Beams covering one-story industrial buildings. Foundations and foundation beams of industrial buildings Bearing structures of industrial buildings
The frame of one-story industrial buildings is a system of interconnected columns (racks), load-bearing elements of the coating, crane beams and ties. The frame also includes foundation and strapping beams installed in the plane of the frame walls.
Frames of multi-storey buildings form a so-called spatial whatnot, consisting of a system of interconnected crossbars, columns and floor slabs (horizontal stiffening diaphragms).
The material for the frame device is mainly reinforced concrete, less often - steel, various alloys and wood. When choosing a frame material, they are guided by the nature of the force and non-force effects perceived by the frame, and also take into account the dimensions of the spans, column pitch, building height, construction site, fire resistance requirements and technical and economic considerations.
3.3.1. Reinforced concrete frame of one-story buildings
In modern industrial construction, mainly prefabricated reinforced concrete frames are used, the structural elements of which are typified. The reinforced concrete frame is arranged from prefabricated or monolithic elements; prefabricated frame structures are considered the most economical and common.
The framework is the bearing basis of the building and consists of cross and longitudinal elements. Transverse elements - frames - perceive loads from the coating, snow, wind acting on the outer walls and lanterns, as well as from curtain walls. Precast concrete frame frames consist of columns and load-bearing roof structures - beams or trusses. These elements are hingedly connected in nodes using metal embedded parts, anchor bolts and a small number of welds. Frames are assembled from standard prefabricated elements. The longitudinal structures of the building ensure the stability of the transverse frames and perceive the longitudinal loads from the wind acting on the end walls of the building and the ends of the lanterns, as well as loads from the braking of cranes. Longitudinal elements include subrafter structures and bracing elements located at the level of the supporting parts of the bearing structures of the coatings. In buildings equipped with cranes, crane beams serve as connecting elements in the longitudinal direction.
3.3.2. The main elements of the frame of industrial buildings and their purpose
The main elements of the building frame are divided into 3 groups:
1) bearing - perceiving the main loads in the building;
2) enclosing - designed to protect the internal space of the building from atmospheric influences, dividing the building into rooms and maintaining the specified temperature and humidity conditions;
3) performing simultaneously bearing and enclosing functions.
Industrial buildings are erected from the following architectural and structural elements (parts): foundations, foundation beams, walls, vertical supports (columns), load-bearing elements of coatings and ceilings - beams, trusses, crossbars, roofs, parapets, partitions, lanterns, stairs, floors, windows and doors (Fig. 3.3.).
Foundations are an underground structure that takes loads from the weight of the building and equipment and transfers them to the base.
Ceilings divide the interior space into floors, serve as enclosing and load-bearing structures, and also provide spatial rigidity of the building.
Vertical supports (columns) are designed to support roofs and ceilings.
The covering of the building protects it from atmospheric influences. The upper waterproofing shell of the coating is called the roof.
Partitions serve to divide the internal space within one floor into separate rooms. Partitions carry only their own weight and rest on the ceilings of the lower floor.
Stairs serve to communicate between floors.
3.3.3. Columns, their classification, types and main sizes
The design of prefabricated reinforced concrete columns depends on the space-planning solution of the industrial building and the presence in it of one or another type of handling equipment and its carrying capacity. In this regard, precast concrete columns are divided into two groups:
1) designed for craneless workshops and workshops equipped with overhead handling equipment;
2) for workshops equipped with overhead cranes.
According to the constructive solution, the columns are divided into single-branch and two-branch, and according to the location in the building - into the columns of the extreme rows, middle and located at the end walls. In cases where a craneless building must have a height of more than 9.6 m, columns for buildings with overhead cranes can be used. For buildings equipped with overhead cranes with a lifting capacity of up to 20 tons, single-branch columns of rectangular section are used (Fig. 3.4.).
The choice of the section of the column depends on the size of the span and their number, the pitch of the columns, the presence and type of sub-rafter structures, overhead transport and the constructive solution of the coating.
The height of the columns includes the distance from the level of the finished floor to the bottom of the truss structure plus the depth of the embedment in the foundation glass.
The floor height of industrial buildings is assumed to be: 3.6; 4.8; 6.0; 7.2; 8.4; 9.6; 10.8 (after 1.2 m), 12.6; 14.4; 16.2; 18.0 (after 1.8 m).
For buildings without overhead cranes, having a height from the floor to the bottom of the supporting structures of the coating up to 9.6 m, rectangular columns of 400x400, 500x500 and 560x600 mm are used. The middle columns have double-sided consoles in the upper part from the side faces to increase the area of support for the bearing structures of the coating.
Standard columns are designed for the maximum design load from the total weight of the roof with light-aeration lamps, snow load and overhead transport with a lifting capacity of up to 5 tons, as well as from the roof and overhead cranes with a lifting capacity of up to 50 tons.
Columns in buildings with overhead cranes must have a cantilever, stand or a separate branch to support the crane beams. The middle columns have two crane consoles, the outer columns are made with one-sided location of the crane console. Columns for buildings with overhead cranes consist of a crane section (from the top of the column to the crane consoles) and a crane section (from the crane consoles to the foundation). The over-crane part (over-column) serves to support the supporting structure of the roof, and the under-crane part transfers the load from the over-column and under-crane beams, supported on the consoles of the columns, to the foundation. Columns of crane buildings are solid and two-branch (through).
Two-branch (through) columns are used for buildings equipped with general-purpose overhead cranes with a lifting capacity of 10 to 50 tons, as well as for craneless buildings with a floor height of 10.8; 12.6; 14.4; 16.2; 18.0 m with spans equal to 18, 24 and 30 m. The pitch of the columns for the outer rows is 6 and 12 m, for the middle rows - 12 m. .8 - 18 m. Sections of the outer and middle columns at a step
6 m are 400x600 and 400x800 mm, and with a step of 12 m - 500x800 mm. With cranes with a lifting capacity of up to 30 tons and a building height of more than 10.8 m, stepped (for the outer rows) and stepped-cantilever (for the middle rows) two-branch columns are used.
The depth of the columns below the zero mark depends on the type and height of the columns, the lifting capacity of the crane equipment and the presence of rooms or pits located below the floor level.
Columns are usually made in the form of one solid element of heavy concrete grade 300, reinforced with welded frames made of hot-rolled steel of class AI. The middle columns, experiencing the action of the moments of two signs, are reinforced symmetrically.
The gaps between the struts of the branches of the columns are used to pass sanitary and technological communications.
In buildings with highly aggressive environments, it is undesirable to use two-branch columns, since they have a complex geometric cross-sectional shape that is inaccessible for inspection and painting of places where moisture and hygroscopic dust can accumulate. In such cases, it is recommended to use solid columns.
3.3.4. Foundation and crane beams
External and internal self-supporting walls of the building are installed on foundation beams, through which the load is transferred to the foundations of the frame columns. The foundation beams are laid on special concrete columns installed on the edges of the foundations. The beams are laid under the outer walls close to the outer faces of the columns, under the inner walls - between the columns.
Foundation beams with a column spacing of 6 m are used prefabricated reinforced concrete of concrete grades 300 - 350, with a column spacing of 12 m - with prestressed reinforcement. The cross section of the foundation beams can be T-shaped, trapezoidal or rectangular. The main foundation beams are made 450 mm high (for a column spacing of 6 m) and
600 mm (for a column spacing of 12 m), and a width of 260, 300, 400 and 520 mm. These dimensions correspond to the most common external wall thickness in industrial buildings. In places where expansion joints are installed, beams shortened by 500 mm are laid.
To protect the wall strip of the floor from freezing and to prevent deformation of the beams on heaving soils, they are covered with slag from below and from the sides. The upper face of the foundation beam will be placed on
30 - 50 mm below the level of the finished floor, which in turn is located 150 mm above the ground level. On top of the foundation beams, waterproofing is laid from a cement-sand mortar or two layers of rolled material on bituminous mastic. On the surface of the earth along the foundation beams around the entire perimeter of the building, an asphalt concrete pavement is arranged to prevent the foundations under the outer walls from getting wet from precipitation.
Crane beams are designed to support the rails of overhead cranes and provide longitudinal spatial rigidity of the building frame.
Reinforced concrete crane beams can be T-trapezoidal or I-section; they are used for cranes of light and medium duty with a column spacing of 6 and 12 m and a lifting capacity of cranes up to 30 tons. At the ends of the building, stops for overhead cranes are installed on the crane beams.
3.3.5. Reinforced concrete frame of multi-storey industrial buildings
Frame elements of multi-storey industrial buildings must have high strength, stability, durability and fire resistance. Therefore, reinforced concrete structures are used for these buildings, which can be monolithic, prefabricated or precast-monolithic.
The steel frame is used for heavy loads, in the presence of dynamic effects on the load-bearing structures from the operation of equipment or in the construction of buildings in hard-to-reach areas.
The positive quality of multi-storey buildings is their compactness, and therefore the length of various engineering and transport communications is noticeably reduced. In multi-storey buildings, production facilities are located in which the technological process is organized vertically. In this case, the materials are lifted to the upper floor, from where they are moved by gravity to the lower floors for processing. So, for example, at the enterprises of the food, pharmaceutical and chemical industries, many workshops are equipped with vertically located high-altitude equipment, and liquid materials are processed during their transportation by gravity. It is also advisable to use multi-storey buildings or whatnots.
