The truss is semicircular from a profile pipe. How to build metal trusses: calculation and welding of trusses from a shaped pipe.

Sheds on a metal frame make life easier. They will protect the car from bad weather, cover the summer veranda and gazebo. They will replace the roof of the workshop or the visor above the entrance. Turning to professionals, you will get any kind of canopy. But many will cope with the installation work themselves. True, an accurate calculation of the farm from shaped pipe... You cannot do without the appropriate equipment and materials. Of course, welding and cutting skills are also required.

Frame material

The basis of awnings is steel, polymers, wood, aluminum, reinforced concrete. But, more often the frame is made up of metal trusses from a profile pipe. This material is hollow, relatively lightweight, but strong. In section it looks like:

rectangle;
square;
oval (as well as semi- and flat-oval shapes);
polyhedron.

When welding from a profile truss pipe, a square or rectangular section is often chosen. These profiles are easier to process.

Variety of pipe profiles

Permissible loads depend on wall thickness, metal grade, manufacturing method. The material is often high-quality structural steels (1-3ps / cn, 1-2ps (cn)). For special needs, low-alloyed alloys and galvanizing are used.

The length of profile pipes usually ranges from 6 m for small cross-sections to 12 m for large ones. The minimum parameters are from 10 × 10 × 1 mm and 15 × 15 × 1.5 mm. With increasing wall thickness, the strength of the profiles increases. For example, on sections 50 × 50 × 1.5 mm, 100 × 100 × 3 mm and more. Products of maximum dimensions (300 × 300 × 12 mm and more) are more suitable for industrial structures.

As for the parameters of the wireframe elements, there are the following recommendations:

for small sheds (up to 4.5 m wide), pipe material with a cross section of 40 × 20 × 2 mm is used;
if the width is up to 5.5 m, the recommended parameters are 40 × 40 × 2 mm;
for canopies of larger sizes, it is advised to take pipes 40 × 40 × 3 mm, 60 × 30 × 2 mm.

What is a farm

A truss is called a pivot system, the basis of a building structure. It consists of rectilinear elements connected at nodes. For example, the design of a truss made of a shaped pipe is considered, in which there is no misalignment of the rods and no off-node loads. Then, only tensile and compressive forces will arise in its component parts. The mechanics of this system allows it to maintain geometric constancy when replacing rigidly mounted units with hinged ones.

The farm consists of the following elements:

upper belt;
lower belt;
stand perpendicular to the axis;
brace (or brace) inclined to the axis;
auxiliary support brace (sprengel).

The lattice system should be triangular, diagonal, half-diagonal, cross. For connection, kerchiefs, paired materials, rivets, welds.

Mounting options in knots

The manufacture of trusses from a profile pipe involves the assembly of a belt with certain outlines. By type they are:

segment;
polygonal;
gable (or trapezoidal);
with parallel belts;
triangular (d-i);
with a raised broken lower belt;
single-slope;
console.

Some systems are easier to install, others are more economical in terms of material consumption, and still others are easier in terms of the arrangement of support units.

Farm Calculation Basics

Influence of the angle of inclination

The choice of the structure of canopy trusses from a profile pipe is associated with the slope of the designed structure. There are three possible options:

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

At the minimum angle (6 ° -15 °), trapezoidal belts are recommended. To reduce weight, a height of 1/7 or 1/9 of the total span is allowed. When designing a sloping canopy of complex geometric shape, it is necessary to raise it in the middle above the supports. Take advantage of the Polonso farms recommended by many experts. They are a system of two tightened triangles. If you need a tall structure, it is better to choose a polygonal structure with a raised lower chord.

When the slope angle exceeds 20 °, the height should be 1/7 of the total span. The latter reaches 20 m. To increase the structure, the lower belt is made broken. Then the increase will be up to 0.23 of the span length. Tabular data is used to calculate the required parameters.

Table for determining the slope of the rafter system

With a slope over 22 °, calculations are carried out according to special programs. Sheds of this kind are more often used for roofs made of slate, metal and similar materials. Here, triangular trusses from a profile pipe are used with a height of 1/5 of the entire length of the span.

The greater the angle of inclination, the less precipitation and heavy snow will accumulate on the canopy. The load-bearing capacity of the system increases with its height. Additional stiffeners are provided for additional strength.

Base angle options

To understand how to calculate a truss from a profile pipe, it is imperative to find out the parameters of the basic nodes. For example, the span dimensions should usually be specified in the terms of reference. The number of panels, their dimensions are assigned in advance. Let's calculate the optimal height (H) in the middle of the span.

