External walls and their elements. External walls of modern buildings and their design features in terms of the location of window openings
The thickness of the outer walls is chosen according to the largest of the values \u200b\u200bobtained as a result of static and thermotechnical calculations, and are assigned in accordance with the design and heat engineering features of the building envelope.
In prefabricated concrete housing construction, the estimated thickness outer wall are linked to the nearest larger value from a unified series of outer wall thicknesses adopted in the centralized manufacture of molding equipment 250, 300, 350, 400 mm for panel and 300, 400, 500 mm for large-block buildings.
The calculated thickness of the stone walls is coordinated with the dimensions of the brick or stone and is taken equal to the nearest greater structural thickness obtained during masonry. With brick dimensions of 250 × 120 × 65 or 250 × 120 × 88 mm (modular brick), the thickness of the walls of solid masonry is 1; 1.5; 2; 2.5 and 3 bricks (taking into account vertical joints of 10 mm between individual stones) is 250, 380, 510, 640, and 770 mm.
The structural thickness of a wall made of sawn stone or lightly concrete small blocks, the unified dimensions of which are 390 × 190 × 188 mm, when laid in one stone is 390 and in 1.5 - 490 mm.
Wall design is based on the comprehensive use of the properties of the materials used and solves the problem of creating the required level of strength, stability, durability, insulating and architectural and decorative qualities.
In accordance with modern requirements for the economical use of materials, when designing low-rise residential buildings with stone walls, they try to use the maximum amount of local building materials. For example, in areas remote from highways, small locally produced stones or monolithic concrete are used for the construction of walls in combination with local heaters and on local aggregates, which require only imported cement. In settlements located near industrial centers, houses are designed with walls made of large blocks or panels manufactured at the enterprises of this region. At present, stone materials are being increasingly used in the construction of houses in garden plots.
When designing low-rise buildings, two schemes for the constructive solution of external walls are usually used - solid walls made of homogeneous material and lightweight multilayer walls made of materials of different densities. For the construction of internal walls, only solid masonry is used. When designing external walls according to the solid masonry scheme, preference is given to less dense materials. This technique allows you to achieve the minimum thickness of the walls in terms of thermal conductivity and more fully use the load-bearing capacity of the material. Construction Materials high density is advantageous to use in combination with low density materials (lightweight walls). The principle of lightweight walls is based on the fact that the bearing functions are performed by a layer (layers) of high-density materials (γ> 1600 kg / m 3), and a low-density material serves as a heat insulator. For example, instead of a solid outer wall made of clay bricks 64 cm thick, you can use a lightweight wall structure made of a layer of the same brick 24 cm thick, with a fiberboard insulation 10 cm thick. Such a replacement leads to a decrease in wall mass by 2.3 times.
For the manufacture of walls of low-rise buildings, artificial and natural small stones are used. Currently, artificial firing stones are used in construction (clay brick, solid, hollow, porous and ceramic blocks); fireless stones (silicate brick, hollow blocks of heavy concrete and solid blocks of lightweight concrete); natural small stones - torn rubble, sawn stones (tuff, pumice, limestone, sandstone, shell rock, etc.).
The size and weight of the stones are designed in accordance with the manual laying technology and taking into account the maximum mechanization of work. The walls are laid out of stones with filling the gap between them with mortar. Most often, cement-sand mortars are used. For laying internal walls, ordinary sand is used, and for external walls, sand of low density (perlite, etc.). Wall laying is carried out with obligatory observance suture dressing(4.6) in series.
As already noted, the width of the masonry wall is always a multiple of the number of halves of the brick. Rows facing the front surface of the masonry are called front verst, and turned to inside – inner verst. The rows of masonry between the inner and front mile are called backfill. Bricks laid long side along the wall form spoon row, and laid across the walls - bonder row. masonry system(4.7) is formed by a certain arrangement of stones in the wall.
The row of masonry is determined by the number of spoon and bond rows. With a uniform alternation of spoon and bond rows, a two-row (chain) masonry system is obtained (Fig. 4.5b). A less labor-intensive multi-row masonry system, in which one row of bricks binds five spoon rows (Fig. 4.5a). In the walls of small blocks erected according to a multi-row system, one row of bonders binds two rows of spoon masonry (Fig. 4.5c).
