Coverage links include vertical links between farms horizontal connections along the upper and lower belts of farms. We arrange connections along the upper chords in order to perceive part of the wind load and prevent the compressed rods of the upper chords from buckling. We arrange transverse truss trusses at the ends and in the middle of the building. We install connections along the lower belts for the perception of wind and crane loads of the longitudinal and transverse directions. A truss connection is a spatial block with adjacent truss trusses attached to it. Adjacent trusses along the upper and lower chords are connected by horizontal truss ties, and along the lattice posts - by vertical truss ties.
The lower truss belts are connected by transverse and longitudinal horizontal ties: the first ones fix vertical ties and stretch marks, thereby reducing the vibration level of the truss belts; the latter serve as supports for the upper ends of the racks of the longitudinal fachwerk and evenly distribute the load on adjacent frames. The upper chords of the trusses are connected by horizontal cross braces in the form of spacers or girders to maintain the designed position of the trusses.
Connections between columns of industrial buildings
Column ties provide lateral stability metal structure building and its spatial immutability. The connections of columns and racks are vertical metal structures and structurally represent struts or disks that form a system of longitudinal frames. Struts connect the columns in horizontal plane. Spacers are longitudinal beam elements. Inside the connections of the columns, the connections of the upper tier and the connections of the lower tier of the columns are distinguished. The connections of the upper tier are located above the crane beams, the connections of the lower tier, respectively, below the beams. Main functional purposes loads of two tiers are the ability to transfer the wind load to the end of the building from the upper tier through the transverse links of the lower tier to the crane beams. Top and bottom ties also help keep the structure from tipping over during installation. The connections of the lower tier also transfer loads from the longitudinal braking of cranes to the crane beams, which ensures the stability of the crane part of the columns. Basically, in the process of erecting the metal structures of the building, the connections of the lower tiers are used.
Communication systems for frames of industrial buildings
Metal ties are used to connect the structural elements of the frame. They perceive the main longitudinal and transverse loads and transfer them to the foundation. The metal ties also distribute loads evenly between the trusses and frame frames to maintain overall stability. Their important purpose is to counteract horizontal loads, i.e. wind loads. Column connections provide transverse stability of the metal structure of the building and its spatial immutability. Inside the connections of the columns, the connections of the upper tier and the connections of the lower tier of the columns are distinguished. The connections of the upper tier are located above the crane beams, the connections of the lower tier, respectively, below the beams. The main functional purposes of the loads of two tiers are the ability to transfer the wind load to the end of the building from the upper tier through the cross braces of the lower tier to the crane beams. Top and bottom ties also help keep the structure from tipping over during installation. The connections of the lower tier also transfer loads from the longitudinal braking of cranes to the crane beams, which ensures the stability of the crane part of the columns. Basically, in the process of erecting the metal structures of the building, the connections of the lower tiers are used. To give spatial rigidity to the structure of a building or structure, metal trusses are also connected by ties. Adjacent trusses along the upper and lower chords are connected by horizontal truss ties, and along the lattice posts - by vertical truss ties. The lower truss belts are connected by transverse and longitudinal horizontal ties: the first ones fix vertical ties and stretch marks, thereby reducing the vibration level of the truss belts; the latter serve as supports for the upper ends of the racks of the longitudinal fachwerk and evenly distribute the load on adjacent frames. Cross ties unite the upper chords of the truss into a single system and become the “closing edge”. The spacers just prevent the displacement of the trusses, and the transverse horizontal trusses of the connection prevent the spacers from moving.
Solid purlins
Solid runs are used with a truss step of not more than 6 m n, depending on the purpose, they have a different design section. Solid runs are made according to split and continuous schemes. Most often, split circuits are used because of their property to simplify installation, however, a continuous circuit also has positive distinctive features, for example, with a continuous scheme, less steel is consumed for the runs themselves.
Runs located on a slope, taking into account the roof with a large slope, always work on bending in two planes. The stability of the purlins is achieved by fixing the roof slabs or by attaching the decking to the purlins, taking into account all the friction forces between them. It is customary to fasten the girders to the truss belts using short corners and bent elements made of sheet steel.
