felt or a layer of roofing felt.

Tools

• perforator;
• drill;
• hammer;
• brush;
• Bulgarian;
• axe.

In addition, various levels, roulette, etc.

Nuances of anchor fastening and arrangement of the beam support unit

In order to add rigidity, it is necessary to perform additional fastening of the beams. The fastening is not carried out across all beams, but through one.

1. To do this, when doing brickwork, a steel anchor is installed. It is positioned in such a way that its end does not reach the outer wall (its surface) by about 12 cm.
2. This is done to prevent the occurrence of so-called “cold bridges”. Its other end protrudes into the room at a distance of about 20 cm.

The anchor and wooden beam are fastened using a steel plate, the cross-section of which is 50 by 6 mm, as well as nails with a diameter of about 5 mm.

There are also sealing options in which it is considered open. But keep in mind that when choosing this method, the room must be normal humidity(less than 60%) and sufficient good ventilation ceiling, and it will also be necessary to provide sufficient thermal insulation of the nest, in particular, its rear wall.

You need to know that in in this case if there is an existing brick wall, the wall of the nest should have a thickness of at least 46 cm. If the thickness is still less, then additional insulation is necessary.

1. If the wall thickness corresponds to the size of two bricks, then supporting the beam (node) is performed as follows. A nest is made in the wall, the depth of which corresponds to 25 cm (approximately one brick).
2. The vertical wall of the nest is covered with heat-insulating material, which can be used as antiseptic or mineral felt. The lower part of the nest is covered with roofing felt, preferably in two layers.
3. After which the wooden box is installed. It is made using tarred antiseptic wood. It is used to press the felt. The floor beam should rest on the surface of the box (its lower part), to a depth of approximately 15 cm.

But keep in mind that an air gap is necessary between the beam and the surfaces of the box. As an option for this design, you can consider installing a wooden box, which has three vertical sides and one horizontal (upper part). The lower horizontal surface is completely absent.

With this installation, the end of the beam with antiseptic treatment will have support in the nest on roofing felt (two or three layers). And along the side, end and top sides of the beams there will be wooden surfaces boxes

Supporting floor beams on brick walls: at the top - sealing the interfloor floor beams: 1 - roofing felt; 2 - lags; 3 - floor; 4 - boards (25 mm); 5 - felt (2 layers); below - sealing of attic floor beams: 1 - roofing felt; 2 - backfill; 3 - boards (25 mm); 4 - felt (3 cm).

If the thickness of your walls corresponds to a size of 2.5 bricks or more, then the beam must be supported in a nest, the depth of which will be 25 cm. The nest, its lower part, must be treated with bitumen, on top of which only two layers or roofing felt are laid .

Surfaces located on the sides and top are also covered with roofing felt. The back surface of the nest should be well insulated with heat-insulating material, such as felt (mineral). Pressing the felt to the wall is done using wooden board with a thickness of 2.5 centimeters.

Do not forget about a four-centimeter air gap between the floor beam and the surfaces of the nest.

A number of defects allowed during the installation of beams (crossbars) and trusses

Like any other type construction work, installation of reinforced concrete beams and crossbars can

Embedding the ceiling into the outer wall: a - supporting the beam on the wall; b - sealing of floor slabs: 1 - wall, 2 - lining, 3 - end of the beam to be sealed, 4 - floor slab.

be made with various defects. The most common are:

• displacement of the axis of the beam (crossbar) from the axis of the column;
• displacement of the beam (crossbar) in the plane of the transverse frames;
• incorrect connection of the beam (crossbar) with the column;
• laying a beam (crossbar) on a brick wall without providing a special support pad;
• the existing deviation of the crossbar (its plane) from the vertical;
• performance installation work using a beam (crossbar) with obvious defects.

Defects and their consequences

When there is a displacement of the axis of the beam (crossbar) from the axis of the column, additional forces appear in the column of bending moments, which act in the perpendicular direction relative to the plane of the transverse frames. The consequence of such defects is a decrease in the bearing capacity of the columns.

If there is a displacement of the beam (crossbar) in the plane of the transverse frames, then one of the platform supports will have a shorter length when compared with the design one.

This can cause pulling of the reinforcement (longitudinal), the appearance of cracks and destruction of the beam (crossbar). And also, since the support area is small, concrete destruction at the point of support is possible, since it is crushed or chipped.