Fig.4.5. Types of manual laying of walls: a) - multi-row brickwork; b) - chain brickwork; c) - multi-row masonry; d) - chain masonry
Solid masonry of high density stones is used only for the construction of internal walls and pillars and external walls of unheated premises (Fig. 4.6a-g). In some cases, this masonry is used for the construction of external walls in a multi-row system (Fig. 4.6a-c, e). The two-row stone laying system is used only when necessary. For example, in ceramic stones void slots are recommended to be placed across the heat flow in order to reduce the thermal conductivity of the wall. This is achieved with a chain laying system.
Lightweight external walls are designed in two types - with insulation between two walls of solid masonry or with an air gap (Fig. 4.6i-m) and with insulation lining the solid masonry wall (Fig. 4.6n, o). In the first case, there are three main structural options for walls - walls with horizontal outlets of anchor stones, walls with vertical stone diaphragms (well masonry) and walls with horizontal diaphragms. The first option is used only in cases where lightweight concrete is used as a heater, which monolithizes anchor stones. The second option is acceptable for insulation in the form of pouring lightweight concrete and laying thermal liners (Fig. 4.6k). The third option is used for insulation from bulk materials (Fig. 4.6l) or from lightly concrete stones. Solid masonry walls with an air gap (Fig. 4.6m) also belongs to the category of lightweight walls, since the closed air gap acts as a layer of insulation. It is advisable to take the thickness of the interlayers equal to 2 cm. An increase in the interlayer practically does not increase its thermal resistance, and a decrease sharply reduces the effectiveness of such thermal insulation. More often, the air gap is used in combination with insulation boards (Fig. 4.6k, o).
Fig. 4.6, Variants of manual laying of the walls of low-rise residential buildings: a), b) - solid outer walls made of bricks; c) - a solid internal brick wall; e), g) - solid outer walls made of stones; d), f) - solid internal walls made of stones; i) -m) - lightweight walls with internal insulation; n), o) - lightweight walls with external insulation; 1 - brick; 2 - plaster or cladding with sheets; 3 - artificial stone; 4 - slab insulation; 5 - air gap; 6 - vapor barrier; 7 - wooden antiseptic rail; 8 - backfill; 9 - solution diaphragm; 10 - lightweight concrete; 11 - natural frost-resistant stone
To insulate stone walls from the side of the street, a rigid slab insulation made of lightweight concrete, foam glass, fiberboard is used in combination with a weather-resistant and durable cladding (asbestos cement sheets, boards, etc.). The option of wall insulation from the outside is effective only if there is no access of cold air to the zone of contact between the carrier layer and the insulation layer. To insulate the outer walls from the side of the room, a semi-rigid slab insulation (reed, straw, mineral wool, etc.) is used, located close to the surface of the first or with the formation of an air gap, 16–25 mm thick - “at a distance”. Slabs "at a distance" are attached to the wall with metal zigzag brackets or nailed to wooden antiseptic slats. The open surface of the insulation layer is covered with sheets of dry plaster. Between them and the insulation layer, a vapor barrier layer of glassine, polyethylene film, metal foil, etc. is necessarily placed.
Study and analyze the above material and answer the proposed question.
Question 4.2. Can rows of bricks laid long side along a wall be called poke rows?
4.2. answer: yes
[ outdoor house walls, technology, classification, mason, design and masonry of load-bearing walls]
Fast passage:
- Temperature-shrinkage and sedimentary seams
- Exterior wall classification
- Structures of single and multilayer walls
- Panel concrete walls and their elements
- Design of panels of load-bearing and self-supporting single-layer walls
- Three-layer construction concrete panels
- Methods for solving the main problems of designing walls in concrete panel structures
- Vertical joints and Connections of panels of external walls with internal
- Heat and insulating ability of joints, types of joints
- Compositional and decorative features of panel walls
The designs of the outer walls are extremely diverse; they are determined by the construction system of the building, the material of the walls and their static function.