Lattice purlins
Rolled or cold-formed channels are used as runs, with a truss step of more than 6 m - lattice runs. Simple and most lightweight construction The lattice purlin is a bar-trussed purlin with a lattice and a lower belt made of round steel. The disadvantage of such a run is the complexity of the control of welds in the junctions of the lattice rods with the lower chord, as well as the need for careful transportation and installation.
The upper chord of lattice purlins, in case of its high rigidity from the plane of the purlin, should be calculated for the combined action of axial force and bending only in the plane of the purlin, and in the case of low rigidity of the upper chord from the plane of the purlin, it is necessary to calculate the upper chord for the combined action of axial force and bending as in the plane run, and in a plane perpendicular to it. The flexibility of the upper belt of lattice, runs should not exceed 120, and lattice elements - 150. The upper chord of this run consists of two channels, and the lattice elements - from a single bent channel. Usually, the braces are fixed to the upper chord using arc or resistance welding.
Lattice purlins are calculated as trusses with a continuous upper chord, which always works in compression with bending in one or two planes, while other elements experience longitudinal forces.
To ensure spatial stability metal structures, special steel elements- vertical connections between columns. Production Association"Remstroymash" offers metal structures own production for various manufacturing and construction companies.
In the assortment of the enterprise:
- Rods.
- Beams.
- Farms.
- Frames and other connection systems.
The main purpose of the connections of metal structures
With the help of light structural elements, spatial systems are formed that have unique properties:
- stiffness in bending and transverse twisting;
- resistance against wind loads, inertial influences.
During assembly, the binding systems perform the listed functions aimed at increasing the resistance against external influences. Wind connections of metal structures give finished structures additional sailing stability during operation. Spatial rigidity and stability of buildings, columns, bridges, trusses, etc. is ensured due to connections installed in horizontal planes in the form of upper and lower chords.
At the same time, at the ends and in the intervals between spans, special connections metal structures vertical arrangement- diaphragms. The resulting system of connections provides the required spatial rigidity of the finished structure. 
Transverse links of superstructures
a - the design of the main communication nodes; b - diagram of cross-links
Types of connections of metal structures
Products differ in manufacturing and assembly methods:
- Welded products.
- Prefabricated (bolted, screw).
- Riveted.
- Combined.
The materials for the manufacture of binding metal structures are black and stainless steel. Thanks to unique technical specifications, stainless steel products do not require additional anti-corrosion treatment. 
Vertical connection schemes:
A cross; B two-tiered cross, C - diagonal inclined, G - multi-tiered diagonal inclined
Relationship examples
The main elements of the frame are frames. They consist of columns and load-bearing structures of roofs - beams or trusses, long decks, etc. These elements are hinged at nodes using metal embedded parts, anchor bolts and welding. Frames are assembled from standard prefabricated elements. Other frame elements are foundation, strapping and crane beams and truss structures. They ensure the stability of the frames and perceive the loads from the wind acting on the walls of the building and lanterns, as well as loads from cranes.
Composite elements of the frame of one-story industrial buildings
As an example, a single-span building equipped with an overhead crane (Fig. 1).
The frame consists of the following main elements:
- Columns located in increments of W along the building; the main purpose of the columns is to support the runway beams and cover.
- The load-bearing structures of the roof (truss * beams or trusses), which rest directly on the columns (if their pitch coincides with the pitch of the columns) and form with them the transverse frames of the frame.
- If the step of the supporting structures of the coating does not coincide with the step of the columns (for example, 6 and 12 m), the subrafter structures located in the longitudinal planes (also in the form of beams or trusses) supporting intermediate bearing structures coatings located between the columns (Fig. 1b).
- In some (rare) cases, girders are introduced into the framework, based on the supporting structures of the coating and located at distances of 1.5 or 3 m.
- Crane beams supported by columns and carrying overhead crane tracks. In buildings with overhead or floor cranes, crane beams are not needed.
