Calculation of a farm from a profile pipe. How to weld trusses from a profile pipe

Using a profile pipe for mounting trusses, you can create structures designed for high loads. Light metal structures are suitable for the construction of structures, the arrangement of frames for chimneys, the installation of roof supports and canopies. The type and dimensions of farms are determined depending on the specifics of use, whether it be household or industrial area. It is important to correctly calculate the farm from profile pipe Otherwise, the design may not withstand the operational loads.

Canopy of arched trusses

Pipe-rolled metal trusses are labor-intensive to install, but they are more economical and lighter than solid beam structures. A profiled pipe, which is made from a round pipe by hot or cold working, in cross section has the form of a rectangle, square, polyhedron, oval, semi-oval or flat-oval shape. It is most convenient to mount trusses from square pipes.

The farm is a metal structure, which includes the upper and lower belts, as well as the grate between them. The lattice elements are:

• stand - located perpendicular to the axis;
• brace (strut) - installed at an angle to the axis;
• sprengel (auxiliary strut).

Structural elements of a metal truss

Trusses are primarily designed to cover spans. Due to the stiffening ribs, they do not deform even when using long structures on structures with large spans.

The manufacture of metal trusses is carried out on the ground or in production conditions. Elements from shaped pipes are usually fastened together using a welding machine or riveting; scarves and paired materials can be used. To mount the frame of the canopy, visor, roof of a capital building, the finished trusses are lifted and attached to the upper trim according to the markings.

Used to cover spans various options metal farms. The design can be:

Triangular trusses made of a profile pipe are used as rafters, including for mounting a simple shed canopy. Metal structures in the form of arches are popular due to their aesthetic appearance. But arched structures require the most accurate calculations, since the load on the profile must be distributed evenly.

Triangular truss for single slope construction

Design features

The choice of the design of canopy trusses from a profile pipe, canopies, truss systems under the roof depends on the calculated operational loads. The number of belts differ:

• supports, the components of which form one plane;
• suspended structures, which include the upper and lower belt.

In construction, trusses with various contours can be used:

• with a parallel belt (the simplest and most economical option, assembled from identical elements);
• single-pitched triangular (each support node is characterized by increased rigidity, due to which the structure withstands serious external loads, the material consumption of trusses is small);
• polygonal (withstand loads from heavy flooring, but are difficult to install);
• trapezoidal (similar in characteristics to polygonal trusses, but this option is simpler in design);
• gable triangular (used for constructing a roof with steep slopes, characterized by high material consumption, there is a lot of waste during installation);
• segmental (suitable for structures with a translucent polycarbonate roof, installation is complicated due to the need to make arched elements with ideal geometry for even distribution of loads).

Outlines of truss belts

In accordance with the angle of inclination, typical farms are divided into the following types:

Calculation basics

Before calculating the farm, it is necessary to choose a suitable roof configuration, taking into account the dimensions of the structure, the optimal number and angle of inclination of the slopes. You should also determine which belt contour is suitable for the selected roof option - this takes into account all operational loads on the roof, including precipitation, wind load, the weight of people performing work on the arrangement and maintenance of a canopy from a profile pipe or roof, installation and repair of equipment on the roof.

To calculate a truss from a profile pipe, it is necessary to determine the length and height of the metal structure. The length corresponds to the distance that the structure should cover, while the height depends on the designed angle of inclination of the slope and the selected contour of the metal structure.

The calculation of the canopy ultimately boils down to determining the optimal gaps between the nodes of the farm. To do this, it is required to calculate the load on the metal structure, to calculate the profile pipe.

Incorrectly calculated roof frames pose a threat to human life and health, since thin or insufficiently rigid metal structures may not withstand loads and collapse. Therefore, it is recommended to entrust the calculation of a metal truss to professionals familiar with specialized programs.

If it is decided to perform the calculations on your own, you must use the reference data, including the resistance of the pipe to bending, be guided by SNiP. It is difficult to correctly calculate the design without the relevant knowledge, therefore it is recommended to find an example of calculating a typical farm of the desired configuration and substitute the necessary values ​​\u200b\u200binto the formula.

At the design stage, a drawing of a truss from a profile pipe is drawn up. Prepared drawings indicating the dimensions of all elements will simplify and speed up the manufacture of metal structures.

Dimensional Drawing

We calculate the farm from a steel profile pipe

1. The size of the span of the building to be covered is determined, the shape of the roof and the optimal angle of inclination of the slope (or slopes) are selected.
2. Suitable contours of the metal structure belts are selected, taking into account the purpose of the building, the shape and size of the roof, the angle of inclination, and the expected loads.
3. Having calculated the approximate dimensions of the truss, it should be determined whether it is possible to manufacture metal structures in the factory and deliver them to the facility by road, or welding of trusses from a profile pipe will be performed directly on the construction site due to the large length and height of the structures.
4. Next, you need to calculate the dimensions of the panels, based on the indicators of loads during the operation of the roof - constant and periodic.
5. To determine the optimal height of the structure in the middle of the span (H), the following formulas are used, where L is the length of the truss:
   • for parallel, polygonal and trapezoidal belts: H=1/8×L, while the slope of the upper belt should be approximately 1/8×L or 1/12×L;
   • for triangular metal structures: H=1/4×L or H=1/5×L.
6. The angle of installation of the lattice braces is from 35° to 50°, the recommended value is 45°.
7. The next step is to determine the distance between the nodes (usually it corresponds to the width of the panel). If the span length exceeds 36 meters, the calculation of the building lift is required - a back-suppressed bend that acts on the metal structure under loads.
8. Based on measurements and calculations, a scheme is being prepared, according to which trusses will be manufactured from a profile pipe.

Making a structure from a profile pipe To ensure the necessary accuracy of calculations, use a construction calculator - a suitable special program. This way you can compare your own and software calculations in order to avoid a big size discrepancy!

Arched structures: calculation example

In order to weld a truss for a canopy in the form of an arch using a profile pipe, it is necessary to correctly calculate the design. Consider the principles of calculation using the example of a proposed structure with a span between supporting structures (L) of 6 meters, a step between arches of 1.05 meters, a truss height of 1.5 meters - such an arched truss looks aesthetically pleasing and is able to withstand high loads. In this case, the length of the arrow of the lower level of the arched truss is 1.3 meters (f), and the radius of the circle in the lower chord will be 4.1 meters (r). The value of the angle between the radii: a=105.9776°.

Scheme with the dimensions of the arched canopy

For the lower belt, the profile length (mn) is calculated by the formula:

mn is the length of the profile from the lower belt;

π is a constant value (3.14);

R is the radius of the circle;

α is the angle between the radii.

As a result, we get:

The nodes of the structure are located in the sections of the lower belt with a step of 55.1 cm - it is allowed to round the value up to 55 cm to simplify the assembly of the structure, but the parameter should not be increased. The distances between the extreme sections must be calculated individually.

If the span is less than 6 meters, instead of welding complex metal structures, you can use a single or double beam by bending the metal element under the selected radius. In this case, the calculation of arched trusses is not required, but it is important to choose the right cross-section of the material so that the structure can withstand the loads.

Profile pipe for mounting trusses: calculation requirements

In order for finished floor structures, primarily large-sized ones, to withstand the strength test throughout the entire service life, pipe rolling for the manufacture of trusses is selected on the basis of:

• SNiP 07-85 (interaction of snow load and weight of structural elements);
• SNiP P-23-81 (on the principles of working with profiled steel pipes);
• GOST 30245 (correspondence of the section of profile pipes and wall thickness).

Data from these sources will allow you to get acquainted with the types of profile pipes and choose best option taking into account the configuration of the section and the thickness of the walls of the elements, the design features of the truss.

Canopy for a car from a pipe

Farms are recommended to be made of high quality pipe, for arched structures it is desirable to choose alloy steel. In order for metal structures to be resistant to corrosion, the alloy must include a large percentage of carbon. Metal structures made of alloy steel do not need additional protective painting.

Useful tips for installation

Knowing how to make a lattice truss, you can mount a reliable frame under a translucent canopy or roof. It is important to take into account a number of nuances.

• The most durable structures are mounted from a metal profile with a section in the form of a square or rectangle due to the presence of two stiffeners.
• The main components of the metal structure are fastened together using twin corners and tacks.
• When joining the frame parts in the upper belt, it is required to use I-beam versatile corners, while connecting should be on the smaller side.
• The conjugation of the parts of the lower belt is fixed with the installation of equilateral corners.
• When joining the main parts of metal structures of great length, overhead plates are used.

It is important to understand how to weld a truss from a profile pipe if the metal structure needs to be assembled directly at the construction site. If there are no welding skills, it is recommended to invite a welder with professional equipment.

Truss elements welding

Racks of metal structures are mounted at a right angle, braces - at an inclination of 45 °. At the first stage, we cut elements from the profile pipe in accordance with the dimensions indicated on the drawing. We assemble the main structure on the ground, check its geometry. Then we cook the assembled frame, using corners and overlay plates where they are required.

