Types and design solutions of walls of civil buildings. Constructive solutions for buildings Constructive solutions for insulating external walls

Walls are the main load-bearing and enclosing structures of a building. They must be strong, rigid and stable, have the required fire resistance and durability, be low thermal conductivity, heat resistant, sufficiently air and soundproof, and also economical.
Basically, external influences on buildings are perceived by roofs and walls (Fig. 2.13).

The wall has three parts: the lower one is the plinth, the middle one is the main field, the upper one is the entablature (cornice).

Figure 2.13 External impacts on the building: 1 - permanent and temporary vertical force impacts; 2 - wind; 3 - special force impacts (seismic or others); 4- vibrations; 5 - lateral soil pressure; 6- ground pressure (resistance); 7 - ground moisture; 8 - noise; 9 - solar radiation; 10 - precipitation; 11 - state of the atmosphere (variable temperature and humidity, presence of chemical impurities)

By the nature of perception and transmission of loads walls (external and internal) are divided into load-bearing, self-supporting and curtain walls (with a load-bearing frame) (Fig. 2.14). Load-bearing walls must ensure the strength, rigidity and stability of the building from the effects of wind loads, as well as loads on floors and coverings, transferring the resulting forces through the foundations to the base. Self-supporting walls must maintain their strength, rigidity and stability when exposed to loads from wind, their own weight and the overlying part of the wall. Curtain walls intended only to protect premises from atmospheric influences(cold, noise), designed using highly efficient thermal insulation lightweight materials multilayer. They usually transfer the load (wind) within one panel and from their own mass to the elements load-bearing frame buildings.

By the nature of placement in the building a distinction is made between external walls, i.e. enclosing the building, and internal walls - separating rooms.

By type of materials used the walls can be wooden (logs, paving stones, frame-panel, etc.), made of stone materials, concrete, reinforced concrete, as well as multilayer (using highly effective heat-insulating materials as a heat-insulating layer).

The main parts of external walls are plinths, openings, piers, lintels, pilasters, buttresses, pediment, cornices and parapets (Fig. 2.14). Basement - the lower part of the wall adjacent to the foundation. The walls have openings for windows, doors and gates. The sections of walls between the openings are called piers, and those above the openings are called lintels. The crown cornice is the upper protruding part of the wall. Parapet is part of the wall enclosing the roof in buildings with internal drainage.

Figure 2.14 Wall structures: a - load-bearing in a frameless building; b - the same in a building with an incomplete frame; c - self-supporting; g - mounted; d - main parts of the walls; 1- foundation; 2 - wall; 3 - overlap; 4 - crossbar; 5 - column; 6 - foundation beam; 7 - strapping beam; 8 - base; 9 - opening; 10 - cornice; 1 - pier; 12 - jumper

In frame one-story industrial buildings with large openings, significant height and length of walls, to ensure their stability, half-timbering is used, which is reinforced concrete or steel frame, which supports the walls, and also absorbs the wind load and transfers it to the main frame of the building.

According to the design solution, the walls can be solid, or layered.

Walls are the most expensive structures. The cost of external and internal walls is up to 35% of the cost of the building. Consequently, the effectiveness of the structural design of the walls significantly affects the technical and economic indicators of the entire building.

When selecting and designing the wall structure of civil buildings, it is necessary to:

reduce material consumption, labor intensity, estimated cost and cost;
use the most effective materials and wall products;
reduce the mass of walls;
make maximum use of the physical and mechanical properties of materials;
use materials with high construction and performance qualities, ensuring the durability of the walls.

In terms of thermal engineering, the enclosing parts of buildings must meet the following requirements:

provide the necessary resistance to the passage of heat through them;
not have a temperature on the inner surface that is significantly different from the indoor air temperature so that cold is not felt near the fences and condensation does not form on the surface;
possessing sufficient heat resistance (thermal inertia) so that fluctuations in external and internal temperatures are less reflected in fluctuations in the temperature of the internal surface.
maintain normal humidity conditions, as humidification reduces the heat-protective properties of the fence.

Brick walls. The materials for masonry are bricks: ordinary clay, silicate, hollow plastic pressed; hollow brick semi-dry pressed. (Fig. 2.15) When making a stack of bricks, their thickness can be different, depending on climate zone. So, in Almaty conditions the wall thickness is 510 mm (2 bricks), and for internal load-bearing walls- 380mm (one and a half bricks) and even 250mm. Ceramic hollow stones and small concrete blocks (eg 490x340x388) can be used. Brick grades 50 - 150.