- Foundation beams that rest on column foundations and support the exterior walls of a building.
- Strapping beams supported by columns and supporting individual tiers outer wall(if it does not rest on the foundation beams over its entire height).
- With a distance between the main columns of the frame, in the planes of the outer walls of 12 m or more, as well as at the ends of the building, auxiliary columns (fachwerk) are installed to facilitate the construction of the walls.
Rice. 1. The frame of a one-story single-span building (scheme):
a - with the same pitch of columns and load-bearing structures of the coating; b - with unequal pitch of columns and supporting structures of the coating; 1 - columns; 2 - bearing structures of the coating; 3 - truss structures; 4 - runs; 5 - crane beams; 6 - foundation beams; 7 - strapping beams; c - longitudinal connections of the columns; 9 - longitudinal vertical connections of the coating; 10 - transverse horizontal connections of the coating; 11 - longitudinal horizontal connections of the coating.
In steel frames, strapping beams are also referred to as fachwerk (Fig. 2, a). The frame as a whole must work reliably and stably under the action of crane, wind and other loads.
Rice. 2 half-timbered schemes
a - fachwerk of the longitudinal wall, b - end fachwerk, 1 - main columns, 2 - fachwerk columns, 3 - fachwerk crossbar, 4 - roof truss
Vertical loads P from overhead crane(Fig. 3), transmitted through crane beams to columns with large eccentricity, cause eccentric compression of those columns against which it is located in this moment crane bridge.
Rice. 3. Scheme of an overhead crane
1 - crane dimension, 2 - trolley, 3 - crane bridge, 4 - hook, 5 - crane wheel; 6 - crane rail; 7 - crane beam; 8 - column
The braking of the overhead crane trolley during its movement along the crane bridge (across the span) creates horizontal transverse braking forces T1 acting on the same columns.
The braking of the overhead crane as a whole during its movement along the span creates longitudinal braking forces T2 acting along the rows of columns. With a lifting capacity of overhead cranes reaching 650 tons and above, the loads transferred by them to the frame are very large. Suspension cranes move along tracks suspended from the supporting structures of the pavement, and through them they transfer their loads to the columns.
Wind loads at different wind directions can act on the frame both in transverse and longitudinal directions.
To ensure the stability of individual elements of the frame during its installation and their joint spatial work when exposed to various loads on the frame, connections are introduced into the structure of the frame.
The main types of connections of the frame of one-story buildings
1. Longitudinal connections columns, ensuring their stability and joint work in the longitudinal direction during the longitudinal braking of the crane and the longitudinal action of the wind, are installed at the end or in the middle of the length of the frame.
The stability of the remaining columns in the longitudinal plane is achieved by attaching them to the tie columns with horizontal longitudinal frame elements (crane beams, strapping beams or special spacers).
Relationships of this type can be different scheme depending on the requirements for the designed building. The simplest are cross connections (Fig. 4, a). In cases where they interfere with the installation of equipment or cut into the passageway (Fig. 4, b), they are replaced by portal connections.
In craneless buildings of small height, such connections are not needed. The operation of columns in the transverse direction in all cases is ensured by their large cross-sectional dimensions in this direction and by their rigid fastening to the foundations.
Fig.4. Scheme of vertical connections by columns. 1 - columns, 2 - cover, 3 - connections, 4 - passage
2. Longitudinal vertical ties of the coating, ensuring the stability of the vertical position of the supporting structures (trusses) of the coating on the columns, since their attachment to the columns is considered to be hinged, are located at the ends of the frame. The stability of the remaining trusses is achieved by attaching them to the truss trusses with horizontal braces.
3. Cross horizontal connections, which ensure the stability of the upper compressed belt of trusses against buckling, are located at the ends of the frame and are formed by combining the upper belts of two adjacent trusses into a single structure, rigid in the horizontal plane. The stability of the upper chords of the remaining trusses is achieved by attaching them to the truss trusses in the plane of the upper chord using spacers (or enclosing elements of the coating).