Be sure to check the strength of each weld. The strength and reliability of welded metal structures, their bearing capacity depend on their quality and the accuracy of the location of the elements. The finished trusses are lifted up and attached to the harness, observing the installation step according to the project.

Farms from a profile pipe: manufacturing, how to calculate and weld

Metal supporting roof structure

The truss is a hanging structure, which consists of upper and lower chords, braces and racks, which is part of the common roof truss system of the house. Today it can be made of various materials, but metal structures are becoming increasingly popular.

The truss truss can be made of various materials, but metal structures are becoming increasingly popular.

The construction of a metal roof is carried out according to modern technology, which today is considered optimal for a wide variety of buildings. frame houses made of lightweight metal structures are resistant to various external conditions, they are durable and reliable.

The calculation of such truss systems is carried out using special programs that take into account numerous factors, which makes the entire structure very reliable.

Benefits of using metal trusses

Metal trusses used to be used wherever high structural strength was needed, today the advantage of using just such structures is also used for private construction, and not only during the construction industrial enterprises. Today, metal trusses are in demand, which can be divided into two groups: spatial and flat.

Flat structures are distinguished by the fact that each metal rod is located in only one plane. Spatial structures form bars that perfectly withstand loads from all sides. This is similar to the device of a tower crane, which is resistant to fairly strong, continuous loads during use.

The main elements of a metal truss are the rafter belt and gratings, the belt has a longitudinal force and moment, and the grating is a transverse force. The space that is located between them is called the panel, the free gap between the trusses is the span, the space between the axes of the belts is the height.

Types of metal trusses.

The metal trusses used today can be very different, which greatly distinguishes them from others. They differ in the form of belts, spans, sizes, manufacturing schemes. So, static trusses can be frame, beam, cable-stayed, arched. Beams in this case are distinguished by a more economical consumption of materials, less weight than the rest, they can be used for the manufacture of structures that need resistance to large, constant loads. Arched ones are used to create unusual attractive roof shapes, but during their construction, the expense building materials somewhat enlarged.

In addition, combined schemes are used, polygonal, segmented, triangular, trapezoidal, with parallel belts. All of them are distinguished by high strength, low weight, stability. The high quality of the installation of the truss system is ensured by the fact that any calculation for such a design is carried out using special programs.

As materials for the manufacture of metal trusses, lightweight galvanized metal profiles (the so-called LSTK, that is, light steel thin-walled structures) are used, fastened with self-tapping screws and special bolts, or special steel beams for which welded joints are used.

Features of the calculation of metal structures

Calculating metal roof trusses is a procedure that requires special knowledge. Typically, such calculations are performed by designers using special programs, taking into account numerous factors. This calculation makes metal structures as reliable as possible. When calculating the truss system, it is necessary to take into account the following factors:

• constant loads on the roof (the weight of the roofing material and the truss system itself);
• additional loads (wind, snow, the weight of people who rise to the roof surface for repairs, etc.);
• periodic and special loads (presence of hurricanes, seismic loads, other random factors).

The scheme of snow load on the roof.

Snow load is calculated by the formula: N= Q*k

Wind loads should also be taken into account, which include data on top speed wind in the area, the number of storeys of the building, the design features of the roof, its area.

The exact calculation of metal trusses can only be done by a specialist, you should not try to do it yourself!

Types of metal trusses

1. Universal for industrial buildings: single-pitched and double-pitched. The spans for them are unified, they are taken as multiples of 3 m, they can be 18, 24, 30 meters. The angle of inclination of the braces is usually 45-50°, the overall shape ensures the rigidity of the structure, the ability to withstand heavy loads.
2. Metal trusses with additional trusses are used in non-purlin structures for large-panel reinforced concrete slabs with a width of 1.5 m. This makes it possible to reduce the weight of the truss by 4-6%.
3. Triangular trusses are used for residential buildings when the roof slope is planned to be quite steep.

Rafter metal structure: installation work

Installation of metal roof trusses should be carried out only by professionals. All fastenings are carried out only according to the project. These are bolted and welded fasteners (for various types material). Installation rules depend not only on the type of structure, but also on its specification; with a span of more than 4.5 m, it is recommended to pre-install additional supports for any type of truss.

The choice of coating for depending on the angle of the roof

All metal rafters, or rather their appearance and design, depend largely on the angle of the roof slope. Consider the options for the device truss systems:

1. The slope is 22-30 degrees. When installing a roof with a slope of 22-30 °, you can use coating options such as eternite, iron or slate. Farms at the same time make a triangular shape, their height should be one third of the span length. The weight of such a truss will be relatively small, for supports you can use the outer walls, which are erected at a low height for the attic. If the span is 14-20 m, then each half of the truss should have an even number of panels, the panel length should be 1.5-2.5 m. For the specified span, the optimal number of panels is eight;

For large buildings, where the span is from 20 to 35 meters, it is necessary to use the so-called Polonso trusses, that is, a metal structure that consists of two triangular trusses connected by puffs. This makes it possible to remove the long braces for the middle panels to reduce weight. The upper belt in this case must be divided into 12-16 panels with a length of 2-2.75 meters for each. The calculation for filing the ceiling should take into account the presence of a tightening of 4-6 panels, which is attached to the nodes of the upper belt.

1. Slope 15-22°. With such a roof slope, the calculation of metal trusses provides for a structure height of 1/7 of the span length, while the lower chord is made broken, which makes it possible to reduce weight by 30% compared to a conventional triangular truss. The length of one span should not be more than 20 meters;
2. Slope from 6 to 15°. For roofs with a slight slope, trapezoidal trusses are used with a height of 1/7 to 1/9. In the case when the ceiling is not suspended, you can use braces made in the form of a triangular lattice. The walls of the attic for the installation of such a system must have the proper height, or a roof is designed that has fractures at the supports. In this case, the panels of the lower chord must be equal to the size of the panels of the upper chord. The calculation is carried out taking into account the fact that the length itself should be 1.5-2.5 m, racks are added to all braces. In order for the structure not to be heavy, a lattice is used.

The use of metal for the manufacture of truss systems is not such a novelty. Such structures have been known since the end of the 19th century, although they were used extremely rarely, mainly for the construction of palaces and temples. Today, metal has gained a second life; reliable and very durable buildings, residential buildings, and industrial facilities are made from it.

The calculation of such structures should be carried out only by specialists, for this there are special programs. The fastenings of metal trusses can be different, as well as the material of manufacture: these are welded steel structures, lightweight galvanized, which are fastened with self-tapping screws and bolts. The type of trusses themselves and the dimensions largely depend on what slope of the roof will be made, what loads are expected.

Metal roof truss

Metal roof trusses: roof support structure

Trusses are structural elements that, having perceived the load in the span, transfer it to the supports. Metal roof trusses have the form of a lattice through structure, made of rectangular rods, "assembled" with each other into nodes. The choice of their design for a particular roof determines the location attic floor, roof slope and required span.

Metal roof trusses are mainly made from steel profiles, more often from a corner. For heavier structures, the profile has a T- or I-section, and for hydraulic structures - a round, shaped pipe. Steel truss truss is widely used in structures for covering and overlapping buildings, often with a span width of more than 24 m.

Metal construction

The strength and rigidity of these elements of the supporting structure is provided by their shape. The classic version of a metal truss consists of rods - two parallel and another between them, welded in a zigzag manner. Thanks to this arrangement, even with a relatively small consumption of material, the resistance of the metal structure is increased.

Main structural elements:

• belts, upper and lower, forming a contour;
• lattice assembled from braces and racks.

Nodal connection of elements is performed by direct adjoining one to the other. The lattice rods are fixed to the belts either by welding or by means of shaped elements. In addition to rafters, there can also be rafters. They are used as supports for load-bearing structures and floors, if the distance between the columns exceeds the step of the beams or the columns have an unequal step.

Types: by belts and lattices

They are classified according to the geometry of the belts and the type of lattice.

According to the belt

• with parallel belts - have enough design advantages. The greatest repeatability of parts, associated with equal lengths of rods for chords and gratings, the same scheme of nodes, a minimum number of chord joints, makes it possible to unify designs, which makes it possible to industrialize their production. They are optimal for soft roofs.

• trapezoidal (single-pitched) - in conjunction with columns, it makes it possible to arrange rigid frame assemblies that increase the rigidity of the building. In the middle of the span, there are no long rods on the lattice of these trusses. They do not require large slopes.
• polygonal - suitable for heavy structures used for large spans, while they provide significant savings in steel. The polygonal outline for light options is irrational, since the slight savings are not commensurate with the complexity of the design.

• triangular - they are usually used for steep roofs or, based on the operating conditions of the building or the type of roofing material. Although they are simple in execution, they have certain design flaws, for example, the complexity of a sharp support unit, increased consumption of materials in the manufacture of too long rods in the central part of the lattice. The use of triangular systems is mandatory in some cases, for example, in buildings where it is necessary to ensure, on the one hand, a significant and uniform influx of natural light.