Whatnots are multi-tiered structures without enclosing structures and coatings. They place such technological equipment on which atmospheric influences do not have a harmful effect.
The predominant structural scheme of multi-storey buildings is frame with curtain walls. Buildings with load-bearing walls and an internal frame have been used relatively rarely in recent years.
Multi-storey frame buildings are constructed according to a frame scheme with rigid nodes. The frame consists of vertical racks (columns) rigidly connected to beams (crossbars) of interfloor floors and roofs. Together, they form a transverse multi-tiered frame, rigidly fixed in the foundations. In the longitudinal direction, the transverse frames are connected by a deck of ceilings and coatings that form rigid diaphragms. Longitudinal rigidity is also provided by additional steel ties, which are placed in the middle of each temperature block.
The height of the floors can be 3.6; 4.8; 6.0; 7.2 and 10.8 m. A height of 7.2 m is used for the first and upper floors, a height of 10.8 m is used only for the upper one. The height of the floor is considered between the marks of the finished floor; the height of the upper floor with an enlarged span is measured from the level of the finished floor of this floor to the bottom of the building structure.
For the construction of multi-storey buildings, standard prefabricated reinforced concrete columns of two types are used - extreme and middle. To support the crossbars at the columns, consoles are provided. In terms of height, the columns can be two-story cut, two floors high and floor-by-story - one floor high (Fig. 3.5.).
For the two lower floors, as a rule, only two-story cutting columns are used. For the third and fourth floors - 3.6 m and 4.8 m high - they also install columns of two-story cutting. Floor-by-floor columns are used at a height of the third floor and above, equal to 6 m.
Crossbars (beams) of interfloor ceilings and roofing are supported on the consoles of multi-storey buildings. The size between the consoles is taken equal to the height of the floor. The distance from the console to the upper end of the column is 1780 mm for the columns of the middle floors and 720 mm for the columns of the upper floor. Thus, the joining of columns is carried out at a height of 1.0 or 0.6 m from the plane of the floor slabs, depending on the type of reinforced concrete crossbar. This ensures the convenience of work during installation. This arrangement of the joint is also explained by the least effort that occurs at the joint, in the frame rack during the operation of the building.
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The cross section of the columns is rectangular 600x400 or 400x400 mm, and for the columns of the lower floors, the section is 600x400 mm. The transition to a section of 400x400 mm usually occurs at the level of the upper plane of the second floor console.
Crossbars (beams of interfloor ceilings) are made of two types:
a) type I - for supporting plates on shelves;
b) type II - for supporting plates on the upper plane of the crossbar.
Type II crossbars differ from type I cross-sectional cross-sections. They have a rectangular shape with a height of 800 and a width of 300 mm. The length of the crossbars depends on their location in the building (extreme, middle), as well as on the location by floor, which is associated with the section of the columns, and is 5000; 5300; 5500 for a 6-meter span and 8000; 8300; 8500 mm for a 9 meter span.
For fastening the crossbars at their ends in the upper part there are recesses with the release of reinforcement bars, which are welded with the reinforcement of the columns, after which the joint is monolithic with concrete M 100-150 on fine gravel. Crossbars for spans of 6 m are made of concrete M 200 without prestressing reinforcement. Crossbars for 9-meter spans are made with prestressing of the lower reinforcement bars. Interfloor ceilings in multi-storey industrial buildings, as a rule, are made prefabricated. They consist of crossbars and reinforced concrete ribbed slabs.
Plates are divided into two groups depending on the type of crossbar. To support the slabs on the shelves of type I crossbars, two standard sizes of slabs are provided:
a) main slabs having a ribbed box-shaped structure 5500 and 5050 mm long and 1500 mm wide, as well as shortened slabs 5050 mm long, which are laid at the ends of the building and in places where expansion joints are installed;
b) additional slabs, laid near the longitudinal walls and having the same length as the main ones, 740 mm wide and 400 mm high.
When using crossbars II. type of slab is laid on top of them. Plates of type II have one standard size: 5950x1490 mm; type I slab is used as an additional one. These plates also have a box-shaped design. Intercolumn slabs, having cutouts for the column at the ends, serve as spacers that transfer horizontal longitudinal loads to the building frame; they are laid on top of the crossbars.
In the case of a frame of a multi-storey building (or whatnot), for light equipment or auxiliary premises, buildings are built with beamless (prefabricated reinforced concrete) floors, which have a number of advantages, such as the ability to create smooth ceilings without ribs, which contributes to better ventilation and prevents air stagnation, this is especially important for rooms with explosive emissions and the need to ensure a high degree of hygiene. In addition, rooms with smooth ceilings are better lit.
In such ceilings, square capitals are put on columns with consoles, which serve as supports for the above-column panels. These panels form a closed loop, on which the span panels, which are square in shape, rest.
3.3.6. Conditions for the use of steel structures for frames of one-story industrial buildings
The use of steel structures for frames of industrial buildings in accordance with the "Technical rules for the economical use of basic building materials" (TP 101-81) is allowed only in the following cases.
a) For roof and sub-rafter structures:
in heated buildings with spans of 30 m or more;
in unheated buildings and sheds for various purposes with asbestos-cement roofing with spans up to 12 m inclusive with a load capacity of overhead handling equipment of more than 2 tons, with a span of 18 m with a load capacity of overhead handling equipment of more than 3.2 tons;
in buildings and sheds with a span of 24 m or more;
in unheated single-span buildings with rolled roofs with spans of 30 m or more;
in multi-span buildings with spans of 18 m or more;
· in buildings with suspended lifting and transport equipment with a carrying capacity of more than 5 tons or other suspended devices that create loads exceeding those provided for standard reinforced concrete structures;
· in buildings on sites with a developed network of overhead conveyor transport;
in buildings with a design seismicity of 8 points with spans of 24 m or more;
In buildings with a design seismicity of 9 points with spans of 18 m or more, as well as in the following cases:
erection of buildings in hard-to-reach areas of construction;
in buildings with high dynamic loads (copra shops, explosive departments, etc.);
over hot areas of workshops with intense heat radiation at a temperature of heating of the surface of structures of more than 100 ° C (refrigerators of rolling shops, sections of heating wells, furnace and casting bays, etc.).
b) Columns:
in buildings with a height from the floor to the bottom of the truss structures of more than 18 m;
· in the presence of bridge cranes of general purpose with a lifting capacity of 50 tons or more, regardless of the height of the columns, as well as with a lower lifting capacity of heavy-duty cranes;
with a column spacing of more than 12 m;
· at a two-level arrangement of bridge cranes.
c) For crane beams, light and aeration lamps, crossbars and half-timbered racks.
d) For typical light load-bearing and enclosing structures of complex delivery.
The use of steel structures for the frames of one-story industrial buildings using new efficient heat insulators compared to similar traditional structures made of reinforced concrete and conventional heat-insulating materials can significantly reduce the mass (weight) of the building as a whole.
The steel frame of an industrial building has a structural scheme similar to a reinforced concrete frame.
Steel columns and their types
Steel columns, depending on their cross section, are divided into the following:
a) solid:
- permanent;
– variable section;
b) lattice (through) variable section;
c) separate variable section.
Columns suit for craneless buildings and for buildings equipped with cranes. Columns perceive jointly loads from the coating and cranes; with a large lifting capacity of the cranes, the columns separately perceive the loads from the coating and from the cranes. The connections of the elements of the columns are made welded, and in case of especially heavy crane loads - riveted.
In cross section, steel columns are most often a combination of several rolled profiles (channels, I-beams, angles, steel sheets) connected by overlays. Crane beams rest on columns of constant section through consoles specially arranged for this purpose, and in stepped beams - on ledges of columns (Fig. 3.6.).
Solid columns compared to through columns are less labor-intensive to manufacture, but require more steel consumption. They are used in craneless buildings, as well as in workshops with overhead cranes with a lifting capacity of up to 20 tons. In other cases, columns of variable section are used, while the over-columns can be solid or through. The lower crane part of the columns with a width of up to 800 mm is made solid, and in other cases it is through. Separate type columns are in some cases the most economical, since the division of the transmitted loads from the coating and cranes into two branches gives the most complete use of the material. Solid columns are most often made from one rolled profile or several vertical sheets welded together along the entire height of the column. Through columns consist of several separate branches, which are interconnected by gratings.
The load from the columns to the foundations is transferred through shoes, the dimensions of which are determined by calculation depending on the magnitude of the transferred loads; shoes are placed 500 - 800 mm below the floor level. The shoes are concreted to avoid corrosion.
Foundation beams with steel frames are made of reinforced concrete.
Steel crane beams
Steel crane beams can be split and continuous, solid And latticed. Split crane beams are the most widely used - due to the simplicity of the design solution and industrial character, although continuous crane beams have better operating conditions for crane tracks.
Lattice crane beams should be used for spans of 12 m or more when using light and medium-duty crane equipment with a lifting capacity not exceeding 50 tons. In all other cases, solid crane beams are used.
For the perception of horizontal forces from the braking of the trolley and the distortion of the crane, as well as to ensure the overall stability of the crane beams, it is necessary to provide for the installation of brake beams or trusses that are welded to the upper chords of the crane beams. The width of the brake beams and trusses is assigned taking into account the necessary rigidity and the possibility of passage along the crane runways. With a height of crane beams over 1200 mm, it is necessary to additionally introduce diaphragms.