If the belts are parallel, polygonal, trapezoidal, H = 1/8 × L, where L is the length of the truss. The upper chord should have a slope of about 1/8 × L or 1/12 × L.
For the triangular type, on average, H = 1/4 × L or H = 1/5 × L.

The lattice braces should have a slope of approximately 45 ° (within 35 ° -50 °).

Use a ready-made standard project, then you don't have to make a calculation

In order for the canopy to be reliable and to serve for a long time, its project requires precise calculations. After the calculation, materials are purchased, and then the frame is mounted. There is a more costly way - to purchase ready-made modules and assemble the structure on site. Another option is more difficult - to do the calculations yourself. Then you will need data from special reference books on SNiP 2.01.07-85 (impact, load), as well as SNiP P-23-81 (data on steel structures). You need to do the following.

Decide on the block diagram in accordance with the functions of the canopy, the angle of inclination, the material of the rods.
Select options. Consider the relationship between the height and the minimum weight of the roof, its material and type, slope.
Calculate the panel dimensions of the structure according to the remoteness of the individual parts responsible for the transfer of loads. The distance between adjacent nodes is determined, usually equal to the width of the panel. If the span is more than 36 m, the building lift is calculated - the reverse bend that is absorbed due to the loads on the structure.

Among the methods for calculating statically definable trusses, one of the simplest is the cutting of nodes (sections where the rods are pivotally connected). Other options are the Ritter method, the Henneberg rod replacement method. And also a graphical solution by drawing up a Maxwell-Cremona diagram. In modern computer programs, the method of cutting out nodes is more often used.

For a person with knowledge of mechanics and strength of materials, it is not so difficult to calculate all this. The rest should take into account that the service life and safety of the canopy depend on the accuracy of the calculations and the magnitude of the errors. It may be better to consult a specialist. Or choose an option from ready-made design solutions, where you simply substitute your values. When it is clear what kind of truss is needed from a profile pipe, a drawing for it will probably be found on the Internet.

Significant factors in site selection

If the shed belongs to a house or other building, it will require official permission, which will also have to be taken care of.

First, a site is selected where the structure will be located. What is taken into account in this case?

Constant loads (fixed weight of battens, roofing and other materials).
Variable loads (impact of climatic factors: wind, precipitation, including snow).
A special type of load (is there seismic activity in the region, storms, hurricanes, etc.).

Also important are the characteristics of the soil, the influence of nearby buildings. The designer must take into account all significant factors and refinement factors that are introduced into the calculation algorithm. If you plan to carry out calculations on your own, use the programs 3D Max, Arkon, AutoCAD or similar. There is a calculation option in online versions of construction calculators. It is imperative to find out for the intended project the recommended step between the bearing supports, the crate. As well as the parameters of materials and their quantity.

An example of a software calculation for a canopy covered with polycarbonate

Sequence of work

The assembly of the frame from metal profiles should only be carried out by a welding specialist. This responsible business requires knowledge and skillful handling of the tool. It is necessary not only to understand how to weld a truss from a profile pipe. It is important which nodes are more correct to assemble on the ground, and only then raise them on the supports. If the structure is heavy, a technician is required for installation.

Usually the installation process takes place in the following sequence:

The plot is being marked. Embedded parts, vertical supports are installed. Often, metal pipes are immediately placed in the pits, and then they are concreted. The verticality of the installation is checked with a plumb line. To control parallelism, a cord or thread is pulled between the extreme posts, the rest are set along the resulting line.
Longitudinal pipes are fixed to the supports by welding.
Knots and elements of trusses are welded on the ground. With the help of braces and jumpers, the belts of the structure are connected. Then the blocks should be raised to the desired height. They are welded to the longitudinal pipes along the vertical support areas. Longitudinal jumpers are welded between the trusses along the slope for further fastening of the roofing material. Holes are made in them for fasteners.
All connecting sections are thoroughly cleaned. Especially the upper edges of the frame, where the roof will lie in the future. The surface of the profiles is cleaned, degreased, primed and painted.

Using the ready-made project, you will quickly start assembling the canopy

Experts advise to carry out such important work only with the appropriate experience. It is not enough to know in theory how to properly weld a truss from a profile pipe. Having done something wrong, ignoring the nuances, the home master takes risks. The canopy will fold and collapse. Everything under it will suffer - cars or people. Therefore, take knowledge into service!