Lattice systems

• triangular - the most effective in the case of parallel belts and a trapezoidal outline, it is possible to use them in a system with a triangular outline;
• diagonal - braces, the longest elements, should be stretched, while the racks, on the contrary, should be compressed. Such a lattice, compared with a triangular one, is more laborious and has a greater consumption of material;
• special - trussed, cross and others.

Calculation of a triangular farm and its features

The calculation takes into account the requirements of SNiP for "Steel structures" and "Loads and impacts". It is possible to correctly calculate truss systems made of metal only if you have special knowledge. This takes into account numerous factors, so designers, as a rule, turn to the help of special programs when calculating.

What underlies the calculations of a triangular truss: an example

Trusses are under the constant influence of loads such as the weight of the roof, lanterns, hanging drainage systems, fans, own weight of the supporting structure and others. The temporary loads include the pressure of wind, snow, the weight of people on the roof, suspended transport.

Special or periodic loads are also taken into account, such as seismic, hurricane, etc.

Fabrication and connection of elements

• Assembly. They are assembled in stages from parts on tacks.

• A bunch of belts is produced using one or two paired corners:

• the upper belts are made of unequal two corners having a tee section, docking is carried out on the smaller sides;
• for the lower belts, respectively, isosceles corners are used.

• If the element is long, use connecting and patch plates. In the case of loads formed within the boundaries of its panels, paired channels are used.
• The angle of installation of the braces is 45°, and the racks are 90°. For their manufacture, isosceles corners are used, fastening the elements by means of plates. The corners in the section are either cruciform or tee.
• Fully welded systems are made using brands.

• Welding. When the assembly on tacks is completed manually or semi-automatically, welding is performed, after which each seam is cleaned.
• Coloring. AT roof structure at the final stage, holes are drilled and coated with anti-corrosion compounds.

Some device rules

The type and design of metal rafters largely depends on the slope of the roof. Consider the relationship between the roof slope and the arrangement of truss systems:

• 6–15° – trapezoidal truss, height 1/7–1/9 of its length. To equip the attic, either its walls must have an appropriate height, or the projected roof must have fractures at the supports. The size of the panels of the lower and upper chords must be the same. To make it easier, use a grid.
• 15–22 ° - the height of the metal structure is equal to 1/7 of the length, the lower belt should be broken - this allows you to reduce weight compared to the usual triangular order of 30%. In this case, one span in length should not exceed 20 m.
• 22–30° – triangular system, height 1/3 of length. Since its weight is relatively small, external walls erected to a small height can serve as a support.

Series 1.263.2-4. Issue 1. Trusses with spans of 18, 21 and 24 m from rolling corners. KM drawings(7.1 MiB, 368 hits)

1.263-2-4.1KM-4 Truss diagrams with node marking. Breakdown of farms into shipping marks

1.263-2-4.1KM-5 Diagrams of the arrangement of trusses with a span of 18 m and connections

1.263-2-4.1KM-6 Diagrams of the arrangement of trusses with a span of 21 m and connections

1.263-2-4.1KM-7 Layout diagrams of trusses with a span of 24 m and ties

1.263-2-4.1KM-8 Scheme of trusses with marking of elements

1.263-2-4.1KM-9 Truss assortment with span L=18 m and H=1.2 m

1.263-2-4.1KM-10 Truss assortment with span L=18 m and H=1.8 m

1.263-2-4.1KM-11 Truss assortment with span L=21 m and H=1.8 m

1.263-2-4.1KM-12 Truss assortment with span L=24 m and H=1.8 m

1.263-2-4.1KM-13 Schemes of vertical connections B-1, B-2

1.263-2-4.1KM-14 Node 1

1.263-2-4.1KM-15 Knot 2.3

1.263-2-4.1KM-16 Node 4

1.263-2-4.1KM-17 Knot 5

1.263-2-4.1KM-18 Node 6

1.263-2-4.1KM-19 Node 7

1.263-2-4.1KM-20 Knot 8

1.263-2-4.1KM-21 Knot 9

1.263-2-4.1KM-22 Knot 10

1.263-2-4.1KM-23 Node 11

1.263-2-4.1KM-24 Knot 12-15

1.263-2-4.1KM-25 Instructions for the calculation of welded joints of truss units

1.263-2-4.1KM-26 Marking holes along the upper chords of trusses for fastening ties

1.263-2-4.1KM-27 Layout of reinforced concrete slabs and details of their welding to truss belts

1.263-2-4.1KM-28 Specification of steel trusses with a span of 18 m

1.263-2-4.1KM-29 Specification for steel trusses with a span of 21 m

1.263-2-4.1KM-30 Specification of steel trusses with a span of 24 m

Approved: State Committee for Civil Engineering and Architecture under Gosstroy of the USSR 10/13/1982

Series 1.263.2-4. Issue 2. Farms with a span of 27, 30 and 36 m from rolling corners. KM drawings(8.8 MiB, 129 hits)

1.263-2-4.2KM-2 Truss schemes with node marking. Breakdown of farms into shipping marks

1.263-2-4.2KM-3 Layout of trusses with a span of 27 m and connections

1.263-2-4.2KM-4 Diagram of the arrangement of trusses with a span of 30 m and connections

1.263-2-4.2KM-5 Layout of trusses with a span of 36 m and connections

1.263-2-4.2KM-6 Truss diagrams with element marking

1.263-2-4.2KM-7 Assortment of trusses with span L=27 m; H=1.8 m

1.263-2-4.2KM-8 Truss assortment with span L=27 m; H=2.1 m

1.263-2-4.2KM-9 Truss assortment with span L=30 m; H=1.8 m

1.263-2-4.2KM-10 Truss assortment with span L=30 m; H=2.1 m

1.263-2-4.2KM-11 Truss assortment with span L=36 m; H=2.1 m

1.263-2-4.2KM-12 Truss assortment with span L=36 m; H=2.4 m

1.263-2-4.2KM-13 Schemes of vertical connections B-1, B-2; B-3

1.263-2-4.2KM-14 Node 1

1.263-2-4.2KM-15 Knot 2.3

1.263-2-4.2KM-16 Node 4

1.263-2-4.2KM-17 Node 5

1.263-2-4.2KM-18 Node 6

1.263-2-4.2KM-19 Node 7

1.263-2-4.2KM-20 Knot 8

1.263-2-4.2KM-21 Knot 9

1.263-2-4.2KM-22 Knot 10-13

1.263-2-4.2KM-23 Instructions for the calculation of welds in truss nodes

1.263-2-4.2KM-24 Marking holes along the upper chords of trusses for fastening ties

1.263-2-4.2KM-25 Layout of reinforced concrete slabs and details of their welding to truss belts

1.263-2-4.2KM-26 Specification of steel trusses with span L=27 m; H=1.8 m

1.263-2-4.2KM-27 Specification of steel trusses with span L=27 m; H=2.1 m

1.263-2-4.2KM-28 Specification of steel trusses with span L=30 m; H=1.8 m

1.263-2-4.2KM-29 Specification of steel trusses with span L=30 m; H=2.1 m

1.263-2-4.2KM-30 Specification of steel trusses with span L=36 m; H=2.1 m

1.263-2-4.2KM-31 Specification of steel trusses with span L=36 m; H=2.4 m

Accepted: MADI of the Ministry of Higher Education of the USSR (Moscow Automobile and Road Institute)

Accepted: President of Russian Federation

Accepted: CITP Gosstroy of the USSR

Approved: State Committee for Civil Engineering and Architecture under the Gosstroy of the USSR 01/04/1983

Series 1.263.2-4. Issue 3(11.6 MiB, 80 hits)

1.263-2-4.1KM-2 Truss diagrams with node marking. Breakdown of farms into shipping marks

1.263-2-4.1KM-3 Layout of trusses with a span of 18 m, purlins and ties

1.263-2-4.1KM-4 Layout of trusses with a span of 21 m, girders and ties

1.263-2-4.1KM-5 Layout diagrams of trusses with a span of 24 m, purlins and ties

1.263-2-4.1KM-6 Layout diagrams of trusses with a span of 27 m, purlins and ties

1.263-2-4.1KM-7 Layout diagrams of trusses with a span of 30 m, runs and ties

1.263-2-4.1KM-8 Layout diagrams of trusses with a span of 36 m, purlins and ties

1.263-2-4.1KM-9 Scheme of trusses with marking of elements

1.263-2-4.1KM-10 Truss assortment with span L=18 m; H=1.2 m

1.263-2-4.1KM-11 Truss assortment with span L=18 m; H=1.8 m

1.263-2-4.1KM-12 Truss assortment with span L=21 m; H=1.8 m

1.263-2-4.1KM-13 Truss assortment with span L=24 m; H=1.8 m

1.263-2-4.1KM-14 Truss assortment with span L=27 m; H=1.8 m

1.263-2-4.1KM-15 Truss assortment with span L=27 m; H=2.1 m

1.263-2-4.1KM-16 Truss assortment with span L=30 m; H=1.8 m

1.263-2-4.1KM-17 Truss assortment with span L=30 m; H=2.1 m

1.263-2-4.1KM-18 Truss assortment with span L=36 m; H=2.1 m

1.263-2-4.1KM-19 Truss assortment with span L=36 m; H=2.4 m

1.263-2-4.1KM-20 Schemes of vertical connections V-1…V-4

1.263-2-4.1KM-21 Node 1

1.263-2-4.1KM-22 Knot 2.3

1.263-2-4.1KM-23 Node 4

1.263-2-4.1KM-24 Node 5

1.263-2-4.1KM-25 Node 6

1.263-2-4.1KM-26 Node 7

1.263-2-4.1KM-27 Knot 8

1.263-2-4.1KM-28 Node 9

1.263-2-4.1KM-29 Knot 10

1.263-2-4.1KM-30 Node 11

1.263-2-4.1KM-31 Knot 12-15

1.263-2-4.1KM-32 Instructions for the calculation of welded joints of truss units

