Building structure is called an enlarged building element of a building, structure or bridge, made of building materials and products.

Building structures are classified by purpose and building material.

By appointment there are:

1. Carriers - those structures of buildings and structures that can withstand power loads. They provide their stability and strength, and also allow the safe operation of the building. These include: load-bearing walls, columns, foundations, floors and coverings, etc.

2. Fencing - structures that limit the volume of the building and divide it into separate functional rooms. Divided into: external (protect from weathering) and internal (to ensure sound insulation and dividing the internal space). The enclosing structures include partitions, self-supporting walls, filling openings, etc.

By material, building structures are divided into:

Concrete and reinforced concrete;

Steel structures;

Wooden;

Stone and reinforced stone;

Plastic;

Complex (combine several types of materials).

The main requirements for building structures:

1. Reliability. This concept includes three components: strength, rigidity and stability.

Strength is the ability of a structure to withstand all loads without destruction;

Stiffness is a property that allows a building structure to deform under the action of loads within acceptable limits;

Stability - the ability of a structure to maintain a constant position in space under the action of loads.

2. Ease of use- this is the ability to use buildings and structures for their intended purpose. It is necessary that the structures are designed in such a way that it is possible to easily inspect, repair, reconstruct and strengthen them.

3... Profitability... When designing, it is necessary to make sure that there is no overspending of building materials and try to ensure minimum labor costs when installing the structure.

9.2. Reinforced concrete structures and products

Reinforced concrete structures and products, elements of buildings and structures made of reinforced concrete, and combinations of these elements.

High technical and economic indicators of reinforced concrete structures, the ability to relatively easily give them the required shape and dimensions while maintaining the specified strength, have led to their widespread use in almost all branches of construction. Modern reinforced concrete structures (reinforced concrete structures) are classified according to several criteria: by the method of execution (monolithic, prefabricated, precast-monolithic), the type of concrete used for their manufacture (from heavy, light, cellular, heat-resistant, etc. concretes), the type of stress state ( normal and pre-stressed).

Monolithic reinforced concrete structures, performed directly on construction sites, are usually used in buildings and structures that are difficult to divide, with non-standard and low repeatability of elements and with especially heavy loads (foundations, frames and floors of multi-storey industrial buildings, hydraulic engineering, reclamation, transport and other structures).

In some cases, they are advisable when performing work by industrial methods using inventory formwork - sliding, movable (towers, cooling towers, silos, chimneys, multi-storey buildings) and mobile (some thin-walled coating shells).

The erection of monolithic reinforced concrete structures is technically well developed. There are also significant advances in the application of the prestressing method in the production of monolithic structures. A large number of unique structures are made in monolithic reinforced concrete (television towers, industrial pipes of great height, reactors of nuclear power plants, etc.). In modern construction practice in a number of foreign countries (USA, Great Britain, France, etc.), monolithic reinforced concrete structures have become widespread, which is mainly due to the absence in these countries of a state system for unifying parameters and typing structures of buildings and structures. In the USSR, monolithic structures predominated in construction until the 30s.

The introduction of more industrial prefabricated structures in those years was held back due to the insufficient level of mechanization of construction, the lack of special equipment for their mass production, as well as high-performance assembly cranes. The share of monolithic reinforced concrete structures in the total volume of reinforced concrete production in the USSR is approximately 35% (1970).

Precast concrete structures and products- the main type of structures and products used in various sectors of construction: housing and civil, industrial, agricultural, etc.

Prefabricated structures have significant advantages over monolithic ones, they create wide opportunities for the industrialization of construction. The use of large-sized reinforced concrete elements allows the bulk of the work on the construction of buildings and structures to be transferred from the construction site to a plant with a highly organized technological production process. This significantly reduces the construction time, ensures a higher quality of products at the lowest cost and labor costs; The use of prefabricated reinforced concrete structures makes it possible to widely use new efficient materials (lightweight and cellular concrete, plastics, etc.), and reduces the consumption of timber and steel, which are necessary in other branches of the national economy. Prefabricated structures and products must be technological and transportable, they are especially advantageous with a minimum number of standard sizes of elements, repeated many times.

With the growth of production and use of prefabricated reinforced concrete in construction, the technology of its manufacture has improved. The unification of the basic parameters of buildings and structures for various purposes was also carried out, on the basis of which standard designs and products for them were developed and introduced.

Depending on the purpose in the construction of residential, public, industrial and agricultural buildings and structures, the following most common prefabricated reinforced concrete structures are distinguished:

For foundations and underground parts of buildings and structures (foundation blocks and slabs, panels and blocks of basement walls);

For building frames (columns, girders, girders, crane beams, rafter and rafter beams, trusses);

For external and internal walls (wall and partition panels and blocks);

For intermediate floors and building coverings (panels, slabs and decking); for stairs (flights of stairs and landings);

For sanitary devices (heating panels, ventilation and waste chute blocks, sanitary cabins).

Prefabricated reinforced concrete structures are manufactured mainly at mechanized enterprises and partially at equipped landfills. The technological process for the production of reinforced concrete products consists of a number of successively performed operations: preparation of concrete mixture, production of reinforcement (reinforcing cages, meshes, bent rods, etc.), reinforcement of products, molding of products (laying of concrete mixture and its compaction), heat and moisture treatment, providing the necessary strength of concrete, finishing the front surface of products.

In modern technology of precast concrete, 3 main methods of organizing the production process can be distinguished: the aggregate-flow method of manufacturing products in movable forms; conveyor production method; bench method in non-movable (stationary) forms.

With the aggregate-flow method All technological operations (cleaning and lubrication of molds, reinforcement, shaping, hardening, stripping) are carried out at specialized stations equipped with machines and installations that form a production line. Molds with products are sequentially moved along the technological line from one station to another with an arbitrary time interval depending on the duration of the operation at a given station, which can vary from several minutes (for example, mold lubrication) to several hours (hardening of products in steaming chambers). This method is advantageous to use at medium-sized factories, especially when producing designs and products of a wide range.

Conveyor method used in factories of high power when producing the same type of products of a limited range. With this method, the technological line operates on the principle of a pulsating conveyor, i.e., the forms with products move from one station to another after a strictly defined time required to perform the longest operation.

A variation of this technology is vibratory rolling method used for the manufacture of flat and ribbed plates; in this case, all technological operations are performed on one moving steel belt. With the bench method, the products during their manufacture and until the concrete hardens remain in place (in a stationary form), while the technological equipment for performing individual operations moves from one form to another. This method is used in the manufacture of large products (trusses, beams, etc.). For molding products of complex configuration (flights of stairs, ribbed slabs, etc.), matrices are used - reinforced concrete or steel forms that reproduce the imprint of the ribbed surface of the product. In the case of the cassette method, which is a kind of bench method, products are made in vertical forms - cassettes, which are a series of compartments formed by steel walls. On the cassette installation, the products are molded and hardened. The cassette installation has devices for heating products with steam or electric current, which significantly accelerates the hardening of concrete. Cassette method usually used for mass production of thin-walled products.

Finished products must meet the requirements of applicable standards or specifications. The surfaces of products are usually made with such a degree of factory readiness that no additional finishing is required at the construction site.

During installation, prefabricated elements of buildings and structures are connected to each other by solidifying or welding embedded parts, designed to absorb certain force effects. Much attention is paid to reducing the metal consumption of welded joints and their unification. Prefabricated structures and products are most widely used in housing and civil construction, where large-scale housing construction (large-panel, large-block, volumetric) is considered as the most promising. Precast reinforced concrete is also used for mass production of products for engineering structures (so-called special reinforced concrete): bridge spans, supports, piles, culverts, trays, blocks and tubing for lining tunnels, slabs of roads and airfields, sleepers, contact supports networks and power lines, fencing elements, pressure and non-pressure pipes, etc.

A significant part of these products is made of prestressed reinforced concrete by bench or flow-aggregate method. For shaping and compacting concrete, very effective methods are used: vibrocompression (pressure pipes), centrifugation (pipes, supports), vibration stamping (piles, trays).

The development of prefabricated reinforced concrete is characterized by a tendency towards further enlargement of products and an increase in the degree of their factory readiness. So, for example, for building coverings, multilayer panels are used, supplied for construction with insulation and a layer of waterproofing; blocks of 3x18 m and 3x24 m in size, combining the functions of bearing and enclosing structures. Combined roofing slabs made of lightweight and aerated concrete have been developed and successfully applied. In multi-storey buildings, prestressed reinforced concrete columns are used to a height of several floors. For the walls of residential buildings, panels are made in sizes for one or two rooms with a variety of external finishes, equipped with window or door (balcony) blocks. Significant prospects for the further industrialization of housing construction have a way of erecting buildings from volumetric blocks. Such blocks for one or two rooms or for an apartment are manufactured at the factory with full interior decoration and equipment; assembling houses from these elements takes only a few days.