Steel load-bearing roof structures: beams, trusses, frames and arches
Rolled or composite beams, trusses, arches, spatial and hanging systems are used as steel load-bearing structures of the coating.
Rolled steel and composite beams most often have an I-section, they are used for spans of 6–12 m.
Steel trusses used in construction practice have various types, shapes and outlines, the choice of which depends on the purpose and space-planning solution of an industrial building. Geometric diagrams of typical unified steel trusses are shown in Fig. 3.7.
The most commonly used trusses are segmental, parabolic, with parallel belts, polygonal, triangular, with parallel belts with tightening, etc. Trusses with parallel belts are designed for buildings with a flat roof, as well as for the installation of truss structures; their span can reach 60 m or more. Polygonal trusses are used for roofing with rolled roofs with spans up to 36 m. Triangular trusses make it possible to make roofs with steep roofs from asbestos-cement or steel sheets, as a result of which the height of trusses in the middle of the span reaches a significant size; this limits the spans covered by them to 36–48 m. In mass industrial construction, unified polygonal trusses are used with a span of 24, 30 and 36 m with a slope of the upper belt 1: 8 and a height at the support node of 2200 mm, flat with parallel belts with a span of 24, 30 and 36 m and a height at the support node of 2550, 3750 and 3750 mm, respectively, and a slope of the upper belt of 1.5%, along which roll roofs are arranged. In some cases, farms of this type are used to cover 18-meter spans. Farms with steep slopes are used for spans of 18, 24, 30 and 36 m with roofs made of sheet materials; their height
on the supports, 0.45 m is adopted, and in the middle part 3000, 3860, 4730 and 5560 mm, respectively. Large-span trusses can cover spans up to 90 m and have various lattice schemes: triangular, diagonal, cross and others, the choice of which depends on the nature of the load application and the height of the truss.
In the vast majority of cases, trusses have fixed supports, however, in the expansion joint on one column (and not on twin columns), one of the columns is installed on rollers or spherical surfaces.
Steel frames intended for the installation of load-bearing structures for coatings with large spans are made as single or multi-span, with horizontal or broken chords. Frame structures are effective when the rigidity of the columns is close to the rigidity of the crossbars, the height of which is taken: with solid sections 1/20 - 1/30 of the span, with lattice sections - 1/12 - 1/18 of the span.
Steel arches are used in industrial buildings for pavements with significant - from 50 to 200 m - span sizes. The spread of the arches is transmitted through the foundations to the ground; the arch lifting boom is within 1/2 - 1/15 of the span. Arches, like frames, can have a solid or through section; the height of the section of the through arches is 1/30 - 1/60 of the span and 1/50 - 1/80 of the solid arches.
Connections
Spatial rigidity and stability of trusses, arches, frames and other planar structures of building frames are provided by a system of connections established between these structures.
Horizontal (longitudinal and transverse) and vertical connections are arranged in the coatings, and longitudinal vertical connections are arranged between the columns.
Longitudinal horizontal connections are placed along the rows of columns in the planes of the lower and upper chords of the extreme panels of the trusses. They are longitudinal braced trusses with parallel belts. Transverse horizontal connections are formed by belts of two adjacent roof trusses and a lattice located between them. They are arranged at the ends of the building, as well as on both sides of each expansion joint, and with a large distance between the expansion joints - every 60 m.
3.3.7. Reinforced concrete bearing structures of the coating, their types and types
The load-bearing structures of the coatings of industrial buildings are divided into rafters, under-rafters and load-bearing elements of the enclosing part of the coating. In industrial buildings, two types of truss load-bearing structures are used:
1) planar - beams, trusses, arches and frames;
2) spatial - shells, folds, domes, vaults and hanging systems.
Beams and trusses are widely used as sub-rafter structures of industrial buildings, and large-sized slabs are used as load-bearing structures of the enclosing part of the coating. According to the unified dimensions of the space-planning elements of industrial buildings, the value of the transverse spans and the longitudinal step of the supporting structures is assigned as a multiple of the enlarged module of 6 m; in some cases, the use of a 3 m module is allowed.
Reinforced concrete beams are used for coating in industrial buildings with spans of 6, 9, 12, 18 and in some cases 24 m. The need for beam coatings for spans of 6, 9 and 12 m (spans of such dimensions can be covered with slabs) arises in the case of suspension to the supporting structures of handling equipment. Reinforced concrete beams can be single-pitched, double-pitched and with parallel chords (Fig. 3.8.).
Shed beams are used in buildings with a column spacing of 6 m and in buildings with external drainage with spans of 6 and 9 m. The cross section of the beams is tee, there are vertical stiffeners in the supporting nodes. Slope top-
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its belt of single-pitched beams with a span of 6 m is 1:10, with a span of 9 m - 1:15, with a span of 12 m - 1:20. The height of the beams in the support unit is 600 (for a span of 6 m) and 800 mm (for a span of 9 m). For the device of pitched roofs of buildings with a span of 12 m, prestressed single-pitched beams with a height of 1200 mm at the support node are used. Such beams are designed for overhead transport in the form of two crane-beams with a lifting capacity of 1.5 tons each and a load from the coating in the range of 350 ÷ 550 kg / m 2; cross-section of beams is two-tee.
Gable beams are used for the device of broken roofs in buildings with spans of 6, 9, 12 and 18 m. Beams with a span of 6 and 9 m have a T-section and vertical stiffeners in the support nodes. The height in the support node of 6-meter beams is 400 mm, 9-meter - 600 mm. Beams with a span of 6, 9, 12 m are installed only with a step of 6 m, and beams with a span of 18 m - with a step of 6 and 12 m. The cross section of the beams is an I-beam. The height in the middle part of the 12-meter beam is 1290 mm, the 18-meter beam is 1540 mm, the height in the support nodes is 800 mm. The slope of the upper belt of gable beams is 1:20.
Beams with parallel chords are used for buildings with flat roofs and spans of 12, 18 and 24 m. The cross section of the beams is I-beams, height 1200 mm. In order to reduce the weight of the beams, through holes are arranged in their vertical wall for laying various intra-shop communications, which makes it possible to more rationally use the interior space of the premises.
Rafter beams are designed as supports for roof beams with a column spacing of 12m in buildings with flat or pitched roofs. The length of the beams corresponds to a span of 12 m, their height is 500 mm, the section is tee with a shelf at the bottom.
Farms, their types
Reinforced concrete trusses are used for spans of 18, 24 and 30 m and a step of 6 and 12 m. For spans of 36 m or more, steel trusses are usually used. The use of 18-meter trusses is advisable when it is necessary to place communication pipelines within the coverage or use the inter-truss space for arranging technical floors.
There are the following main types of farms:
a) segmented, with an upper belt of a broken outline and straight sections between the nodes;
b) arched diagonal with a rare lattice and an upper belt of a smooth curvilinear outline;
c) arched bezraskosnye;
d) polygonal with parallel belts or a trapezoidal outline of the upper belt;
e) polygonal with a broken lower belt.
The height of trusses of all types in the middle of the span is taken equal to
1/7 - 1/9 of the span. Trusses are made of high-grade concrete (B30 - B50) and the lower chord and tensioned braces are reinforced with prestressed AIV class reinforcement with tension on stops. The cross-sectional width of the truss belts with their step of 6 m is taken 200 - 250 mm, and with a step of 12 m - 300 - 350 mm (Fig. 3.9.).
In the modern practice of industrial construction, segment roof trusses are most widely used. They are used for the device of pitched coatings with or without lanterns. These trusses are used to cover spans of 18, 24 and 30 m. The sections of the upper and lower belts are rectangular of the same width. Trusses are installed on reinforced concrete columns with a column spacing of 6 m or on truss trusses with a column spacing of 12 m.
Farms with parallel belts are used for building flat roofs of buildings without lanterns. The length of the trusses is designed for spans of 18 and 24 m. Trusses installed every 6 m are designed for overhead transport with a carrying capacity of up to 5 tons.
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Sub-rafter structures
Under-rafter structures in the form of reinforced concrete trusses and beams are used in the roofs of one-story industrial buildings with a column spacing of 12 and 18 m and with spans equal to 18, 24 and 30 m to support truss structures installed on them with a step of 6 m, in cases where the technological process requires a wide step of supports.
The rafter structures are prestressed from concrete of classes B30-B40 and reinforced with ropes of class K-7,
K-10, rod class A1U or wire reinforcement Vr-11 with tension on stops.
Reinforced concrete sub-rafter structures are arranged in the form of beams 1500 mm high and trusses 2200 and 3300 mm high.
3.3.8. Bearing elements of the enclosing part of the coating
With flat and pitched load-bearing structures, the load-bearing elements of the enclosing part of the coatings are carried out as purlins - using purlins along which small-sized slabs are laid, or non-purlin - in the form of large-sized slabs.
The flooring of non-purlin coatings of industrial buildings is usually arranged from prestressed ribbed reinforced concrete slabs with dimensions of 3x12, 1.5x12, 3x6 and 1.5x6 m, as well as from lightweight reinforced concrete 1.5x6 m in size. The slabs are laid along the upper belt of truss structures (beams or trusses) and welded to it. The joints between the plates are monolithic with cement mortar or concrete, and the flooring works as a single rigid diaphragm for the perception of horizontal and vertical loads.
The main slabs are considered to be 3 m wide slabs, the additional slabs are 1.5 m wide, which are used in places with a heavy load on the coating.