1.263-2-4.1KM-33 Marking holes along the upper chords of trusses L = 18-24 m for fastening ties

1.263-2-4.1KM-34 Marking holes along the upper chords of trusses L = 27-36 m for fastening ties

1.263-2-4.1KM-35 Tables for the selection of grades of purlins and the profile of the dimensions of the flooring

1.263-2-4.1KM-36 Specification of steel trusses with span L=18 m; H=1.2 m; H=1.8 m

1.263-2-4.1KM-37 Specification of steel trusses with span L=27 m; L=24 m; H=1.8 m

1.263-2-4.1KM-38 Specification of steel trusses with span L=27 m; H=1.8 m; H=2.7 m

1.263-2-4.1KM-39 Specification of steel trusses with span L=30 m; H=1.8 m; H=2.1 m

1.263-2-4.1KM-40 Specification of steel trusses with span L=36 m; H=2.1 m

1.263-2-4.1KM-41 Specification of steel trusses with span L=36 m; H=2.4 m

Approved: State Committee for Civil Engineering and Architecture under Gosstroy of the USSR 05/06/1983

Series 1.263.2-4. Issue-4. Farms with a span of 15, 18, 21, 24, 27 and 30 m from welded bent-closed profiles (with reduced height)(6.8 MiB, 139 hits)

1.263-2-4.4-01KM Truss schemes with node marking. Breakdown of farms into starting marks

1.263-2-4.4-02KM Plans of arrangement of trusses with a span of 15.18 m and ties

1.263-2-4.4-03КМ Plans of arrangement of trusses with a span of 21.24 m and connections

1.263-2-4.4-04КМ Plans of arrangement of trusses with a span of 27.30 m and connections

1.263-2-4.4-05KM Truss schemes with element marking

1.263-2-4.4-06KM Assortment of trusses with a span of 15.18.21 m

1.263-2-4.4-07KM Assortment of trusses with a span of 24 m

1.263-2-4.4-08KM Assortment of trusses with a span of 27 m

1.263-2-4.4-09KM Assortment of trusses with a span of 30 m

1.263-2-4.4-10KM

1.263-2-4.4-11KM Node 1.2

1.263-2-4.4-12KM Node 3…8

1.263-2-4.4-13KM Truss support units (options)

1.263-2-4.4-14КМ Fragments of the flooring plan with the location of fasteners

1.263-2-4.4-15KM Permissible design load on decking

1.263-2-4.4-16KM

1.263-2-4.4-17KM Truss welds

1.263-2-4.4-18KM Parts D-1…D-3

1.263-2-4.4-19KM Specification of steel trusses with a span of 15,18,21 and 24 m

1.263-2-4.4-20KM Specification of truss steel with a span of 27 and 30 m

1.263-2-4.4-21KM Bill of materials consumption

Approved: State Committee for Civil Engineering and Architecture under Gosstroy of the USSR 03/29/1984

Metal roof trusses: design calculation, manufacturing

Profile pipe trusses have many advantages. With their help, today they build residential buildings of any configuration, garages, as well as some backyard structures. They are used, among other things, to create greenhouses. In terms of cost, farms are not expensive at all for land owners. They can be quickly constructed and fastened to load-bearing elements. For reliable fastening of this design, you will need a high-quality profile, a welding machine, a grinder and care when designing.

Anyone who decides to use this type of construction in their structure should have a clear plan consisting of:

• Choosing the right profile;
• Clear calculation of the farm;
• Correct location of jumpers;
• Reliable installation.

At its core, a truss is a unique structure that connects supporting elements and forms a finished frame as a result. Among specialists, it is considered a simple architectural metalwork. This configuration is different large quantity advantages:

1. The strength of the entire frame and separately the farm itself;
2. High performance;
3. Acceptable cost, taking into account the prices for pipes and consumables;
4. Excellent resistance to external influences, deformation.

Profile pipe trusses have become very popular due to the fact that they are ideal for creating strong supports for any type of roof. At the same time, these indicators are not affected by the weight of roofing materials.

Roof trusses can have absolutely different shape structures and arbitrary braces. For example, for backyard buildings use a shed form. It is easy to mount, and such a configuration can withstand a variety of loads. Gable samples are more suitable for garages and houses.

The shape of the arched farm is also distinguished. It has a convex shape and is considered one of the most durable.

For the correct calculation of farms, certain rules must be followed.

Making farms does not take much time. It all starts with the choice of quality material. It will determine the durability of the entire structure. The connection of all metal parts is used with tacks, as well as special paired corners.

Corners with equal sides are mounted only if the parts are mated.

Racks are attached at an angle of 90 degrees, and braces - 45 degrees.

An example of a finished truss structure

Requirements for the calculation of a profile pipe for the construction of a farm

Primary requirements:

• Calculations are made using all measurements of the length of the structure and the angle of inclination of the roofing material. The preparation of the farm should begin only after taking clear measurements of indicators.
• The exact dimensions depend on many factors. A certain type of structure will be determined based on the weight of the entire product, the load, the height of the roofing material, as well as the methods of its movement. Only the length of the workpiece determines the angle of the roof.
• Initially, it is necessary to include supports in the calculations and clearly define their belts. Length matters. The contours also depend on the slope and type of structure.

Basically, two legislative documents are responsible for this, which determine the calculation procedure. One contains information about exposure standards and allowable loads, and the other will help determine the type of steel structure. With their help, the calculation of a truss from a profile pipe can be carried out quickly and as correctly as possible.

The most important thing to consider is that the calculation is based on the principle of economy. After determining the span height, length and angle of inclination of the entire structure, the calculation ends with the last point - establishing the optimal distance between all component parts. The span load affects the amount of material and its location.

Carrying out the calculation of an arched truss from a profile pipe

It is possible to determine the optimal values ​​of the structure using a specific example of an arched truss. The length of the structure is 600 cm. Each section is located at a distance of 105 cm from each other. The height of the arched ceiling is 300 cm. The arrow of the lower belt in such a product will be 130 cm. The radius of the circle below will be 410 cm. According to the calculation conditions, the angle between the radii is 105.9776˚.

Designations:

mn - the length of the profile, which is necessary for laying the lower tier;

π - constant value;

R - radius.

To calculate the required indicator, specialists use a certain formula:

The result is the following calculation:

mn \u003d 3.14 × 4.1 × 106 / 180 \u003d 758 cm.

It should be noted that the step between the points at the corners will be 55 cm.

A good example demonstrates that profile pipe trusses are calculated quite simply and quickly.

Calculation example

Training video with calculation rules.

Design features of a truss from a profile pipe

The profile pipes from which the trusses are made are durable, and therefore have distinctive characteristics. Features of all designs are divided into several main factors.

The number of belts and the load indicator are considered critical indicators.

According to these characteristics, farms are divided into:

1. A type of configuration in which all elements are located in the same plane;
2. Type in which individual parts of the span are located in two or more tiers.

Both design features are stable and can withstand extreme loads, while the angle of inclination can be arbitrary. But to ensure the construction of a longer service life, it is recommended to use the second type. He is more reliable.

Farms from a profile pipe are also designed depending on the contours and their shapes. As mentioned earlier, according to the last criterion, the designs are divided into single-slope, gable, straight, and also in the form of an arch. Each of the samples is used for different purposes.

For example, products with a parallel belt are ideal for soft roofing. The support is quite simple and all its parts are identical. It is the easiest to mount, since this process does not require special knowledge.

Shed metal trusses are best suited for fastening a hard roof with the required height.

W-truss

Types of farms from a profile pipe

There are many different types of trusses that allow you to implement a wide variety of design solutions.