Precast-monolithic reinforced concrete structures are such a combination of prefabricated elements (reinforced concrete columns, girders, slabs, etc.) with monolithic concrete, which ensures reliable joint operation of all components.

These structures are used mainly in the floors of multi-storey buildings, in bridges and overpasses, in the construction of certain types of shells, etc.

They are less industrial (in terms of construction and installation) than prefabricated ones. Their use is especially advisable at high dynamic (including seismic) loads, as well as when it is necessary to divide large-sized structures into component elements due to the conditions of transportation and installation. The main advantage of prefabricated monolithic structures is the lower (in comparison with prefabricated structures) steel consumption and high spatial rigidity.

Most of the reinforced concrete and concrete products are made of heavy concrete with an average density of 2400 kg / m 3. However, the share of products made of structural, heat-insulating and structural lightweight concrete on porous aggregates, as well as from aerated concrete of all types, is constantly increasing. Such products are used mainly for enclosing structures (walls, coatings) of residential and industrial buildings.

Bearing structures made of high-strength heavy concrete of C30 / 35 and C32 / 40 classes and lightweight concrete of C20 / 25 and C25 / 30 classes are very promising. A significant economic effect is achieved as a result of the use of structures made of heat-resistant concrete (instead of piece refractories) for thermal units in metallurgical, oil refining and other industries; for a number of products (for example, pressure pipes), the use of tensioning concrete is promising.

Reinforced concrete structures and products are mainly made with flexible reinforcement in the form of individual rods, welded meshes and flat frames. For the manufacture of non-tensioned reinforcement, it is advisable to use contact welding, which provides a high degree of industrialization of reinforcement work. Structures with bearing (rigid) reinforcement are used relatively rarely and mainly in monolithic reinforced concrete when concreting in suspended formwork. In bending elements, longitudinal working reinforcement is installed in accordance with the diagram of maximum bending moments; in columns, longitudinal reinforcement predominantly perceives compressive forces and is located along the perimeter of the section. In addition to longitudinal reinforcement, distribution, assembly and transverse reinforcement (clamps, bends) are installed in reinforced concrete structures, and in some cases, the so-called. indirect reinforcement in the form of welded meshes and spirals.

All these types of reinforcement are interconnected and provide the creation of a reinforcing cage that is spatially unchanged during the concreting process. For prestressed reinforcement of prestressed reinforced concrete structures, high-strength bar reinforcement and wire, as well as strands and ropes from it, are used. In the manufacture of prefabricated structures, the method of tensioning the reinforcement on the stops of stands or forms is mainly used; for monolithic and precast-monolithic structures - the method of tensioning the reinforcement on the concrete of the structure itself.

The wide form-building and technical capabilities of reinforced concrete structures had a huge impact on the world architecture of the 20th century. On the basis of reinforced concrete structures, new scales, architectonics and spatial organization of buildings and structures have developed. Rectilinear frame structures give buildings a strict geometrical form and a measured rhythm of divisions, a clear structure. Horizontal floor slabs rest on thin supports, a light wall, being deprived of a load-bearing function, often turns into a glass curtain screen. The uniform distribution of static forces creates tectonic equivalence of the building elements. Curvilinear structures (especially thin-walled shells of various, sometimes bizarre outlines), with their complex tectonics of forms (sometimes approaching sculptural ones) and continuously changing rhythm of elements, have great plastic and spatial expressiveness. Curvilinear structures allow to overlap huge halls without intermediate supports and create volumetric-spatial compositions of unusual shape. Some modern reinforced concrete structures (for example, lattice) have ornamental and decorative qualities that form the appearance of facades and coatings. Plastically meaningful modern reinforced concrete structures give aesthetic expressiveness not only to residential and civil buildings, but also to engineering and industrial structures (bridges, overpasses, dams, cooling towers, etc.).

Bearing structures.

Reinforced concrete columns:

Rice. 9.1. Column two-branch middle row

Rice. 9.2. Two-branch column of the extreme row

Rice. 9.3. ... Columns of a girderless frame

Rice. 9.4. Column of one-story industrial buildings

a) Column of the middle row with two consoles

Rice. 9.5. Single-branch column of the middle row

b) Column of the outer row with one console

Rice. 9.6. Single-branch column of the extreme row

Rice. 9.7. Column of the middle row with one branch for multi-storey buildings

Rice. 9.8. Single-branch column of administrative buildings

Rice. 9.9. Single-branch column of warehouse buildings

Rice. 9.10. Single-branch columns of multi-storey administrative buildings

Rice. 9.11. Reinforced concrete ledger with shelves

Rice. 9.12. Reinforced concrete crossbar

Crossbars are intended for frames of multi-storey buildings, industrial, administrative and domestic purposes, industrial enterprises, residential buildings and shopping and entertainment complexes.

Frost resistance not lower than F50.

Rice. 9.13. Reinforced concrete T-section beams

Rice. 9.14. Reinforced concrete T-section beams

The beams are designed for the frames of multi-storey buildings, industrial, administrative and residential buildings of industrial enterprises, residential buildings and shopping and entertainment complexes.

Frost resistance not lower than F50.

Basic structural elements of buildings

Structural elements, or building structures of buildings, represent the material basis of buildings, ensuring their performance throughout the entire service life.

Construction constructions are designed to absorb without destruction and noticeable deformations of all loads acting on the building (dead weight constructions, furniture, equipment; loads from people in it, wind, snow, seismic vibrations, etc.) and influences (from solar radiation, atmospheric moisture, etc.), as well as the protection of premises from the effects of the external environment (cold, heat, noise, wind and other adverse non-force effects).

According to their location in the volume of the building, structural elements are divided into vertical and horizontal.

By functional purpose, constructive the elements divided into load-bearing and fencing... Moreover, one element can perform both load-bearing and enclosing functions, for example, an external wall.

Such building structures are called Combined type constructions. Vertical load-bearing elements in civil buildings, as a rule, are differentiated into load-bearing and fencing.

Bearing structures are designed to absorb loads in the place of their application and to transfer loads to other the elements... From a geometric point of view, we distinguish: point elements (nodes, supports, hinges); linear the elements(beams, truss rods, cables); planar the elements(plates, discs); corpus (spatial) the elements... Bearing structures must meet the requirements of strength, geometric invariability, stability and durability.

Structural bearing the elements characterized by three signs (one from each pair):

1.planar - spatial;

2.solid (solid-wall) - lattice (through, mesh);

3. Spreadless - spacer.

Walling They protect the premises from external influences or shield individual rooms in the volume of the building. By perceiving loads and transferring them to others constructions distinguish between self-supporting, hinged and combined enclosing structures.

Self-supporting fencing constructions Apart from their own weight (sometimes also the wind), they do not perceive any other loads. They usually rest on their own foundations or on foundation beams, which in turn rest on foundations.

In Combined Building Structures Some elements perform load-bearing, while others - enclosing functions.

Suspended enclosing structures They are supported by supporting structural elements at the level of each floor and, of all types of loads, they only perceive their own mass, for example, roofs (coverings). They consist of a carrier constructions in the form of planar, spatial or linear elements and enclosing (protecting the building from atmospheric precipitation).

Coating- the upper part of the building, protecting it from atmospheric precipitation. Consists of bearing and enclosing (base under the roof, roof) parts. If there is a passage or semi-passage space in the coverage, the roof is called Attic, In the presence of residential premises in the volume of the roof - Attic... If engineering equipment is placed in the volume of the attic, the term is used Technical floor.

The visible planes of the roof are called Slopes, they are given a slope for the drainage of rain and melt water. Atmospheric moisture from the coatings is either dumped along the entire facade line (unorganized drainage), or removed through a downpipe system (organized drainage). In the latter case, an external and internal drainage system is distinguished.

Classification of building structures

Separation of construction constructions in terms of functional purpose, for load-bearing and fencing is largely conditional. If structures such as arches, trusses or frames are only load-bearing, then wall and roof panels, shells, vaults, folds, etc. usually combine enclosing and load-bearing functions, which corresponds to one of the most important trends in the development of modern building structures. Depending on the design scheme, load-bearing building structures are subdivided into:

flat (for example, beams, trusses, frames)

spatial (shells, vaults, domes, etc.).

Spatial constructions are characterized by a more favorable (in comparison with flat) distribution of forces and, accordingly, lower consumption of materials. However, their manufacture and installation in many cases turns out to be very laborious. New types of spatial structures, such as structural structures made of rolled sections on bolted joints, are distinguished by both cost-effectiveness and relative ease of manufacture and installation. By the type of material, the following main types of building structures are distinguished: concrete and reinforced concrete, steel, stone, wooden.