Video: how to weld a truss from a profile pipe

Before you start creating a canopy with your own hands, you need to make a drawing and calculate all the elements and attachment points, this will allow you to build a reliable structure with minimal financial and labor costs. The drawing and project of a canopy made of metal structures will help in solving a number of issues, ranging from the nomenclature and quantity of purchased building materials and ending with the exterior of the building and the general design of the site.

The article will provide a list of requirements for the structure, examples of calculations of the most common structures and general recommendations for designing a carport for a car with your own hands, drawings and diagrams.

What should a canopy project contain?

Strength calculation of supporting structures - supports and trusses;
Calculation of the roof windage (resistance to wind load);
Calculation of the snow load on the roof;
Sketches and general drawings of the canopy;
Drawings of the main structural elements with indications of overall dimensions;
Design and estimate documentation, including the calculation of the quantity building materials of each type and their cost. Depending on the developer's experience, consumption rates (trimming during installation) can be taken into account or 10-15% is simply added to the metric area of rolled metal.

Canopy to the house - projects, photos of structures that perform various functions

General requirements for a carport

Structures that are being erected to protect the vehicle must meet the following operational and technical requirements:

The dimensions of the canopy according to the drawing must be sufficient for the free placement of the car;
The shape of the canopy, which provides protection against moisture ingress, takes into account the prevailing wind whenever possible;
The design protects from direct sunlight throughout the day;
Unobstructed, sufficient width access to the shed, if possible without turns along the entire route;
The machine must be freely accessible from all sides;
Sufficient simplicity of the drawing, supporting structures and a frame for a canopy made of a profile pipe or other material;
Harmonious combination with the house and buildings on the personal plot;
Minimization of costs for the purchase of building materials and installation work.

The simplest do-it-yourself shed from a metal profile for a device, a drawing with basic dimensions

Varieties of canopy shapes and their operational features and drawings

The main spatial structure of the canopy, in accordance with the drawing, is a truss truss. The calculation of its shape, thickness and section of metal, as well as the drawing of the placement of slopes, causes the greatest difficulties.

The main structural elements of the canopy truss are the upper and lower chords, which form a spatial contour. Materials for assembly can be rolled or welded I-beams, angles, channels or professional pipes of square and round cross-section. Assembling a farm for a canopy with your own hands can be done in the following forms:

Parallel belts. The slope of the finished canopy in accordance with the drawing does not exceed 1.5%, suitable for flat roll roofs. The ratio of height to length is from 1/6 to 1/8. This type of frame has several advantages:

All rods of lattice chords are of the same length;
The minimum number of connectors;
Simple calculation of the conjugation of structures.

Creating a gazebo - do-it-yourself polycarbonate canopy, drawing, photo of the finished structure

Trapezoidal (single slope). The draft angle according to the drawing ranges from 6-15 0. the ratio of height and length in the center of the product is 1/6. Has increased frame rigidity
Polygonal - are used exclusively for extended spans of 10 m or more, their use for small sheds is irrational due to the unjustified complication of the drawing and the product itself. Exceptions can be sheds with factory-made curved (arc) trusses.

Do-it-yourself canopy, polygonal canopy from a metal profile, drawing

Triangular. They are used with increased snow loads, the slope of the gable canopy is 22-30 0. The main design flaw is the complexity of the drawing and the execution of a sharp knot at the base of the product, as well as too long rods in the center. The ratio of height to width in small trusses for a polycarbonate canopy, according to the drawing, does not exceed 1/4, 1/5.

Do-it-yourself installation of a triangular canopy made of corrugated board, a design drawing indicating the main dimensions

Arched beams. The most ergonomic type of farm. Its feature is the ability to minimize bending moments in the cross-sections of the structure. In this case, the arch material is subjected to compression effects. That is, the drawing and calculations of the truss for the canopy, the calculation of the canopy structure is allowed to be performed according to a simplified scheme, in which the load from the roofing, fastening lathing and snow will be taken as evenly distributed over the entire area.

An example of calculating a carport

When designing a canopy and creating its drawing, it is necessary to calculate:

Horizontal and vertical support reactions of the truss, determine the effective stresses in the transverse directions and, based on the data obtained, select the size of the cross-section of the bearing profile;
Snow and wind loads on the roofing;
The value of the cross-section of the eccentrically compressed column.

Arched truss calculation

A drawing for calculating a truss from a profile pipe for an optimal canopy - an arched shape

For example, we take the distance between the supports 6m, and the height of the arch is 1.3 m. Transverse and longitudinal forces act on the overlap of the canopy, which form tangential and normal stresses. We calculate the cross-section of the profile pipe used in the structure according to the formula:

σ pr = (σ 2 +4 τ 2) 0.5 ≥ R / 2, where

R - strength of steel grade C235 - 2350 kgf / cm 2;

σ – normal voltage calculated by the formula:

σ = N / F, where

F is the required cross-sectional area of the pipe.