4. Longitudinal horizontal ties of the coating located along the outer walls at the level of the lower truss belt.
All three types of pavement ties are intended to combine separate flat load-bearing pavement elements that are rigid only in vertical plane, into a single unchanging spatial structure that perceives local horizontal loads from cranes, wind loads and distributes them between the frame columns.
The frames of one-story industrial buildings are most often erected from precast concrete, steel structures are allowed only in the presence of particularly large loads, spans or other conditions that make the use of reinforced concrete impractical. Steel consumption in reinforced concrete structures is less than in steel ones: in columns - 2.5-3 times; in covering farms - 2-2.5 times. Types of industrial buildings on one floor.
However, the cost of steel and reinforced concrete structures of the same purpose differs slightly and at present the frames are made mainly of steel.
The complex of bonds described above is found in the most complete and clear form in steel frames, individual elements which have a particularly low rigidity. More massive elements of reinforced concrete frames also have greater rigidity. Therefore, in reinforced concrete frames certain types links may be missing. For example, in a building without skylights, with load-bearing structures, roofing in the form of beams and flooring from large-panel slabs, no connections are made in the coating.
In monolithic reinforced concrete frames (which are very rare in domestic practice), the rigid connection of the frame elements at the nodes and the large massiveness of the elements make all types of connections unnecessary.
The connections are most often made of metal - from rolled profiles. Reinforced concrete ties are also found in reinforced concrete frames, mainly in the form of spacers.
The frame of a multi-span building differs from the frame of a single-span building primarily in the presence of internal middle columns that support the roof and crane beams. Foundation beams along the inner rows of columns are installed only for support internal walls, and strapping - with their high height. Connections are designed according to the same principles as in single-span buildings.
With seasonal fluctuations in temperature, frame structures experience temperature deformations, which, with a large frame length and a significant temperature difference, can be very significant. For example, with a frame length of 100 m, a linear expansion coefficient α = 0.00001 and a temperature difference of 50° (from +20° in summer to -30° in winter), i.e. for structures located on outdoors, the deformation is 100 0.00001 50 = 0.05 m - 5 cm.
free deformation horizontal elements the frame is prevented by columns rigidly fixed to the foundations.
In order to avoid the appearance of significant stresses in the structures from this cause, the frame is divided in the above-ground part by expansion joints into separate independent blocks.
The distances between the expansion joints of the frame along the length and width of the building are chosen so that it is possible to disregard the forces arising in the frame elements from climatic temperature fluctuations.
Maximum distances between expansion joints for frames made of various materials installed by SNiP within the range of 30 m (open monolithic reinforced concrete structures) up to 150 m (steel frame of heated buildings).
The temperature seam, the plane of which is located perpendicular to the spans of the building, is called transverse, the seam separating two adjacent spans is called longitudinal.
The design of expansion joints is different. Transverse seams are always carried out by installing paired columns, longitudinal seams are made both by installing paired columns (Fig. 5, a) and by installing movable supports (Fig. 5, b), which provide independent deformation of the coating structures of neighboring, temperature blocks. In frames separated by expansion joints into separate blocks, connections are established in each block, as in an independent frame.
Fig.5. Longitudinal expansion joint options
a - with two columns, b - with a movable support, 1 - beams, 2 - table, 3 - column, 4 - skating rink
The frame also includes the supporting structures of the work sites, which are necessary inside the main volume of the building (if they are connected with the main structures of the building).
The structures of the working platforms consist of columns and ceilings based on them. Depending on the technological requirements work platforms can be located on one or more levels (Fig. 6).
Rice. 6. Multi-tiered work platform.
Thus, in the construction of one-story and multi-story industrial buildings, as a rule, frame system. The frame allows the best way to organize a rational layout of an industrial building (to obtain large-span spaces free from supports) and is most suitable for absorbing significant dynamic and static loads that an industrial building is subject to during operation.