Ordinary clay brick is manufactured in dimensions 250x120x65 mm (88 mm) and has a volumetric mass of 1700 - 1900 kg/m 3.
Effective clay bricks are produced hollow and lightweight. The volumetric mass of hollow brick is 1300 - 1450 kg/m 3, lightweight brick is 700 - 1000 kg/m 3 or more.

Sand-lime brick has a volumetric mass of 1800 - 2000 kg/m 3 ; dimensions 250x120x65 (88 mm).

Slag brick has a volumetric mass of 1200 -1400 kg/m 3.
Hollow ceramic stones differ from hollow bricks in height dimensions (138, 188, 298 mm), shape and location of voids. Ceramic stones of plastic pressing with 7 and 18 voids and have dimensions 250x120x138 mm, volumetric mass 1400 kg/m 3

Lightweight concrete stones There are solid and hollow ones with a volumetric mass of 1100 - 1600 kg/m 3.

The dimensions of stones with slot-like blind voids are 190x390x188 and 90x390x188, three-hollow ones - 120x250x138 mm.

Stones with slot-like voids have the best thermal performance.

Facing bricks and stones are divided into profile and ordinary (solid and hollow).

Shaped ceramic slabs are either embedded or leaned.

Except ceramic products, concrete and other non-fired slabs and stones can be used for wall cladding. Natural stones and slabs from: natural stone is used for laying foundations and walls, for cladding (in the form of facing slabs - sawn, chipped, hewn, polished). Natural stone is also used to make floors, window sills and stair steps. Solid masonry made from ordinary brick and heavy stone materials is used to a limited extent - where increased strength is required, as well as in rooms with high humidity. In other cases it is recommended; use lightweight masonry.
Masonry is carried out using heavy (sand) or light (slag) mortars of grade 10; 25 - 50 and 100.

Continuous masonry is carried out using a multi-row (spoon) or single-row (chain) suture ligation system, masonry of narrow walls (no more than 1.0 m wide) is the same as masonry brick pillars, is carried out according to a three-row system. The thickness of horizontal seams is assumed to be 12 mm, vertical 10 mm. For lightness and insulation, wells filled with lightweight concrete are left in the wall.

Figure 2.15 Walls made of brick and ceramic stones: a- single-row; b- multi-row; c - systems L.I. Onishchika; g - brick and concrete; d-well; e- with an air gap; g - with slab insulation; 1- poke; 2 spoons; 3-light concrete; 4-air gap; 5-plaster; 6-board insulation; 7-grout.

Walls made of large blocks. Buildings from large blocks are constructed without frames and with frames (Fig. 2.16.). According to their purpose, large blocks are divided into blocks for external and internal walls, for walls of basements and plinths, and special blocks (eaves, for bathrooms, etc.). The material for large blocks is lightweight concrete of class not lower than B5 (slag concrete, expanded clay concrete, cellular concrete, large-porous concrete, concrete on porous crushed stones) with a volumetric weight of 1000; 1400 and 1600 kg/m3.
Concrete blocks for external walls they have a thickness of 300; 400 and 500 mm, for internal walls 300 mm. The outer surface of the blocks is textured with decorative concrete or facing tiles, and the inner surface is prepared for finishing.

Walls made of large panels. According to their design, the panels are divided into single-layer and multi-layer (Fig. 2.17). Single-layer panels are made from lightweight concrete with a volumetric weight of up to 1200 kg/m 3, which has the required frost resistance and heat-insulating qualities.

Multilayer panels (two-layer and three-layer) consist of a load-bearing shell that absorbs all loads and insulation. The outer surface of the panels can be textured with a 20mm thick decorative layer of white and colored cement, lined ceramic tiles etc. The inner surface of the panels must have a finishing layer 10 mm thick.

The transmission of vertical forces in horizontal joints between panels represents the most difficult task large-panel construction.

Figure 2.16.Large-block walls of civil buildings: a - two-, three- and four-row cutting of external load-bearing walls; b-main types of wall blocks; c - double-row cutting of self-supporting walls; I, II, III, IV - rows of blocks; d - diagrams of the arrangement of blocks in axonometry; blocks: 1- wall; 2 - jumper; 3 - window sill; 4-belt.