1. Another defect involves the deviation of the beam (crossbar), or rather its plane, from the vertical. This becomes possible as a result of the skew of the supporting part in the beam. As a result, torques appear for which the beam (crossbar) design is not designed.
2. Basically, all of the above defects can also occur when performing installation work on installing a reinforced concrete truss. The consequences caused by these defects (during installation of the truss) are also similar to those mentioned above.
3. I would like to note that when making trusses, special attention must be paid to the procedure for reinforcing the nodes. If anchoring of a high degree of reliability is performed in the truss nodes, this guarantees good strength.

Another important point: change parameters such as the quantity and diametrical size of reinforcement (structural) without obtaining consent design organization, is not possible, or rather, not allowed. Reinforced concrete trusses are stored and transported only in a vertical position.

When installing the truss, before you install the slabs, do not forget to check such quality as the stability of the compressed belt in the horizontal plane.

Floors on wooden beams used in modern low-rise construction (where wood is local building material), have a low dead weight, but are rotten, insufficiently fire-resistant and labor-intensive.

To increase the durability of wooden floors, the wood is antiseptic.

Wooden beams are beams or thick boards made of softwood.

The cross-sectional height of a wooden beam is usually 1/20-1/25 of the span being overlapped, but is always determined by calculation. Step plank beams ranges from 600 to 800 mm, and paving stones - from 600 to 1000 mm. Supporting the ends wooden beams on stone walls(Fig. 94) can be with a blind or open seal. When sealing blindly, the gap between the beam and the socket of 20-30 mm is filled with mortar. Blind sealing protects the beams from wet access, warm air, thereby preventing the appearance of condensation on the walls in winter and the moistening of the ends of the beams. When sealing is open, the gaps between the beam and the walls of the nests are not filled with anything.

Open embedding is allowed when the thickness of the external walls is more than 510 mm and when the beams are supported on the internal walls. In external walls with a thickness of 510 mm or less, with such sealing, the beam nests must be insulated with liners made of thermal insulation materials. In this case, ventilation of the nests is ensured with air penetrating from the interbeam space of the ceiling.

To connect the walls with the floors, the ends of the beams are anchored into the walls. and the ends of the beams, resting on the internal walls or purlins, are connected to each other by steel ties. Anchors are placed at least through one beam.

Rice. 94 Supporting floor beams;
a - on external walls; b - on internal walls; c - for runs; 1 - wooden beam; 2 - anchor; 3 - roofing felt; 4 - solution; 5 - wooden composite purlin; 6 - reinforced concrete girder; 7 - plate dowel

Purlins are made of reinforced concrete, steel and wood (composite section on plate dowels or glued).
The space between the beams is filled with an interbeam roll. The roll is laid on cranial bars (section 40x40 or 40X x50 mm), nailed to the beams. They use rolls from single or double board panels, from undercut wooden plates, from slabs, from gypsum or lightweight concrete blocks, reed or fiberboard slabs(Fig. 95).

To ensure the necessary sound insulation of the floors along the runway, apply clay-sand lubricant 20-30 mm thick or lay a layer of rolled material; they simultaneously serve as a vapor barrier, preventing the penetration of air water vapor into the thickness of the ceiling, and protect the roll-up from water accidentally entering the ceiling. Additional improvement of sound insulation of interfloor floors, sound and heat insulation of floors separating rooms from different temperatures air, reached by laying on top of the lubricant insulating material(dry sand, expanded clay, slag, etc.) with a layer of 60-80 mm for interfloor and 220-260 mm for attic floors. To lay the floor on the beams, every 500-700 mm, logs are laid from boards or plates, to which the floor boards are nailed. The horizontalness of the logs is checked by level. In places where the joists rest on the beam, soundproofing pads made of roll materials, rubber or hardboard strips. By improving the sound insulation of the floor, the logs promote ventilation of the air gap formed under the entire floor through openings in the floors covered by gratings.

The ceilings are plastered or sheathed with sheets of dry plaster.

The design of the floor on wooden beams with a roll of lightweight concrete blocks or slabs allows you to reduce wood consumption, but its weight increases. The seams between the blocks and the places where they join the beams are sealed with mortar. Waterproofing is done on top of the roll-up with hot bitumen or a layer of rolled material.