N is the concentrated load on the arch lock (we take 914.82 kgf from the table of loads of building structures by the "Designer's Guide" edited by AA Umansky).

τ - shear stress, which is calculated by the formula:

τ = QS ref / b × I, where

I - moment of inertia;

b - section width (taken equal over the entire calculated height);

QS ot - static moment, which is determined by the formula:

S ex = ∑y i F i .

Using the approximation method (sequential selection of indicators from the available data array), we select sections from the assortment of building materials available from the dealers of rolled metal products. We use the most popular profile - a metal square tube 30x30x3.5 mm. Therefore, the cross section is F = 3.5 cm 2. And the moment of inertia I = 3.98 cm 4. ∑y i- the indicator of the calculated cut-off part (the more these indicators are calculated at various points of the structure, the more accurate the obtained indicators of the strength of the entire product), for simplicity, we take a coefficient of 0.5 (calculations are made for the middle of the arch - the place of greatest conjugation of loads).

We substitute the data into the formula:

S op = 0.5x3.5 = 1.75 cm 3;

The primary formula after substitution will look like this:

σ pr = ((914.82 / 3.5) 2 + 4 (919.1 1.854 / ((0.35 + 0.35) 3.98) 2) 0.5 = 1250.96 kg / cm 2

Consequently, the selected cross-section of a square-section pipe 30x30x3.5 mm made of steel grade C235 is quite enough for the device of a 6 m arched truss covered with polycarbonate, corrugated board, metal tile or metaloprofile.

Column calculation

The calculation is made in accordance with SNiP II-23-81 (1990). According to the methodology for calculating metal columns, when arranging a carport for a car with your own hands, the drawings should take into account that it is virtually impossible to apply a concentrated load exactly to the center of the cross-section. Therefore, the formula for determining the area of the support will be as follows:

F = N / φR y, Where

F is the required cross-sectional area;

φ - coefficient of longitudinal bending;

N - concentrated load applied to the center of gravity of the support;

R y - the design resistance of the material, determined by reference books.

φ - depends on the material (steel grade) and the flexibility of the structure - λ, determined by the formula:

λ = l ef / i, Where

l ef - the estimated length of the column, depending on the method of fixing the ends, is determined by the formula:

l ef = μ l where

l - the actual length of the column (3m);

μ - coefficient from SNiP II-23-81 (1990), taking into account the method of fixing.

Column fastening factor according to the drawing of the canopy from the profile pipe

We substitute the data into the formula:

F = 3000 / (0.599 · 2050) = 2.44 cm², round up to 2.5 cm².

In the table of assortment of profile products, we are looking for the value of the radius of gyration greater than that obtained. The required indicators correspond steel pipe with a cross section of 70 × 70 mm and a wall thickness of 2 mm, which has a radius of gyration of 2.76.

Snow and wind loads on roofing

The averaged data on wind and snow loads by regions are taken from the SNiP “Loads and Impacts”. Take, for example, the maximum value for Moscow and the Moscow region, it is 23 kg / m 2. However, this is a wind load on a structure that has walls. In our case, the supporting structures are columns, therefore, the coefficient of positive wind pressure on the inner surface of the roof will be 0.34. At the same time, the indicator taking into account changes in the wind load along the height of the building for awnings of 3 m is 0.75. Substituting the data into the formula, we get:

W m = 23 0.75 0.34 = 5.9 kg / m2.

The maximum snow load for the same region is Sg = 180 kg / m 2, but for the arch it is necessary to calculate the distributed load according to the formula:

S = S g μ, where

μ is the value of the transition coefficient, which is taken separately for the center of the arch and the extreme supports.

Calculation of snow load when creating a polycarbonate canopy with your own hands, drawings of the direction of pressure in two positions

The value of the coefficient µ for the center of the arch, according to the drawing, is µ 1 = cos1.8 · 0 = 1, and for the extreme supports µ 2 = 2.4sin1.4 · 50 = 2.255. Substituting the calculated data into the formula, we obtain the total load on the roofing:

q = 180 2.255 cos 2 50 o + 5.9 = 189.64 kg / m 2 = 1.8964 kg / cm 2.