Figure 2.17 Panel walls of civil buildings: Cutting of external walls: a- single-row with panels per room; b- the same for two rooms; c- double-row cutting of the panel structure; g-single-layer concrete; d - two-layer reinforced concrete; e - the same three-layer; g - from rolled slabs; 1- panel with an opening; 2- strip panel; 3- wall panel; 4 - reinforcement frame; 5 - lightweight concrete; 6 - decorative concrete; 7 - insulation; 8 - heating panel; 9 - reinforced concrete slab; 10 - rolled plate.

Four main types of connections have been used in practice (Fig. 2.18):

platform joint, the peculiarity of which is that the floors are supported by half the thickness of the transverse wall panels, i.e. stepwise transmission of forces, in which forces are transmitted from panel to panel through the supporting parts of the floor slabs;
serrated joint, which is a modification of a platform-type joint, provides deeper support for floor slabs, which, like a “dovetail,” rest across the entire width wall panel, but forces are transferred from panel to panel not directly, but through the supporting parts of the floor slabs;
contact joint with the ceilings supported on remote consoles and direct transfer of forces from panel to panel;
contact-socket the joint with the support of the panels is also based on the principle of direct transfer of forces from panel to panel and the support of the floors through consoles or ribs (“fingers”) protruding from the slabs themselves and placed in specially placed slots in the transverse panels.

Platform junction applied for all types of nine-story buildings, and also, as an experiment, in 17-story and 25-story buildings with a narrow pitch of transverse load-bearing walls.

Figure 2.18 Types of horizontal joints between load-bearing panels: a-platform; b-toothed; c- contact on remote consoles; g-contact-socket

Constructions of external walls of civil and industrial buildings classified according to the following criteria:

1) by static function:

a) load-bearing;

b) self-supporting;

c) non-load-bearing (mounted).

Load-bearing external walls perceive and transfer to the foundations their own weight and loads from adjacent building structures: floors, partitions, roofs, etc. (at the same time they perform load-bearing and enclosing functions).

Self-supporting external walls take vertical load only from their own weight (including the load from balconies, bay windows, parapets and other wall elements) and transfer them to the foundations through intermediate load-bearing structures– foundation beams, grillages or plinth panels(simultaneously perform load-bearing and enclosing functions).

Non-load-bearing (curtain) external walls, floor by floor (or through several floors), rest on adjacent load-bearing structures of the building - floors, frames or walls. Thus, curtain walls perform only an enclosing function.

Load-bearing and non-load-bearing external walls are used in buildings of any number of floors. Self-supporting walls rest on their own foundation, so their height is limited due to the possibility of mutual deformations of the external walls and internal structures of the building. The higher the building, the more difference in vertical deformations, therefore, for example, in panel houses It is allowed to use self-supporting walls with a building height of no more than 5 floors.

The stability of self-supporting external walls is ensured by flexible connections with the internal structures of the building.

2) According to the material:

a) stone walls are built from bricks (clay or silicate) or stones (concrete or natural) and are used in buildings of any number of floors. Stone blocks are made from natural stone (limestone, tuff, etc.) or artificial (concrete, lightweight concrete).

b) Concrete walls made of heavy concrete class B15 and higher with a density of 1600 ÷ 2000 kg/m3 (load-bearing parts of the walls) or lightweight concrete classes B5 ÷ B15 with a density of 1200 ÷ 1600 kg/m3 (for heat-insulating parts of walls).

For the production of lightweight concrete, artificial porous aggregates (expanded clay, perlite, shungizite, agloporite, etc.) or natural lightweight aggregates (crushed stone from pumice, slag, tuff) are used.

When constructing non-load-bearing external walls, cellular concrete (foam concrete, aerated concrete, etc.) of classes B2 ÷ B5 with a density of 600 ÷ 1600 kg/m3 is also used. Concrete walls are used in buildings of any number of floors.

V) Wooden walls used in low-rise buildings. For their construction, pine logs with a diameter of 180 ÷ 240 mm or beams with a section of 150x150 mm or 180x180 mm are used, as well as board or glue-plywood panels and panels with a thickness of 150 ÷ 200 mm.

d) walls made of non-concrete materials are mainly used in the construction of industrial buildings or low-rise civil buildings. Structurally, they consist of outer and inner cladding made of sheet material (steel, aluminum alloys, plastic, asbestos cement, etc.) and insulation (sandwich panels). Walls of this type are designed as load-bearing only for one-story buildings, and for larger numbers of floors - only as non-load-bearing.

