The metal frame, as many people know, is the main structure of frame-panel buildings. It includes a wide variety of structural elements: beams, trusses, half-timbers, spacers and others. In this review we will look at such structural elements as connections.
Metal bonds are intended for the overall stability of the metal frame in the longitudinal and transverse directions, so their importance is quite high. They counteract the main horizontal load on the frame coming from the wind. The greatest effect here is noticeable when using anti-corrosion materials. What factors and materials need to be taken into account? Siding series "Mitten" and all types of siding from the manufacturer. Fiberglass septic tanks are also important for sewerage in the residential sector or country house, where repairs and improvement are provided. Thanks to them you can achieve positive results. And, of course, important foundation work, preceded by land activities. Which ones should I highlight? Drilling water wells, water treatment and water supply all year round- all this is relevant for an industrial building. However, any real estate objects are interesting. The fashion for real estate allows you to buy an apartment in a new building under convenient conditions. What is the reason for this? Huge selection. New buildings in Moscow from developers. No commission.
There are three types of connections in a metal frame: cross, corner and portal. Today, such products are easy to purchase not only from industrial manufacturing enterprises; equipment of the Eurostandard brand stands out especially. These products are also available on the Internet. According to experts, the cost of creating a construction online store is low, so hardware It's very profitable to buy there. An energy audit will help to estimate the cost, regardless of the calculations.
Cross ties represent the classic and simplest option, when the elements of the ties intersect and are attached to each other in the middle of the length. Such technologies, as professionals note, are often used during installation utility rooms and structures. What can be noted? Cabins and containers with dry closets. Toilet cabins, according to experts, have a wide range. Currently they are very popular. As practice shows, it is only necessary here. Durable installation metal doors with the existing modernization in 4 hours it will be an excellent technological solution for these structures. This is also relevant for the facade. Hurry up to buy with a rational approach facade thermal panels with clinker and light tiles at a special price! Order a car for this. Forward! A car loan is almost like buying a car. Lawyer consulting are also appropriate here.
Corner braces are usually used for small spans and are arranged in a row of several parts. They are smaller in height than cross-links. Of course, it is recommended to use insulating materials here. Today this is not a problem. Just look at the advertising applications of some companies that require you to buy “technological” insulation on favorable terms - only with best filling! And this, according to experts, the right approach to construction.
Portal connections are the largest in terms of working area. They have a U-shaped appearance and find their application in those spans metal frame where window or door openings or furniture elements are provided. Find out all the secrets of furniture makers: custom-made kitchens with furniture according to individual orders. Also provided excellent renovation one-room and complex apartment to order.
If we talk about what is used for making connections, then most often it is a corner or a bent square or rectangular profile, less often a channel or an I-beam.
From existing frame most applicable for connections bolted connections, as technologically and structurally the most efficient and convenient for installation.
In accordance with the rules of the metal frame, the connections are located as in longitudinal direction of the structure being designed, and transversely - along its ends. In this case we're talking about about vertical metal bonds. They are used in many systems, even in everyday life. What can you take as an example? Electrical system steam generators and air conditioners - this is a unique combination. This is a very popular modern technological device.
Sometimes the design of a metal frame requires the use of horizontal connections. For the most part, this occurs on a large scale, with long spans and significant heights for typical columns. Horizontal connections here are usually of the cross type and are located in several modules in a row in longitudinal spans between trusses, which are always designed for large-sized metal frames.
As for the designations of metal connections in a metal frame, a thick dash-dotted line is usually used for them.

From the influence of an external load applied to the nodes of the truss, compressive and tensile forces appear in its elements. In this case, the upper belt works for compression, and the lower belt works for tension. Lattice elements depending on character and direction effective load can work in both compression and tension. In this case, compressive forces create a danger of loss of stability of the structure. Loss of stability of the upper chord can occur in two planes: in the plane of the truss and from its plane. In the first case, loss of stability occurs due to buckling between the truss nodes (along the length of the panel). In the second case, loss of stability occurs between points of the belt, secured against displacement in the horizontal direction. The stability of the truss from its plane is significantly less than the stability in its plane, which is obvious due to the fact that the length of one panel is significantly less than the length of the compressed chord.