Video - phased assembly of metal structures
1. horizontal cross braces along the lower truss chords are placed at the ends of the temperature block with a column spacing of the outer and middle rows of 12 m. With a block length of more than 144 m, they are additionally arranged in the middle of the block. Formed by combining the lower belts of 2 adjacent roof trusses using a grid. As a result, they perform joint functions: they perceive from the racks of the end half-timbered wind load and transfer it to the connections between the columns and further to the foundation, and also prevent the movement of vertical connections and stretching between the lower chords of the trusses. Spacers between the lower truss chords - secure these chords from displacement, thereby reducing the estimated length from the truss plane, reduces vibrations of the lower truss chords.
2. horizontal longitudinal ties along the lower chords of trusses serve as supports for the upper ends of the racks of the longitudinal fachwerk; under the action of crane loads, adjacent frames are involved in the work, reducing transverse deformations and avoiding jamming of overhead cranes. These connections are obligatory in single-span buildings of great height, with heavy overhead cranes, in the presence of longitudinal fachwerk. Spacers provide the design position of the trusses during installation, limit the flexibility of the trusses from their plane. The role of spacers is performed by runs that are fixed from displacement.
3. horizontal cross braces along the upper chords of trusses in terms of structures and layouts, they are similar to the connections along the lower chords. They serve to prevent the displacement of struts along the upper chords of the trusses. They can be abandoned if vertical ties are installed between adjacent truss trusses of the block and through them the struts will be fastened to the cross braces along the lower chords of the trusses.
4. 4. vertical connections between supports of trusses or beams put only in buildings with flat roof, and in buildings without truss structures they are placed in each row of columns, and with truss structures - only in the extreme rows of columns at a step of 6 m. They are placed no more than one step later. With a temperature block length of 60-72 m, for each row of columns there should be no more than 5 of them at a step of 6 m and no more than 3 at a step of 12 m. In the presence of these connections, spacers are placed on top of the columns.
United modular system in construction
Typification in construction is carried out on the basis of the Unified Modular System. These are the rules by which the sizes of buildings and structures are assigned and coordinated with each other.
Dimensions according to EMC rules are assigned according to the base of the module. The main module (M) is 100 mm. When choosing sizes for buildings, structures, an enlarged module is used: 6000 mm = 60M; 7200 mm = 72M. The fractional module is used to designate sections of structures: 50 mm = ½M.
EMC is a single modular system, which is a set of rules that coordinate the dimensions of space-planning and structural parts construction sites and dimensions of prefabricated modules and equipment.
MKRS - modular coordination of dimensions in construction. The standard, the use of which in the design of buildings allows you to unify the dimensions building structures and space-planning dimensions of buildings. This standard assumes the unification of the following parameters: floor heights (H0), steps (B0) and spans (L0).
EMC is based on the principle of multiplicity of dimensions. The size of any of the elements of the building must be a multiple of a value called the module. In the EMC system, a module of 100 millimeters is adopted, which in technical documentation denoted by the letter M. Accordingly, the dimensions of large structural elements will be designated as derived from the module. For example, 6000mm is 60M, 3000mm is 30M and so on. Small elements are designated as fractional from the module: 50 mm - ½ M, 20 mm - 1/5 M.
15 basis for the planning of industrial buildings
Industrial buildings are divided into two types of planning:
separate (detached) buildings, the layout of which, although it gives constructive simplicity and high level industrialization in the production of buildings, however, it has such disadvantages as a large building area, a large length of engineering and transport networks, the impossibility of organizing mass production, and significant energy costs for space heating;
solid (interlocked) buildings, which represent
multi-span buildings large area(up to 30...35 thousand sq.m). technological equipment, reducing the area of the plant by 30...40%, reducing the cost of construction by 10...15%, reducing the length of engineering and transport communications, reducing the perimeter of the outer walls by 50% with a reduction in operating costs. However, the disadvantages of solid buildings are the rise in the cost of natural lighting, difficult drainage from coatings, and the complication of the movement of vehicles and personnel. It is advisable to block workshops in cases where adjacent industries do not need to be separated by capital walls and at the same time the conditions of production technology and labor of workers do not worsen.