3) according to a constructive solution:

a) single-layer;

b) two-layer;

c) three-layer.

The number of layers of the building’s external walls is determined based on the results of thermal engineering calculations. To comply with modern standards for heat transfer resistance in most regions of Russia, it is necessary to design three-layer external wall structures with effective insulation.

4) according to construction technology:

a) by traditional technology Hand-laid stone walls are being erected. In this case, bricks or stones are laid in rows in layers cement-sand mortar. The strength of stone walls is ensured by the strength of the stone and mortar, as well as the mutual bandaging of vertical seams. To further increase the load-bearing capacity of masonry (for example, for narrow walls), horizontal reinforcement is used welded mesh after 2 ÷ 5 rows.

The required thickness of stone walls is determined by thermal calculations and linked to standard sizes bricks or stones. Brick walls with a thickness of 1; 1.5; 2; 2.5 and 3 bricks (250, 380, 510, 640 and 770 mm, respectively). Walls made of concrete or natural stones when laying 1 and 1.5 stones, the thickness is 390 and 490 mm, respectively.

5) by location window openings:

From considering these options, it can be seen that functional purpose building (residential, public or industrial) determines the design of its external walls and appearance generally.

One of the main requirements for external walls is the necessary fire resistance. According to requirements fire safety standards Load-bearing external walls must be made of fireproof materials with a fire resistance rating of at least 2 hours (stone, concrete). The use of fire-resistant load-bearing walls (for example, wooden plastered walls) with a fire resistance limit of at least 0.5 hours is allowed only in one- and two-story houses.

A study of the old residential buildings of Moscow, St. Petersburg, Kaliningrad, Kaluga and other Russian cities showed that within the long-established central part of the city the main objects overhaul and reconstructions are two to five storeys residential buildings built at the beginning of the last century. The variety of structural forms of objects of the old stock is distinguished by a relatively small assortment: material - rubble stone, brick, wood; construction technology - manual labor.

Design solutions houses old building

Foundations in normal soils were, as a rule, built as strip foundations from torn rubble stone, or less often from burnt iron ore bricks with a complex mortar. On weak, unevenly compressed soils, for example, in St. Petersburg, foundations were often built on an artificial foundation - on wooden piles or beds.

The load-bearing walls of residential buildings were laid out with heavy cement and lime mortars from solid red brick of the highest (by today's standards) quality. As a result, they have been preserved much better than other types of structures. The thickness of the walls ranges from 2.5 to 4 bricks. The rigid connection of the longitudinal and transverse stone walls of the buildings was ensured by installing hidden connections made of the strongest wrought iron. In general, civil buildings built before the revolution are characterized by a wide variety of design solutions and the presence of a significant number of transverse walls that provide high spatial rigidity of the load-bearing frame. Vertical load In these buildings, as a rule, external and internal longitudinal walls are perceived. Occasionally there are load-bearing wooden half-timbered partitions. Interior partitions They were made of wood (plastered on both sides with shingles) or brick.

The main type of floors in old stone buildings is the floor wooden beams with a roll of plates or boards. Step load-bearing beams according to the pre-revolutionary “standard regulations” it was usually assigned equal to 1-1.5 m. Floors in the living area are wooden, parquet or linoleum. In wet rooms and in the area of staircases and elevators - from metlakh tiles, or cement with iron reinforcement.

Rafter system pitched roofs were constructed from layered and hanging logs. The design of stairs in most stone buildings is made in the form of stone or concrete steps laid on steel stringers. In staircases with one stringer per flight, one end of the steps was embedded in the masonry of the walls.

Typification of design solutions of the old foundation

A number of research organizations are engaged in research and typification of design solutions in the field of major repairs and reconstruction of old residential buildings. The research results are compiled into a single system and sorted into groups and categories according to a variety of classification criteria.

In Fig. 1. a schematic plan and section of a residential building is presented, indicating the structural elements and technical and economic parameters that are of greatest interest to designers and builders working in the field of reconstruction of old buildings.