According to the data obtained, the thickness of the roofing material is calculated by the formula:

I tr = ql 4 / (185Ef), where

l - span length;

E - modulus of elasticity in bending (for polycarbonate it is 22500 kgf / cm 2);

f is the deflection coefficient at maximum load (according to the data of polycarbonate manufacturers it is 2 cm);

Substituting the data into the formula, we get the admissible value of inertia:

I tr = ql 4 / (185Ef) = 1.8964 63 4 / (185 22500 2) = 3.59 cm 4

At the same time, from the data of polycarbonate manufacturers, the indicator of the moment of inertia for cellular polycarbonate with a width of 1 m and a thickness of 0.8 mm is 1.36 cm 4, and for a thickness of 16 mm 9.6 cm 4. Using the correlation method, we determine the required value of 3.41 cm 4 for cellular polycarbonate with a thickness of 12 mm.

The calculation method is valid for any sheet roofing material: profiled sheet, metal tiles, slate, etc. But at the same time, the extremely limited range of these products should be taken into account.

Summing up

It makes sense to make the specified calculations and create a drawing manually if the erected canopy must correspond to the unique operating conditions and the original layout. To check the elements of typical metal structures for compliance and create structural drawings, there are many programs: Astra WMs (p), SCAD Office 11, ArkaW, GeomW and many others or online calculators. The rules for working with such software describe in sufficient detail various video instructions, for example, calculation and drawings of an arch in SCAD:

At the heart of the overlap of any outbuilding, be it a residential building, a hangar, an industrial workshop or a whole stadium, a special frame is laid - a farm. The most popular in recent years have become trusses from a profile pipe. We will tell you about the types of trusses made of shaped pipes, as well as how to make calculations for the manufacture of a particular structure, later in the material.

There are many varieties of metal trusses from a profile pipe, and in some cases they even become the basis for chimneys. But in order for the whole structure to be strong and reliable, you need to correctly complete the drawing, according to which the frame will be made.

Variety of metal pipe trusses

As a rule, a metal profile is used for the manufacture of trusses from a shaped pipe. Its shape is oval, round, square, but most often a rectangular shaped pipe is used.

By their structure, structures made of shaped pipes are divided into two types: structural elements of the frame can be fixed in one plane; the truss can be folded from the lower and upper chords.

In addition, the classification of rectangular pipe trusses is based on factors such as the level of load on the profile, the angle of inclination of the elements, the overall slope of the structure, the length of individual spans, and the nature of the location of the floors.

Based on these parameters, all typical trusses from a profile pipe consist of the following groups:

Farms, the slope angle of which reaches the order of 22-30º. For such a structure to be stable, its height should be equal to 1/5 of the length of the product, or be slightly less. As a rule, this norm is taken as a basis when calculating the required height of the structure, that is, the given length of the product is simply divided by 5. This type of truss is preferable if the structure should be as lightweight as possible. If the estimated length of the structure is more than 14 meters, then the position of the braces in the structure of the truss from the shaped pipe for the canopy will be vertical. On the upper tier, pieces of a profile with a length of 150-250 cm are fixed. As a result, the entire frame will consist of two belts, with the number of panels being a multiple of two. Pay attention to the fact that if the truss is very long - more than 20 meters, additional support pillars will be needed that will support the rafter system and allow the load to be redistributed throughout the structure. Often, for the construction of a frame for floors, they use the Polonso farm scheme. It is a triangular structure, in which the connection is in the form of a tightening. During its construction, the braces are not very long, which significantly lightens the weight of the entire farm. Due to this quality, the trusses from the Polonso shaped pipe are used quite often.
The roof slope on the farm reaches 15-22º. This type of structure is preferable for buildings, the length of which does not exceed 20 meters. In height, such a structure should not exceed 1/7 of the length of the structure. If it is necessary to increase the height of the truss, then its lower belt should consist of broken segments.
Frames with a total slope of no more than 15º. As a rule, if we are talking about this kind of farm, then it is made in the shape of a trapezoid. Based on the purpose of the building, as well as the angle of the roof, the owner determines the height of the structure independently. It should be based on indicators between 1/7 and 1/12 of the length of the building. A trapezoid-shaped roof frame is made using metal panels, the length of which should be in the range of 1.5-2.5 meters. If the drawing of a truss from a profile pipe does not provide for a suspended ceiling, then instead of braces, you can use a triangular lattice.

According to the shape, the trusses made of steel profile pipes can be divided into:

straight;
arched;
single-pitch and gable.

The most popular and frequently used type of steel profile trusses are arched. Their design is quite durable and effective, in addition, such a truss can be covered with polycarbonate sheets. However, in order to achieve the most even distribution of the load on the profile of the arched truss, calculations should be carried out carefully. For the construction of arch-type trusses, both single profile pipes and pre-welded pipes can be used.