The layout of industrial buildings is accompanied by zoning within the volume of industrial buildings, premises, plots and zones, allocated according to the signs of the same type of technology, the level of industrial hazard, the level of fire and explosion hazards, the direction of transport and human flows, according to the prospects for expansion and re-equipment.
Choice of floors industrial building affect:
production technology;
climatic conditions of the region;
building requirements (urban, peripheral);
the nature of the allotted area (free, cramped relief);
advantages and disadvantages.
One-story buildings have the following advantages:
simple space-planning solution;
propensity for unification and blocking;
reduction in the cost of 1 sq. m by 10% compared to the cost multi-storey buildings;
facilitating the installation of technological equipment;
simplification of the ways of cargo flows and the use of horizontal transport;
uniform illumination of workplaces with natural light through the lanterns;
ensuring natural air exchange.
The disadvantages of one-story buildings are:
large building area;
large length of engineering and transport networks;
increased spending on landscaping;
a large area of external enclosing structures and, as a result, significant heating costs.
Multi-storey buildings are devoid of most of the shortcomings of single-storey buildings and are rational in use, especially at loads up to 10 kN/sq. m.
The main disadvantages of multi-storey buildings include:
the need for vertical transport;
increased cost;
width limitation if natural lighting is needed (width not more than 24 m);
high specific gravity utility rooms.
temperature block.
To limit the forces arising in the structures from temperature differences, the building is cut by expansion joints into compartments (temperature blocks), the dimensions of which depend on the material of the frame, the thermal regime of the building and climatic conditions construction area. These dimensions are determined by calculation.
Longitudinal and transverse temperature expansion joints indicated in blue and red, respectively.
For a reinforced concrete and mixed frame, the length of the temperature block A ≤ 72 m - if there are continuous elements along the length of the building (for example, crane beams). For craneless buildings, the norms allow increasing A to 144 m. However, if the building has suspended equipment (monorail, etc.), the length of the temperature block should not exceed 72 m. It is allowed to increase A to 280 m, but the height of the building should not exceed 8.4 m.
The width of the temperature block B should not exceed 90-96 m.
In special climatic regions and for unheated rooms, the length of the temperature block A is assigned according to instructions tied to local climatic conditions.
In steel frames of buildings with overhead cranes A ≤ 120 m, in craneless buildings A ≤ 240 m, and B ≤ 210 m. exceed 96 m.
Temperature joint
First of all, it is necessary to understand the concept of an expansion joint and the function it performs. The temperature joint is a through slot in the wall of the building or its roofing slab. For each building, several such cuts are made, as a result of which it is divided into several independent blocks. As a result, each of these blocks can be freely deformed, which does not lead to the formation of cracks in the slabs. The fact is that expansion joints are a kind of artificial cracks, which are designed in such a way as not to create any problems during the operation of the building. The width of the expansion joint determines the value within which it is possible to change the linear dimensions of each of the blocks. It would be more accurate to say the opposite, the width of the expansion joint should be selected based on the possible magnitude of the deformations.
The design of expansion joints is one of the most important stages in the construction of a building. In this case, it is necessary, first of all, to determine the length of each of the blocks into which the walls are divided by expansion joints, as well as the width of the joints. Any expansion joints, including temperature ones, are arranged in those areas where the stresses caused by the corresponding deformations are concentrated. In this case, the length of the blocks should be such that each of them can be subjected to thermal deformations without loss of structural rigidity and without destruction. Therefore, to determine this parameter, a number of factors are taken into account, including the type wall material, design features, average temperatures in summer and winter period characteristic of the region of construction.
An important feature expansion joints is that they are arranged only at the height of the above-ground part of the building, while some other expansion joints, such as sedimentary joints, are arranged over the entire height of the building to the base of the foundation. This is due to the fact that the foundation of the building is much less susceptible to temperature changes and does not need special protection.