Fig.1. Schematic plan and section of an old residential building with the designation of the main typification parameters

Analysis of the data accumulated by engineers and builders during the research process allows us to draw the following conclusions:

1. The most common is a two-span layout of residential buildings (with 1 internal wall), less often - a three-span layout (with 2 internal walls). The share of these schemes accounts for 53-54%, i.e. more than half of all houses.

2. The “clear” distance between load-bearing walls is:

in Moscow from 4 to 7 m - 51%; from 7 or more - 46.9%;
in St. Petersburg from 4 to 7 m - 77.1%; from 7 or more - 16.7%.

3. The most common distances between the axes of external walls:

in Moscow from 2 to 2.5 m - 80.5%;
in St. Petersburg from 1.75 to 2.75 m - 87.9%.

4. External walls in their upper part, at the level attic floor, have a thickness from 60 to 90 cm, and interior walls- from 40 to 80 cm.

5. The thickness of ceilings and floors ranges from 33 to 40 cm (89.6%).

6. Floor heights also vary within wide limits. However, in Moscow, buildings with floor heights from 3 to 4 m are 93.1%, and in St. Petersburg - 84.3%.

The considered design characteristics of old residential buildings should form the basis for the development of industrial engineering solutions.

The appearance of building facades is primarily formed by the walls. Therefore, stone walls must meet appropriate aesthetic requirements. In addition, walls are subject to numerous force, humidity and other influences: their own weight, loads from floors and roofs, wind, seismic shocks and uneven deformation of foundations, solar radiation, variable temperature and precipitation, noise, etc. Therefore, walls must meet strength requirements , durability, fire resistance, protect premises from adverse external influences, provide them with favorable temperature and humidity conditions for comfortable stay and work activity.

The wall construction complex often includes filling the openings of windows and doors, other structural elements, which must also meet the specified requirements.

According to the degree of spatial rigidity, buildings with stone walls can be divided into buildings with a rigid structural design, which include buildings with a frequent arrangement of transverse walls, i.e. predominantly civil buildings, and buildings with an elastic structural design, which include one-story industrial, warehouse and other similar buildings (in which the longitudinal walls have a significant height and large distances between the transverse walls).

Depending on the purpose of the building or structure, operating loads, number of storeys and other factors, stone walls are divided into:

? on bearings that absorb all vertical and horizontal loads;
? self-supporting, perceiving only their own mass;
? non-load-bearing (half-timbered), in which masonry is used to fill panels formed by crossbars, braces and frame posts.

The strength of stone walls largely depends on the strength of the masonry:

where A is a coefficient depending on the strength of the stone; R K- stone strength; Rp- strength of the solution.

Accordingly, even if the strength of the mortar is O, the masonry will have a strength equal to 33% of its maximum possible strength.

To ensure collaboration and form a spatial box, the walls are usually connected to each other, to the floors and frame using anchors. Therefore, the stability and rigidity of stone walls depend not only on their own rigidity, but also on the rigidity of floors, coverings and other structures that support and secure the walls at their height.

Walls can be solid (without openings) or with openings. Solid walls without structural elements and architectural details are called smooth. The following structural elements of walls are distinguished (Fig. 7.1):

? pilasters - vertical projections on the wall surface rectangular section, serving to divide the plane of the wall;
? corbels are the same protrusions that increase the stability and load-bearing capacity of the wall;
? pylons - brick or stone pillars that support the ceiling or form the entrance to the building;
? masonry edge - the place of transition in height from the base to the wall;
? belt - the overlap of a row of masonry in order to divide individual parts of the building's facade along its height;
? sandrik - a small canopy over the openings on the facade of the building;
? cornice - an overlap of several rows of masonry (no more than 1/3 of a brick in a row);
? furrows - extended vertical or horizontal depressions in the masonry to hide communications;
? niches - recesses in the masonry in which heating devices, electrical and other cabinets are located;
? piers - areas of masonry located between adjacent openings;
? lintels (quarters) - protrusions of masonry in the outer part of the wall and piers for installing window and door fillings;
? wooden plugs (bosses) - bars installed in masonry for fastening window and door frames.