Attic floors do not have a floor, and the thermal insulation backfill is protected from accidental moisture by a lime-sand (rarely clay-sand) crust 20 mm thick.

The ceilings above the bathrooms are equipped with waterproof floors and reliable waterproofing along the continuous boardwalk made of tongue-and-groove boards nailed to floor beams open at the bottom.

Six schemes of classical design solutions for supporting load-bearing structures are presented metal beams ceilings on brick walls of buildings. ● The design of buildings includes the process of designing beam floors, associated with many mathematical calculations - calculation of installation connections, arrangement of support nodes of beams, selection of sections of individual elements that are designed to ensure the operability of the nodes.

● The choice of one of the presented options should be based on the value of the support pressure under the end of the beam - i.e.

The support reaction is the fundamental factor when choosing a solution. Steel floor beams must not only be laid on load-bearing brick walls, but must be supported through reinforced concrete or steel distribution pads. The main purposes of these pillows include:

– pressure equalization under the ends of the beams; – prevention of local destruction of brickwork under the supporting sections of beams.

● The first four nodes (out of six) involve a hinged method of supporting beams directly on a brick wall through a layer of mortar 15 mm thick. The support pressure is transmitted to brickwork through 20 mm thick metal support plates. The dimensions of the support plates are selected in such a way that the average pressure under them - i.e.

i.e. on the compression area - there was no greater than the calculated resistance of brickwork on rigid cement mortar. The load-bearing brick wall must be made of solid brick with good strength characteristics.

If the value of the support pressure exceeds 10 tons, then required thickness reinforced concrete distribution pad must already be at least 100 mm, and the cushion itself must be equipped with two reinforcing meshes. In this case, the supporting nodes of the metal beams must be rigid and it is strictly forbidden to rest the floor beam directly on a brick wall. The guidance in this matter is the requirements of SNiP II-22-81* Stone and reinforced masonry structures.

● Support unit No. 1 hinged. Brick wall thickness b=380 mm. Limit value of support reaction R=0.6 t.

● Support unit No. 2 is hinged. Brick wall thickness b>380 mm. Limit value of support reaction R=0.7-3.0 t.

● Support unit No. 3 is hinged. Brick wall thickness b>380 mm. Limit value of support reaction R=3.1-5.0 t.

● Support unit No. 4 is hinged. Brick wall thickness b>380 mm. Limit value of support reaction R=5.1-7.0 t.

● Support unit No. 5 is rigid. Brick wall thickness b>380 mm. Limit value of support reaction R=10.1-18.0 t.

● Support unit No. 6 is rigid. Brick wall thickness b>380 mm. Limit value of support reaction R=18.1-20.0 t.

In all units, all frictional connections of elements are made on anchor bolts of accuracy class B, with strength classes 5.8 and 8.8. In all units, the legs of all fillet welds should be taken according to the smallest thickness of the elements being welded. The minimum values ​​are indicated in Table 38 of SNiP II-23-81* Steel structures.●If any dynamic loads occur during the operation of the structure, then all elements and parts of the supporting units must be checked by endurance calculations. In this article Diagrams of classical design solutions for support nodes of load-bearing metal beams of floors (coverings) on brick walls of buildings are considered. The use of these diagrams when designing beam floors will relieve the designer from many routine calculations associated with the layout of the support nodes of the beams, the selection of sections of individual elements (ensuring the operability of the nodes) and the calculation of their installation connections. Deciding on the choice of one of the options proposed below for the design of the support nodes of the beams on the walls is carried out based on the magnitude of the support reaction (support pressure under the end of the beam). According to the requirements current standards, steel beams must rest on load-bearing stone walls through steel or reinforced concrete distribution pads, the main function of which is to equalize the pressure under the ends of the beams and prevent local collapse of the masonry (local destruction of the masonry under the supporting sections of the beams from collapse). Nodes No. 1, 2, 3 , 4 provide for hinged support of beams directly on the brickwork of the walls through a layer cement-sand mortar 15 mm thick.