Concrete and reinforced concrete structures- the most common both in terms of volume and areas of application. For modern construction, the use of prefabricated reinforced concrete is especially characteristic constructions industrial production used in the construction of residential, public and industrial buildings and many engineering structures. Rational areas of application of monolithic reinforced concrete - hydraulic structures, road and airfield pavements, foundations for industrial equipment, tanks, towers, elevators, etc. Special types concrete and reinforced concrete are used in the construction of structures operated at high and low temperatures or in conditions of chemically aggressive environments (heating units, buildings and structures of ferrous and nonferrous metallurgy, chemical industry, etc.). Application of high strength concrete and reinforcement, growth in the production of prestressed structures, expansion of the use of lightweight and cellular concrete help to reduce weight, cost and material consumption in reinforced concrete structures.

Steel structures They are mainly used for frames of large-span buildings and structures, for workshops with heavy crane equipment, blast furnaces, large-capacity tanks, bridges, tower-type structures, etc. steel and reinforced concrete constructions in some cases coincide. In this case, the choice of the type of structures is made taking into account the ratio of their costs, as well as depending on the construction area and the location of the construction industry enterprises. Significant advantage steel structures in comparison with reinforced concrete - their less weight. This determines the feasibility of their use in areas with high seismicity, hard-to-reach areas of the Far North, desert and highland areas. Expanding the scope of use steels high strength and economical rolled profiles, as well as the creation of effective spatial structures, including those made of thin sheet steel, will significantly reduce the weight of buildings and structures.

Main area of ​​application Stone structures- walls and partitions. Building made of bricks, natural stone, small blocks, etc., to a lesser extent meet the requirements of industrial construction than large-panel buildings. Therefore, their share in the total volume of construction is gradually decreasing. However, the use of high-strength bricks, reinforced stone and complex constructions(stone structures reinforced steel reinforcement or reinforced concrete elements) allows you to significantly increase the bearing capacity buildings with stone walls, and the transition from manual masonry to the use of prefabricated brick and ceramic panels will significantly increase the degree of industrialization of construction and reduce the labor intensity of construction buildings from stone materials.

The main direction in the development of modern Wooden structures- transition to glued timber structures. The possibility of industrial production and obtaining constructive elements the required dimensions by gluing determines their advantages over other types of wooden structures. Load-bearing and fencing Glued constructions They are widely used in rural construction.

In modern construction, new types of industrial structures are becoming widespread - asbestos-cement products and structures, pneumatic building structures, structures made of light alloys and with the use of plastics. Their main advantages are low specific weight and the possibility of factory production on mechanized production lines. Lightweight three-layer panels (with sheathing made of profiled steel, aluminum, asbestos cement and with plastic insulation) are used as enclosing structures instead of heavy reinforced concrete and expanded clay concrete panels.

Folds, etc. usually combine enclosing and supporting functions, which corresponds to one of the most important trends in the development of modern Building construction Depending on the settlement scheme carriers Building construction subdivided into flat (for example, beams, trusses, frames) and spatial (shells, vaults, domes etc.). Spatial structures are characterized by a more favorable (compared to flat) distribution of forces and, accordingly, less material consumption; however, their manufacture and installation in many cases turns out to be very time consuming. New types of spatial structures, for example, the so-called. Structural structures made of rolled sections on bolted joints are distinguished by both cost-effectiveness and comparative ease of manufacture and installation. The following main types are distinguished by the type of material Building construction: concrete and reinforced concrete (see. Reinforced concrete structures and products ), steel structures, stone structures, wooden structures.

Concrete and reinforced concrete structures are the most common (both in terms of volume and areas of application). For modern construction, the use of reinforced concrete in the form of prefabricated industrial structures used in the construction of residential, public and industrial buildings and many engineering structures. Rational areas of application of monolithic reinforced concrete are hydraulic structures, road and airfield pavements, foundations for industrial equipment, tanks, towers, elevators, etc. Special types concrete and reinforced concrete are used in the construction of structures operated at high and low temperatures or in conditions of chemically aggressive environments (heating units, buildings and structures of ferrous and non-ferrous metallurgy, chemical industry, etc.). Reducing weight, reducing the cost and consumption of materials in reinforced concrete structures are possible on the basis of the use of high-strength concrete and reinforcement, production growth prestressed structures, expanding the areas of application of lightweight and cellular concrete.

Steel structures are mainly used for frames of large-span buildings and structures, for workshops with heavy crane equipment, blast furnaces, large-capacity tanks, bridges, tower-type structures, etc. The areas of application of steel and reinforced concrete structures in some cases coincide. At the same time, the choice of the type of structures is made taking into account the ratio of their costs, as well as depending on the construction area and the location of the construction industry enterprises. A significant advantage of steel structures (in comparison with reinforced concrete) is their lower weight. This determines the feasibility of their use in areas with high seismicity, inaccessible areas of the Far North, desert and high-mountain areas, etc. Expansion of the scope of application of high-strength steels and economical rolled profiles, as well as the creation of effective spatial structures (including from sheet steel) will significantly reduce the weight of buildings and structures.

The main area of ​​application of stone structures is walls and partitions. Buildings made of bricks, natural stone, small blocks, etc. to a lesser extent meet the requirements of industrial construction than large-panel buildings (see article Large-panel structures ). Therefore, their share in the total volume of construction is gradually decreasing. However, the use of high-strength bricks, reinforced stone, etc. complex structures (stone structures reinforced with steel reinforcement or reinforced concrete elements) can significantly increase the load-bearing capacity of buildings with stone walls, and the transition from manual masonry to the use of factory-made brick and ceramic panels - significantly increase the degree of industrialization of construction and reduce the labor intensity of building buildings from stone materials ...

The main direction in the development of modern wooden structures is the transition to glued timber structures. The possibility of industrial production and obtaining structural elements of the required dimensions by means of gluing determines their advantages over other types of wooden structures. Load-bearing and fencing glued structures find wide application in agricultural. construction.

In modern construction, new types of industrial structures are widely used - asbestos-cement products and structures, pneumatic building structures, structures made of light alloys and using plastics. Their main advantages are low specific weight and the possibility of factory production on mechanized production lines. Lightweight three-layer panels (with cladding made of profiled steel, aluminum, asbestos cement and with plastic insulation) are beginning to be used as enclosing structures instead of heavy reinforced concrete and expanded clay concrete panels.

Requirements for Building construction WITH in terms of operational requirements Building construction must meet their intended purpose, be fire-resistant and corrosion-resistant, safe, convenient and economical to operate. The scale and pace of mass construction impose on Building construction the requirements of the industrial nature of their manufacture (in the factory), efficiency (both in cost and in material consumption), ease of transportation and speed of installation at a construction site. Particularly important is the reduction in labor intensity - as in the manufacture Building construction, and in the process of erecting buildings and structures from them. One of the most important tasks of modern construction is weight reduction Building construction based on the widespread use of lightweight effective materials and the improvement of design solutions.

Calculation with. To. Building structures must be designed for strength, stability and vibration. This takes into account the force effects to which the structures are subjected during operation (external loads, dead weight), the influence of temperature, shrinkage, displacement of supports, etc., as well as the forces arising during transportation and installation. Building construction In the USSR, the main method of calculation Building construction is the method of calculation by limit states, approved by the State Construction Committee of the USSR for mandatory use from January 1, 1955. Prior to that Building construction calculated depending on the materials used for permissible stresses (metal and wood) or for destructive forces (concrete, reinforced concrete, stone and reinforced masonry). The main disadvantage of these methods is the use in the calculations of a single (for all acting loads) safety factor, which did not allow correctly assessing the variability of loads of different nature (permanent, temporary, snow, wind, etc.) and the ultimate bearing capacity of structures. In addition, the method of calculating the allowable stresses did not take into account the plastic stage of the structure's operation, which led to an unjustified waste of materials.

When designing a particular building (structure), the optimal types Building construction and materials for them are selected in accordance with the specific conditions of construction and operation of the building, taking into account the need to use local materials and reduce transport costs. When designing objects of mass construction, as a rule, standard Building construction and unified dimensional schemes of structures.

Lit .: Baikov V. N., Strongin S. G., Ermolova D. I., Building structures, M., 1970; Building codes, part 2, section A, ch. 10. Building structures and foundations, M., 1972: Building structures, ed. A.M. Ovechkin and R.L.Mailyan. 2nd ed., M., 1974.

G. Sh. Podolsky

Article about the word " Building construction"in the Great Soviet Encyclopedia was read 27210 times

All building structures are subdivided into carriers and non-bearing(basically - enclosing). In some cases, the functions of load-bearing and enclosing structures are combined (for example, external load-bearing walls, attic floors, etc.).

By the nature of the static work, the supporting structures are subdivided into planar and spatial... In planar, all elements work either separately or in the form of rigidly interconnected plane systems (the rest of the elements - racks, beams, walls, floor slabs). In space, all elements work in two directions. This increases the rigidity and load-bearing capacity of structures and reduces the consumption of materials for their construction.

The main structural elements of civil buildings are foundations, steps and pillars, floors, roofs, stairs, windows, doors and partitions (Figure 13.1).