Steel profile truss drawing

Drawing up a drawing and calculating a truss from a profile pipe is carried out in compliance with the following method:

First of all, you should do the calculations of the planned or actual length of the room, for example, a garage, hangar, shed or summer shed. The data obtained will be taken into account when calculating the height of the truss from the profile. But the length of the steel frame can vary depending on the angle of inclination of the roof.
The next step is to determine what shape the profile will be used. The choice largely depends on the functional purpose of the hangar, the angle of the roof slope, as well as the type of roofing material.
After carrying out all the measurements, it is necessary to find out whether it will be possible to transport the farm to the installation site if it is assembled on the construction site.
You will also have to take care of equipping the mechanism for building roof lifting, if the length of the object reaches values within 12-36 meters.
Further, the calculations of the parameters of the panels are made, based on the level of the expected loads to which the building will be subjected permanently or periodically. For a triangular truss, the slope will be 45 degrees.
At the final stage, a step is laid between the nodes and a drawing of the future truss is made from a shaped pipe, based on the data obtained.

Note that in order to obtain the most correct calculations when preparing drawings for an arched truss, it is better to use an engineering calculator. In addition, special computer programs and algorithms have now been developed to help designers, so there is no need to count manually.

How to calculate an arched profile truss

In order to disassemble the methodology for calculating an arched truss from a shaped pipe, we will give an example with specific numbers.

The individual sections of the truss will be placed at a distance of 105 cm, with the maximum load falling on the nodal points. In this case, the height of the arch will not be more than 3 meters. Moreover, it is advisable to make an arch with a height of 1.5 m, which will make it more durable, safe and quite attractive in appearance. The truss length (L) will be 6 meters and the lower chord boom (f) is 1.3 meters. In the lower tier, the radius of the circle (r) will be 4.1 meters, and the angle between the radii is α = 105.9776º.

To calculate the length of the profile for the lower tier, use the formula:

mн = π × Rα / 180, where

mн - the length of the profile for the lower tier;

R is the radius of the circle;

π is a constant.

Thus, we get the following calculation:

mн = 3.14 × 4.1 × 106/180 = 7.58 meters.

At the same time, in the lower belt, the step between the corner points will be 55.1 cm, but for the extreme segments on both sides in the belt, the step must be determined independently. You can use the rounded value of 55 cm, however, in any case it is undesirable to increase the stride length.

If a profile truss is required for small-sized structures, then you can limit yourself to the number of spans in 8-16 pieces. If we take a smaller number of spans, then the panels in length will reach 95.1 cm with a step between the belts within 87-90 cm.With the greatest number of segments, the step will be 40-45 cm.

Profile calculation standards for a farm

For the correct choice of a profile, especially if it will be used in large structures, one should build on the SNiP indicators:

07-85 - information on the nature of the relationship between the weight of structural elements of a structure and the effect of snow loads;
P-23-81 - the sequence of work with steel shaped pipes.

Guided by these documents, you can decide which type of truss to choose for a particular type of building, which one to lay the angle of the roof, and also to choose the correct section and dimensions of the profile pipe for the supporting pillars. In particular, the regularity and intensity of rainfall during winter can greatly influence the choice of profile for a farm.

For clarity, consider a real example of calculations for a single-pitched truss from a profile pipe. A shed with dimensions of 4.7 × 9 meters will be built. In the front, it should rest on the support posts, and the back will be fixed to the residential building. The building will be located in the Krasnodar Territory, where the level of snow load in winter time is 84 kg / m 2. The total slope of the structure will be only 8 degrees.

Each of the racks will be 2.2 meters high and weigh about 150 kg. In this case, the load on them will reach 1100 kg. In this case, neither round nor oval shaped pipes are acceptable. You need to use square 45 mm profiled products with a wall thickness of 4 mm.

Alternatively, the structure of the truss can be slightly modified by adding to it 2 parallel belts with an oblique lattice between them, in which case it is possible to do with profiles with a wall of 3 mm and a section of 25 mm. The truss height of 40 cm assumes the use of profiled pipes with a cross section of 35 mm and walls of 4 mm.

The ratio of the profile section and wall thickness depending on the load can be found in GOST 30245.

So that the profiles in the arch truss are protected from impact the environment and were reliable, they must be made of quality material preferably alloy steel with sufficient carbon inclusion.