The supporting pressure under the end of the beam embedded in the wall is transmitted to the masonry through supporting metal plates 20 mm thick, the dimensions of which are assigned in such a way that the average pressure under the slab (within the compression area) does not exceed the minimum acceptable by standards the value of the calculated resistance of the masonry, provided that the masonry is made of solid ceramic bricks normal strength on rigid cement mortar. If the value of the support pressure exceeds 100 kN (≈10 tons), then, in accordance with the requirements of SNiP ll-22-81*, it is necessary to install a reinforced concrete distribution pad with a thickness of at least 100 mm, reinforced two grids according to calculation (supporting the load-bearing steel floor beam directly on the brickwork of the walls in this case is not allowed). In this case, the supporting nodes of the beams are made rigid - see Nodes No. 4, 5.

Unit No. 1 (hinged) Brick wall thickness b = 380 mm. Limit value of support reaction R=0.6 t.

Unit No. 2 (hinged) Brick wall thickness b>380 mm. Limit value of support reaction R=0.7 - 3.0 t.

Unit No. 3 (hinged) Brick wall thickness b>380 mm. Limit value of support reaction R=3.1 - 5.0 t.

Unit No. 4 (hinged) Brick wall thickness b>380 mm. Limit value of support reaction R=5.1 - 7.0 t.

Unit No. 5 (hard) Brick wall thickness b>380 mm. Limit value of support reaction R=10.1 - 18.0 t.

Unit No. 6 (hard) Brick wall thickness b>380 mm.

Limit value of support reaction R=18.1 - 20.0 t. Notes (important!!!): All frictional connections of elements (in all units) are made on anchor bolts of accuracy class B, strength classes 5.8 and 8.8. The use of high-strength bolts is also allowed. The legs of all fillet welds (in all assemblies) should be taken according to the smallest thickness of the elements being welded, but not less than the values ​​​​specified in table 38 of SNiP II-23-81 *. In the event that the operating mode of the building is characterized by the presence of dynamic loads , - all elements and parts of units must be tested for endurance. The steel grade of all metal elements and parts of units are accepted according to table 50x SNiP II-23-81*, as for structures of the 2nd group (in the absence of dynamic, vibration and moving loads). Supporting brick pillars - important element in technology brick construction small buildings with load-bearing external walls. The pillars rest on nodes in the foundation and are laid out of high-quality solid bricks using high-strength mortar. The most small area The cross-section of a load-bearing brick pillar should be 510 x 380 mm. Types of bricks for laying pillars. If the building is small and the height of the pillars is up to 5 m, a cross-sectional area of ​​380 x 380 mm is allowed.

To build higher brickwork, it is necessary to reinforce it, which will increase its load-bearing qualities and ensure reliable fastening to the walls. To evenly distribute the pressure of the structure, a support unit is used - a reinforced concrete slab laid under the base of the pillar. Supporting brick pillars requires accurate calculation, since pillars under strong pressure can collapse, especially from lateral loads. In technology modern construction The following approaches are proposed to strengthen the manufactured structure: internal reinforcement of external pillars; external (external) reinforcement.

Laying brick pillars

Brick pillars.

Standard brick pillars for low-rise construction have a square or rectangular cross-section. They are laid out in a three-row system with ligation of the seams.

Fastenings of other types are usually not used: tying through several rows (more than three) does not guarantee that the masonry will be monolithic and strong, and masonry with tying through one row requires large labor costs. The accuracy of the laid corners of the future pillar is checked using a wooden square, the correct location of the horizontal rows is checked using a rule or level twice or more often at each level (every 100-120 cm). If the masonry surface deviates from the horizontal by an acceptable amount, this deficiency is eliminated when laying out the next rows.

Surface Compliance corner walls verticals are checked using a level and plumb line twice or more often (every meter). All permissible discrepancies between vertical surfaces are eliminated later, when laying out a tier or floor. It is mandatory to check the thickness of the seams.

Internal reinforcement of external brick pillars

The strength of a brick pillar is achieved by the integrated use of technologies for installing metal reinforcement and pouring concrete. In construction, it is necessary to lay inside a brick structure profile pipe or channel, reinforcing materials. By modern technologies construction of brick pillars, metal reinforcement, installed at the same time as pouring and concreting the foundation.

The metal reinforcement installed simultaneously with the foundation will subsequently be hidden by brickwork, and a concrete solution will be poured into the hollow space inside the column. Important Requirements This solution has its plasticity and liquid properties, which then allow it to be compacted using a vibrator. The described method is considered the most reliable and technologically advanced in the process of internal strengthening of brick pillars.

External reinforcement of brick pillars

The decision to strengthen a brick pillar from the outside is not always the right one.