Rice. 13.1. The main elements of civil buildings(but - old building;b - frame-panel modern;in - from volumetric blocks):

1 – foundation; 2 – base; 3 – load-bearing longitudinal walls; 4 - intermediate floors; 5 - partitions; 6 – roof rafters; 7 - roof; 8 – staircase; 9 – attic floor; 10 – crossbars and columns of the frame; 11 – hinged wall panels; 12 – piles; 13–13 - volumetric blocks (13 – rooms; 14 – bathrooms and kitchens; 15 – staircase); 16 - blind area

Foundations are used to transfer loads from the dead weight of a building, from people and equipment, from snow and wind to the ground. They are underground structures and are located under load-bearing walls and pillars. The ground is the basis for the foundations. The base must be strong and not compressible when loaded. Topsoil is usually not strong enough. Therefore, the base of the foundation is placed (laid) at a certain depth from the surface of the earth. The depth of the foundation is determined not only by the strength of the soil, but also by its composition and climatic features of the area. So, in clayey, loamy sandy loam soils and in fine sands, the depth of the foundation should be lower than the depth of soil freezing. This depth is given in SNiP 29-99 "Construction climatology". In heated buildings

the depth of the foundation can be reduced depending on the thermal regime in the building (central or stove heating, calculated internal temperatures), since the heated building heats up the soil under it and the freezing depth decreases. The above types of soils are prone to heaving. The water accumulating under the foot of the foundation freezes and increases in volume. This leads to uneven soil bulging and cracks in foundations and walls.

In buildings with a basement, the depth of the foundation depends on the height of the basement.

The foot of the foundation should have such an area that the load transferred to the ground does not exceed the stress allowed for this soil, which is usually 1-3 kg / cm2. Foundations are usually made of waterproof material (concrete blocks, monolithic reinforced concrete). In buildings of historical buildings, the foundations were usually made of natural stone (quarrystone) or of rubble concrete. The brick was practically not used, with the exception of the very well-fired so-called engineering brick, which practically did not absorb water.

The main types of foundations are as follows: strip, columnar, pile and in the form of a monolithic reinforced concrete slab iodine throughout the building.

Tape foundations are divided into prefabricated and monolithic. Monolithic ones are made of rubble stone masonry.

They are laborious to manufacture and are currently used for low-rise construction only where rubble stone is a local building material. It is more rational to make foundations from monolithic concrete using inventory panel formwork. Strip foundations made of precast concrete blocks are the most rational solution if there are such blocks and crane equipment for their installation in the construction area.

The strip foundations are shown in Fig. 13.2.

Rice. 13.2.

but - on a sandy pillow; b - rubble concrete foundation of a low-rise building; in - rubble foundation of a low-rise building; G - rubble foundation with ledges; d - rubble foundation of a building with a basement; e - rubble concrete foundation of a house with a basement; f - prefabricated foundation of a low-rise building; s - prefabricated foundation of a multi-storey building; and - prefabricated foundation of a multi-storey building on highly compressible or subsiding soil; 1 – monolithic or prefabricated foundation; 2 - foundation wall; 3 – foundation wall block; 4 – waterproofing; 5 - wall of the above-ground part of the building; 6 – a layer of sand or crushed stone 50–100 mm thick; 7 – reinforced belt; 8 – ground floor level; 9 - brick cladding; 10 – basement floor; 11 – sand pillow; 12 – basement floor

Columnar foundations are used in the construction of low-rise buildings that transmit pressure to the ground less than the standard, or in the construction of frame buildings (Figure 13.3). Columnar foundations can be monolithic or prefabricated. With the wall structural system of the building being erected, they are installed at the corners of the walls, as well as at the intersection of the longitudinal outer and transverse inner walls, but not less often than 3-5 m. The foundation pillars are connected with reinforced concrete foundation beams of rectangular or T-section. To prevent damage from uneven settlements and from bulging of the soil during heaving, a gap of 5-7 cm is arranged between the soil and the beams, and sand preparation is made to a depth of 50 cm. For frame buildings of industrial construction, columnar foundations of the glass type are arranged.

Rice. 13.3.

but - under a brick or wooden (log or cobbled) wall: b – d - from blocks for brick pillars; d, e - for reinforced concrete columns; 1 – reinforced concrete foundation beam; 2 - bedding; 3 – blind area; 4 – waterproofing; 5 - brick pillar; 6 "- cushion blocks; 7 – reinforced concrete column; 8 – Column; 9 – glass-type shoe; 10 - plate; 11 – glass block

Pile foundations are used mainly in soft soils. Driven and rammed piles are distinguished by the method of immersion in the ground. Driven - pre-made reinforced concrete piles driven into the ground using pile drivers. Historic buildings can have wood and steel piles. Driven piles are made directly in the ground in pre-drilled wells. By the nature of the work in the soil, there are piles-piles that transmit the load through soft soil to a deeply located solid layer of soil, and hanging piles that transmit the load due to frictional forces between the surface of the pile and the soil (Figure 13.4).

Rice. 13.4.

but - rack piles; b, c - friction piles, or hanging; 1 - driven piles; 2 - rammed piles; 3 - reinforced concrete grillage

The structures of foundations, basement walls and floors above the basement are called zero cycle constructions. They require a waterproofing device. The choice of a constructive solution for waterproofing depends on the nature of the effect of ground moisture, which can be non-pressure (capillary moisture and water from rainfall and snow melting) and pressure (when the ground water level is above the basement floor).

In fig. 13.5 shows the waterproofing of foundations and basements at different heights of the groundwater table (GWL) above the basement floor. The expansion joint in the basement floor is arranged because the settlement of the foundation under the wall can be greater than the settlement of the basement floor. Without a seam, cracks appear in this place, which are called "forgotten seams". When the groundwater level is more than 1 m above the basement floor level, the reinforced concrete basement floor slab should be wound under the basement wall, since otherwise it can float up according to Archimedes' law. The vertical waterproofing of the basement walls is protected by brick protective walls from rebar scraps and broken glass, which can damage it when backfilling the foundation pit. Recently, for this purpose, pasting of the basement walls, protected by waterproofing, with special synthetic tiles, has been used.

Rice. 13.5.

a, b - waterproofing in the absence of groundwater pressure; c – d - the same, with the pressure of groundwater (but - a building without a basement; in other drawings of a building with a basement); 1 – horizontal waterproofing; 2 – vertical waterproofing; 3 – wrinkled oily clay; 4 – concrete preparation; 5 - clean floor; 6 – basement wall; 7 – hot bitumen coating; 8 – waterproofing carpet; 9 - protective wall; 10 – concrete; 11 – reinforced concrete slab, 12 – expansion joint filled with mastic, waterproofing with an expansion joint

A horizontal waterproofing is arranged between the wall of the foundation and basement and the wall and ceiling above the basement, which protects the wall from moisture capillary moisture. Currently, as a rule, glued vertical and horizontal waterproofing from rolled bituminous or synthetic materials is arranged. Coating with hot bitumen is allowed only when the groundwater level is significantly lower than the basement floor. In this case, under the concrete slab of the basement floor, it is desirable to arrange a layer of coarse gravel covered with wired paper, which prevents the rise of capillary moisture from the ground into the basement floor slab due to large voids between the gravel, interrupting capillarity. The waxed paper prevents the penetration of cement laitance into the gravel layer, which, when hardened, will create capillary suction.

The basement part of the wall is protected by finishing plates that increase the durability of the basement. To drain rainwater, a concrete blind area is arranged around the building, which is often covered with asphalt concrete. The blind area should be 0.7-1.3 m wide with a slope i = 0.03 from the building. It prevents the penetration of surface water to the base of the foundation, keeps the soil near the basement wall dry and serves as an element of external improvement (Fig. 13.6).

Rice. 13.6.

Walls are divided into load-bearing, self-supporting and non-bearing (mounted and wall-fill). At the location in the building, they can be external and internal. Load-bearing walls are usually called capital (regardless of their capital, this word denotes the main, main, more massive). These walls rest on foundations. Self-supporting walls transfer the load to the foundations only from their own weight. Curtain walls only bear their own weight within one floor. They transfer this load either to the transverse load-bearing walls or to the intermediate floors. Internal curtain walls are usually partitions. They serve to divide large rooms within a storey, bounded by capital walls, into smaller rooms. They, as a rule, do not rely on foundations, but are installed on ceilings. During the operation of the building, without violating its structural integrity, partitions can be removed or moved to another place. Such restructuring is limited only by administrative regulations.

The walls of traditional building systems are built from small-sized elements (this is a traditional type of wall construction). These are bricks, small expanded clay concrete and aerated concrete blocks or blocks of sawn natural stone, tuff or shell rock with low thermal conductivity (Figure 13.7). The walls of traditional buildings can also be made of logs, beams, or frame-panel. This type includes half-timbered buildings in the medieval towns of Europe. Here, the frame of the walls made of logs is filled with bricks on a clay or lime binder (Fig. 13.8).