The most widespread are ribbed slabs made of heavy reinforced concrete.
Coating slabs made of lightweight and cellular concrete, combining the functions of flooring and insulation, are used for the installation of warm coatings in buildings with a step of supporting structures of 6 m. The slabs are made of expanded clay concrete, from autoclaved reinforced cellular concrete (foam concrete or foam silicate with a bulk density of 700 to 1000 kg / m 2).
The main slabs of lightweight concrete have a length of 6 m and a width of
1.5 m, additional plates - 0.5 m wide with a thickness of 200, 240 mm. The support of all types of large-sized slabs on the supporting structures is carried out through steel embedded parts, welding them to the embedded parts of the upper belt of the supporting structures of the coating.
3.3.9. Easily shed coatings
Easily shedding coatings are arranged on buildings of categories A and B (for fire hazard). Such coatings are easily released under the action of increased pressure as a result of a possible explosion of gases or dust; the walls of buildings and the main load-bearing structures in this case are not destroyed. The total area of easily dropped sections of wall coverings, as well as windows and doors, must be at least 0.05 m 2 per 1 m 3 of an explosive room.
The flooring of the easy-to-reset coating is made of special reinforced concrete slabs and asbestos-cement corrugated sheets.
Reinforced concrete slabs have a length of 6 m, a width of 3 or 1.5, a height of 300 mm. The plates are box-shaped with transverse stiffeners and holes. The 3 m wide slabs are laid as usual and attached to the bearing structures of the pavement, and the 1.5 m wide slabs are placed at intervals.
Corrugated asbestos-cement sheets of reinforced profile are laid on reinforced concrete slabs. Slab insulation is laid on asbestos-cement sheets, the cavities are filled with bulk insulation. A leveling layer is made on top of the insulation, along which a rolled roof is spread.
A spatial system consisting of columns, crane beams and supporting structures of the coating is called carcass one-story industrial building.
The vertical load-bearing elements of a reinforced concrete frame are called columns. By location in the building, the columns are divided into extreme and middle.
Columns of constant section (cantilevered)(Fig. 7) are used in buildings without overhead cranes and in buildings with overhead cranes.
The columns of the extreme rows are of a rectangular cross-section of constant height. The middle columns, having a cross-sectional size of less than 600 mm in the plane of the transverse frame, are equipped at the top with double-sided consoles with such a protrusion that the length of the platform for supporting the roof structure is 600 mm. With a section size of 600 mm or more, the columns do not have consoles.
In the columns adjacent to the end walls, embedded parts must be provided on the side of the walls for fastening the fachwerk pillars, which have zero reference to the longitudinal axes.
Rice. 7. Prefabricated reinforced concrete columns for craneless spans of one-story buildings:
a - extreme columns; b, c - middle columns;
1 - embedded steel parts for fastening trusses or roof beams;
2 - the same for welding anchors fastening the wall with columns;
3 - risks; 4 - anchor bolt
The columns are made of concrete class B15-B30. The main working reinforcement is rod made of hot-rolled steel of a periodic profile of class A-III.
Columns of rectangular section for a building with overhead cranes, having consoles(Fig. 8, a, b) used in buildings with a span of 18 and 24 m, up to 10.8 m high, equipped with overhead cranes with a lifting capacity of 10-20 tons. The columns have a rectangular cross-section both in the upper (over-crane) and in the lower (under-crane) part.
Rice. 8. Precast concrete columns for crane spans:
a, b- single-branched (extreme and middle); c, g - two-branched;
1 - embedded parts for fastening beams or roof trusses; 2 - the same
for welding anchors fastening the wall with columns; 3 - risks;
4 - anchor bolts; 5 - embedded parts for fastening crane beams
The columns of the inner and outer rows, installed at the locations of the vertical ties, must have embedded parts for fastening the ties.
The columns are made of concrete class B15, B25. The main working fittings - rod from hot-rolled steel of a periodic profile of a class A-III.
Two-branch columns(Fig. 8, c, d) are used in buildings with a span of 18, 24, 30 m, height from 10.8 to 18 m, equipped with overhead cranes with a lifting capacity of up to 50 tons.
For the extreme columns with a step of 6 m, a height of not more than 14.4 m and a crane capacity of less than or equal to 30 tons, a zero binding was adopted, and in other cases - 250 mm.
The columns are designed at the bottom with two branches and connecting braces. Branches, braces and the top of all columns have a solid rectangular section.
The columns are made of concrete class B15, B25. The main working reinforcement is rod made of hot-rolled steel of a periodic profile of class A-Sh.
The lower parts of reinforced concrete columns inserted into the sleeve are not included in the nominal height of the column. The columns are intended for use in conditions where the top of the foundations has a mark of -0.150. The length of the columns is selected depending on the height of the workshop and the depth of embedding in the foundation glass.
In buildings with rafter structures, the length of the middle columns is reduced by 700 mm.
Crane and strapping beams
Reinforced concrete crane beams(Fig. 9) are used in buildings with a column spacing of 6 and 12 m, with a lifting capacity of cranes up to 30 tons. The beams have a T-section and an I-section with a thickening of the walls on the supports. The unified dimensions of the beams are taken depending on the spacing of the columns and the lifting capacity of the cranes: with a column spacing of 6 m, the beams have a length of 5950 mm, a section height of 800, 1000, 1200 mm; with a column spacing of 12 m, the length of the beams is 11,950 mm, the height is 1400, 1600, 2000 mm. They are made of concrete class B25, B30, B40 with prestressed reinforcement.
By location in the building, crane beams are ordinary and end beams. They differ in the location of the embedded plates.
In the beams, embedded elements are provided for attaching to columns (steel sheets) and for attaching crane rails to them (tubes with a diameter of 20-25 mm through 750 mm of the length of the shelf).
Crane beams are fixed to columns by welding embedded elements and anchor bolts. Bolted connections are welded after final alignment. The rails to the crane beams are fixed with steel paired legs located at 750 mm intervals. Elastic pads made of rubberized fabric 8-10 mm thick are laid under the rails and paws.
To avoid impacts of overhead cranes on the end walls of the building, steel stops equipped with a wooden bar are arranged at the ends of the crane runways.
Strapping reinforced concrete beams(Fig. 10) are designed to support brick and small-block walls in places where the heights of spans vary, as well as to increase the strength and stability of high self-supporting walls. Usually, beams are arranged above window openings. Reinforced concrete strapping beams have a length of 5950 mm, a section height of 585 mm, a width of 200, 250, 380 mm. They are installed on steel support tables and attached to the columns using steel strips welded to the embedded elements.
Rice. 9. Prefabricated reinforced concrete crane beams:
a - span 6 m; b - span 12 m; V - crane beam support
on the column (general view); g - the same, from the facade and in section;
1 - embedded parts of the column; 2 - the same crane beam; 3 - steel bar; 4 - steel lining; 5 - embedding with concrete; 6 - holes for fastening the rail
The walls above the strapping beams can be provided as solid, with separate openings, with strip glazing.
The beams are made of B15 class concrete.
Rice. 10. Strapping beams, their support on columns:
a - a beam of rectangular section; b - rectangular beam
sections with a shelf; c - support of beams (bottom view) on a steel console;
1 - embedded parts; 2 - welded metal console; 3 - mounting pad
Rafters, under-rafters and trusses
In the coatings of buildings, the load-bearing elements are beams and trusses, laid across or along the building.
By the nature of the laying, beams and trusses are: truss, if they overlap the span, support the roof structures supported on them, and truss, if they cover the 12-18-meter steps of the columns of the longitudinal row and serve as a support for truss structures.
Reinforced concrete rafters(Fig. 11) cover spans of 6, 9, 12 and 18 m.
Rice. eleven. Reinforced concrete truss beams:
a - single-pitched tee section; b - single-pitched I-section;
c - gable (span 6-9 m); g - gable (span 12-18 m);
d- lattice (span 12-18 m); e - with parallel belts;
1 - supporting steel sheet; 2 - embedded parts
For their manufacture, concrete of class B15-B40 is used. On the upper belt of the beams, embedded parts are provided for fastening roof slabs or girders, on the lower shelf and the wall of the beam - embedded parts for fastening the tracks of an overhead crane.
The beams are attached to the columns by welding embedded parts.
The names of the beams depend on the outline of the upper chord.
Shed beams are used in single-span buildings. The beams have a T-section with a thickening on the supports and a wall thickness of 100 mm. For 12-meter spans, I-beams with prestressed reinforcement are used.
gable beams are designed for buildings with pitched roofs. For spans of 6 and 9 m, T-beams are used with a thickening on the support and a wall thickness of 100 mm. For 12-18-meter spans, I-beams are intended with a vertical wall 80 mm thick and with prestressed reinforcement.
lattice beams have a rectangular cross-section with holes for the passage of pipes, electrical cables, etc.
beams With parallel belts used for buildings with flat roofs. They have an I-section with a thickening in the support nodes and a vertical wall thickness of 80 mm.
Reinforced concrete roof trusses(Fig. 12) are used in buildings with a span of 18, 24, 30, 36 m. A system of racks and braces is placed between the lower and upper belts of trusses. The lattice of trusses is provided in such a way that floor slabs 1.5 and 3 m wide rest on trusses at the nodes of racks and braces. Basically, 3 m slabs are used, in especially loaded areas - 1.5 m.
Have been widely used segmented without diagonal trusses with a span of 18 and 24 m, the sections of the upper and lower chords are rectangular.