Sometimes it’s faster, easier and more profitable to post brick structure again. Then the pillar can be laid out on a high-quality mortar and reliably reinforced from the inside. The only difficulty in erecting a pillar again is the need to remove the pressure on it.

If such a method of reinforcement cannot be implemented, a so-called clip is arranged, which is made and mounted from 4 metal corners, placed on the corner surfaces of the pillar in the form of racks. These devices need to be tightened with a round rod, angle or reinforcement, which significantly increases its strength.

Instead of a metal clip, you can use a reinforced concrete clip. To install it, you need to weld a frame made of reinforcement or reinforcing mesh around the pole. With external reinforcement, the thickness of the reinforced concrete frame is 4-5 cm or more.

When supporting a wooden beam on brick pillars, the joint between the beam and the masonry must be protected from moisture penetration.

Particles of water contained in warm, damp air when ingested cold wall condensation forms into the beam socket, moistening the beam wood and causing it to gradually rot. For this reason, the edges of wooden beams adjacent to the wall must be treated with an antiseptic and sealed with a two-layer roofing felt coating (without gluing the end part of the beams with a roofing felt coating).

The beam is supported in compliance with following rules: the depth of the cavity for installing the beam on a brick wall should be 2-3 cm greater than the area of ​​the beam end. The depth of the beam socket is usually 18 cm, the beam is inserted into the beam socket at 12-15 cm, thanks to the three-centimeter empty gap, the wood of the beam does not touch the wall, and water vapor is vented out through the end part of the beam, which is not covered with roofing material.

When all the beam floors are installed, all the voids in the nests are filled with mortar, which protects the joint from the penetration of air masses and the effects of dampness and makes the wooden floor reliable.

Reinforcement of brick pillars

The laying of brick pillars should be carried out with dressing according to the system of Professor L.I. Onishchik. This dressing technology includes the possibility of matching seams vertically in 3 adjacent rows of masonry, but absolutely does not allow the use of chopped bricks (3/4).

Installing reinforcement across, that is, into masonry seams running horizontally, increases the load-bearing characteristics of brick pillars. This method uses mesh reinforcement from 3 to 8 mm in diameter.

The most important element in the construction of any house is the floor.

The design of the floor can be based on the use of beams and slabs, which, in turn, can be wooden, metal, or concrete. Of particular interest is the specifics of installing floors on a brick wall, since the construction of brick houses is very common. Supporting a beam on a brick wall or, respectively, supporting a slab on a brick wall is the most important factor reliability and safety of the entire floor.

The choice of support design depends on the material, embedment depth, and fastening (anchoring) in the wall.

Main characteristic feature Supporting the structure on a brick wall is the possibility of fairly free deformation of the ends of the beam when it bends. Safety and reliability of the structure can only be achieved by ensuring proper connection between the beam and the wall, eliminating dangerous stresses in the material even when exposed to extreme temperature conditions. When choosing a support design, the material, embedment depth, and fastening (anchoring) in the wall are fully taken into account.

Floor material and design

Table for calculating the cross-section of floor beams.

In general, the floor is a load-bearing building construction, subdivided by purpose: interfloor, attic, attic. Structurally, the floor can be divided into two types: prefabricated (longitudinal beam and transverse flooring) and monolithic (slab).

During the construction of private houses greatest application find prefabricated floors using wooden beams. This material is made from durable deciduous and coniferous wood. The size of a standard specimen, depending on the purpose of the floor and loads, ranges from:

height - 150-300 mm; width - 100-250 mm.

To increase durability, the timber is impregnated with an antiseptic and oiled.

Reinforced load-bearing structures are sometimes made using metal beams. Standard steel beams are available for these purposes. Safety standards state that if such beams are used, their ends must rest on the brickwork through distribution pads.

Monolithic floors are made from reinforced concrete slabs. Factory slabs are used, consisting of reinforcement and concrete mass with standard sizes. To reduce weight, the slabs are usually made hollow.

1 – anchor; 2 – nails and screws; 3 - antiseptic paste (750 mm from the end); 4 – 2 layers of roofing felt.

Supporting unit for a beam on an internal wall.