General requirements and classification of structures
Fig. 2. Expansion joints
Fig. 3. Details of the installation of expansion joints in brick and panel buildings
Thermal shrinkage seams arrange in order to avoid the formation of cracks and distortions caused by the concentration of efforts from exposure to variable temperatures and shrinkage of the material (masonry, monolithic or prefabricated concrete structures, etc.). Temperature-shrinkage joints cut through the structures of only the ground part of the building. The distances between the temperature-shrinkage seams are assigned in accordance with climatic conditions and physical and mechanical properties wall materials. For external walls made of clay bricks on a solution of grade M50 and more, the distances between temperature-shrinkage joints of 40-100 m are taken according to SNiP "Stone and reinforced masonry structures", for external walls made of concrete panels 75-150 m according to VSN32-77, Gosgrazhdanstroy "Instruction on the design of structures of panel residential buildings. At the same time, the smallest distances refer to the most severe climatic conditions.
In buildings with longitudinal load-bearing walls, seams are arranged in the area of adjacency to transverse walls or partitions; in buildings with transverse load-bearing walls, seams are often arranged in the form of two paired walls. The smallest joint width is 20 mm. Seams must be protected from blowing, freezing and through leaks with metal expansion joints, sealing, insulating liners. Examples of constructive solutions for temperature-shrinkage joints in brick and panel walls are given in fig. 3.
Sedimentary seams should be provided in places of sharp differences in the number of storeys of the building (sedimentary seams of the first type), as well as in case of significant uneven deformation of the base along the length of the building, caused by the specifics of the geological structure of the base (sedimentary seams of the second type). Sedimentary joints of the first type are appointed to compensate for differences in vertical deformations of ground structures of the high and low parts of the building, and therefore they are arranged similarly to temperature-shrinkage joints only in ground structures. The design of the seam in frameless buildings provides for the installation of a sliding seam in the zone of support of the ceiling of the low-rise part of the building on the walls of the high-rise building, in frame buildings - the hinged support of the crossbars of the low-rise part on the columns of the high-rise building. Sedimentary seams of the second type cut the building to its entire height - from the ridge to the base of the foundation. Such seams in frameless buildings are designed in the form of paired transverse walls, in frame buildings - paired frames. The nominal width of settlement joints of the first and second types is 20 mm.
Fig. 4. Exterior wall views
External wall structures classified according to:
- the static function of the wall, determined by its role in the structural system of the building;
- material and construction technology, shared by the building system of the building;
- constructive solution - in the form of a single-layer or layered enclosing structure.
According to the static function, load-bearing, self-supporting or non-bearing wall structures are distinguished (Fig. 4). D
Carriers walls, in addition to the vertical load from their own mass, transmitting loads to the foundations from adjacent structures: ceilings, partitions, roofs, etc.
Self-supporting walls perceive vertical load only from their own mass (including the load from balconies, bay windows, parapets and other wall elements) and transfer it to the foundations directly or through plinth panels, end beams, grillage or other structures.
Table 11 - brick; 2 - small block; 3, 4 - insulation and air gap; 5 - lightweight concrete; 6 - autoclaved cellular concrete; 7 - constructive heavy or light concrete; 8 - log; 9 - caulk; 10 - timber; eleven - wooden frame; 12 - vapor barrier; 13 - airtight layer; 14 - sheathing from boards, waterproof plywood, chipboard or others; 15 - sheathing from inorganic sheet materials; 16 - metal or asbestos-cement frame; 17 - ventilated air gap
External walls can be single layer or layered designs. Single layer walls erected from panels, concrete or stone blocks, cast-in-place concrete, stone, brick, wooden logs or beams. In layered walls, the performance of various functions is assigned to various materials. Strength functions provide concrete, stone, wood; durability features - concrete, stone, wood or sheet material (aluminum alloys, enamelled steel, asbestos cement, etc.); thermal insulation functions - effective heaters(mineral wool boards, fibrolite, expanded polystyrene, etc.); vapor barrier functions - roll materials(laying roofing felt, foil, etc.), dense concrete or mastics; decorative functions - various facing materials. An air gap can be included in the number of layers of such a building envelope. Closed - to increase its resistance to heat transfer, ventilated - to protect the room from radiation overheating or to reduce deformations of the outer facing wall.
Structures of single and multilayer walls can be made prefabricated or in traditional technique.
The main types of structures of external walls and their areas of application are given in Table. 1.