Farm Links are designed to:
- creation (associatively with the connections along the columns) of the overall spatial rigidity and geometric invariability of the frame of the BHT;
- ensuring the stability of the compressed elements of the trusses from the plane of the crossbar by reducing their estimated length;
– perception of horizontal loads on individual frames ( transverse braking of crane trucks) and their redistribution to the entire system of flat frame frames;
- perception and (ashamed of the connections along the columns) transmission to the foundations of some longitudinal horizontal loads on the structures of the turbine hall (wind acting on the end of the building and crane loads);
– ensuring ease of installation of trusses.
Farm links are divided into:
─ horizontal;
─ vertical.
Horizontal connections are placed in the plane of the upper and lower truss chords.
Horizontal links located across the building are called transverse, and along - longitudinal.
Connections along the upper belts of farms
Links along the lower belts of trusses
Vertical ties across trusses
Cross horizontal connections in the plane of the upper and lower chords of the trusses, together with the vertical connections between the trusses, they are installed along the ends of the building and in its middle part, where the vertical connections along the columns are located.
They create rigid spatial bars at the ends of the building and in its middle part.
Spatial beams at the ends of the building serve to perceive the wind load acting on the end fachwerk and transfer it to connections along the columns, crane beams and further to the foundation.
Otherwise they are called wind connections.
2. The elements of the upper chord of the truss trusses are compressed and may lose stability out of the plane of the trusses.
The transverse braces along the upper truss chords, together with the spacers, secure the truss nodes from moving in the direction of the longitudinal axis of the building and ensure the stability of the upper truss chord out of the truss plane.
Longitudinal connection elements (struts) reduce the estimated length of the upper chord of the trusses, if they themselves are secured from displacement by a rigid spatial tie bar.
In non-purlin coatings, the edges of the panels secure the truss nodes from displacement. In purlin coverages, truss nodes from displacement secure the purlins themselves, if they are fixed in a horizontal braced truss.
During installation, the upper chords of the trusses are fixed with spacers at three or more points. It depends on the flexibility of the truss during installation. If the flexibility of the elements of the upper chord of the truss does not exceed 220 , spacers are placed along the edges and in the middle of the span. If a 220 , then spacers are placed more often.
In a non-purlin coating, this fastening is carried out with the help of additional spacers, and in coatings with purlins, the purlins themselves are the struts.
Spacers are also placed in the lower chord to reduce the calculated length of the elements of the lower chord.
Longitudinal horizontal ties along the lower chords trusses are designed to redistribute the horizontal transverse crane load from the braking of the trolley on the crane bridge. This load acts on a separate frame and, in the absence of ties, causes significant transverse movements.
Transverse displacement of the frame from the action of the crane load:
a) in the absence of longitudinal ties along the lower chords of trusses;
b) in the presence of longitudinal ties along the lower chords of trusses
Longitudinal horizontal connections involve adjacent frames in spatial work, as a result of which the transverse displacement of the frame is significantly reduced.
The transverse displacement of the frame also depends on the design of the roof. Roofing made of reinforced concrete panels is considered rigid. Roofing from profiled flooring along the runs, then it cannot take horizontal loads to a large extent. Such a roof is considered not rigid.
Longitudinal ties along the lower chords of trusses are placed in the extreme panels of trusses along the entire building. In the machine rooms of power plants, longitudinal ties are placed only in the first panels of the lower chords of trusses adjacent to the columns of row A. C opposite side farms do not put longitudinal connections, because the force of transverse braking of the crane is taken up by a rigid deaerator stack.
In buildings span 30 m to secure the lower belt from longitudinal movements, spacers are installed in the middle part of the span. These braces reduce the effective length and hence the flexibility of the lower chord of the trusses.
Vertical ties across trusses located between farms. They are made in the form of independent mounting elements (trusses) and are installed together with cross braces along the upper and lower chords of the trusses.
According to the width of the span, vertical truss trusses are located along the supporting nodes of the trusses and in the plane of the vertical racks of the trusses. The distance between vertical ties on trusses from 6 before 15 m.
Vertical connections between trusses serve to eliminate shear deformations of pavement elements in the longitudinal direction.
Loading...