To reduce the slope of the coating for multi-span buildings, special racks (pillars) are provided on the upper chord of the trusses, on which the coating slabs rest. Giving the coating a small slope provides a better possibility of mechanization of roofing, which creates a greater reliability of the roof in operation. However, due to the need to increase the height of the outer walls, low-slope roofs are advisable in multi-span buildings.
rafter farms produce three types:
For low-slope roofs of greater height;
For pitched roofs of lower height with the device of racks on supports that serve as a support for the extreme flooring of the coating;
With sagging bottom belt.
In the supporting parts of the truss truss and in its middle lower node, platforms are provided for supporting the truss trusses. Farms are made of concrete class B25-B40. The lower belt is prestressed and reinforced with bundles of high-strength wire. To reinforce the upper belt, braces and racks, welded frames made of hot-rolled steel of a periodic profile are used.
The trusses are fastened to the columns with bolts and welding of embedded parts. The trusses are provided with embedded details.
Rice. 12. Reinforced concrete trusses:
a, b - truss segmental diagonal;
V _ rafter arched bezraskosny;
g_ truss, bezraskosny with supports for the device of flat coatings;
d _ rafter with parallel belts;
e - rafter for pitched coatings;
g - rafter for flat coatings
Binding of columns to the center axes of the building
In one-story industrial buildings with reinforced concrete and mixed frames, the columns of the outer rows in relation to the longitudinal centering axes have a zero reference, i.e. the outer face of the column is aligned with the longitudinal center axis and coincides with the inner face of the wall enclosure. In this case, a gap of 30 mm must be provided between the inner edge of the panel and the column (Fig. 13).
Rice. 13. Binding of load-bearing structures of one-story
industrial buildings to the center lines:
A- longitudinal outer walls and columns (craneless buildings);
b - longitudinal walls and columns (with cranes with a lifting capacity of up to 30 tons);
V- longitudinal outer walls and columns (with cranes
carrying capacity up to 50 tons); g - in the end walls;
d - c places of expansion joints (DSh); e - a fragment of the building plan;
1 - walls; 2 - columns; 3 - overhead crane; 4 - overhead crane;
5 - half-timbered column; 6 - crane beam
The columns of the middle rows in reinforced concrete, steel and mixed frames have a central binding in relation to the longitudinal center axis, i.e. the center axis of the middle row of columns is aligned with the cross-sectional axis of the overhead part of the columns.
The columns of the outer rows in the steel frame with respect to the longitudinal center axis have a binding of 250 mm and are aligned with the inner edge of the wall panel with a gap of 30 mm.
The end columns of the main rows of any frame in relation to the extreme transverse center axis have a binding of 500 mm, i.e. the axis of the column lags behind this extreme transverse center axis by 500 mm.
All half-timbered columns are installed at the ends of the spans with a step of 6 m and are designed for hanging wall panels on them and absorbing wind loads. Regardless of the type of material in relation to the transverse center axis of the span, half-timbered columns have a zero reference.
In reinforced concrete and mixed frames with a span of 72 m or more, and in a steel frame - 120 m or more, an expansion joint is provided in the middle of the spans in the transverse direction, which is arranged by installing a pair of columns, the axes of which lag behind the axis of the expansion joint, combined with the next stepping axis, by 500 mm each. This creates two temperature blocks that work independently under load. To ensure the spatial rigidity and stability of the columns in the vertical direction, vertical steel ties are provided between the columns in the middle of the temperature block (with a column spacing of 6 m - cross, with a spacing of 12 m - portal).
Longitudinal expansion joints or the transition of the heights of the longitudinal spans are solved on two rows of columns, while paired center axles with an insert of 500, 1000, 1500 mm are provided. In a building with a steel frame, the transition of heights is carried out on one column by changing the height of its branches.
The adjunction of two mutually perpendicular spans is carried out on two columns with an insert along the outer wall and at the level of the coating. The size of the insert is determined depending on the thickness of the outer walls and on the binding of the columns.
In the building, in the presence of electric bridge cranes, the vertical axes of the crane tracks lag behind the longitudinal centering axes of the building by 750 mm (without a passage) and by 1000 mm (with a passage), and in the presence of overhead cranes, the vertical axes of suspension and their movement lag behind the longitudinal centering axes by 1500 mm.
Providing spatial rigidity reinforced concrete frame
The system of connections is designed to provide the necessary spatial rigidity of the frame. It consists of:
· vertical connections;
horizontal connections along the upper (compressed) belt of farms;
communication by lamps.
Vertical connections have:
· between the columns in the middle of the temperature block in each row of columns: with a column spacing of 6 m - cross; 12m - portal. In craneless buildings and with overhead cranes, connections are placed only at a column height of 9.6 m. Connections are made from corners or channels and attached to the columns with the help of scarves (Fig. 14);
Between the supports of trusses and beams, the connection is placed in the extreme cells of the temperature block in buildings with a flat coating. Without truss structures - in each row of columns, with a truss structure - only in the extreme rows of columns.
Horizontal connections are: coating slabs;
· at the ends of the lantern openings, the stability of the rafters and trusses is ensured by horizontal cross ties installed at the level of the upper chord, in subsequent spans (under the lanterns) - by steel struts; with large spans and height of the building at the level of the lower belt of trusses, horizontal connections are arranged between the extreme pairs of trusses located at the ends of the building; in buildings with a spacing of 12 m for the outer and middle columns, horizontal trusses are provided at the ends (two in each span per temperature block). These trusses stand at the level of the lower belt of truss trusses.
Units of precast concrete frame
The places of conjugation of heterogeneous elements of the prefabricated frame are called nodes (Fig. 15). The nodes of reinforced concrete frames must meet the requirements of strength, rigidity, durability; immutability of mating elements under the action of mounting and operational loads; ease of installation and termination.
Pairing the column with the foundation. The depth of embedding of columns of rectangular section is 0.85 m, two-branch - 1.2 m. The joint is cemented with concrete of a class not lower than B15. The grooves on the faces of the column contribute to better adhesion of concrete in the joint cavity.
Supporting the crane beam on the ledges of the column. A steel sheet with cutouts for anchor bolts is welded to the beam supports (before it is installed). On the column supports, the beam is fixed to the anchor bolts and the embedded parts are welded. The upper shelf of the crane beam is fixed with steel strips welded to embedded parts.
Pairing truss trusses and beams with a column. Steel sheets are welded to the supports of the truss structures. After installation and alignment, the supporting sheets of the truss structures are welded to the embedded parts on the head of the column.
Supporting subrafter structures on the head of the column. Embedded parts of the joined elements are welded with a ceiling seam.
Attachment of overhead cranes to roof structures. The bearing beams of cranes are bolted to steel clips on truss structures. Overhead beams redistribute the load from overhead cranes between the truss truss nodes.
Pairing rafter and rafter elements similar to the fastening of trusses and beams on the head of columns.
Multi-storey precast concrete frame
Multi-storey industrial buildings are erected, as a rule, frame.
Depending on the type of flooring, the structural scheme of the building can be beamed and beamless.
IN beam reinforced concrete frames (Fig. 16), the bearing elements are foundations with foundation beams, columns, crossbars, floor panels and coatings, as well as metal ties.
Rice. 14 Ensuring the spatial rigidity of the frame:
a - placement of horizontal bonds in the coating; b - strengthening of the end
walls with crown trusses; V- placement of vertical connections in buildings
with flat coverings (without rafter structures);
d - vertical connections in buildings with truss structures;
d - vertical cross connections; e - vertical portal connections;
1 - columns; 2 - roof trusses; 3 - coating slabs; 4 - lantern;
5 - wind farm; 6 - horizontal cross connection (at the ends of the lantern opening); 7 - steel struts (at the level of the upper belt of trusses); 8 - crane beams; 9 - metal truss trusses between the supports of truss trusses; 10 - vertical cross connections (in the longitudinal row of columns); 11 - truss trusses; 12 - vertical portal connections (in a longitudinal row of columns)
Rice. 15. Knots of the reinforced concrete frame of one-story industrial buildings: A - conjugation of the column with the foundation; b - crane beam support
on a column; V - pairing beams and trusses with a column; g - support
subrafter structures on the head of the column; d - suspension mount
cranes to the bearing beams of the coating; e - rafter support
and rafter beams on the head of the column;
g - pairing of truss, truss trusses;
1 - foundation; 2 - column; 3 - monolithic concrete; 4 - grooves;
5 - embedded part; 6 - mounting plate; 7 - M20 bolts;
8 - support sheet 12 mm thick; 9 - rafter beams;
10 - welded ceiling seam; 11 - rafter beam;
12 - steel clip; 13 - carrier beam of an overhead crane;
14 - roof truss
Rice. 16. Multi-storey building with beam ceilings:
a - a cross section of a building with slabs supported on the shelves of crossbars;
b - plan; c - frame details; 1 - self-supporting wall; 2 - crossbar with shelves;
3 - ribbed plates; 4 - column console;
5 - reinforced concrete element for filling expansion joints
Rice. 17. Pairing columns with each other and with crossbars:
a - the design of the joint of the columns; b - general view of the conjugation of the column and the crossbar;
1 - abutting column heads; 2 - centering gasket;
3 - straightening plate; 4 - working reinforcement of the column;
5 - the same transverse; 6 - butt rods;
7 - caulking and embedding with B25 class concrete; 8 - crossbar;
9 - floor slab (bonded); 10 - embedded parts of the column
crossbar and plates; 11 - welding of reinforcement released from the column and crossbars;
12 - pad for plate welding
The foundations are arranged columnar glass type.