Rice. 7.1. Structural elements of walls: a - pilasters; b - buttresses; c - pylons; g - edge of masonry; d - belt; e - sandrik; g - cornice; h - furrows; and - niches; k - piers; l - lintels; m - wooden plugs

Walls are laid with obligatory bandaging of vertical seams. On the outside of the wall, the rows of masonry can alternate as follows:

? bonded with bonded;
? spoon with spoon;
? spoon with tychkovy;
? spliced with mixed;
? some are mixed.

In practice, systems with alternating spoon and butt rows are most widespread. The more adjacent rows of spoons, the less durable the masonry is (but also less labor-intensive), since the number of longitudinal vertical rows increases and the number of bricks that are split into pieces decreases. Therefore, when choosing a masonry dressing system, they are guided by these indicators. The systems for ligating stone walls shown in Fig. have become widespread. 7.2.

Rice. 7.2. Systems for dressing masonry of stone walls: a, b, c, d - single-row, respectively chain, cross, Dutch, Gothic; d - two-row English; e - double-row with insertion pins; g - three-row; z - five-row; and - wall incision with five-row dressing; j - wall incision with single-row dressing

Structures of external walls of civil and industrial buildings

The structures of external walls of civil and industrial buildings are classified according to the following criteria:

1) by static function:

a) load-bearing;

b) self-supporting;

c) non-load-bearing (mounted).

In Fig. 3.19 shown general view these types of external walls.

Load-bearing external walls perceive and transfer to the foundations their own weight and loads from adjacent building structures: floors, partitions, roofs, etc. (at the same time they perform load-bearing and enclosing functions).

Self-supporting external walls perceive vertical load only from their own weight (including the load from balconies, bay windows, parapets and other wall elements) and transfer them to the foundations through intermediate load-bearing structures - foundation beams, grillages or plinth panels (at the same time they perform load-bearing and enclosing functions).

Non-load-bearing (curtain) external walls floor by floor (or through several floors) they rest on adjacent supporting structures of the building - floors, frames or walls. Thus, curtain walls perform only an enclosing function.

Rice. 3.19. Types of external walls according to static function:
a – load-bearing; b – self-supporting; c – non-load-bearing (suspended): 1 – building floor; 2 – frame column; 3 – foundation

Load-bearing and non-load-bearing external walls are used in buildings of any number of floors. Self-supporting walls rest on their own foundation, so their height is limited due to the possibility of mutual deformations of the external walls and internal structures of the building. The higher the building, the greater the difference in vertical deformations, therefore, for example, in panel houses, the use of self-supporting walls is allowed when the building height is no more than 5 floors.

The stability of self-supporting external walls is ensured by flexible connections with the internal structures of the building.

2) According to the material:

A) stone walls They are built from brick (clay or silicate) or stones (concrete or natural) and are used in buildings of any number of storeys. Stone blocks are made from natural stone (limestone, tuff, etc.) or artificial (concrete, lightweight concrete).

b) Concrete walls made from heavy concrete of class B15 and higher with a density of 1600 ÷ 2000 kg/m 3 (load-bearing parts of the walls) or light concrete of classes B5 ÷ B15 with a density of 1200 ÷ 1600 kg/m 3 (for heat-insulating parts of the walls).

When constructing non-load-bearing external walls, cellular concrete (foam concrete, aerated concrete, etc.) of classes B2 ÷ B5 with a density of 600 ÷ 1600 kg/m 3 is also used. Concrete walls are used in buildings of any number of floors.

V) Wooden walls used in low-rise buildings. For their construction, pine logs with a diameter of 180 ÷ 240 mm or beams with a section of 150x150 mm or 180x180 mm are used, as well as board or glue-plywood panels and panels with a thickness of 150 ÷ 200 mm.

G) walls made of non-concrete materials mainly used in the construction of industrial buildings or low-rise civil buildings. Structurally, they consist of outer and inner cladding made of sheet material (steel, aluminum alloys, plastic, asbestos cement, etc.) and insulation (sandwich panels). Walls of this type are designed as load-bearing only for one-story buildings, and for larger numbers of floors - only as non-load-bearing.

3) according to a constructive solution:

a) single-layer;

b) two-layer;

c) three-layer.

4) according to construction technology:

a) by traditional technology Hand-made stone walls are being erected. In this case, bricks or stones are laid in rows over a layer of cement-sand mortar. The strength of stone walls is ensured by the strength of the stone and mortar, as well as the mutual bandaging of vertical seams. To further increase the load-bearing capacity of masonry (for example, for narrow walls), horizontal reinforcement with welded mesh is used every 2 ÷ 5 rows.