A separate truss truss is a beam structure with very low lateral stiffness. In order to ensure the spatial rigidity of a structure made from flat trusses, they must be braced with connections that, together with the trusses, form geometrically unchangeable spatial systems, usually lattice parallelepipeds (Fig. below).

In addition to ensuring spatial immutability, the bracing system must ensure the stability of the compressed chords in the direction perpendicular to the planes of the braced trusses (from the plane of the truss), absorb horizontal loads and create conditions for high-quality and convenient installation structures.

Connections for building roof structures are located:

• in the plane of the upper chords of the trusses - horizontal transverse braced trusses 1 and longitudinal elements - spacers 2 between them (Fig. below);
• in the plane of the lower chords of the trusses - horizontal transverse and longitudinal braced trusses 3 and spacers 2 (Fig. below);
• between the trusses - vertical connections 4 (Fig. below).

Coverage links

Horizontal connections in the plane of the upper (compressed) chords of the trusses are required in all cases. They consist of braces and struts, which, together with the belts of the trusses, form horizontal braced trusses with a cross lattice. Horizontal connections are placed between the outermost pairs of trusses at the ends of the building (or at the ends of the temperature compartment), but not less than every 60 m.

To connect the upper chords of intermediate rafter trusses, special spacers are placed above the supports and at the ridge unit when the trusses span up to 30 m; for large spans, intermediate struts are added so that the distance between them does not exceed 12 m. Horizontal connections along the upper chords of the trusses ensure the stability of the compressed chords from the plane of the truss during installation: during this period, the estimated length of such chords is equal to the distance between the spacers. During the operation of the building, the displacement of the upper nodes from the plane of the truss is prevented by the ribs of the roofing slabs or purlins, but only under the condition that they are secured against longitudinal displacements by connections located in the plane of the roof.

Horizontal connections along the lower chords of trusses are installed in buildings with crane equipment.

They consist of transverse and longitudinal braced trusses and struts. In buildings with light and medium duty cranes, operation is often limited only to transverse braced trusses located between the lower chords of adjacent trusses at the ends of the building (or temperature compartment). If the length of the building or compartment is large, then an additional transverse braced truss is installed so that the distance between such trusses does not exceed 60 m. The width of the longitudinal braced truss is usually taken equal to the support panel of the lower chord of the rafter truss.

Horizontal braced trusses absorb horizontal loads from wind and braking (transverse and longitudinal) of cranes.

Rafter trusses have insignificant lateral rigidity, so the installation process without their preliminary mutual fastening is impossible. This function is performed by vertical connections between the trusses, located in the plane of the support posts of the trusses and in the plane of the middle posts (in trusses with a span of up to 30 m) or posts closest to the ridge unit, but not less than every 12 m Most often, vertical connections are designed with a cross lattice, but with a truss pitch of 12 m, a triangular lattice can also be used. The middle posts of the trusses, to which the vertical braces are attached, are designed with a cross section.

Connections between columns.

The system of connections between the columns ensures the geometric immutability of the frame and its structure during operation and installation. bearing capacity in the longitudinal direction, as well as the stability of columns from the plane of the transverse frames.

The connections that form HDD, are located in the middle of the building or temperature compartment, taking into account the possibility of columns moving due to thermal deformations of the longitudinal elements.

If you install connections (hard drives) at the ends of the building, then in all longitudinal elements (crane structures, under roof trusses, spacers) large thermal forces F t arise

When the length of a building or temperature block is more than 120 m, two systems of tie blocks are usually installed between the columns.

Limit dimensions between vertical links in meters

Dimensions in brackets are given for buildings operated at design outdoor temperatures t= –40° ¸ –65 °С.