Columns with a section of 400 x 400, 400 x 600 mm cantilever one floor high (for buildings with a floor height of 6 m and for the upper floors of three- and five-story buildings), two floors (for the two lower, as well as for the upper floors of four-story buildings) and three floors (for buildings with a floor height of 3.6 m). The outer columns for supporting the crossbars have consoles on one side, the middle columns have consoles on both sides. The columns are made of concrete class B15-B40.
Crossbars are laid on the console of the columns in the transverse direction. They are made of concrete class B25, B30. Crossbars of the first type (with shelves for supporting plates) cover spans of 6 and 9 m. Crossbars of the second type have a rectangular section, they are used in ceilings when installing sagging equipment.
Floor and roof slabs are made with longitudinal and transverse ribs from concrete class B15-B35. According to their width, they are divided into main and additional, laid at the outer longitudinal walls. The main slabs laid on the top of the crossbars have cutouts at the ends (to skip the columns). With floor loads up to 125 kN / m 2, flat hollow slabs are used, and sanitary panels are laid along the middle rows of columns.
Connections between the columns they are installed floor by floor in the middle of the temperature block along the longitudinal rows of columns. They are made from steel corners in the form of portals or triangles of the same design as in one-story buildings.
Binding columns of extreme rows and outer walls to the longitudinal center lines, the zero or center axis of the building passes through the center of the column. The binding of the columns of the end walls is assumed to be 500 mm, and in buildings with a grid of columns 6x6 m - axial. The columns of the middle rows are located at the intersection of the longitudinal and transverse axes. Frame nodes(Fig. 17) - these are support connections of the same type or different types of prefabricated elements that provide spatial rigidity of structural rods. The main nodes include:
pairing of crossbars with columns is achieved by welding the embedded parts of the crossbars and consoles of the columns, as well as by welding the outlets of the upper reinforcement of the crossbars with rods passed through the body of the column. The gaps between the columns and the ends of the crossbars are filled with concrete;
column joints multi-storey buildings for ease of installation are provided at a height of 0.6 m from the floor level. The ends of the columns are equipped with steel heads. The joint is carried out by welding the butt rods to the metal heads, followed by embedding;
floor slab joints. The laid slabs are connected by welding embedded parts with crossbars, with columns and with each other. The cavities of the joints between the ribs are monolithic with concrete. Beamless reinforced concrete frame with a grid of columns 6x6m in the form of a multi-tiered and multi-span frame with rigid nodes and floor loads from 5 to 30 kN / m 2 (Fig. 18).
The main elements of the frame: columns, capitals, inter-column and span slabs - are made of concrete class B25-B40.
Columns with a height of one floor are installed on a grid of 6x6m. In the upper part of the column there is a widening (heads) for supporting the capitals, which has the form of an inverted truncated pyramid with a through cavity for mating with the ends of the columns.
Rice. 18. Multi-storey building with beamless ceilings:
a - cross section; b - plan; 1 - self-supporting wall;
2 - column capital; 3 - intercolumn plates; 4 - the same span
Fig.19. Prefabricated beamless ceiling:
a - plan and sections; b - general view;
1 - column head; 2 - capital; 3 - intercolumn plate;
4 - the same span; 5 - monolithic concrete; 6 - monolithic reinforced concrete;
7 - shelf for supporting the span plate; 8 - column
The capital is put on the head and fixed by welding steel embedded parts. Multi-hollow intercolumn slabs are laid on the capitals in two mutually perpendicular directions and welded at the ends to the embedded parts of the capitals. After installing the column of the next floor, the joint is poured with concrete. Then, steel reinforcement is laid in the area between the ends of the intercolumn plates, welding it to the embedded parts. After concreting, the slabs work as continuous structures.
The sections of the overlap, limited by the intercolumn slabs, are filled with square-shaped span slabs, resting them along the contour on the quarters provided in the side faces of the intercolumn slabs.
The main nodes of the beamless frame include (Fig. 19): column joints, located 1 m above the ceiling, of the same design as in the beam frame; the junction of the capital with the column. The capital is supported on the four-sided console of the column, by welding embedded parts from below, and reinforcing plates from above. The gap between the column and the capital is monolithic with class B25 concrete; floor slab joints. Intercolumn slabs are supported by reinforcement outlets on embedded parts, monolithic joint with concrete. The span slabs are supported by reinforcement outlets on the embedded parts of the intercolumn panels. After welding, the wedge-shaped grooves of the joints are monolithic.
The coating of an industrial building determines the durability, the nature of the interior space and the appearance of the building. It accounts for 20 to 50% of the total cost of a one-story building.
According to thermal properties coatings are divided into insulated and non-insulated (cold). They are selected taking into account the requirements of the microclimate conditions of the premises, the climatic features of the construction area and the method of removing snow from the roof of the building.
Insulated coatings are arranged above heated rooms. The thickness of the insulation is prescribed with the expectation to exclude the formation of condensate on the inner surface of the coating. Valleys are often made less insulated than the main coating, which contributes to their greater heating and eliminates the accumulation of snow and the formation of ice.
Non-insulated coatings suit in unheated buildings and with excessive heat emissions.
According to design plans coatings are classified into planar and spatial. In the first, load-bearing and enclosing structures work mostly independently of each other. Secondly, the functions of load-bearing and enclosing structures are combined. Spatial coatings, having curved surfaces of a rational geometric shape, have high rigidity, reduce material consumption and are appropriate in buildings with spans exceeding 30 m.
Coatings must have good waterproofing, thermal protection, must be strong, durable and reliable in operation, have the necessary fire resistance and fire safety, be industrial, have simple and reliable nodal interfaces of structural elements.
Coating structures
Coatings of industrial buildings, as a rule, suit without attic. They consist of load-bearing and enclosing structures.
Bearing truss structures are trusses, beams, arches and frames. They support the enclosing part, giving it the necessary slope corresponding to the roofing material.
The fencing includes flooring (reinforced concrete slabs, asbestos-cement or metal sheets, etc.), vapor barrier, insulation, leveling screed and waterproofing.
In non-insulated (“cold”) coatings, there is no vapor barrier and insulation.
In one-story industrial buildings, the most common coatings are made of large-sized slabs laid along the upper chords of truss structures. When using floorings from small-sized elements, the latter are supported by girders laid on truss structures.
Supporting structures of coatings
The bearing structures of the coatings are made of reinforced concrete, metal, wood and combined (from the materials listed above, for example, metal-wood trusses, etc.).
Metal covers are strong and lightweight structures. They are easy to manufacture and install, are highly assembled structures. Coatings made of reinforced concrete are fire resistant and durable.
Reinforced concrete roof beams and trusses.
Reinforced concrete beams are used in single-slope, multi-slope and low-slope, as well as flat ( i=1:20) coatings of one-story industrial buildings with spans ( L) from 6 to 18 m.
Beams of single-pitched, flat and low-slope coatings have a straight upper chord (Fig. 1 a, b, c), and in gable beams the upper chord has a broken outline with a slope i= 1:12 (Fig. 2).
The design of the beams allows the attachment of overhead cranes with a lifting capacity of up to 50 kN.
For spans of 6 and 9 m, the beams have a T-section with a height on the support of 590 and 890 mm.
Beams with spans of 12 and 18 m are made of I-beam or rectangular sections with a height on the support of 890, 1190 and 1490 mm. I-beams with a wall thickness of 80 mm are reinforced on supports with massive vertical ribs. To reduce the mass in beams of rectangular section, holes are arranged (Fig. 2 b). Such beams
the supporting parts are easy to manufacture and facilitate the wiring of the upper communications, but have more weight than beams of tee or I-sections.
On the upper chord of reinforced concrete beams, embedded elements (M) are provided for attaching girders or roof slabs, on the lower chord and wall - for attaching overhead tracks, and in - steel sheets with cutouts for attaching beams to columns. The support of the beam on the column is shown in fig. 3.
b) d)
V 
)
Rice. 1. Reinforced concrete beams with a span of 6, 9 and 12 m:
a) for single-sided coatings ( L= 6.9 m);
b) for flat coatings ( L= 12 m);
c) for low-slope coatings ( L= 12 m)
d) section of beams for b) and c)
A
2 - 2
Rice. 2. Gable reinforced concrete beams:
a) solid section for L= 6.9 m;
b) lattice for L= 12 and 18 m
Rice. 3. Supporting a reinforced concrete beam on a column
Reinforced concrete trusses used to cover spans of 18, 24 and rarely 30 m. According to the outline of the belts, they are segmented, arched, diagonal and diagonal, with parallel belts and polygonal (Fig. 4).
Rice. Fig. 4. Outlines of truss belts: a - segmental; b - polygonal;
c - trapezoidal; g - with parallel belts; d - triangular
Triangular trusses are used mainly for roofs made of asbestos-cement and metal sheets, and with parallel belts - for flat roofing under roll roofing.
To give the roof a slight slope, segmental and arched trusses with posts are used to support the covering panels on them. Such "horn" farms for low-slope coatings are shown in fig. 5 a.