• The first, and most common variety is the triangular shape of the metal structure. This is a classic type of workpiece, suitable for structures different kind destination. In order to select the optimal cross-section of pipes in such a sample, it is necessary to take into account the characteristics of the further operation of the structure, and its nominal weight. The length is also taken into account. The advantage of such products is strength, ease of installation and a constant supply of natural light through triangular frames.
• The second most popular type is polygonal farms from a profile pipe. This configuration is indispensable in large rooms. When it comes to designing a large building or a canopy, it is polygonal products that meet all the requirements. The only disadvantage of such structures is the difficulty in welding them. Despite the usual angle of inclination, it is necessary to use a certain principle and technique of welding. And this is not suitable for lightweight structures.
• In terms of strength characteristics, it is not inferior to the previous types and the farm, which has parallel belts. A distinctive feature of such a metal structure is that all rods, gratings and belts are of the same length. It is considered the easiest to calculate.
• Also a reliable type of farm - single slope trapezoidal shape. Such farms are based on columns. According to its characteristics of rigidity, this type has no equal.

Farm types

The main structure of the truss from a profile pipe

Experienced specialists can assemble trusses from a profile pipe quickly. To do this, it is necessary to give the exact dimensions and drawings of the metal structure. But, if the task is to save the construction budget, installation can be done independently. To do this, you first need to assemble the main structure.

In order to create it, mainly rectangular or square metal products are used. They allow the entire workpiece to remain strong throughout its entire service life. In addition to this, the main structure of the square profile is easier to attach to the base.

At the first stage, using drawings and calculations, all metal parts of the farm itself are welded. This is done on the ground or in a prepared room with flat floors. The length and width of the product is checked.

This is followed by the stage of installation and fixation of the support elements arranged vertically. Their correct installation determines the reliability of the entire metal structure. You can use a plumb line to check. It will show how accurately it was possible to fix the bearing supports.

How to weld trusses from a profile pipe

As soon as the supports are ready, longitudinally located pipes are welded to the racks. They are attached for reliable coupling of elements. They give the entire structure stability.

When the base is ready, it's time to attach a truss to it from a profile pipe. A pre-prepared configuration with gratings is lifted and installed from above. Immediately you need to check the correctness of the assembly, including the braces. All corners should be in place and fit snugly against the base. When all dimensions and layout of the structure have been verified, metal elements welded to each other. Don't forget the grips.

Connection example

Ultimately, it is necessary to clean all the connecting places where the welding machine was used, and carefully paint all parts of the metal structure.

As a result, correct calculations, high-quality materials and attentive welding work allows you to create the perfect cover.

Video explaining the welding process of the structure:

Today, profile pipe trusses are rightfully considered ideal solution for the construction of a garage, residential building and outbuildings. Strong and durable, these designs are inexpensive, quick to build, and can be handled by anyone with a modicum of math and cutting and welding skills.

And how to choose the right profile, calculate the farm, make jumpers in it and install, we will now tell you in detail. For this we have prepared for you detailed master classes making such farms, video tutorials and valuable tips from our experts!

So what is a farm? This is a structure that ties the supports together into one single whole. In other words, the farm belongs to simple architectural structures, among the valuable advantages of which we highlight the following: high strength, excellent performance, low cost and good resistance to deformations and external loads.

Due to the fact that such trusses have a high bearing capacity, they are placed under any roofing materials, regardless of their weight.

The use in the construction of metal trusses from new or rectangular closed profiles is considered one of the most rational and constructive solutions. And for good reason:

1. The main secret is in savings due to the rational shape of the profile and the connection of all elements of the lattice.
2. Another valuable advantage of profile pipes for use in their manufacture of trusses is equal stability in two planes, excellent streamlining and ease of use.
3. With all their low weight, such trusses can withstand serious loads!

Roof trusses differ in the shape of the belts, the type of section of the rods and the types of lattice. And with the right approach, you can independently weld and install a truss from a profile pipe of any complexity! Even this one:

Stage II. We acquire a quality profile

So, before drafting future farms, you first need to decide on such important points:

• contours, size and shape of the future roof;
• material for the manufacture of the upper and lower chords of the truss, as well as its lattice;

Remember one simple thing: the profile pipe frame has so-called balance points, which are important to determine for the stability of the entire truss. And it is very important to choose under this load quality material:

Farms are built from a profile pipe of such types of sections: rectangular or square. These are available in different section sizes and diameters, with different wall thicknesses:

• We recommend those that are specially sold for small buildings: these go up to 4.5 meters long and have a section of 40x20x2 mm.
• If you will make farms longer than 5 meters, then choose a profile with parameters 40x40x2 mm.
• For a full-scale construction of the roof of a residential building, you will need profile pipes with the following parameters: 40x60x3 mm.

The stability of the entire structure is directly proportional to the thickness of the profile, so do not use pipes for the manufacture of trusses, which are intended only for welding racks and frames - here are other characteristics. Also pay attention to which method the product was made: by electric welding, hot-formed or cold-formed.

If you undertake to make such trusses on your own, then take square-section blanks - it is easiest to work with them. Get a square profile 3-5 mm thick, which will be strong enough and close in its characteristics to metal bars. But if you will make a farm just for a visor, then you can give preference to a more budget option.

Be sure to consider snow and wind loads in your area when designing. After all, when choosing a profile (in terms of the load on it), the angle of inclination of the trusses is of great importance:

You can more accurately design a truss from a profile pipe using online calculators.

We only note that the simplest design of a truss from a profile pipe consists of several vertical racks and horizontal levels on which roof rafters can be attached. You can buy such a frame ready-made on your own, even on order in any city in Russia.

Stage III. We calculate the internal stress of the trusses

The most important and responsible task is to correctly calculate the truss from the profile pipe and select the desired format of the internal lattice. To do this, we need a calculator or other software similar to it, as well as some tabular data of SNiPs, which for this:

• SNiP 2.01.07-85 (impacts, loads).
• SNiP p-23-81 (data on steel structures).

Please review these documents if possible.

Roof shape and slope

The farm is needed for which specific roof? Shed, gable, domed, arched or hipped? The easiest option, of course, is the manufacture of a standard shed canopy. But you can also calculate and manufacture quite complex farms yourself:

A standard truss consists of such important elements as the upper and lower chords, racks, braces and auxiliary struts, which are also called sprengels. Inside the trusses there is a system of gratings, for connecting pipes is used welds, staves, special paired materials and kerchiefs.

And, if you are going to make a roof with a complex shape, then such trusses will be an ideal option for it. It is very convenient to make them according to a template right on the ground, and only then lift them up.

Most often, in the construction of a small country house, garage or change house, the so-called Polonso trusses are used - a special design of triangular trusses connected by puffs, and the lower belt here comes out raised.

In fact, in this case, in order to increase the height of the structure, the lower chord is made broken, and then it is 0.23 of the flight length. For the interior space of the room is very convenient.

So, in total there are three main options for making a truss, depending on the slope of the roof:

• from 6 to 15°;
• from 15 to 20°;
• from 22 to 35°.

What is the difference you ask? For example, if the angle of the structure is small, only up to 15 °, then it is rational to make the trusses in a trapezoidal shape. And at the same time, it is quite possible to reduce the weight of the structure itself, taking in height from 1/7 to 1/9 of the total flight length.

Those. follow this rule: the lower the weight, the greater the height of the truss. But if we already have a complex geometric shape, then you need to choose a different type of truss and gratings.

Types of trusses and roof shapes

Here is an example of specific trusses for each type of roof (single, double, complex):

Let's look at the types of farms:

• triangular trusses are a classic for making the base for steep roof slopes or sheds. The cross section of pipes for such farms must be selected taking into account the weight of the roofing materials, as well as the operation of the building itself. Triangular trusses are good because they have simple shapes, are easy to calculate and execute. They are valued for under-roofing providing natural light. But we also note the disadvantages: these are additional profiles and long rods in the central segments of the lattice. And also here you will have to face some difficulties when welding sharp reference corners.
• The next view is polygonal farms from a profile pipe. They are indispensable for the construction of large areas. They already have more welding complex shape, and therefore they are not designed for lightweight structures. But such trusses are distinguished by greater metal savings and strength, which is especially good for hangars with large spans.
• It is also considered strong truss with parallel belts. Such a farm differs from others in that it has all the details - repeating, with the same length of rods, belts and gratings. That is, there are a minimum of joints, and therefore it is easiest to calculate and cook one from a profile pipe.
• A separate species is single slope trapezoidal truss supported by columns. Such a farm is ideal when a rigid fixation of the structure is necessary. She has slopes (braces) on the sides and there are no long rods of the upper crate. Suitable for roofs where reliability is especially important.

Here is an example of making trusses from a profile pipe as a universal option that is suitable for any garden buildings. We are talking about triangular farms, and you have probably already seen them many times:

A triangular truss with a crossbar is also quite simple, and is quite suitable for building gazebos and change houses:

And here arched farms are already much more difficult to manufacture, although they have a number of valuable advantages:

Your main task is to center the metal truss elements from the center of gravity in all directions, saying plain language, minimize the load and correctly distribute it.

Therefore, choose the type of farm that is more suitable for this purpose. In addition to those listed above, a scissor truss, asymmetric, U-shaped, two-hinged, a truss with parallel belts and an attic truss with and without supports are also popular. As well as attic view farms:

Grating types and point load

You will be interested to know that a certain design of the internal lattices of trusses is selected not at all for aesthetic reasons, but for quite practical ones: for the shape of the roof, the geometry of the ceiling and the calculation of loads.