The purpose of the static function of the outer wall, the choice of materials and structures is carried out taking into account the requirements of SNiP " Fire regulations design of buildings and structures". According to these standards, load-bearing walls, as a rule, must be fireproof. The use of slow-burning load-bearing walls (for example, wooden plastered) with a fire resistance limit of at least 0.5 hours is allowed only in one-two-story houses. The fire resistance limit of non-combustible wall structures must be at least 2 hours, and therefore they must be made of stone or concrete materials. High requirements for the fire resistance of load-bearing walls, as well as columns and pillars, are due to their role in the safety of a building or structure. Fire damage to vertical load-bearing structures can lead to the collapse of all structures based on them and the building as a whole.
Non-load-bearing external walls are designed to be fireproof or slow-burning with significantly lower fire resistance limits (0.25-0.5 h), since the destruction of these structures from exposure to fire leads only to local damage to the building.
Fireproof non-bearing external walls should be used in residential buildings above 9 floors, with a lower number of storeys, the use of fire-retardant structures is allowed.
The thickness of the outer walls is chosen according to the largest of the values obtained as a result of static and heat engineering calculations, and is assigned in accordance with the design and heat engineering features of the enclosing structure.
In prefabricated concrete housing construction, the design thickness of the outer wall is linked to the nearest larger value from the unified series of outer wall thicknesses adopted in the centralized production of molding equipment 250, 300, 350, 400 mm for panel and 300, 400, 500 mm for large-block buildings.
The calculated thickness of the stone walls is coordinated with the dimensions of the brick or stone and is taken equal to the nearest greater structural thickness obtained during masonry. With brick dimensions of 250X120X65 or 250X X 120x88 mm (modular brick), the thickness of the walls of solid masonry is 1; 1 1/2; 2; 2 1/2 and 3 bricks (taking into account vertical joints of 10 mm between individual stones) is 250, 380, 510, 640 and 770 mm.
The structural thickness of a wall made of sawn stone or lightweight concrete small blocks, the unified dimensions of which are 390X190X188 mm, is 390 mm when laid in one stone and 490 mm in 1/2 g.
The thickness of walls made of non-concrete materials with effective heaters in some cases is taken more than that obtained by thermotechnical calculation because of design requirements: an increase in the dimensions of the wall section may be necessary for the device of reliable insulation of joints and mates with filling openings.
Wall design is based on the comprehensive use of the properties of the materials used and solves the problem of creating the required level of strength, stability, durability, insulating and architectural and decorative qualities.
The appearance of the facades of buildings, first of all, is formed by the walls. Therefore, stone walls must meet the relevant aesthetic requirements. In addition, the walls are subject to numerous force, humidity and other influences: their own weight, loads from ceilings and roofs, wind, seismic shocks and uneven deformation of the bases, solar radiation, variable temperature and precipitation, noise, etc. Therefore, the walls must meet the strength requirements , durability, fire resistance, protect the premises from adverse external influences, provide them with a favorable temperature and humidity regime for comfortable living and working.
The wall construction complex often includes window and door opening fillings, 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 scheme, which include buildings with a frequent arrangement of transverse walls, i.e. predominantly civil buildings, and buildings with an elastic structural scheme, 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, acting loads, number of storeys and other factors, stone walls are divided into:
- ? on carriers, perceiving all vertical and horizontal loads;
- ? self-supporting, perceiving only their own mass;
- ? non-bearing (half-timbered), in which masonry is used as a filling of panels formed by crossbars, braces and frame posts.
The strength of stone walls to a large extent depends on the strength of the masonry:
where A is a coefficient depending on the strength of the stone; R K- the strength of the stone; Rp- the strength of the solution.
In accordance with this, even if the strength of the mortar is equal to 0, the masonry will have a strength equal to 33% of its maximum possible strength.
To ensure joint work and the formation of a space box, the walls are usually connected to each other, to the floors and the frame using anchors. Therefore, the stability and rigidity of stone walls depend not only on their own rigidity, but also on the rigidity of ceilings, coatings and other structures that support and fix the walls along their height.
Walls are solid (without openings) and with openings. Solid walls without structural elements and architectural details are called smooth. There are the following structural elements of the walls (Fig. 7.1):
- ? pilasters - vertical protrusions on the surface of a wall of rectangular section, which serve to divide the plane of the wall;
- ? buttresses - the same protrusions that increase the stability and bearing capacity of the wall;
- ? pylons - brick or stone pillars that serve as a support for the ceiling or make out the entrance to the building;
- ? masonry edge - the place of transition in height from the basement to the wall;
- ? corbel - an overlap of a row of masonry in order to divide individual parts of the facade of the building 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 recesses in the masonry to hide communications;
- ? niches - recesses in the masonry, in which heating devices, electrical and other cabinets are located;
- ? piers - masonry sections located between adjacent openings;
- ? lintels (quarters) - masonry protrusions in the outer part of the wall and piers for installing window and door fillings;
- ? wooden plugs (lugs) - bars installed in masonry for fastening window and door frames.