Rice. 13.7. :

a, b, gm - internal walls - load-bearing and bracing (i.e. stiffening diaphragms); a – c - brick walls; Mrs - walls made of solid or hollow lightweight concrete stones; g, f, f - natural stone walls; s, and - brick-concrete walls; To - brick-slag wall with brick diaphragms; l - brick wall with thermal inserts made of lightweight concrete stones; m - brick-slag wall with mortar diaphragms, reinforced with asbestos cement tiles (or brackets); n - brick or stone wall, insulated from the outside with reed or fiberboard

Rice. 13.8.

The most common material for traditional walls is solid and hollow ceramic bricks (hollow bricks have better thermal performance compared to solid ones). The weight of the brick does not exceed 4.3 kg, so that it can be freely lifted by the hand of the bricklayer. The dimensions of an ordinary brick are standard: 250 × 120 × 65 mm. The largest face on which a brick is laid is called bed, long side - spoons and small - jab. Ceramic stones are bricks of double height - 250 × 120 × 138 mm. Clay bricks are fired in special ovens. This gives them strength and water resistance. In addition to fired ceramic products, there are silicate bricks (a mixture of lime and quartz sand). They cannot be used in the construction of foundations and plinths of a building, since they are less water resistant, and for laying stoves. At present, expanded clay and aerated concrete blocks with dimensions of 200 × 200 × 400 mm, as well as super-warm bricks "Termolux" are used as small-sized wall elements (Fig. 13.9). They have a low coefficient of thermal conductivity of masonry 0.18–0.20 W / (m ° C) and high strength, allowing the construction of buildings up to nine floors high.

Rice. 13.9. Super-warm bricks "Termolux"

Strength a stone wall made of small-sized elements is ensured by the strength of the stone and mortar and the laying of stones with bandaging of vertical joints both in the plane of the wall and in the planes of the adjacent walls. In fig. 13.10 shows solid masonry with various binding systems. Here, the chain one is more durable, and the six-row one is more technologically advanced, since it has a higher masonry speed.

Rice. 13.10. :

but - brick wall of double-row chain masonry; b - brick wall of multi-row (six-row) masonry

Sustainability such walls are ensured by their joint work with internal supporting structures - walls and ceilings. For this, the elements of the outer walls are inserted into the inner walls by tying the masonry and connected to the inner walls using steel embedded elements - anchors. In low-rise buildings with wooden floors, the pitch of the transverse load-bearing walls should not exceed 12 m, and in houses with prefabricated reinforced concrete floors, it reaches 30 m.

Durability stone walls are provided with frost resistance of materials used for the outer part of the masonry. In walls made of aerated concrete, as well as in walls with external thermal insulation, the facade surface is covered with porous hydrophobic plaster or finished with facing bricks or facade slabs. The connection between the cladding and the masonry is provided by galvanized steel brackets.

Heat shielding ability modern stone walls are provided with thermal insulation requirements. Since 1995, in accordance with the norms, in most of the territory of Russia, single-layer brick walls do not provide thermal protection requirements. Therefore, layered structures began to be used for the outer walls (Fig. 13.11).

Rice. 13.11. :

but - made of bricks with insulation and an air gap; b - made of monolithic reinforced concrete with insulation and brick cladding

The main elements of brick walls are openings, lintels, piers, basement and cornice.

Jumpers made of brick (ordinary or arched) are arranged over openings for architectural reasons. Privates - no more than 2.0 m above the openings on temporary wooden floorings. Steel reinforcement, anchored into the walls, is laid in the lower row along a layer of cement mortar. The above-window part of the wall with a height of at least four rows, sometimes reinforced, is taken out along it. Arched lintels take the load well, but are laborious to manufacture. They are arranged for architectural reasons and can have a different shape - arched and wedge-shaped. The most common lintels in mass construction are prefabricated bars made of reinforced concrete (load-bearing - reinforced and non-load-bearing). For non-load-bearing lintels, the embedding in the piers is at least 125 mm, and for load-bearing lintels - 250 mm. The different types of jumpers are shown in fig. 13.12.

Rice. 13.12. :

a-d - precast concrete lintels (a, b - squared (type B); in - plate (type BP); G - beam (type BU); d - arched; e - flat wedge; 1 - keystone; 2 - jumper heel

The basement - the lower part of the outer wall (Fig. 13.13), exposed to unfavorable atmospheric and mechanical influences, is made of well-fired ceramic bricks, followed by finishing with plaster, facing bricks, stone or ceramic slabs. The plinth is exposed to rain falling on the ground, melt water, and adjacent snow cover. This moisture wets the base material and, when frozen and thawed, contributes to its destruction. The plinth also has an architectural significance, giving the building an impression of greater stability. The upper ledge of the basement (edge) is usually located at the floor level of the first floor, thereby emphasizing the beginning of the building volume used for the main purpose.

Rice. 13.13.

but - lined with brick; b - lined with stone blocks; in - lined with plates; G - plastered; d - from concrete blocks for cutting; e - from reinforced concrete panels with trimming; 1 - foundation; 2 – wall; 3 - blind area; 4 - waterproofing; 5 - burnt brick; 6 - basement stone blocks; 7 - side plinth stone; 8 - facing plates; 9 - plaster; 10 – roofing steel; 11 – concrete block; 12 - foundation wall panel; 13 - construction of the ground floor floor

Below the floor of the first floor, a basement, basement or underground is arranged. Ground floor- This is a room below the first floor, the height of which is more than half the level of the ground. Basement- This is a room below the first floor, the height of which is less than half the height of the ground. Underground- this is a room under the floor of the first floor, the height of which is equal to the distance from the lower floor to the ground level. The underground protects the building structures from the direct impact of groundwater. This could be the so-called cold underground. Sometimes they arrange semi-through technical undergrounds to accommodate various utilities (water supply inlets, sewer outlet pipes, central heating pipes). In this case, the basement part of the wall must protect the technical underground, as well as the basement and basement floors from freezing.

Eaves(fig. 13.14) - horizontal protrusions from the plane of the wall. They are designed to drain rainwater from the wall surface and often have architectural functions. Along the height of the wall, there can be several small cornices in the form of belts, forming architectural divisions along the height of the building. The uppermost cornice is called crowning. The removal of the eaves from bricks should not exceed 300 mm. The removal of a reinforced concrete cornice can be very large.

Rice. 13.14. :

but - general layout of the wall with waterproofing devices; b - cornice formed by overlap of bricks; c, d - eaves made of precast concrete slabs: d - a cornice formed by the overhang of a continuous covering panel; e - cornice formed by the overhang of the ventilated roof panel; f - parapet with a flat surface with an internal drainage system; 1 - roof overhang; 2 – waterproofing of the architectural belt; 3 - window sill drain; 4 - waterproofing of the basement cordon; 5 - base; 6 - waterproofing; 7 – blind area; 8 - galvanized steel drain and gutter; 9 – fencing; 10 – drain pipe; 11 – drying air

By their design, wooden walls are subdivided into log, cobbled, frame sheathing and panel board. Coniferous wood, the most widespread in Russia, is an effective building material and has good mechanical and thermal insulation properties. Previously, the main disadvantages of wooden structures were their susceptibility to decay and flammability. Modern technologies can eliminate these disadvantages.

Log wall structures are shown in Fig. 13.15. Cobblestone walls (Fig. 13.16) are erected from beams made in advance at the factory, which excludes manual processing of logs and knitting of corners. Particular attention should be paid to the caulking of the seams between the crowns (horizontal rows of logs or beams). During the first 1.5-2.0 years, a log house with a height of a storey gives a draft of 15–20 cm in height, which should be taken into account when erecting it.

Rice. 13.15.

but - log house; b - conjugation of logs and beams with a secret frying pan; in - conjugation of logs and beams with a through frying pan; G - cutting the corner with the remainder "into the bowl"; d - cutting a corner without a remainder "in the paw"; e - processing of logs for felling without residue; 1 – the crowns of the log house; 2 - caulk; 3 - plug-in thorn; 4 - protective board; 5 - secret thorn; 6 – a groove for a countersunk spike; 7 – low tide; 8 - base

Rice. 13.16. :

but - sections of cobbled walls; b – d - mating the beams in the corner and with the inner wall; 1 - timber; 2 - caulk; 3 - dowel; 4 – Thorn; 5 - root spine

The stability of log and cobbled walls is ensured by their connection in the corners and at the intersections with transverse walls, located at distances of no more than 6–8 m from each other. Walls can bulge at great distances. To prevent bulging, they are strengthened with clamps from vertical paired beams installed on both sides of the wall and fastened in height to each other through 1.0-1.5 m with bolts.