The required thickness of stone walls is determined by thermal engineering calculations and linked to standard sizes of bricks or stones. Brick walls with a thickness of 1; 1.5; 2; 2.5 and 3 bricks (250, 380, 510, 640 and 770 mm, respectively). Walls made of concrete or natural stones when laid with 1 and 1.5 stones have a thickness of 390 and 490 mm, respectively.

In Fig. Figure 3.20 shows several types of solid masonry made of brick and stone blocks. In Fig. 3.21 shows the design of a three-layer brick wall 510 mm thick (for the climatic region of the Nizhny Novgorod region).

Rice. 3.20. Types of solid masonry: a – six-row brickwork; b – two-row brickwork; c – masonry made of ceramic stones; d and e – masonry made of concrete or natural stones; e – masonry of cellular concrete stones with external cladding brick

The inner layer of the three-layer stone wall supports the floors and load-bearing structures of the roof. Outer and inner layers brickwork are connected to each other by reinforcing mesh with a vertical pitch of no more than 600 mm. The thickness of the inner layer is assumed to be 250 mm for buildings with a height of 1 ÷ 4 floors, 380 mm for buildings with a height of 5 ÷ 14 floors and 510 mm for buildings with a height of more than 14 floors.

Rice. 3.21. Three-layer stone wall:

1 – internal load-bearing layer;

2 – thermal insulation layer;

3 – air gap;

4 – outer self-supporting (cladding) layer

b) fully assembled technology used in the construction of large-panel and volumetric block buildings. In this case, the installation of individual elements of the building is carried out by cranes.

The external walls of large-panel buildings are made of concrete or brick panels. Panel thickness – 300, 350, 400 mm. In Fig. Figure 3.22 shows the main types of concrete panels used in civil engineering.

Rice. 3.22. Concrete panels external walls: a – single-layer; b – two-layer; c – three-layer:

1 – structural and thermal insulation layer;

2 – protective and finishing layer;

3 – load-bearing layer;

4 – thermal insulation layer

Volume-block buildings are buildings of increased factory readiness, which are assembled from separate prefabricated block-rooms. The outer walls of such volumetric blocks can be one-, two-, or three-layer.

V) monolithic and prefabricated-monolithic construction technologies allow the construction of one-, two- and three-layer monolithic concrete walls.

Rice. 3.23. Prefabricated monolithic external walls (in plan):
a – two-layer with an outer layer of thermal insulation;

b – the same, with an inner layer of thermal insulation;

c – three-layer with an outer layer of thermal insulation

When using this technology, the formwork (mold) is first installed into which the concrete mixture. Single-layer walls are made of lightweight concrete with a thickness of 300 ÷ 500 mm.

Multilayer walls are made prefabricated monolithic using an outer or inner layer of stone blocks made of cellular concrete. (see Fig. 3.23).

5) according to the location of window openings:

In Fig. 3.24 shown various options location of window openings in the external walls of buildings. Options A, b, V, G used in the design of residential and public buildings, option d– when designing industrial and public buildings, option e– for public buildings.

From considering these options, it can be seen that the functional purpose of the building (residential, public or industrial) determines the design of its external walls and the overall appearance.

One of the main requirements for external walls is the necessary fire resistance. According to the requirements of fire safety standards, load-bearing external walls must be made of fireproof materials with a fire resistance limit of at least 2 hours (stone, concrete). The use of fire-resistant load-bearing walls (for example, wooden plastered walls) with a fire resistance limit of at least 0.5 hours is allowed only in one- and two-story houses.

Rice. 3.24. Location of window openings in the external walls of buildings:
a – wall without openings;

b – wall with a small number of openings;

V - panel wall with openings;

d – load-bearing wall with reinforced partitions;

d – wall with hanging panels;
e – fully glazed wall (stained glass)

High requirements for the fire resistance of load-bearing walls are caused by their main role in the safety of the building, since the destruction of load-bearing walls in a fire causes the collapse of all structures resting on them and the building as a whole.

Non-load-bearing external walls are designed to be fireproof or difficult to burn with lower fire resistance limits (from 0.25 to 0.5 hours), since the destruction of these structures in a fire can only cause local damage to the building.