Rice. 7.1. Structural elements of the walls: a - pilasters; b - buttresses; in - pylons; g - masonry edge; d - belt; e - sandrik; g - cornice; h - furrows; and - niches; to - piers; l - lintels; m - wooden plugs
Wall laying is carried out with obligatory dressing of vertical seams. On the outside of the wall, the rows of masonry can alternate as follows:
- ? bonder with bonder;
- ? spoon with spoon;
- ? spoon with bonder;
- ? bonder with mixed;
- ? some are mixed.
In practice, systems with alternating spoon and bonder rows are most widely used. The more adjacent rows of spoons, the less durable the masonry is (but also less laborious), 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. Bandaging systems for stone walls, shown in fig. 7.2.
Rice. 7.2. Systems for dressing the laying of stone walls: a, b, c, d - single-row, respectively chain, cross, Dutch, Gothic; d - two-row English; e - two-row with plug-in pokes; g - three-row; h - five-row; and - a section of the wall with a five-row dressing; j - wall incision with single-row dressing
Table 3.2 shows a diagram showing the dependence and variability of constructive solutions and methods for the reconstruction of the old housing stock. In the practice of reconstruction work, taking into account the physical wear of non-replaceable structures, several solutions are used: without changing the structural scheme and with its change; without changing the building volume, with an addition of floors and an extension of small volumes.
Table 3.2
The first option provides for the restoration of the building without changing the building volume, but with the replacement of floors, roofing and other structural elements. At the same time, a new layout is being created that meets modern requirements and the needs of social groups of residents. The reconstructed building must retain the architectural appearance of the facades, and its operational characteristics must be brought up to modern regulatory requirements.
Variants with a change in structural schemes provide for an increase in the construction volume of buildings by: adding volumes and expanding the building without changing its height; superstructures without changing the dimensions in the plan; superstructures with several floors, extensions of additional volumes with a change in the dimensions of the building in the plan. This form of reconstruction is accompanied by redevelopment of the premises.
Depending on the location of the building and its role in development, the following options for reconstruction are carried out: with the preservation of residential functions; with partial reprofiling and complete reprofiling of building functions.
Reconstruction of residential buildings should be carried out in a comprehensive manner, capturing, along with the reconstruction of the intra-quarter environment, its landscaping, improvement and restoration of engineering networks, etc. In the process of reconstruction, the range of built-in premises is being revised in accordance with the standards for providing the population with primary service institutions.
In the central areas of cities, reconstructed buildings may contain built-in citywide and commercial institutions of periodic and permanent service. The use of built-in spaces turns residential buildings into multifunctional buildings. Non-residential premises are located on the first floors of houses located along the red building lines.
On fig. 3.5 shows structural and technological options for the reconstruction of buildings with the preservation ( A) and with change ( b,V) structural schemes, without changing the volumes and with their increase (superstructure, extension and expansion of the planned dimensions of buildings).
Rice. 3.5. Options for the reconstruction of residential buildings of early construction A- without changing the design scheme and building volume; b- with an extension of small volumes and the transformation of the attic floor into an attic; V- with a superstructure of floors and an extension of volumes; G- with an extension of the body to the end part of the building; d, e- with the construction of buildings; and- with addition of curvilinear volumes
A special place in the reconstruction of urban development centers should be given to the rational development of the underground space adjacent to buildings, which can be used as shopping centers, parking lots, small businesses, etc.
The main constructive and technological method for the reconstruction of buildings without changing the design scheme is the preservation of non-replaceable structures of external and internal walls, staircases with the device of overlappings of the increased capitality. With a significant degree of wear of the internal walls as a result of frequent redevelopment with the installation of additional openings, the transfer of ventilation ducts, etc. Reconstruction is carried out by installing built-in systems with the preservation of only the outer walls as load-bearing and enclosing structures.