You need to design your farm in such a way that all forces are concentrated specifically in the nodes. Then there will be no bending moments in the belts, braces and trusses - they will only work in compression and tension. And then the cross section of such elements is reduced to the required minimum, while significantly saving on the material. And the farm itself, to everything, you can easily make articulated.

Otherwise, the force distributed over the rods will constantly act on the truss, and a bending moment will appear, in addition to the total stress. And here then it is important to correctly calculate the maximum bending values ​​for each individual rod.

Then the cross section of such rods should be larger than if the truss itself was loaded with point forces. To summarize: trusses, on which the distributed load acts evenly, are made of short elements with hinged nodes.

Let's see what is the advantage of one or another type of lattice in terms of load distribution:

• triangular Lattice systems are always used in trusses with parallel chords and trapezoidal truss. Its main advantage is that it gives the smallest total grating length.
• Diagonal the system is good at low truss heights. But the consumption of material for it is considerable, because here the entire path of effort goes through the nodes and rods of the lattice. And therefore, when designing, it is important to lay a maximum of rods so that the long elements are stretched and the racks are compressed.
• Another view - trussed lattice. It is made in case of loads of the upper belt, as well as when it is necessary to reduce the length of the lattice itself. Here, the advantage is to maintain the optimal distance between the elements of all transverse structures, which, in turn, allows you to maintain a normal distance between the runs, which will be a practical moment for the installation of roof elements. But creating such a lattice with your own hands is a rather laborious task with additional metal costs.
• cruciform the lattice allows you to distribute the load on the farm in both directions at once.
• Another type of grid cross where the braces are attached directly to the truss wall.
• And finally semi-diagonal and rhombic lattices, the most rigid of the listed. Here two systems of braces interact at once.

We have prepared an illustration for you, where we have collected all types of trusses and their lattices together:

Here is an example of how a triangular lattice truss is made:

Making a truss with a diagonal lattice looks like this:

This is not to say that one type of truss is definitely better or worse than the other - each of them is valuable for less material consumption, lighter weight, bearing capacity and method of fastening. The figure is responsible for which load scheme will act on it. And the weight of the truss will directly depend on the type of lattice chosen, appearance and laboriousness of its production.

We also note such an unusual version of the manufacture of a farm, when it itself becomes a part or support for another, wooden one:

Stage IV. We manufacture and install farms

We will give you some valuable tips on how to weld such farms on your own without much difficulty right on your site:

• Option one: you can contact the factory, and they will make to order all the necessary individual elements according to your drawing, which you will only have to weld on the spot.
• The second option: purchase a ready-made profile. Then you will only have to sheathe the trusses from the inside with boards or plywood, and in between lay insulation if necessary. But this method will cost, of course, more expensive.

Here, for example, is a good video tutorial on how to lengthen a pipe by welding and achieve the perfect geometry:

Here is also a very helpful video on how to cut a pipe at a 45° angle:

So, now we come directly to the assembly of the farms themselves. The following step-by-step instructions will help you deal with this:

• Step 1: Prepare the trusses first. It is better to weld them in advance directly on the ground.
• Step 2. Install vertical supports for future farms. It is imperative that they are truly vertical, so test them with a plumb line.
• Step 3. Now take the longitudinal pipes and weld them to the support posts.
• Step 4 Raise the trusses and weld them to the longitudinal pipes. After that, it is important to clean all junctions.
• Step 5. Paint the finished frame with special paint, having previously cleaned and degreased it. Special attention at the same time, pay attention to the junctions of the profile pipes.

What else do those who make such farms at home face? First, consider in advance the support tables on which you will lay the truss. far from the best way throw it on the ground - it will be very inconvenient to work.

Therefore, it is better to put small support bridges that will be slightly wider than the lower and upper chords of the truss. After all, you will manually measure and insert jumpers between the belts, and it is important that they do not fall to the ground.

Next important point: profile pipe trusses are heavy in weight, and therefore you will need the help of at least one more person. In addition, help will not hurt in such a tedious and painstaking work, like sanding metal before cooking. Also keep in mind that you will need to cut a lot of trusses for all elements, and therefore we advise you to either purchase or build homemade machine like the one in our master class. Here is how it works:

In this way, step by step, you will draw up a drawing, calculate the truss lattice, make blanks and weld the structure already in place. Moreover, you will also have the remains of profile pipes in your consumption, therefore, you will not need to throw anything away - all this will be needed for the secondary parts of the canopy or hangar!

Stage V. We clean and paint finished trusses

After you install farms on their permanent place, be sure to treat them with anti-corrosion compounds and painting with polymer paints. Ideal for this purpose paint, which is durable and resistant to ultraviolet radiation:

That's all, the profile pipe farm is ready! All that remains is the finishing work on sheathing the trusses from the inside with finishing and from the outside with roofing material:

Believe me, making a metal truss from a profile pipe is really not difficult for you. A well-designed drawing, high-quality welding of a truss from a profile pipe and the desire to do everything correctly and accurately play a huge role.

Sooner or later, the owners of a private house need to build a carport on the site or summer holidays, a gazebo, a small fence with a roof for pets, a canopy over a woodpile. In order for the roof over such a structure to be securely fixed, it is necessary to correctly design and install metal supporting structures.

We welcome our esteemed reader and offer him an article about what trusses from a profile pipe are, how to calculate and mount them correctly.

A truss is a structure of rectilinear elements interconnected at nodes into a solid system of an unchanging geometric shape. Most often found flat designs, but in large loaded structures, volumetric (spatial) trusses are used. Practically in private houses, farms are made of wood and metal. Small structures of rafters, canopies, arbors are made of wood. But durable and high-tech metal - practically perfect material for load-bearing metal structures.

For the manufacture of complex structures apply rolled solid section and pipes. Profile pipes (square, rectangle) have greater resistance to crushing and bending, small structures for the house are mounted without the use of welding, therefore, a profile pipe is most often used for estate buildings.

Structural features of trusses

The constituent elements of the farm structure:

• Belt.
• Rack - a vertical element connecting the upper and lower chords.
• Brace (strut).
• Sprengel - support brace.
• Cut-outs, overlays, scarves, rivets, bolts - all kinds of auxiliary and fastening materials.

The height of the farm is considered from the lowest point of the lower belt to the highest point. Span - the distance between the supports. Rise - the ratio of the height of the truss to the span. The panel is the distance between the nodes of the belt.

Types of farms from a professional pipe

Farms are subdivided according to the outline of the belts. There are two-layer and three-layer varieties. In small structures, simpler two-belt trusses are used. Each variety has a certain slope and height depending on the length of the span and the shape of the truss.

Types of trusses according to the contours of the chords: beams with parallel chords (rectangular), triangular (double and single pitch), trapezoidal (double and single pitch), segmental (parabolic), polygonal (polygonal), cantilever; with a broken raised or concave lower chord and a varied shape of the upper chord; arched with a horizontal and arched lower belt; complex combined forms.

Farms are also distinguished by the types of lattices - see the figure. In private buildings, triangular and diagonal gratings are most often found - simpler and less metal-intensive. Triangular gratings are usually used in rectangular and trapezoidal structures, diagonal gratings - in triangular ones.

Before building any structure, you should decide on the choice of material. At the time of buying metal profile or pipes, you should carefully examine the workpieces - for cracks, shells, sagging, inconsistencies along the seam, a large number of dented and bent workpieces. When buying galvanized materials - it is advisable to make sure the quality of the coating - whether there are any delaminations and sagging.

When buying, you must require a copy of the certificate and a receipt. Be sure to make sure that the wall thickness of the pipe is stated in the documents. You can’t make pipes in a garage on your knee, and there are no fakes, but on poor quality material can be encountered, so it is better to buy in fairly large stores.

What material to choose for the frame

In most cases, steel is chosen for the frame of manor buildings or the roof of a house. For very small structures, aluminum is sometimes used and - usually in purchased products (awnings, rocking chairs). For the erection of metal structures, pipes of a hollow section and a profile of a solid section (circle, strip, square, channel, I-beam) can be used.

A huge advantage of rectangular and square pipes compared to a profile of the same weight is the high resistance to crushing and other deformations. Therefore, solid profiles can be replaced with much lighter corrugated pipes - this greatly facilitates (2 times or more) and reduces the cost of tubular-type construction.

The dimensions of the pipe section are selected depending on the span length and the distance between supports and trusses. In private estates, sheds and other structures are not very large, and you can take the advice of experts or find ready-made drawings on the Internet.

With a distance between supports of up to 2 m, for small canopies with spans up to 4 m long, a profile of 40 × 20x2 mm is suitable, with spans of up to 5 m - 40 × 40x3, 60 × 30x3 mm; spans longer than 5 m - 60 × 40x3, 60 × 60x3 mm. If a carport for two cars with a width of 8-10 m is planned, then the profile will be required from 60 × 60 to 100 × 100 with a wall thickness of 3-4 mm. The dimensions of the profile depend on the distance between the trusses.