When developing a metal farm project, you should pay attention to a number of nuances:

to lighten the total weight of the metal truss, it is possible to install auxiliary gratings during the construction of the hangar - the option is acceptable if the slope of the roof is small enough;
the broken shape of the lower belt will help to significantly reduce the mass of the structure with an average slope angle;
the strength of the roof can be ensured if the trusses are placed in increments of no more than 175 cm.

Assembling and welding of trusses from profiled metal pipes must be carried out in compliance with the following standards:

For a strong connection of all structural parts of the structure, paired corners and tacks are used.
In the lower chord, equilateral corners are used for welding elements.
For the upper chord of the truss, I-beams are used for welding. They are fixed end-to-end on the smallest sides of different lengths.
To ensure that the load is evenly distributed throughout the structure, paired channels and lining plates are used. As a rule, this technique is used when you need to make the canopy longer.
All welds should be carefully checked at the end of the work. After that, you can clean up.
If necessary, at the end, the farm is painted with an anti-corrosion compound. If the profile is made of alloy steel, then it does not need painting.

Thus, for numerous buildings of economic or industrial use, trusses are very often made from profiled pipes. Due to the significant complexity and laboriousness of the calculation process, it is better to entrust the design and creation of a drawing to professionals.

Sheds have long and firmly entered our life. Under the canopy, your family gathers on a summer evening to have a cup of tea, under the canopy you can safely leave your car, and your pool stays clean under the canopy.

Despite the fact that the canopy is the simplest architectural structure, their design features can be very different. The simplest and most easily do-it-yourself canopy is a structure on four or more supports, with an upper strapping and a rafter system. But such a canopy is only suitable to protect a small space. For more massive structures, so-called shed trusses will be needed.

What does the concept of a canopy farm mean? A truss is a metal frame structure that has two belts at the top and bottom. Using a welding machine, these belts are connected by means of vertical posts and braces. The use of trusses in the construction of do-it-yourself sheds helps the structure to withstand increased loads.

You can buy ready-made farms, but you can make them yourself. In order for a canopy or other self-built structure to turn out to be strong and durable, you will need some calculations.

The shape of the canopy roof. For each forms, single-slope, arched, gable, hipped-roof, the calculation will be made, since the type of belt will be individual.
Another important factor will be the size of the canopy. Remember, the wider the gap between the trusses, the more load they will have to withstand. When making the calculation, determine the stingrays extreme points vertically. The steeper the slope angle, the less snow will remain on it.
Knowing the dimensions of the panels of cellular polycarbonate, it is easier to calculate the distance between the trusses.
By referring to the maps, you can calculate the maximum load from precipitation and wind.

In general, it is not so easy to calculate the trusses yourself, unless you are an engineer. Without a technical education, you can, with the size of the canopy, find a suitable scheme and project on the Internet. But nevertheless, the best solution to the problem would be to contact a specialist in the construction industry. He will help you make the calculation correctly, taking into account all the permissible loads, and will also advise which materials are suitable for your type of canopy. Based on this, you can correctly calculate the approximate cost of the canopy, and this is one of the fundamental factors that everyone is interested in before starting the manufacture of the canopy.

Profile pipes have always been considered the best material for making trusses. Profile pipes made of of stainless steel have their own advantages:

Profile pipes do not deform under heavy loads.
The cavity inside reduces the weight of the pipes.
Cheapness.
The ability to create strong and durable structures.

For the roof, it is better to use one of the types of polycarbonate - honeycomb or cast. Polycarbonate sheets are attached with self-tapping screws. The polycarbonate coating allows to create a roof that is not subject to corrosion,

Calculation of trusses for a lean-to shed

A gable canopy is one of the most common types of such structures, which are built with their own hands and used for temporary storage of equipment and other needs. The standard dimensions of the canopy, as a rule, have dimensions6, width 4 meters, length 6 meters. The standard width of the polycarbonate plates is 2.1 m.

The location of the trusses under the polycarbonate plates will be as follows: in the middle and under the edge of the sheet. The truss for the canopy, as mentioned above, will be made of a square shaped pipe made of a metal profile with a cross section of 30 mm. The length of the upper pipe will be 4000 mm, the lower one - 3200 mm. Square pipes that play the role of spacers should have a cross section of 20 mm. They are connected to the upper and lower pipes in the form of a zigzag, at an angle equal to 25 °. Next, the trusses are connected with their own hands to each other, they are welded to guides made of a square profile, the cross-section of which is 30 mm.

A small number of trusses can be connected at the bottom and then lifted up. This is easy enough to do, but for heavier structures, you will have to involve additional equipment and resort to the help of third parties.