Frame cladding wooden walls(fig. 13.17) are much easier to manufacture and require less wood than log or paving stones. They can be arranged directly on site. The racks placed with a certain pitch, taking into account the location of windows and doors, are fastened from below and from above by horizontal strapping bars and have connecting struts at the corners of the building. The frame is sheathed from the inside. Then a roll vapor barrier is laid from a special vapor-proof material or from a polyethylene film. After that, insulation plates (mineral wool, fiberglass or expanded polystyrene) are installed. Outside, the walls are sheathed with 2.5 cm thick boards or siding, i.e. artificial facing elements in the form of boards made of metal or synthetic material. The frame sheathing share provides any degree of thermal protection. The disadvantages are busyness, the possibility of insulating material settling during operation. In fig. 13.18 shows the construction of wooden walls of a sandwich type, allowing to preserve the appearance of a log or cobbled wall, but ensuring the fulfillment of modern requirements for thermal protection.

Rice. 13.17. :

but - general view of the frame; b - support of the beams on the outer wall in the corner; in - supporting the beams on the inner wall; 1 - bottom strapping 2 (50 × 100 mm); 2 - frame rack 50 × 100 mm; 3 - top strapping 2 (50 × 100 mm); 4 - floor beams 50 × 200 mm; 5 - spacer 500 × 200 mm; 6 - jumper beam; 7 - shortened rack; 8 - bracing of rigidity; 9 - additional posts in the corners 50 × 100 mm; 10 - additional rack of the opening; 11 - base; 12 - blind area; 13 – insulation between the racks; 14 - insulation outside; 15 - plaster; 16 - foundation beam; 17 - anchor bolts

Rice. 13.18.

1 - wooden beams; 2 - insulation; 3 - inner lining board; 4, 6 – half-baked; 5 - rounded timber; 7 - decorative croaker

Panel walls are assembled from prefabricated enlarged elements - wall insulated panels. At the same time, houses can be frame and frameless. In the second case, the vertical uprights of the shield strapping play the role of the frame racks. Shields are installed on the lower strapping and fastened from above with the upper strapping.

Post-beam construction it is used in frame buildings, as well as in buildings with an incomplete frame (external load-bearing walls, inside - pillars and cisterns). Pillars in buildings with an incomplete frame are installed instead of internal load-bearing walls where it turns out to be necessary to open the internal space. Frame structures are the most common in public and industrial buildings (Fig. 13.19, 13.20). The uprights (columns) of the frame work for central and eccentric compression. They can buckle under load.

Rice. 13.19.

1 – column with a cross section of 400 × 400 mm; 2 - floor spacer; 3 - crossbar of T-section; 4 - flooring of the floor; 5 - column joint

Rice. 13.20. :

but - general view of the unit; b - design and design diagram of the unit; 1 – Column; 2 - crossbar; 3 - floor spacer; 4 – embedded parts; 5 - top plate; 6 - "hidden console" of the column; 7 - welded seams

The horizontal element of the rack-and-beam system is a beam (crossbar) - a bar that works in transverse bending under the action of a vertical load (Figure 13.21). It has a solid cross-section with spans up to 12 m. For larger spans, it is advisable to use beam structures of a through-section in the form of trusses (Figure 13.22). The walls of buildings with a reinforced concrete frame can be self-supporting, infill walls (installed on reinforced concrete floors, transmitting the load to the floors and working on their own weight load within one floor) and hinged, fixed on the columns and crossbars of the frame.

Rice. 13.21.

a, d - single-slope and flat I-sections; b - the same for multi-slope surfaces; in - lattice for multi-slope coverings; d - unit for supporting the beam on the column; 1 - anchor bolt; 2 - washer; 3 - base plate

Rice. 13.22.

but - segment; b - arched bevelless; in - with parallel belts; G - trapezoidal

Overlapping are horizontal load-bearing structures resting on load-bearing walls or pillars and columns and perceiving loads acting on them. The slabs form horizontal diaphragms that divide the building into floors and serve as the horizontal stiffeners of the building. Depending on the position in the building, the ceilings are divided into interfloor, attic - between the upper floor and the attic, basements - between the first floor and the basement, the lower ones - between the first floor and the underground.

In accordance with the effects, different requirements are imposed on floor structures:

• static - ensuring strength and rigidity. Strength is the ability to withstand loads without collapsing. Rigidity is characterized by the relative deflection of the structure (the ratio of deflection to span). For residential buildings, it should be no more than 1/200;
• soundproof - for residential buildings; ceilings should provide sound insulation of the divided premises from airborne and impact noise (see Section IV);
• heat engineering - are presented to the ceilings that separate rooms with different temperature regimes. These requirements are established for attic floors, ceilings over basements and driveways;
• fireproof - are installed in accordance with the class of the building and dictate the choice of material and structures;
• special - water and gas tightness, bio and chemical resistance, for example, in sanitary facilities, chemical laboratories.

According to the constructive solution, the ceilings can be divided into girder and non-girder, according to the material - into reinforced concrete slabs (prefabricated and monolithic) and into floors with steel, reinforced concrete or wooden beams, according to the installation method - into prefabricated, monolithic and precast-monolithic.

Beamless (slab) floors are made of reinforced concrete slabs (panels) with various structural support schemes (Fig. 13.23-13.25). When supported on four or three sides, the slabs act like plates and have deflections in two directions. Therefore, the bearing reinforcement is located in two mutually perpendicular directions. These slabs are solid. The slabs, supported on both sides, have working reinforcement located along the span. To facilitate them, they are most often made hollow (Fig. 13.26). In the case of supporting the slabs at the corners and other atypical support schemes, the slabs are reinforced in a certain way, reinforcing the reinforcement at the points of support.

Rice. 13.23.

a - c longitudinal lines of supports; b - with transverse support lines; in - with support on three or four sides (along the contour); 1 – floor panels supported by load-bearing walls; 2 - internal longitudinal or transverse load-bearing wall; 3 – external load-bearing wall; 4 – floor panel based on the purlin; 5 - runs; 6 – columns; 7 - a room-sized floor panel resting on four (three) load-bearing walls

Rice. 13.24. Decking slabs for spans 9 (i), 12(b) and 15 (c) m:

1 - mounting loops; 2 - longitudinal ribs; 3 - transverse ribs

Rice. 13.25.

but - general form; b - the diagram of the support of the slab on the column; 1 – plate; 2 – capital; 3 - Column

Rice. 13.26.

Beam ceilings are assembled from load-bearing beams and fill between them - roll. Beams can be made of wood, reinforced concrete or metal. Overlappings on wooden beams are arranged only in one- and two-story houses. In higher buildings, wooden beams are prohibited by fire regulations. The arrangement of wooden floors is shown in Fig. 13.27. To ensure sound insulation, a soundproof layer is placed on the reel, which makes the structure heavier to protect it from airborne noise. It can be sand, brick breakage or effective porous materials with increased sound absorption. Plank floors in wooden floors are made along logs laid on beams with elastic soundproofing pads. For ventilation of the underfloor space, ventilation openings covered with grilles are arranged in the corners of the room. Ceilings are plastered or hemmed with dry plaster sheets. Sometimes roll boards are sanded and coated with colorless varnish, keeping the texture of the wood.

Rice. 13.27.

1 – cranial bars; 2 – beam; 3 – parquet; 4 – black floor; 5 - lag; 6 – plaster; 7 - roll forward; 8 – clay lubrication; 9 – backfill

Overlappings on reinforced concrete beams consist of T-section beams installed with a pitch of 600, 800 or 1000 mm, and an inter-girder filling made of concrete run-up slabs, hollow lightweight concrete blocks or hollow ceramic liners (Figure 13.28). The bottom of the floor is plastered. Above arrange a leveling cement-sand screed, on which the floor structure is laid on a soundproofing pad.

Rice. 13.28.

a, b - monolithic; c, d - prefabricated on reinforced concrete beams with gypsum slabs; d, f - the same, with lightweight concrete inserts ( b - junction point of a monolithic section with precast floors on reinforced concrete beams; d - example of a linoleum floor device); 1 – monolithic reinforced concrete; 2 – elastic pad; 3 – boardwalk but lagam; 4 – sand not less 20 mm; 5 - conventionally shown prefabricated floor; 6 – roofing paper; 7 - reinforced concrete T-beam; 8 – gypsum or lightweight concrete slab; 9 - insulation (mineral wool, etc.); 10 - vapor barrier; 11 – wooden frame; 12 – two-hollow lightweight concrete liner; 13 – linoleum on a layer of cold mastic from waterproof binders; 14 – lightweight concrete screed 20 mm

Overlapping on steel beams is currently used more often in renovation than in new construction. The bearing beams of the I-section are installed with a step of 1.0-1.5 m. The ends of the beams are brought onto the walls with a device in the places of the supports of concrete distribution pads. Design options are shown in Fig. 13.29. In public buildings, as well as in hotels, floors are often used on metal beams, on which corrugated sheets are laid (profiled steel galvanized sheets); then a monolithic concrete slab 60–100 mm thick is laid over it above the corrugated board ridges. The depressions of the corrugated board serve at the same time as the formwork of the ribbed concrete slab and its stretched reinforcement. Sometimes additional reinforcing cages are installed in the ribs, and a reinforcing mesh is laid over the ridges. A suspended ceiling is arranged along the lower chords of the steel beams. In the space between the ribbed slab and the suspended ceiling, various communications, ventilation ducts, electrical wiring, etc. are usually located. The device of such an overlap is shown in Fig. 13.30.