Professional pipes go on sale in lengths of 6 and 12 m. With a length of 12 m, metal is consumed more economically, but a length gauge is needed to transport such pipes. Before buying materials, you should consider how you will cut the blanks and how many of them will fit in a pipe 6 m or 12 m long, and calculate how many sections of the professional pipe you will need.

It is impossible to focus on the nominal weight - the weight is 1 r.m. in a particular batch will differ from the nominal, and most likely upwards (it is more profitable for sellers to manufacture products with a thicker wall - the price is per ton). When buying by weight, the material will have to be bought and transported - and these are extra costs.

Advantages and disadvantages of different metals

In practice, the following types of steel are used for structural profile pipes: carbon ordinary quality and high-quality, structural, alloyed. Pipes come with a protective zinc coating. Aluminum is also used - but rarely, for small, more often seasonal structures. Aluminum profiles are used for small structures.

Traditionally, for small structures in a private estate, for the construction of steel structures with trusses, carbon steel St3sp, St3ps, sometimes galvanized, is used. Such steel has sufficient strength to ensure the reliability of the structure, there is practically no difference in corrosion resistance for all three types of steel.

If precipitation falls on structures, sooner or later both structural and alloy steel products will rust. A small amount of alloying elements does not protect against corrosion (for structures, low-alloy steels such as 30KhGSA, 30KhGSN, 38XA can be used - the content of alloying elements in them is 2-4%, and this amount does not affect corrosion resistance).

In terms of strength, structural and alloy steels should be slightly more durable than carbon steels - they are more resistant to cyclic loads. But this quality in steels manifests itself after heat treatment - and quenching with tempering can warp pipes, and usually no one does such heat treatment on finished products. Annealing can be carried out on seamless pipes - after annealing, residual stresses (hardening) are removed in the metal, but it becomes softer.

Structural steels (20A, 45, 40, 30A) are of higher quality and higher price. Alloyed steels are even more expensive (and there is a chance that you will be sold pipes made of steel 3 instead of alloyed). Therefore, when installing structures with a width of less than 20 m, it makes no sense to buy professional pipes made of alloyed or structural steel. It definitely makes sense to use a galvanized professional pipe if the installation will be carried out using crab systems.

If the assembly is to be carried out by welding, the welds will rust as quickly as normal uncoated metal.. But if you carefully monitor the seams, regularly carry out anti-corrosion treatment (cleaning, priming, painting), then a galvanized pipe is preferable. If you need a temporary shed for 10 years for building materials, and then you will demolish the shed - all the more so do not bother, buy ordinary carbon steel pipes without coating.

If you plan to build a very large shed or a hangar with a long span on the site, you should contact professional builders and make a project - they will determine which steel you choose.

Do it yourself or order

Trusses for a canopy over a car or a gazebo roof are small and simple design- most often triangular with several struts and racks. You can also complete such a design yourself if you have at least the initial skills of a welder and you are not afraid to learn new jobs.

But the manufacture of farms requires accuracy, the presence of an assistant, a very flat area in the estate - for laying out and welding structures, the presence of a welding machine and time. You can order ready-made structures at a factory or a construction company, and mount it yourself.

Requirements for the calculation of a profile pipe for the construction of a farm

When calculating the dimensions and wall thickness of profile pipes required for the construction of your metal structures; the following conditions are taken into account:

• The dimensions of the metal structure, and in particular, the length, the pitch of the supports - the distance between the supports.
• The height of supports and trusses.
• Farm shape.
• Possible features of geological conditions (seismic activity, the possibility of landslides).
• Coating weight.

What happens if you calculate incorrectly

In case of incorrect calculations, the following consequences are possible:

• Farm structures will deform under the weight of snow, wet foliage.
• In the most unfortunate case, the structures will deform under their own weight.
• The entire structure can collapse in strong winds.
• Deformation sooner or later will lead to the destruction of the farm and the entire structure, which is dangerous for humans and can damage objects under a canopy - a car, for example.
• A fragile and movable structure will lead to the destruction of the roof laid on the farm.
• When using a profile that is too powerful and heavy, the cost of materials and work during the construction of a metal structure unreasonably increases.

We design a farm and its elements

A complete and accurate calculation of the load on the farm, along with diagrams, is complex, and for its implementation, you should contact the specialists.

When designing large sheds, hangars, garages made of metal structures, an accurate calculation of the required profile is necessary, but for the construction of not too large sheds or gazebos in a private estate, you can use the well-known recommendations of specialists.

For very small structures (shed in an animal enclosure, shed over a store of firewood), it is sufficient to use pipes measuring 40 × 20 mm with a wall thickness of 2 mm; for gazebos and canopies over tables, barbecues or places of rest - 40 × 40 mm with a wall thickness of 3 mm; canopy over a place for a car - from 60 × 40 to 100 × 100 mm with a wall thickness of 3-4 mm.

If there are several trusses and supports at the canopy and the step of the supports is less than 2 m, you can take a thinner pipe, if there are only 4 supports and two trusses and a span of 6-8 m or more - a thicker one.

Permissible loads on trusses are shown in the table:

Drawings and diagrams

In the manufacture of metal structures, a drawing with exact dimensions is mandatory! This will allow you to purchase the right amount of material, save time when assembling and preparing blanks, and allow you to easily control the dimensions of the metal structure during installation and the finished structure. In this case, the safety of you and your household depends on the accuracy of the assembly - a building that collapsed from snow or wind can bring a lot of trouble.

Fundamentals of Farm Calculation

The types of trusses depend on the shape of the roof, and the shape of the roof of the building in the estate is chosen depending on the purpose and location of the metal structures. Cantilever and adjoining trusses are usually made with single-sided triangular, free-standing canopies - with polygonal, triangular, segmental structures and arches. Arbors can have a six- and eight-slope roof or a fantasy roof with custom-design trusses.

To calculate the trusses, it is necessary to calculate the load on the roof and on one truss. The calculations take into account the load of the snow cover, roofing, battens, the weight of the structures themselves. Accurate calculations is a task for a professional builder. The basis for the calculation is SP 20.13330.2016 “Loads and impacts. Updated version of SNiP 2.01.07-85” and SP 16.13330.2011 “Steel structures. Updated version of SNiP II-23-81".

For calculations, the cutting method is used - cutting out nodes (sections where the rods are hinged); Ritter method; Henneberg rod replacement method. In modern computer programs the method of cutting knots is more often used.

It is better to use a ready-made standard project or our recommendations for choosing profiles. It is not too difficult to assemble a truss of a simple trapezoid or triangular design, and if you have experience in welding and installing metal structures self-assembly canopies and gazebos is quite possible. If you want to build a large canopy with a truss length of 10 m or more, you need to complete the project with specialists.

Influence of tilt angle

The design of the farm is primarily affected by the angle of inclination of the slopes (ramp). The angle of inclination is selected primarily depending on the shape of the roof and the placement of the metal structure. Sheds adjacent to buildings should have a larger angle of inclination of the roof - for faster rolling of snow sliding from the roof and flowing water.

For single structures, the angle of inclination of the roof may be less. The angle of inclination also depends on the amount of precipitation falling in your region - the more precipitation, the greater the angle of inclination of the roof should be. The steeper the roof, the less precipitation lingers on it.

A slight slope of the slope - up to 15 ° - is used on small free-standing canopies. The height of the slope is approximately equal to 1/7-1/9 of the span length. Trapezoidal trusses are used.

Slope from 15 ° to 22 ° - the height of the slope is 1/7 of the span length.

Slope from 22 ° to 30 ° - 35 ° - the height of the slope is 1/5 of the span length, with such a slope, triangular structures are usually used, sometimes with a broken lower belt to facilitate construction.

Base Angle Options

For the correct calculation of the number and lengths of individual elements of a truss from a professional pipe, it is necessary to determine the basic angles between the elements. In general, the lower chord is perpendicular to the supports, the upper chord has an inclination to the horizontal, depending on the angle of the roof. The optimal angle of inclination of the braces to the horizontal / vertical is 45 °, the posts must be strictly vertical.

The exact angle of inclination of the roof is either set by the project, or is found according to the ratios given above ( for a slope of up to 15 ° - the height of the slope is approximately equal to 1/7-1/9 of the span length; for a slope from 15 ° to 22 ° - 1/7 of the span length; for a slope from 22 ° to 30 ° - 35 ° - the height of the slope is 1/5 of the span length).

Having determined the exact angle of the roof, determine the length of the blanks for the manufacture of the farm - this information will be required when performing work.

Significant Site Selection Factors

If there is a choice, for the installation of metal structures, you should choose a flat area that is not subject to landslides and waterlogging. But in small household plots most often there is no choice - a carport is placed immediately outside the gate, a veranda near the house, a gazebo in the depths of the site. The site may need to be leveled, sometimes dried.

If there is a danger of slipping earth layers, or you live in an earthquake-prone area, the design of the design of any structure above the doghouse should be left to professionals to ensure your own safety.