Most simple circuit braces are cross-shaped, it is used for column spacing up to 12 m. Rational angle of inclination of braces, therefore, with a small spacing, but high altitude columns, two cross connections are installed along the height of the lower part of the column.

In the same cases, sometimes additional decoupling of columns from the plane of the frame with spacers is designed.

Vertical connections placed in all rows of the building. With a large pitch of columns in the middle rows, and also in order not to interfere with the transfer of products from bay to bay, connections of portal and semi-portal schemes are designed.

The vertical connections between the columns receive forces from the wind W 1 and W 2 acting on the end of the building and the longitudinal braking of the cranes T pr.

Elements of cross and portal connections work in tension. Due to their high flexibility, compressed rods are excluded from work and are not taken into account in the calculation. The flexibility of tensile tie elements located below the level of crane beams should not exceed 300 for ordinary buildings and 200 for buildings with “special” crane operating modes; for connections above crane beams - 400 and 300, respectively.

Coverage connections.

Connections along the roof (tent) structures or connections between the trusses create the overall spatial rigidity of the frame and provide: stability of the compressed chords of the trusses from their plane, redistribution of local crane loads applied to one of the frames to adjacent frames; ease of installation; specified frame geometry; perception and transmission of some loads to the columns.

Coverage connections are located:

1) in the plane of the upper chords of the trusses - longitudinal elements between them;

2) in the plane of the lower chords of trusses - transverse and longitudinal braced trusses, as well as sometimes longitudinal braces between transverse braced trusses;

3) vertical connections between trusses;

4) communications via lanterns.

Connections in the plane of the upper chords of the trusses.

The elements of the upper chord of the trusses are compressed, so it is necessary to ensure their stability from the plane of the trusses.

Reinforced concrete roofing slabs and purlins can be considered as supports that prevent the upper nodes from moving out of the plane of the truss, provided that they are secured against longitudinal movements by connections located in the plane of the roof. It is advisable to place such ties (transverse trusses) at the ends of the workshop so that they, together with transverse trusses along the lower chords and vertical ties between the trusses, create a spatial block that ensures the rigidity of the coating.

If the building or temperature block is longer, intermediate transverse braced trusses are installed, the distance between which should not exceed 60 m.

To ensure the stability of the upper chord of the truss from its plane within the lantern, where there is no roofing, special spacers are provided; trusses are required in the ridge unit. During the installation process (before installing the covering slabs or purlins), the flexibility of the upper chord from the plane of the truss should be no more than 220. Therefore, if the ridge spacer does not provide this condition, an additional spacer is placed between it and the spacer on the truss support (in the plane of the columns).

Connections in the plane of the lower chords of trusses

In buildings with overhead cranes, it is necessary to ensure horizontal rigidity of the frame both across and along the building.

When operating overhead cranes, forces arise that cause transverse and longitudinal deformations of the workshop frame.

If the lateral rigidity of the frame is insufficient, the cranes may jam during movement and normal operation will be disrupted. Excessive vibrations of the frame create unfavorable conditions for the operation of cranes and the safety of enclosing structures. Therefore, in single-span buildings of great height (H>18 m), in buildings with overhead cranes Q>100 kN, with cranes of heavy and very heavy operating modes with any load capacity, a system of connections along the lower chords of the trusses is required.

Horizontal forces F from overhead cranes act transversely on one flat frame or two or three adjacent ones.

Longitudinal braced trusses provide working together systems of flat frames, as a result of which the transverse deformations of the frame from the action of concentrated force are significantly reduced.

The end frame posts transmit the wind load F W to the nodes of the transverse braced truss.

To avoid vibration of the lower chord of the truss due to the dynamic impact of overhead cranes, the flexibility of the stretched part of the lower chord from the plane of the frame is limited: for cranes with a number of loading cycles of 2 × 10 6 or more - by a value of 250, for other buildings - by a value of 400. To reduce the length of the stretched part of the lower In some cases, belts are equipped with stretchers that secure the lower belt in the lateral direction.

Vertical connections between farms.