Reconstruction with a change in the building volume provides for the installation of built-in non-replaceable systems with independent foundations. This circumstance allows the superstructure of buildings with several floors. At the same time, the structures of the outer and, in some cases, inner walls are relieved from the loads of the overlying floors and turn into self-supporting enclosing elements.
During the reconstruction with the broadening of the building, constructive and technological options for the partial use of existing foundations and walls as load-bearing ones are possible with the redistribution of loads from the built-up floors to the external elements of buildings.
The principles of reconstruction of buildings of late construction (1930-40s) are dictated by the simpler configuration of sectional-type houses, the presence of ceilings made of small-piece reinforced concrete slabs or wooden beams, as well as the thinner outer walls. The main methods of reconstruction are the extension of elevator shafts and other small volumes in the form of bay windows and inserts, the superstructure of floors and attics, the installation of remote low-rise extensions for administrative, commercial or household purposes.
An increase in the comfort of apartments is achieved through a complete redevelopment with the replacement of floors, and an increase in the volume of the building as a result of the superstructure ensures an increase in the building density of the quarter.
The most characteristic techniques for the reconstruction of buildings of this type are the replacement of floors with prefabricated or monolithic structures with a complete redevelopment, as well as an additional superstructure with 1-2 floors. At the same time, the superstructure of buildings is carried out in cases where the state of the foundations and wall fencing ensures the perception of changed loads. As experience has shown, the buildings of this period make it possible to build up to two floors without strengthening the foundations and walls.
In the case of an increase in the height of the superstructure, built-in building systems from prefabricated, precast-monolithic and monolithic structures are used.
The use of built-in systems makes it possible to implement the principle of creating large overlapped areas, which contribute to the implementation of a flexible layout of the premises.
Vertical structural elements of the building, separating the premises from the external environment and dividing the building into separate rooms called walls. They perform enclosing and bearing (or only the first) functions. They are classified according to various criteria.
By location - external and internal.
Exterior walls- the most complex building structure. They are subject to many and varied forceful and non-forceful influences. The walls perceive their own weight, permanent and temporary loads from ceilings and roofs, wind exposure, uneven deformations of the base, seismic forces, etc. From the outside, the outer walls are exposed to solar radiation, precipitation, variable temperatures and humidity of the outside air, external noise, and from the inside - to the influence of heat flow, water vapor flow, noise.
Performing the functions of an external enclosing structure and a composite element of facades, and often a supporting structure, the external wall must meet the requirements of strength, durability and fire resistance corresponding to the capital class of the building, protect the premises from adverse external influences, provide the necessary temperature and humidity conditions of the enclosed premises, have decorative qualities.
The design of the outer wall must meet the economic requirements of minimum material consumption and cost, since the outer walls are the most expensive structure (20-25% of the cost of building structures).
In the outer walls, there are usually window openings for lighting the premises and doorways - entrances and exits to balconies and loggias. The complex of wall structures includes the filling of window openings, entrance and balcony doors, open space designs.
These elements and their interfaces with the wall must meet the requirements listed above. Since the static functions of walls and their insulating properties are achieved by interacting with internal load-bearing structures, the design of external wall structures includes the solution of interfaces and joints with floors, internal walls or framing.
External walls, and with them the rest of the building structures, if necessary and depending on the natural-climatic and engineering-geological conditions of construction, as well as taking into account the features of space-planning decisions, are cut by vertical expansion joints of various types: temperature, sedimentary, anti-seismic, etc. .
Internal walls are divided into:
Inter-apartment;
Intra-apartment (walls and partitions);
Walls with ventilation ducts (near the kitchen, bathrooms, etc.).
Depending on the adopted structural system and building scheme, the outer and inner walls of the building are divided into load-bearing, self-supporting and non-bearing (Fig. 84).
Fig.84. Wall structures:
a - bearing; b - self-supporting; c - hinged
Partitions- these are vertical, as a rule, non-load-bearing fences dividing the internal volume of the building into adjacent rooms.
They are classified according to the following criteria:
By location - inter-room, inter-apartment, for kitchens and plumbing units;
By function - deaf, with openings, incomplete, that is, not reaching
By design - solid, frame, sheathed on the outside with sheet material;
According to the installation method - stationary and transformable.
Partitions must meet the requirements of strength, stability, fire resistance, sound insulation, etc.