How to calculate load

Snow load per 1 m² of roof is calculated by SP 20.13330.2017 “Loads and impacts. Updated version of SNiP 2.01.07-85" depending on the region. When calculating, it is not the area of ​​\u200b\u200bthe roof that is taken, but the area of ​​​​the projection of the roof onto the horizontal. Similarly, the weight of the crate and roofing is calculated. According to the drawing, the weight of one farm is calculated and multiplied by their number.

The load on one truss is calculated by dividing the sum of the total load on the roof of snow, the weight of the crate and cover, the weight of the structures themselves, by the number of trusses.

Entrance door and canopy

Visors over front door are small in size and are performed console.

The width of the visor should be equal to the width of the porch + 300 mm on each side. In depth, the canopy should cover the steps. The length of the visor is equal to the sum of the length of the platform and steps. The length of the upper platform should be one and a half times wider than the door, that is, 0.9 × 1.5 \u003d 1.35 m. Plus 250 mm for each step.

For example:

for a porch with two steps and a width of 1200 mm, the dimensions of the covered area (horizontal projection of the canopy) are:

length (peak depth) = 1.35 + 2 × 0.25 = 1.85 m;

width \u003d 1.2 + 0.3 × 2 \u003d 1.8 m.

Free programs for calculation

• Online http://sopromatguru.ru/raschet-balki.php.
• Online http://rama.sopromat.org/2009/?gmini=off.

Calculation example

An example of calculating the truss of a free-standing canopy for a medium class car (D):

Vehicle width 1.73 m, length 4.6 m.

Minimum truss width between supports:

1.73 + 1 = 2.73 m, for the convenience of opening doors, we accept a width of 3.5 m.

Truss width including roof overhangs:

3.5 + 2 × 0.3 = 4.1 m.

Canopy length:

4.6 + 1 = 5.6 m, take a length of 6 m.

With this length, you can install supports in 2 m or less. To facilitate the supporting structures, we accept the distance between the supports of 1.5 m.

We accept a triangular gable roof shape - it is the easiest to manufacture and at the same time economical in terms of material consumption. We accept the angle of inclination of the roof as 30 ° - at this angle of inclination, snow and fallen leaves will not linger on the roof.

The height of the truss in the center (center post) will be:

Total: the length of the lower belt of the farm is 4.1 m; upper belt - two halves of 2.355 m each, total length 4.71 m, the stand in the center has a height of 1.16 m.

For such short trusses, it is quite sufficient to use a 40 × 40 mm square pipe with a wall thickness of 3 mm.

The main stages of work on the manufacture and installation of trusses with their own hands

Prior to the installation of the trusses, work is carried out on site planning, installation of supports, concreting of the foundations of the supports, welding of side braces or side trusses. Then the cross trusses are mounted.

The procedure for performing work on the manufacture and installation of trusses:

• Farms are welded on a flat surface.
• Farms are treated with an anti-corrosion primer, painted twice. Do not paint places for welding trusses to supports. It is possible to perform these works after the installation of trusses, but it is inconvenient to paint at a height.
• Farms are raised, installed on supports, angles and horizontality are verified, welded to supports. These works are carried out by a team of several people.
• Paint over the welds.
• Mount the crate, lay the roofing.

How to weld trusses

Farms are assembled on a flat area. Before assembly, workpieces are cut, cleaned of rust, and burrs are ground off on sections. Farm elements are fastened with clamps, dimensions, angles, flatness are checked. The structure is welded on one side, allowed to cool, turned over to the other side. Remove the clamps and boil the second side. Then grind the roller on the seam. You can see the features of truss welding in our video:

If you have little skills as a welder and fitter, you can order the manufacture of a farm in a specialized organization or team.

Conclusion

The installation of a canopy, the installation of trusses is a complex skilled work. Small canopies and gazebos can be done independently with the help of family members.

It is better to entrust the installation of large metal structures to a team of professionals. But professionals also need control. We say goodbye to our esteemed reader and hope that our article will help you understand the types of farms, the choice of design, material and the procedure for constructing sheds and gazebos on your site. Subscribe to the newsletter of our site, bring friends, share interesting information with your interlocutors in social networks.

A construction truss is a metal structure consisting of separate inclined braces or vertical posts, which are interconnected into separate nodes located on the lower and upper chords of the truss using welded joints, their combination forms a rigid structure. The connected posts evenly distribute the load throughout the truss structure, which transfers it through the support columns to the foundation. In this case, the upper belt works in axial compression, and the lower one in tension.

Species and varieties

The interconnected braces form a triangle, which is considered the most durable geometric figure. Therefore, almost any constructive scheme of a truss, regardless of its type, consists of a set of a certain number of unchanging geometric shapes in the form of triangles.

Farms consist of the following elements:

Nodal connections can be:

1. Welded - all structural elements are interconnected by welding.
2. Bolted connections or riveted - the elements are interconnected using bolts or rivets on a common steel mortgage (gusset) made of a thick rolled sheet.

A steel truss, compared to solid beams, is lighter in weight, requires less metal to manufacture, and has a high load-bearing capacity. And in its design and distribution of vertical loads farms are divided into two types:

Structural devices are much more difficult to assemble, but due to their design, they are able to carry both vertical and lateral loads. At the same time, they do not need to mount additional girders for connection with other metal structures, therefore they are often used for one solid overlap of large and rather wide spans with a minimum number of supporting columns.

Design features

Any metal devices, regardless of their design, contour and shape, have their own characteristics and certain parameters. But still, according to the method of installation, in addition to the classical one, when the structural device rests on supports with two ends, sometimes there are structural structures in which one edge turns out to be hanging, that is, without support. Usually they are mounted for floors of buildings, in which the roof slope extends far beyond the outer walls.

Depending on the design, farms can be straight, one or two-slope. The contour is divided into several types:

Types of lattices

There are the following types of grids:

• Triangular grid. is the toughest and efficient system in designs with parallel, triangular and trapezoidal outlines.
• Diagonal lattice. It consists of the longest braces that work simultaneously in compression and tension, but the vertical racks only in compression.

There are also special cross, trussed and other gratings.

An important parameter in the design of trusses is their angle of inclination, and depending on it, the structures are divided into 3 groups:

Almost all construction farms have great advantages in front of all-metal beams, among which the main ones are:

Fabrication of structures

As a rule, truss structures made of metal are selected depending on the projected angle of inclination of their upper chord, the width of the span to be covered, and the purpose. If we take into account the floors of industrial buildings, bridges and flyovers, where they are most often used, then construction trusses are made for this with a standard length of 12, 18, and 24 m / p.

General requirements

For heavier and more critical structures (bridges and overpasses), I-beams and channel. All hydraulic structures are assembled from round sections or shaped pipes.

Most often, a reinforced rolling corner is used to assemble standard construction trusses. At the same time, for the manufacture of all its elements, a paired corner is used, the workpieces of which are interconnected by welding with special ones inserted between them. metal plates(fish). The corners are paired so that their cross section resembles a T-section.

True, recently, metal structures of this configuration have become less in demand due to the laboriousness of assembly, welding and painting. Steel shaped or round pipes are increasingly becoming an alternative to such structures.

Correct calculation

It is necessary to understand that to make a qualitative calculation carrier device possible only when availability of special knowledge taking into account the requirements of SNiP and many other numerous factors. In order to correctly make the calculation, designers use special programs.

When calculating the design of an engineering device, it is imperative that all the obtained values ​​\u200b\u200bare applied to design drawing, without which the assembly of the structure will be almost impossible.

Initially, before drawing up a drawing project, a farm diagram is prepared indicating the main dependence of the slope of the upper belt and the total length of the future product. You should also take into account factors such as:

As soon as the main parameters are calculated, you should decide on the design scheme. The best way to do this is to use special programs that can be freely found on the Internet. For example, you can use the Farm Calculation program.

Construction assembly

All elements of trusses for covering long spans are manufactured and adjusted at the factory, and part of the assembly of the structure is also made there . Complete installation of it is carried out directly at the construction site strictly according to the detailed drawings that come with the product. The drawing shows individual markings of all structural parts and provides instructions explaining the entire assembly process.

Usually, there are special mounting holes on the blanks of the product, with the help of which it is possible to assemble and temporarily fix all the details of the structure without the use of clamps and special fastening clamps in preparation for welding.

If there are no such holes, the workpieces are temporarily fixed with clamps and short welds.

Most parts of metal devices are welded by electric welding or connected using bolted joints. The degree of reliability of such connections depends on the force with which the bolts are tightened. Typically, this work is done by two installers who tighten the nuts using long-handled wrenches or pneumatic nutrunners.

Full connection of structural elements of trusses by electric welding produced in cases where it is required to obtain the most durable connection. Particularly important fixings of parts can be made using thick steel rivets.

Assembly of assembled structures is carried out with a crane, and heavy structural structures can be installed with two cranes. After mounting the fully assembled structure on the columns, it is welded to the embedded plate, which is rigidly fixed on the head of the column.

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