Rice. 13.29.

but - support the ends of the beams on the walls; b - anchor fastening detail; in - overlap filled with reinforced concrete monolithic slab; G - the same, with brick vaults; 1 – steel beam; 2 – concrete pad; 3 – steel anchor; 4 – embedding with concrete; 5 - bolt; 6 - reinforced concrete monolithic slab; 7 – lightweight concrete; 8 – ceramic tiles on a layer of cement mortar; 9 – steel mesh; 10 - plank floor along the logs; 11 – two layers of roofing paper; 12 – soundproofing layer; 13 – cement mortar plaster; 14 - brick vault

Rice. 13.30.

Monolithic slabs are erected at the construction site using different types of formwork. They can be ribbed, consisting of main and secondary monolithic beams and a monolithic slab, coffered with mutually intersecting beams of the same height and in the form of a solid monolithic slab resting on vertical supporting structures (Fig. 13.31). To facilitate the structure, prefabricated monolithic floors are used with a panel formwork device, installing rows of ceramic or lightweight concrete liners on it. Triangular reinforcement cages are installed between the rows of liners. Reinforcement mesh is laid on top of the liners. Then the floor is poured with concrete. After the concrete has hardened, the formwork is removed.

Rice. 13.31.

Foundations, walls, frame elements and floors are the main load-bearing elements of a building. They form the load-bearing frame of the building - a spatial system of vertical and horizontal load-bearing elements. The load-bearing frame carries all the loads on the building. In order for it to be stable when exposed to horizontal loads (wind, seismic, crane equipment in industrial buildings), it must have the required rigidity. This is achieved by arranging longitudinal and transverse walls - stiffening diaphragms, rigidly connected to the columns of the frame or to bearing longitudinal or transverse walls. Rigidity is also provided by special braces and horizontal floor disks.

The supporting frame defines constructive scheme building.

Roof protects premises and structures from atmospheric precipitation, as well as from heating by direct rays of the sun (solar radiation). It consists of a load-bearing part (rafters and battens in traditional buildings) and reinforced concrete roof slabs in industrial buildings, as well as an outer shell - roofs, directly exposed to atmospheric influences. The roof consists of a waterproof so-called waterproofing carpet and a base (lathing, flooring). The material of the waterproofing carpet gives the name of the roof (tiled, metal, onduline, etc.), since such qualities of the roof as water resistance, non-flammability and weight depend on its properties. Roofs are given a slope for the drainage of rain and melt water. The steepness of the slopes depends on the material of the roof, its smoothness, the number of joints through which water can penetrate. The smoother the material, the fewer joints and the denser they are, the flatter the roof slopes can be. During thaws, the snow lying on the slopes is saturated in its lower layers with melt water, which flows through the leaks of the roofing material into the building. Therefore, in tiled and metal roofs, slopes should be significant. However, with an increase in the slope of the roof, the roof area and the volume of the attic increase.

For lighting and ventilation of attics, dormer windows, which should be located closer to the ridge of the roof and serve to extract air from the attic. For the flow of ventilation air into the attic space, it is necessary to arrange jam - openings or slots in the eaves unit of the roof.

For the same purpose, hatches for the exit from the attic to the roof, located closer to the edge of the roof, can serve (Fig. 13.32).

Rice. 13.32.

1 - jam (inflow); 2 – dormer window (hood); 3 - exhaust hole in the pediment; 4 - louver grill

Such attics are called cold. The temperature in them should be close to the outside. In this case, the roof will not leak. Engineering equipment and pipelines with water should not be located in such attics, as it can freeze. In buildings over 12 floors under construction in the central and northern regions, warm attics or technical floors are used (Figure 13.33). The roof of such attics is insulated. In warm attics in winter, a positive temperature is maintained due to the ventilation air entering the attic from the ventilation ducts ending in the attic. Exhaust ventilation air is removed from the attic space through pipes or large-section ducts (one per section). Warm attics house various engineering equipment. Warm attics also protect the premises from roof leaks.

Rice. 13.33.

a, b - with a cold attic with a roll (but) and rollless ( 6 ) roof; c, d - with a warm attic with a roll (in) and rollless (g) roof; d, f - with an open attic with a roll (e) and rollless (e) roof; 1 – support element; 2 – attic slab; 3 – insulation; 4 – non-insulated roofing plate; 5 - roll carpet; 6 - drainage tray; 7 - support frame; 8 - protective layer; 9 – vapor barrier layer; 10 – a strip of roofing material; 11 – support element of the fascia panel; 12 – roof plate of a rollless roof; 13 – waterproofing layer of mastic or paint compounds; 14 – U-shaped cover plate; 15 - drain funnel; 16 – ventilation unit (mine); 17 – ventilation unit head; 18 - lightweight single-layer roofing slab; 19 – elevator engine room; 20 – lightweight concrete tray slab; 21 – two-layer roofing plate; 22 – non-insulated fascia panel; 23 – insulated fascia panel

The roof combined with the attic floor (without a technical floor) is called unventilated combined roof or coated. If there is an air gap between the roof and the attic floor that connects to the outside air, then such a roof is called ventilated combined roof (fig.13.34).

Rice. 13.34.

but - separate construction with roll roofing; b - a separate structure with a roll-free roof; in - combined panel single-layer construction; G - the same, three-layer; d - the same, building manufacture; 1 – attic floor panel; 2 – insulation; 3 – fascia panel; 4 – roof panel of a rollless roof; 5 - supporting element; 6 - one-layer lightweight concrete roofing panel; 7 - rolled carpet; 8 - three-layer roofing panel; 9 - cement strainer; 10 - a layer of expanded clay but on a slope; 11 - a layer of cushioning roofing material on the mastic

Well-executed flat roofs can be used as recreational areas and for other purposes.

The pitched rafter roof is traditional. Depending on the shape of the building in terms of the shape of the roofs can be different (Fig. 13.35). The supporting structures of a traditional pitched roof are called rafters. Rafters are inclined, hanging. For large spans, combined rafter structures are used, where the rafter legs rest on the walls and a rack in the middle of the span, which in turn rests on the lower rafter belt, which is the beam of the suspended attic floor (Figure 13.36). The trusses of the hanging rafters are placed with a pitch of 3.0-3.6 m and are united by longitudinal horizontal beams, on which the racks of lighter intermediate layered rafters are supported with a pitch of 1.0-1.2 m.

Rice. 13.35.

but - single slope; b - gable; in - roof with attic; G - tent; d, f - general view and plan of the roof of the house; f - an example of building a roof slope; s, and - half-hip ends of the gable roof; 1 – eaves; 2 – dormer window; 3 – pediment tympanum; 4 – gable; 5 - skate; 6 – stingray; 7 - tong; 8 – valley (the lowest line of coverage for the organization of the drain); 9 – oblique rib; 10 – hip (hip roof slope, which has a triangular shape and is located on the front side of the building); 11 – half-hip

Rice. 13.36.

but - inclined rafters for pitched roofs; b - the same for gable; in - the same, hanging; G - the same, combined; 1 – mauerlat (a bar lying on the wall and serving to support the rafter legs or tighten the hanging rafters); 2 – inner pilaster; 3 – crossbar; 4 – fight; 5 - rafter leg; 6 – tightening; 7 - suspension; 8 – suspended attic beam

All support nodes of truss structures are located 400-500 mm above the upper level of the attic floor. The device of an organized external drainage system is shown in Fig. 13.37, 13.38. Comparison of steel roof and eaves gutters and overhead gutters shows that overhead gutters have the best performance and are less likely to leak. In order to avoid frost destruction of the external drainage system and the formation of ice and icicles on gutters and eaves and in drainpipes, it is advisable to arrange a heating system for eaves units in winter.