These ties connect the trusses together and prevent them from tipping over. They are installed, as a rule, in axes where connections are established along the lower and upper chords of the trusses, forming together with them a rigid block.

In buildings with suspended transport, vertical connections contribute to the redistribution between the trusses of the crane load applied directly to the covering structures. In these cases, as well as to the rafter trusses, an electric crane is attached - beams of significant lifting capacity; vertical connections between the trusses are located in the suspension planes continuously along the entire length of the building.

The structural diagram of the connections depends mainly on the pitch of the trusses.

Ties along the upper chords of trusses

Ties along the lower chords of trusses

For horizontal connections with a truss pitch of 6 m, a cross lattice can be used, the braces of which work only in tension (Fig. a).

IN Lately Tie trusses with a triangular lattice are mainly used (Fig. b). Here, the braces work in both tension and compression, so it is advisable to design them from pipes or bent profiles, which can reduce metal consumption by 30-40%.

With a pitch of trusses of 12 m, the diagonal elements of the ties, even those working only in tension, turn out to be too heavy. Therefore, the bracing system is designed so that the longest element is no more than 12 m, and the diagonals are supported by this element (Fig. c, d).

It is possible to ensure fastening of longitudinal braces without a grid of braces along the upper chord of the trusses, which does not make it possible to use through purlins. In this case, the rigid block includes covering elements (purlins, panels), trusses and often located vertical braces (Fig. e). This solution is currently standard. The connection elements of the tent (covering) are calculated, as a rule, based on flexibility. The maximum flexibility for compressed elements of these connections is 200, for stretched elements - 400, (for cranes with a number of cycles of 2 × 10 6 or more - 300).

A system of structural elements that serve to support the wall fence and absorb wind loads called half-timbered.

Half-timbered structures are installed for loaded walls, as well as for interior walls and partitions.

With self-supporting walls, as well as with panel walls with panel lengths equal to the column spacing, there is no need for half-timbered structures.

With a pitch of external columns of 12 m and wall panels 6 m long intermediate half-timbered posts are installed.

Half-timbering installed in the plane of the longitudinal walls of a building is called longitudinal half-timbering. A half-timbering installed in the plane of the walls at the end of a building is called an end half-timbering.

The end frame consists of vertical racks, which are installed every 6 or 12 m. The upper ends of the racks in the horizontal direction rest on a transverse braced truss at the level of the lower chords of the trusses.

In order not to prevent the deflection of trusses from temporary loads, the support of the half-timbered posts is carried out using sheet hinges, which are thin sheet t=(8 10mm) 150-200mm wide, which easily bends in the vertical direction without interfering with the deflection of the truss; in the horizontal direction it transmits force. Crossbars are attached to the half-timbered posts for window openings; when the height of the racks is high, spacers are placed in the plane of the end wall to reduce their free length.

Walls made of bricks or concrete blocks are designed to be self-supporting, i.e. taking up their entire weight, and only the lateral load from the wind is transferred by the wall to the column or half-timbered post.

Walls made of large-panel reinforced concrete slabs are installed (hung) on ​​tables of columns or half-timbered posts (one table every 3 - 5 slabs in height). In this case, the half-timbered post works in eccentric compression.

To ensure spatial stability metal structures, special steel elements are used - vertical connections between columns. The production association "Remstroymash" offers metal structures self-made for various manufacturing and construction enterprises.

The company's assortment includes:

• Rods.
• Beams.
• Farms.
• Frames and other connection systems.

The main purpose of connections of metal structures

With the help of lightweight structural elements, spatial systems with unique properties are formed:

• bending and lateral torsional rigidity;
• resistance against wind loads and inertial influences.

When assembled, the connecting systems perform the listed functions aimed at increasing resistance against external influences. Wind connections of metal structures give the finished structures additional sail stability during operation. The spatial rigidity and stability of buildings, columns, bridges, trusses, etc. is ensured thanks to the connections installed in horizontal planes in the form of upper and lower belts.