3. Load-bearing structures of rafter roofs. Design principles and details of roofs.

Roof- a part of a building that protects it from precipitation and consists of a load-bearing part (rafters, slabs) and an enclosing part (roof and its base). According to their design, roofs are divided into attic and non-attic (combined). Combined roofs are designed low-slope (with a slope of 1-5%) with a roof made of rolled materials or mastics. Attic roofs consist of an attic covering, an attic floor and supporting structures (rafter system). There are layered (Fig. 64) and hanging (Fig. 65) rafter systems.

Layered rafters are installed in houses with average load-bearing wall or columnar intermediate supports. Their ends rest on the outer walls of the house, and the middle part rests on interior wall or supports. As a result, their elements work like beams - only in bending.

Hanging the rafters rest only on the two outer supports. Their rafter legs work on compression and bending. In addition, the structure creates a significant horizontal expansion force, which is transmitted to the walls. A tie (wooden or metal) connecting the rafter legs helps reduce this force. It can be located either at the base of the rafters (and in this case serves as a floor beam - this is the option most often used in the construction of attic roofs), or higher.

Layered rafter system of a hipped roof.

1 – lying down; 2 – Mauerlat; 3 – strut; 4 – rafter leg; 5 – wall; 6 – overlap; 7 – stand; 8 – run; 9 – spacer; 10 – fight.

Designs of layered rafter systems.

Hanging rafter system gable roof.

1 – rafter leg; 2 – Mauerlat; 3 – tightening; 4 – suspended headstock; 5 – spacer; 6 – stand; 7 – strut.

Designs of hanging rafter systems.

4. Types of pitched roofs of low-rise buildings. Basic elements of roofs.

The roof is a part of the building that protects it from precipitation and consists of a load-bearing part (rafters, slabs) and an enclosing part (roof and its base). According to their design, roofs are divided into attic and non-attic (combined). Combined roofs are designed low-slope (with a slope of 1-5%) with a roof made of rolled materials or mastics. Attic roofs consist of an attic covering, an attic floor and supporting structures (rafter system).

The following types of roofs are distinguished:

Single-pitch;

Gable;

Hip;

Tent.

The main elements of roofs: slope, horizontal. overhang, end overhang, attic window, dormer window, pediment, gable, hip, ridge, rib, half-hip, valley.

Elements: 1 – slope; 2 – skate; 3 – overhang; 4 – pediment; 6 – forceps; 7 – hip; 8 – half hip; 9 – oblique rib; 10 – valley;

a – single slope; b – gable; c – with an attic; d – tent; d, f - general view and plan of the house; g – plan of a gable roof; half-hip ends.

1. Walls made of piece materials for low-rise buildings that meet modern thermal requirements.

The main piece materials for walls are ceramic bricks and gas silicate blocks.

The structure can be:

Single-layer walls;

Layered walls with layers of other, less thermally conductive materials or with air layers.

The procedure for thermal engineering calculations of enclosing structures and the requirements for standard heat transfer resistance are established by TKP 45-2.04-43-2006 “Building Heat Engineering” and three amendments to it.

The heat transfer resistance of the enclosing structure is determined by the formula:

m 2  S/W

 in - heat transfer coefficient of the internal surface of the enclosing structure, W/(m 2 С), taken according to Table 5.4 of the TKP;

R k - thermal resistance of the enclosing structure, m 2 С/W,

 n - heat transfer coefficient of the outer surface of the enclosing structure for winter conditions, W/(m 2 С), adopted according to Table 5.7 of the TKP.

Thermal resistance of a multilayer enclosing structure with successively arranged homogeneous layers R k, m 2 С/W, should be determined by the formula

Where R 1 , R 2 , ..., R n- thermal resistance of individual layers of the structure, m 2 С/W, and closed air layers.

Standard heat transfer resistanceR t.norm established in the amendments to the TCH:

External walls of buildings R t.norm = 3.2m 2 ·С/W

CoatingsR t.norm = 6,0 m 2 ·  S/W

Ceilings over unheated basementsR t.norm = 2,5 m 2 ·  S/W

Filling light openings for all types of buildingsR t.norm = 1,0 m 2 ·  S/W

The most common designs that meet the established requirements: ventilated insulation system, light plaster system, heavy plaster system.

1 - Insulated wall

2 - Insulation boards

(mineral wool -

special façade

elevated slabs

brand rigidity;

expanded polystyrene

3 - Adhesive composition

4 - Reinforcing mesh

5 - Plaster composition

6 - Dowel for fastening insulation boards