The most rational in terms of material distribution are segmental and arched trusses, which have a broken or curvilinear upper belt. Compared to trusses of other shapes, the forces in the elements of the lattice of these trusses are less, which makes it possible to make the lattice more sparse. Trusses with parallel belts and polygonal have a simple configuration and are good because they are interchangeable with steel trusses. However, their disadvantages include a relatively powerful lattice and a large height, which leads to an overspending of material on the walls and an increase in the volume of the building of little use, in addition, they require additional vertical and horizontal connections in the coating.
The support of a reinforced concrete truss on a column is shown in Fig.6.
Rice. 5. Reinforced concrete beamless trusses:
a - for a low-slope roof;
b - for a pitched roof
Rice. 6. Reinforced concrete truss support on a column
Preface to the second edition 3
Introduction 4
Chapter 1
1.1. Building types. Basic requirements for building solutions. AND
1.2. Column grid, truss pitch 13
1.3. Unification of space-planning solutions and schemes of buildings 15
Chapter 2. Structural schemes of buildings 20
2.1. Building frame diagrams 20
2.2. Structural schemes of coatings 21
2.3. Rigidity and stability of the frame of the building and structures
coatings, solving ties 34
Chapter 3. Basic provisions for the unification of structures. . 46
3.1. Modular system. Nominal and structural dimensions of elements 46
- 3.2. Binding of alignment axes and structures 49
3.3. Unification of loads 53
3.4. Unification of interfaces of structural elements 56
3.5. Unification of elements 58
Chapter 4. Basic provisions for the design of precast concrete structures 60
4.1. Design code 60
4.2. Reinforcing steels 61
4.3. Appointment of reinforcing steel for structures operated at different design temperatures 66
4.4 Reinforcement of precast concrete structures. Unification of reinforcing products. 69
4.5. Issues of designing prestressed concrete structures 74
4.6. Embedded parts: 78
4.7. Requirements for building structures with aggressive environments 82
4.8. Requirements for the structures of buildings constructed in seismic regions 85
4.9. Requirements for transportation and storage of structures 86
Chapter 5. Foundations and foundation beams 88
5.1. Zero work cycle 88
5.2. Types of foundations and their scope 90
5.3. Issues of designing prefabricated foundations. . 92
5.4. Foundation beams 95
5.5. Strapping beams and lintels 99
Chapter 6
6.1. Types of columns and their scope 101
380
6.2. Features of the static calculation of columns
6.3. The main issues of the constructive solution of columns
64. Typical columns of rectangular section for buildings without cranes and with cranes
6 5. Typical two-branch columns for buildings with overhead cranes
6 6. Typical two-branch columns for buildings with passages at the level of crane beams
Teague
6 7. Typical two-branch columns for buildings without cranes and overhead transport
6.8. Typical columns of end and longitudinal half-timbered houses
6.9. Typical columns for buildings erected in seismically:
areas
6.10. Typical columns for buildings with increased temperature blocks
611. Typical columns for buildings with aggressive environment
6 12. Work on further improvement of columns
Head (m ^ Rafter beams
7 1." Scope of beams
7 2.* Basic provisions for the purpose of overall dimensions and static calculation of beams
7.3.b Basic provisions for calculating beams for strength, stiffness, formation and opening of cracks
7 4y Choice of shape and design of roof beams
7 5. Beams with non-stressed reinforcement
7.6. Beams with beam and bar reinforcement, tensioned
on concrete
7.7. Beams with bar and wire reinforcement, tensioned on stops (according to the drawings of the first development)
7.8. Beams with bar reinforcement stretched by electrothermal method (according to the drawings of the first developments)
7.9. Typical beams with rod, wire and strand reinforcement for buildings with a pitched roof
7.|0. Typical beams with bar, wire and strand reinforcement for buildings with a flat roof
7.11. Typical beams for buildings with a highly aggressive environment
12. New developments of roof beams
Head truss trusses
8.1. Scope and types of roof trusses. . .
8 2. Features of collecting loads when calculating trusses ....
8 3. Basic provisions of the static calculation of farms
8 4. Basic provisions for the calculation of truss elements for strength
8 5. Issues of calculating trusses for the formation or opening of cracks and for deformations
8.6. The main conditions for the appointment of overall dimensions of trusses
section sizes and their elements
8 7. Construction of trusses and their elements
88. Design features of truss joints
89. Trusses with beam and rod reinforcement, tensioned
on concrete
8.10. Fetsya with wire and rod reinforcement, pulled on the stops
8.11 Trusses from linear elements
8.12. Trusses with bar reinforcement stretched by electrothermal method 226-
8.13. Typical trusses with parallel belts for coverings
flat roof buildings 228
8.14. Typical segmented trusses for covering buildings with pitched roofs 232
8.15. Beamless prestressed trusses and arches 237
8.16. Application of typical trusses in seismic regions. 245
Chapter (§1 Rafter structures 246
9.1. Scope and types of truss structures 246
9.2. Basic provisions for the static calculation of sub-rafter structures. ". 248
9.3. Appointment of overall dimensions of truss structures and their sections 252
9.4. Features of the design of rafter beams and trusses 253
9.5. Subrafter structures with beam reinforcement. . 260
9.6. The first truss structures with rebar tension on stops 262
9.7. Typical truss beams with rebar tensioned
on stops 265
9.8 Typical truss trusses for pitched buildings
roofing 267
9.9. Typical truss trusses for buildings with a flat
roofing 271
9.10. Selection of typical sub-rafter structures in the design of buildings 273
9.11. Experimental development of truss trusses. . 274
Chapter (a Crane beams 276
10.1. Application area 276
10.2. Issues of designing crane beams 277
10.3. Experience in the use of crane beams of the first developments 279 ■
104. Typical crane beams 280 4
10.5. Options for crane beams based on standard solutions 283 1
10.6. Fastening of crane beams and crane rails. . . 284
Chapter "Covering boards 287
11.1. Types of floor slabs... 287
11.2. Information on the calculation and design of plates 288
11.3. Typical reinforced concrete slabs 6 m long 290 ^
11.4. Typical single-layer slabs 6 m long made of cellular
concrete 296
11.5. Typical 6 x ribbed slabs with cellular concrete flange 297
11.6. Typical slabs, 6 m long, made of lightweight concrete 298
11.7. Typical reinforced concrete slabs 12 m long 300
11.8. Standard perforated slabs for drop roofs and other special applications 307
11.9. Complex plates 308
11.10. Experimental designs of floor slabs.... 31?
Chapter 12 Wall Panels 315
12.1. The use of panels in the construction of one-story industrial buildings 315
12.2. Types of panels and their scope 317
12.3. Structural solutions for panel walls 318
12.4. Panels 6 l long for unheated buildings.... 321
12.5. Single-layer panels 6 m long made of cellular concrete for
heated buildings 324
12.6. Single-layer panels 6 m long made of lightweight concrete for
heated buildings 326
12.7. Three-layer panels 6 m long for heated buildings 327
12.8. Panels 12 m long for unheated buildings. . . 329
12.9. Panels 12 m long for heated buildings.... 330
12.10. Panel walls of buildings designed for operation
under special conditions 333
12.11. Panels for piers, gables, cornices, parapets
and partitions of buildings 336
12.12. Panels with face finish 337
Chapter 13
design and workmanship 339
13.1. Quality control system for the manufacture of precast concrete structures 339
13.2. Basic provisions for control.strength, rigidity and
crack resistance of structures 341
13.3. Test Loads and Evaluation of Test Results 344
13.4. Methods for testing structures at enterprises. . . 346
13.5. Registration of test results of structures .... 353
12..6. Acceptance of elements of prefabricated structures for installation. . 355
Chapter 14
structures 356
14.1. Wholesale prices for precast concrete products. . . 356
14.2. Issues of reducing the cost of precast concrete 360
14 3. District unit prices for construction work on
installation of prefabricated reinforced concrete structures in buildings 362
14.4. Indicators for comparing the estimated cost and labor intensity of structures in case 365
14 5. The concept of the impact of technical and economic indicators
load-bearing and enclosing structures for the estimated cost of industrial buildings 367
Index of series of standard working drawings 372
Reinforced concrete beams are used for spans from 6 to 18 m in the coatings of industrial buildings with single-pitched, double-pitched and flat roof profiles. In order to reduce the weight of the beams, as well as to create the possibility of mounting pipelines, air ducts and other utilities under the coating, through holes of various geometric shapes are made in the vertical walls of the beams. Beams with a span of more than 12 m are extremely bulky and have a large mass, therefore, to facilitate transportation, they are divided into separate prefabricated elements, followed by assembly and the use of stressed beam or strand reinforcement. After tensioning the reinforcement, the embedded tubes in the individual elements of the beam are filled with a liquid cement mortar, which protects the steel reinforcement from corrosion.
With spans of 6 and 9 m, the beams are made of a tee section and have a height on a support from 590 to 790 mm, and for spans of 12 and 18 m, their cross section is an I-beam with a height on a support of 790 to 1490 mm.
Steel plates are laid in the upper belt of the beams, to which girders or coating panels are attached by welding. Embedded devices are also installed on the lower belt and wall to secure the paths of overhead transport. The supporting parts of the beams have steel sheets with cutouts for attaching them to the columns.
Reinforced concrete trusses are designed to cover industrial buildings with spans of 18, 24, 30 m, but in some cases they can cover spans of 36 m or more.
Depending on the construction conditions, the possibility of transportation and the manufacturing method, the trusses can be solid or divided into semi-trusses or into separate blocks up to 6 m long.