At the same time, special connections of vertical metal structures - diaphragms - are installed at the ends and in the spaces between spans. The resulting system of connections provides the required spatial rigidity of the finished structure.


Transverse connections of spans
a - design of the main connection points; b - cross-link diagram

Types of connections of metal structures

Products differ in manufacturing and assembly methods:

• Welded products.
• Prefabricated (bolt, screw).
• Riveted.
• Combined.

The materials used for the manufacture of connecting metal structures are ferrous and stainless steel. Thanks to the unique technical specifications, stainless steel products do not require additional processing against corrosion.

Vertical connection diagrams:
A cross; B two-tier cross, C - diagonal inclined, D - multi-tiered diagonal inclined

Examples of connections

CONNECTIONS in structures- lightweight structural elements in the form of individual rods or systems (trusses); designed to ensure spatial stability of the main load-bearing systems (trusses, beams, frames, etc.) and individual rods; spatial work of the structure by distributing the load applied to one or more elements over the entire structure; giving the structure the rigidity necessary for normal operating conditions; for the perception in some cases of wind and inertial (for example, from cranes, trains, etc.) loads acting on structures. Communication systems are arranged so that each of them performs several of the listed functions.

To create spatial rigidity and stability of structures consisting of flat elements (trusses, beams), which easily lose stability from their plane, they are connected along the upper and lower chords by horizontal connections. In addition, vertical connections - diaphragms - are installed at the ends, and for large spans and in intermediate sections. As a result, a spatial system is formed that has high rigidity during torsion and bending in the transverse direction. This principle of ensuring spatial rigidity is used in the design of many structures.

In the spans of beam or arch bridges, two main trusses are connected horizontal systems connections along the lower and upper chords of the trusses. These connection systems form horizontal trusses, which, in addition to providing rigidity, take part in the transfer of wind loads to the supports. To obtain the required torsional rigidity, transverse links are installed to ensure the invariability of the cross-section of the bridge beam. In towers of square or polygonal cross-section, horizontal diaphragms are installed for the same purpose. In industrial and public buildings With the help of horizontal and vertical connections, two rafter trusses are connected into a rigid spatial block, to which the remaining roof trusses are connected by purlins or ties (ties). Such a block ensures the rigidity and stability of the entire coating system. The most developed system of connections is the steel frames of one-story industrial buildings.

Systems of horizontal and vertical connections of lattice crossbars of frames (trusses) and lanterns provide the overall rigidity of the tent, secure compressed structural elements (for example, the upper chords of trusses) from loss of stability, and ensure the stability of flat elements during installation and operation. Taking into account the spatial work provided by the connection of the main load-bearing structures bracing systems, when calculating structures, results in a reduction in the weight of structures. For example, taking into account the spatial work of the transverse frames of the frames of one-story industrial buildings results in a reduction in the calculated values ​​of moments in columns by 25-30%. A method for calculating spatial systems of beam bridge spans has been developed. In ordinary cases, connections are not calculated, and their sections are assigned according to the maximum flexibility established by the standards.

The lateral stability of the frame of wooden buildings is achieved by pinching the main pillars in the foundations while pivoting the covering structure with these pillars; application of frame or arched structures with hinged support; creation hard drive coating, which is used in small buildings. The longitudinal stability of the building is ensured by placing (after about 20 m) a special connection in the plane frame walls and the middle row of racks. Wall panels (panels), suitably fastened to frame elements, can also be used as connections.

To ensure the spatial stability of planar load-bearing wooden structures, appropriate connections are installed, which are fundamentally similar to the connections in metal or reinforced concrete structures. In arched and frame structures, in addition to the usual (as in beam trusses) bracing of the compressed upper chord, provision is made for bracing the lower chord, which, as a rule, has under one-sided loads, compressed areas. This bracing is carried out by vertical ties connecting the structures in pairs. In the same way, stability is ensured from the plane of the lower chords in trussed structures. Strips of oblique flooring and roof panels can be used as horizontal connections. Spatial wooden structures no special connections are needed.