Carriers walls, in addition to the vertical load from their own mass, perceive and transfer to the foundations loads from adjacent structures: ceilings, partitions, roofs, etc.
Self-supporting walls perceive vertical load only from their own mass (including the load from balconies, bay windows, parapets and other wall elements) and transfer it to the foundations directly or through plinth panels, end beams, grillage or other structures.
Non-bearing walls floor by floor (or through several floors) are supported on adjacent internal structures of the building (floors, walls, frame).
Bearing and self-supporting walls perceive, along with vertical and horizontal loads, being vertical elements of the rigidity of structures.
In buildings with non-load-bearing external walls, the functions of vertical stiffeners are performed by the frame, internal walls, diaphragms or stiffeners.
Bearing and non-bearing external walls can be used in buildings of any number of storeys. The height of self-supporting walls is limited in order to prevent operationally unfavorable mutual displacements of self-supporting and internal load-bearing structures, accompanied by local damage to the finish of the premises and the appearance of cracks. In panel houses, for example, it is permissible to use self-supporting walls with a building height of no more than 4 floors. The stability of self-supporting walls is provided by flexible connections with internal structures.
Load-bearing external walls are used in buildings of various heights.
Maximum number of storeys bearing wall depends on the bearing capacity and deformability of its material, design, the nature of the relationship with internal structures, as well as on economic considerations. So, for example, the use of lightweight concrete panel walls is advisable in houses up to 9-12 floors high, load-bearing brick external walls - in buildings of medium height (4-5 floors), and walls of a steel lattice shell structure - in 70-100 storey buildings.
By design - small-element (brick, etc.) and large-element(from large panels, blocks, etc.)
In terms of mass and degree of thermal inertia, the outer walls of buildings are divided into four groups - massive (more than 750 kg / m 2), medium massive (401-750 kg / m 2), light (150-400 kg / m 2), extra light (150-400 kg / m 2).
According to the material, the main types of wall structures are distinguished: concrete, stone from non-concrete materials and wood. In accordance with the building system, each type of wall contains several types of structures: concrete walls - from monolithic concrete,
large blocks or panels; stone walls - hand-made, walls made of stone blocks and panels; walls made of non-concrete materials - half-timbered and panel frame and
frameless; wooden walls- chopped from logs or beams frame-sheathing, frame-panel, panel and panel. Concrete and stone walls are used in buildings of various heights and for various static functions in accordance with their role in the structural system of the building. Walls made of non-concrete materials are used in buildings of various heights only as a non-bearing structure.
External walls can be single layer or layered construction.
Single layer Walls are erected from panels, concrete or stone blocks, cast-in-place concrete, stone, brick, wooden logs or beams. IN layered walls, the performance of different functions is assigned to various materials. Strength functions are provided by concrete, stone, wood: durability functions - concrete, stone, wood or sheet material (aluminum alloys, clad steel, asbestos cement, etc.); thermal insulation functions - effective heaters (mineral wool boards, fibrolite, expanded polystyrene, etc.); vapor barrier functions - rolled materials (roofing felt, foil, etc.), dense concrete or mastics; decorative functions - various facing materials. An air gap can be included in the number of layers of such a building envelope. Closed- to increase its resistance to heat transfer, ventilated- to protect the premises from radiation overheating or to reduce deformations of the outer facing layer of the wall.
Structures of single-layer and multi-layer walls can be made prefabricated or in traditional technique.
Wall structures must meet the requirements of solidity, strength and stability. The heat-shielding and sound-proofing capacity of the walls is established on the basis of heat-engineering and sound-proofing calculations.
The thickness of the outer walls is chosen according to the largest of the values obtained as a result of static and heat engineering calculations, and is assigned in accordance with the design and heat engineering features of the enclosing structure.
Rice. 85. Homogeneous brickwork:
a - six-row dressing system; b - chain (two-row dressing system).
Fig.86. well masonry brick walls:
a - with horizontal diaphragms made of cement-sand mortar; b - the same, from bonded bricks arranged in a checkerboard pattern; c - the same, located in the same plane; d - axonometry of masonry.
Rice. 87. Exterior wall panels:
a - single-layer; b - two-layer; c - three-layer; 1 - structural and heat-insulating concrete; 2 - protective and finishing layer; 3 - structural concrete; 4 - effective insulation.