Reinforced concrete trusses are more economical than steel structures in terms of metal consumption, but they are much heavier, which complicates transportation and complicates installation work. The geometric scheme of the farm determines the outline of its upper and lower chords, as well as the location of the braces and racks.
Currently, the following types of reinforced concrete trusses used in industrial construction are produced: segmented, arched, triangular, trapezoidal and parallel belts. For the manufacture of trusses, concrete of high grades 300 - 500 is used with prestressing of the reinforcement in the lower tensioned chords. Braces in lattice trusses greatly complicate the use of the inter-truss space during the installation of utilities and air ducts. Therefore, it is more expedient to use Virendel's braced trusses with parallel belts or arched ones. Triangular and trapezoidal trusses are used less frequently.
Reinforced concrete roof trusses are usually installed in increments of 6 or 12 m. In the case of columns in industrial buildings with a pitch of 12 - 24 m, it is not advisable to increase the pitch of roof trusses to more than 6 m if it is necessary to install suspended ceilings, as well as when attaching lifting and transport equipment (cats, hoists, overhead cranes, stacker cranes) to the lower chord of the farm. In this case, truss structures are installed along the columns along the industrial building, on which truss trusses or beams are supported.
Segment trusses for covering industrial buildings with spans of 18, 24, 30 m and a truss spacing of 6 and 12 m are detailed in albums of the PK-01-129/68 series. Issue I contains design materials, and issues II, III and IV contain working drawings. The indicated series was approved by the USSR State Construction Committee on March 24, 1969. (Resolution No. 32).
Bezraskosny prestressed reinforced concrete trusses with a span of 18 and 24 m with a step of 6 and 12 m are designed for covering industrial buildings with a pitched roof, series 1.463 - 3. In issue I of this series, all design materials are given, and in issues II, III, IV and V - working drawings. Decree No. 93 of August 4, 1969 Gosstroy of the USSR approved the series 1.463 - 3 with the entry into force on October 1, 1969.
Spatial rigidity and invariability of the coating system with reinforced concrete trusses is provided by welding the decks to the steel embedded elements in the upper chords of the trusses, as a result of which a hard disk is created in the coating plane.
The trusses are fastened to the columns and to the sub-rafter structures with anchor bolts, followed by welding of embedded supporting parts.
The fencing of the coating structure is performed depending on the operating mode of the industrial building, therefore they are designed unventilated and ventilated.
Walls and partitions
Walls made of reinforced concrete and aerated concrete panels are highly industrial, improve the quality and reduce the mass of buildings, their labor intensity is 30-40% less than that of brick walls. For industrial heated buildings, single-layer, two-layer and three-layer panels are produced. The length of the panels is 6 and 12 m, the height of the main types of panels is 1.2 and 1.8 m, their thickness in order to unify the forms of steel formwork is 200, 240 and 300 mm. If necessary, additional panels are made with a height of 0.9 and 1.5 m. Wall panels with a length of 3 are used to fill the piers; 1.5; 0.75 m
The length of the walls of unheated industrial buildings use reinforced concrete ribbed and often ribbed panels 6 and 12 m long, 0.9 high; 1.2; 1.8 and 2.4 m, rib thickness 100 mm (frequently ribbed), 120 mm (ribbed with a column spacing of 6 m) and 300 mm (ribbed for a spacing of 12 m).
Walls made of asbestos-cement sheets should be used in unheated industrial workshops with excessive heat release or in explosive industries. Asbestos-cement wall panels produce two types - asbestos foam and asbestos-wooden.
Asbestos foam panels they are made of flat asbestos-cement sheets in combination with light plate insulation in the form of rigid fireproof or slow-burning foam plastic with an air gap, foam glass, cement fiberboard and other materials. The thickness of the asbestos-cement sheet is 8 mm, and the thickness of the entire panel is 136 mm. The connection of the individual elements of the panel is carried out on glue and screws coated with waterproofing mastic. The panels are mounted on supporting tables made of galvanized sheet steel and attached to the columns in the same way as fastening reinforced concrete panels. Vertical and horizontal seams between the panels are filled with a vapor barrier protected by drains and flashings made of galvanized steel or aluminum.
Asbestos wood panels have a frame made of wooden bars, which is filled with slab insulation and sheathed on both sides with a flat asbestos-cement sheet 8-10 mm thick. Asbestos-cement sheathing is fastened to wooden bars 50 × 100 mm with screws. Such panels have a length of 5980mm, a height of 1185mm, and a thickness of 170mm. The hinged design of asbestos-wooden panels makes it easy to mount them according to the previously considered method.
For unified structures, several types of fastening panels to columns are used.
The structures of light uninsulated sheathing walls made of asbestos-cement corrugated or steel sheets, in comparison with other materials, have a lower weight and cost, high industrialization, and better resistance to dynamic influences. The lower sections of the walls of industrial buildings are subjected to the most intense moisture and mechanical stress, therefore it is recommended to build walls from other more durable materials (brick, panels or blocks) to a height of 2-3 m from the floor.
For wall cladding, asbestos-cement corrugated reinforced profile sheets (VU) are used with a length of 1750 to 2800 mm, a width of 994 mm and a thickness of 8 mm with a wave height of 50 mm. Corrugated sheets of a unified profile (UV-7.5) have a length of 1750 to 3300 mm, a width of 1125 mm, a thickness of 7.5 mm and a wave height of 54 mm.
Asbestos-cement corrugated sheets are hung on half-timbered crossbars and overlapped by 100 mm vertically, and horizontally by 160 mm (width of one wave) with their fastening with hooks in the crest of the wave.
Partitions are designed from fireproof and slow-burning materials. According to their purpose, they are divided into enclosing and separating.
Enclosing partitions are arranged collapsible to a height of 2.2 to 3 m (not reaching the ceiling) for fencing the premises of workshop offices, tool stores, intermediate warehouses and other auxiliary purposes. Reinforced concrete partitions are made of solid section from lightweight concrete (expanded concrete, gypsum concrete, etc.) and from heavy reinforced concrete. Panel partitions are 6 m long, 1.2 and 1.8 m high, with a thickness of 70 to 120 mm.
In industrial buildings, where fire resistance requirements are not imposed and there are no vibration loads, partitions made of profile glass are used using channel or box section glass profiles.
Dividing partitions (solid for the entire height of the workshop) completely isolate rooms with various production processes and separate hazardous industries, preventing the passage of gases, moisture, heat, dust and noise. Such partitions are made of bricks, blocks, reinforced concrete and cellular concrete panels 6 m long, 1.2 and 1.8 m high and 70-80 mm thick. With a higher height of the partitions, half-timbered columns (reinforced concrete or steel) with separate foundations and a step of 6 m are used for their stability. The upper part of the trunk of half-timbered columns is hinged to trusses or roof beams. The length of half-timbered reinforced concrete columns is 0.1-0.5 m less than the main ones.
Windows and lights
Constructive solutions for filling window openings in industrial buildings depend on the characteristics of the production technology, temperature and humidity conditions and economic considerations. At present, the filling of window openings is designed with reinforced concrete, metal and wooden sashes, and the fencing of industrial buildings is also used with solid translucent panels made of glass-reinforced concrete, fiberglass and fiberglass.
Reinforced concrete bindings it is advisable to use in workshops with high and high air humidity, they are fire resistant, not subject to decay and corrosion, less metal-intensive compared to steel window structures and cheaper to operate. Reinforced concrete bindings are completed without window boxes of the required width and height of eight standard sizes: the height of the first four is 1085 mm, the other four are 1185 mm, and their width for types is 1490, 1990, 2985 and 3985 mm.
Steel bindings used from special rolled profiles in hot shops, as well as in buildings with normal temperature and humidity conditions. They can also be used in buildings with high humidity.
The design dimensions of steel bindings are taken in width 1392 and 1860 mm with a height of 1176 and 2352 mm. Structurally, they are made of special hot-rolled profiles of six types: corners 25 × 35 × 3.3 mm, tauriks 35 mm high and elements of a complex profile. With a significant width and height of window openings (more than 7.2 m), against the action of wind pressure, wind crossbars (horizontal impost) and racks (vertical impost) are provided, which are made of rolling I-beams, channels and corners.
Wooden bindings used in buildings with normal temperature and humidity conditions. Filling window openings and stained-glass windows with wooden bindings is carried out from boxes and sashes. Boxes with bindings are installed in window openings in one or several tiers and fixed with steel ruffs to wooden plugs in the walls. The gaps between the wall and the box are caulked with tow soaked in gypsum mortar. The openings are filled with window blocks with nominal widths of 1461, 2966, 4490, 1445, 2693.2943 mm and heights of 1164, 1764, 1182, 1782 mm. Compared with bindings made of reinforced concrete or steel, wooden bindings are easy to manufacture, have a lower mass, relatively low construction cost, but they are less durable due to the fact that they are prone to rotting, warping and burning.
Lanterns of industrial buildings according to their purpose, they are divided into light, light-aeration and aeration.
With a significant width of industrial buildings (more than 30 m), it is impossible to provide normal natural illumination of the middle working area due to windows or translucent fences in the outer walls. Therefore, in the coatings (roofs) of these buildings, special openings are designed, which are closed with glazed superstructures - lanterns.
The main material for the manufacture of the frame of the supporting lantern-superstructure is steel or reinforced concrete.