Assembling the frame using ready-made trusses

The procedure for assembling a metal frame looks like this:

On the marked area y, supports are installed and concreted, the location should be vertical, which is easy to do by resorting to a level or plumb line.
Longitudinally square pipes are welded to the installed racks.
The truss is mounted on the ground, braces and lintels are welded to the belts at the top and bottom. The trusses are lifted onto supports and welded.
At a distance of half a meter, jumpers are welded to each truss, this is the basis for attaching polycarbonate sheets.
All metal parts are cleaned, degreased, primed and painted. Careful preparation of the framework will help protect it from corrosion.

Necessary construction conditions

All buildings must comply with GOST building standards.

To ensure snow melting, the canopy slope must be installed at an angle of 25-30 °.

Profile pipes must have a wall of at least 3mm.

In order to prevent sagging of polycarbonate sheets, there should be no more than 1.75 m distance between trusses.

The overhang of the polycarbonate sheets beyond the frame by 15 cm is necessary, this will not allow rain drops to fall on the metal parts.

The end parts of the polycarbonate sheets are covered with profiles to prevent the penetration of foreign objects and water into the polycarbonate.

It is possible to make your own farm correctly only if you already had experience in welding. In this case, manufacturing will not require any effort from you, and you can weld the structure very quickly.

In conclusion, I would like to say that the canopy structure is durable, with a proper approach to the technical side of construction. A correctly calculated calculation and application of the latest technologies will allow you to build a functional and convenient structure in the shortest possible time.

Determination of the internal efforts of the farm

Often we do not have the opportunity to use a conventional beam for a particular structure, and we are forced to use a more complex structure, which is called a truss.
although it differs from the calculation of the beam, it will not be difficult for us to calculate it. All that will be required of you is attention, basic knowledge of algebra and geometry, and an hour or two of free time.
So, let's begin. Before calculating the farm, let's ask some real-life situation that you might encounter. For example, you need to cover a garage 6 meters wide and 9 meters long, but you have no floor slabs or beams... Only metal corners of various profiles. Here we are going to build our farm from them!
Subsequently, the girders and corrugated board will rely on the farm. The support of the truss on the walls of the garage is articulated.

First, you will need to know all the geometric dimensions and angles of your truss. This is where we need our mathematics, namely geometry. The angles are found using the cosine theorem.

Then you need to collect all the loads on your farm (see the article). Suppose you have the following loading option:

Next, we need to number all the elements, the nodes of the truss and set the support reactions (the elements are marked in green, and the nodes in blue).

To find our reactions, we write down the equations of equilibrium of efforts on the y-axis and the equation of equilibrium of moments relative to node 2.

Ra + Rb-100-200-200-200-100 = 0;
200 * 1.5 + 200 * 3 + 200 * 4.5 + 100 * 6-Rb * 6 = 0;

From the second equation we find the reference reaction Rb:

Rb = (200 * 1.5 + 200 * 3 + 200 * 4.5 + 100 * 6) / 6;
Rb = 400 kg

Knowing that Rb = 400 kg, from the 1st equation we find Ra:

Ra = 100 + 200 + 200 + 200 + 100-Rb;
Ra = 800-400 = 400 kg;

After the support reactions are known, we must find the node where the least unknown quantities are (each numbered element is an unknown quantity). From this point on, we begin to divide the truss into separate nodes and find the internal forces of the truss rods in each of these nodes. It is for these internal efforts that we will select the sections of our rods.

If it turns out that the efforts in the rod are directed from the center, then our rod tends to stretch (return to its original position), which means that it itself is compressed. And if the efforts of the rod are directed towards the center, then the rod tends to compress, that is, it is stretched.

So, let's move on to the calculation. In node 1, there are only 2 unknown quantities, so we will consider this node (we set the directions of efforts S1 and S2 from our own considerations, in any case, we will get it right as a result).

Consider the equilibrium equations on the x and y axes.

S2 * sin82.41 = 0; - on the x-axis
-100 + S1 = 0; - on the y-axis

From the 1st equation, it can be seen that S2 = 0, that is, the 2nd bar is not loaded!
From the 2nd equation it can be seen that S1 = 100 kg.

Since the S1 value turned out to be positive, it means that we chose the direction of effort correctly! If it turned out to be negative, then the direction should be changed and the sign changed to "+".

Knowing the direction of effort S1, we can imagine what the 1st rod is.

Since one force was directed to the node (node 1), then the second force will be directed to the node (node 2). This means that our rod is trying to stretch, which means it is compressed.
Next, consider node 2. It had 3 unknown quantities, but since we have already found the value and direction of S1, then only 2 unknown quantities remain.