Rice. 13.37.

but - roof section; b - fold (connection of metal flat roofing sheets) recumbent single; in - the same, double; G - standing single; d - the same, double; 1 – T-shaped steel crutch every 700 mm; 2 - funnels of the downspout; 3 – roof overhang picture; 4 – wall gutter; 5 - picture of a wall gutter; 6 – recumbent fold; 7 – roofing steel; 8 – standing seam; 9 – ridge board; 10 – bars and lathing boards; 11 – clamps; 12 – wire twisting; 13 – crutch

Rice. 13.38.

but - roof section: b - ridge device option: in - the device of the valley; 1 – hook for hanging gutter: 2 – roofing steel; 3 – corrugated asbestos-cement sheet of ordinary profile; 4 – solid sections of the lathing at the cornice and in the valleys; 5 - lathing bars; 6 - ridge bars; 7 - shaped ridge detail; 8 – nail or screw; 9 - elastic pad; 10 – twisting

The base of the roof of pitched roofs is a crate for all types of sheet materials and tiles, nailed to the rafter legs and filly. The lathing can be sparse (for sheet steel and for tiles), as well as solid - for modern roofing materials such as "Icopal" or "Ondulin". In the lower junctions of the slopes (trays, valleys), as well as along the eaves, in addition to the continuous sheathing, a steel sheet cover is installed before laying the main roofing material in order to protect it from leaks.

Stairs serve for communication between floors. The rooms in which the stairs are located are called staircases. The walls of staircases in buildings above two floors must be highly fire-resistant, since staircases are ways of evacuating people in case of fire. In buildings with a height of 12 floors and above, staircases must be smoke-free (fig.13.39). The dimensions of the steps should be determined based on the normal step of a person: 2 a + b = 600: 630 mm (where but - height, b - step depth). Based on this condition, the height of the riser (a) is assigned 150–180 mm. In multi-storey buildings, the stairs between the floors have steps of 150 × 300 mm. In wooden staircases inside apartments, the riser height can reach 180 mm or more. Stair structures are mainly composed of marches and sites (Fig. 13.40, 13.41) and are fenced with a railing. In houses of traditional construction, stairs are used from small-sized elements along kosoura (obliquely laid beams of stair flights) and strut beams (Fig. 13.42). The construction of a wooden staircase is shown in Fig. 13.43.

Rice. 13.39.

Rice. 13.40.

1 - staircases; 2 - flights of stairs; 3 - a fragment of the fence

Rice. 13.41.

1 – upper frieze step; 2 – fencing rack; 3 – staircase

Windows (skylights) arranged for lighting and ventilation (natural ventilation or aeration) of premises.

Rice. 13.42.

Rice. 13.43.

They consist of window openings, frames or boxes and filling openings, called window sashes. The windows are designed in accordance with the requirements of the norms for natural light. They connect the outdoor space with the indoor environment and must let in a sufficient amount of natural light, provide insolation, i.e. penetration of sunlight into the room, create a visual connection between external and internal space. At the same time, windows must protect the room from low temperatures in winter, from overheating in summer, from street noise, from rain and wind. The design of skylights is challenging. Its solution is studied in the course "Physics of the environment and enclosing structures" and in the magistracy. In multi-storey buildings, window openings are located in the walls one above the other. In this case, the load transferred to the outer walls is absorbed by the walls. In frame buildings, windows can be positioned on the facade as desired. In fig. 13.44 and 13.45 show the design of traditional windows with double and split sashes, respectively.

Rice. 13.44.

1 - tarred tow (when working in winter) or tow soaked in gypsum solution (when working in summer); 2 - cement mortar; 3 - mastic; 4 - platband; 5 - drain board 20 mm high; 6 - galvanized steel drain; 7 - windowsill; 8 - metal strip 20 × 40 mm (3 pcs. Per opening)

Rice. 13.45.

1 – box; 2 – tarred tow; 3 – nail; 4 – wooden cork; 5 - a loop; 6 – binding binding; 7 - glass; 8 - layout; 9 – glazing bead; 10 – window trim; 11 – window leaf; 12 - sash; 13 – low tide; 14 – humpback; 15 – solution; 16 – galvanized steel outflow; 17 – windowsill

Doors there are external entrances, entrances to the apartment, intra-apartment and balcony. In this regard, various requirements are imposed on them for protection against unwanted penetration, fire resistance, thermal insulation, and noise protection.

The considered structural elements are typical for both civil and industrial buildings. but industrial building have some differences in their structure. Industrial buildings are one-, two- and multi-storey. One-story buildings (Fig. 13.46) are used for various industries with heavy equipment or where products of significant weight are produced. To work with such equipment, bridge and overhead cranes are used. The floor is arranged on the ground. Single-storey industrial buildings usually do not have basements or attics. Structures of industrial buildings, with the exception of historical ones, are mainly frame, consisting of columns arranged in rows, on which rafter structures are laid, mainly trusses. The distance between two parallel rows of columns is called span, its size ranges from 12 to 36 m. However, in buildings where large-sized items (aircraft, ships, nuclear reactors) are manufactured, the span size can be much larger (60, 72, 84 m and more). If a building has several spans, it is called multi-span. For natural illumination of the middle spans, light openings are arranged in the roof of the building - lanterns. Some skylights can be used also or specifically for aeration.

Rice. 13.46.

Multi-storey industrial buildings (Fig. 13.47), as a load-bearing frame, usually have a frame consisting of columns and crossbars, along which floor structures are laid. Technological equipment is installed on ceilings, so the spans do not exceed 12 m. For the same reasons, multi-storey industrial buildings are intended for industries with relatively light equipment (electrical, light, textile, food industry, etc.). In multi-storey industrial buildings, technical floors and basements are usually arranged. When using natural light, the width of such buildings does not exceed 36 m.

Rice. 13.47.

but - facade; b - plan; in - cross section

Two-storey industrial buildings have small spans (6-9 m) in the lower floor. On the second floor, the spans can be the same as in conventional one-story industrial buildings. On the ground floor there are auxiliary production facilities and administrative premises, as well as warehouses, etc. The main production facilities are located on the upper floor, located in large spans. Such a layout of industrial buildings saves expensive building space.

Introduction

Structures are called structural load-bearing structures of industrial and civil buildings and engineering structures, the dimensions of the sections of which are determined by calculation. This is their main difference from architectural structures or parts of buildings, the cross-sectional dimensions of which are assigned according to architectural, thermal engineering or other special requirements.

Modern building structures must meet the following requirements: operational, environmental, technical, economic, production, aesthetic, etc.

Classification of building structures

Concrete and reinforced concrete structures are the most common (both in terms of volume and areas of application). For modern construction, the use of reinforced concrete in the form of prefabricated industrial structures used in the construction of residential, public and industrial buildings and many engineering structures is especially characteristic. Rational areas of application of monolithic reinforced concrete are hydraulic structures, road and airfield pavements, foundations for industrial equipment, tanks, towers, elevators, etc. Special types of concrete and reinforced concrete are used in the construction of structures operated at high and low temperatures or in conditions of chemically aggressive environments (heating units, buildings and structures of ferrous and non-ferrous metallurgy, chemical industry, etc.). Reducing the weight, reducing the cost and consumption of materials in reinforced concrete structures are possible on the basis of the use of high-strength concretes and reinforcement, an increase in the production of prestressed structures, and the expansion of the areas of application of lightweight and cellular concrete.

Steel structures are mainly used for frames of large-span buildings and structures, for workshops with heavy crane equipment, blast furnaces, large-capacity tanks, bridges, tower-type structures, etc. The areas of application of steel and reinforced concrete structures in some cases coincide. At the same time, the choice of the type of structures is made taking into account the ratio of their costs, as well as depending on the construction area and the location of the construction industry enterprises. A significant advantage of steel structures (in comparison with reinforced concrete) is their lower weight. This determines the feasibility of their use in areas with high seismicity, inaccessible areas of the Far North, desert and high-mountain areas, etc. Expansion of the scope of application of high-strength steels and economical rolled profiles, as well as the creation of effective spatial structures (including from sheet steel) will significantly reduce the weight of buildings and structures.

The main area of ​​application of stone structures is walls and partitions. Buildings made of bricks, natural stone, small blocks, etc. to a lesser extent meet the requirements of industrial construction than large-panel ones. Therefore, their share in the total volume of construction is gradually decreasing. However, the use of high-strength bricks, reinforced stone, etc. complex structures (stone structures reinforced with steel reinforcement or reinforced concrete elements) can significantly increase the bearing capacity of buildings with stone walls, and the transition from manual masonry to the use of prefabricated brick and ceramic panels - significantly increase the degree of industrialization of construction and reduce the labor intensity of building buildings from stone materials.

The main direction in the development of modern wooden structures is the transition to glued timber structures. The possibility of industrial production and obtaining structural elements of the required dimensions by means of gluing determines their advantages over other types of wooden structures. Load-bearing and enclosing glued structures are widely used in agriculture. construction.

In modern construction, new types of industrial structures are becoming widespread - asbestos-cement products and structures, pneumatic building structures, structures made of light alloys and with the use of plastics. Their main advantages are low specific weight and the possibility of factory production on mechanized production lines. Lightweight three-layer panels (with cladding made of profiled steel, aluminum, asbestos cement and with plastic insulation) are beginning to be used as enclosing structures instead of heavy reinforced concrete and expanded clay concrete panels.