Calculation of the visor for wind load. How to correctly calculate trusses for canopies: drawing and assembly rules. General calculation methodology

Before starting the manufacture of any structure, you need to develop a sketch that will allow you to see the general view of the object of construction, the appearance of its individual elements. At the next stage, a drawing is created, which indicates the main dimensions of the entire structure, as well as the dimensions of the mating elements. To achieve strength, you need to calculate the polycarbonate canopy.

Design parameters

To ensure the overall strength of the structure, the dimensions of the panels play an important role: thickness, length, width.

The dimensions of the polycarbonate sheet are directly responsible for the strength of the panel +

In order for the roof, the roof of which is built of polycarbonate plates, to have the necessary strength, it is necessary, taking into account the snow and wind loads, to choose the optimal thickness of the panels.

Monolithic sheets are produced in thicknesses of 2, 3, 4, 5, 6, 8, 10 and 12 mm.

Honeycomb sheets have the following thickness parameters:

• up to 32 mm - five-layer with inclined partitions of cells, designated SX;
• 16–20 mm - five-layer, in which the cell is in the form of a rectangle, designated SW;
• up to 16 mm - three-layer, with a rectangular cell structure, as well as adjustable stiffeners - 3X;
• 6-10 mm - three-layer, rectangular cell structure - 3H;
• 4, 6, 6, 10 mm - with square cells - 2H.

There are different types of cellular polycarbonate

The monolithic type polymer has parameters of 3050 × 2050 mm.

Video: "Arched canopy 8 x 6 meters"

From this video you will learn how to make an arched polycarbonate canopy:

How to make calculations correctly

To calculate the strength characteristics of structures made of any plastic compound, you need to know:

• purpose of the structure;
• the place where it will be located;
• design of the surrounding interior;
• the dimensions of the sheltered object;
• snow load, wind strength;
• overall dimensions, mechanical characteristics of polycarbonate panels;
• frame shape;
• material of the frame, rafters, supports, lintels, lathing, fasteners.

Before installing a polycarbonate sheet to create a canopy, you need to know what material the frame is made of.

The calculation of strength is carried out both for the entire structure and for individual elements. The complexity of the calculation requires the use of special knowledge on the strength of materials, the availability of reference data required for use. In practice, empirical data are more acceptable for the construction of individual construction projects.

It is recommended that the length of the canopy be a multiple of the width of the panel, and the width is a multiple of 2, 3, 4, 6, 12 m. The dimensions of the roof should ensure that the shelter is protected from strong winds and inclined rays of the sun. The height of the structure must be greater than the height of the object to be covered, but not less than 180 cm. Above the machine, a ventilated space of up to 10 cm is required. The shape of the canopy roof depends on the owner's taste.

• round steel pipe with a diameter of 100 mm;

For the installation of a polycarbonate canopy, it is recommended to install supports made of steel pipes with a diameter of 100 mm

• profiled steel pipe with dimensions 80 × 80 mm;
• wooden beam 150 × 150 mm;
• logs with a diameter of 150-200 mm.

The lathing in the longitudinal direction is performed in increments of up to 70 cm, in the transverse direction - up to 100 cm.

Calculation of the strength of the structure of the structure depends on the type of roof (pitched, gable, arched).

For a pitched roof

There are two types of pitched roofs:

• with fastening to the building wall;
• without fastening to the wall of the building or a free-standing building.

The method of attaching the frame to the foundation supports is the main difference between the varieties of the shed visor.

There are two types of pitched roofs: wall-mounted or as a separate building

The canopy, attached to the wall of the building, is a structure, the advantage of which is that the number of support posts is half as much, since the function of supports on one side of the canopy is performed by the wall of the house. In this case, a truss in the form of an elongated triangle is installed with the end of its short side on a beam attached to the wall of the house. At the other end, the truss rests on a bearing support.

The elements of each type of visor are counted according to the following scheme:

For gable roof

Calculation of the characteristics of a structure with a gable roof is similar to calculating the strength of a gable canopy.

The calculation of the dimensions of a gable canopy is similar to the calculation of dimensions for a gable

There are three differences:

• the console, which resembles an isosceles triangle in shape, can be either integral or composite;
• due to the increase in the weight of the consoles, for a more even distribution of their weight, it is recommended to increase the number of vertical supports;
• installation of a ridge beam and a ridge is required.

For arched canopy

Arched structural elements are counted in the same way as for a single-pitched one.

Saving of the material used is ensured by a decrease in its cost due to the additional strength achieved due to the design feature:

• bending of polymer panels, since the shape itself contributes to an increase in strength;

Due to its design feature, the arched canopy is a very strong structure.

• the arched form of the trusses, which allows, by reducing the wall thickness of the metal profile or the cross-section of the timber, to reduce the consumption of material.

For freestanding buildings

When calculating a canopy in the yard, it is necessary to take into account not only the size, but also the amount of precipitation in winter, since the snow has a strong mechanical load. For this reason, a triangle is the best option for stiffening the frame. In addition, this is the only geometric figure that does not provide for backlash.

For calculations, the conditional roof width of 6 m is taken, and the length is 10.6 m.Polycarbonate will be needed with a width of 2100 × 600 mm. Rafters can be made both from a pipe profile (60 × 40 mm) and from a wooden board (100 × 50 mm). Of course, a metal profile is preferable due to its very long service life.

When building a canopy as a separate structure, it is necessary to take into account the amount of snow that fell in winter

The best option is a construction where the upper part of the ramp is 240 cm, and the rafter device consists of eleven triangles. Taking into account the fact that metal profiles, as a rule, have a length of 6 m, the width will differ slightly in the smaller direction, however, six profiles are required for each rafter leg, taking into account the vertical and inclined lintels. Thus, you will need six rafters and five sheets of polycarbonate.

Basically, you can save on metal by making only two triangles. Then the calculation of the canopy frame will be reduced by at least two profiles for each rafter leg, but if there are six of them, then this is already twelve profiles. However, for an average amount of precipitation, this is quite enough.

Whatever shed you build, the correct calculation will ensure its long-term flawless operation.

• Sheds belong to the category of the simplest structures that are erected in a suburban or summer cottage. They are used for a variety of purposes: as a parking lot, a storage area and many other options.

  Structurally, the canopy is extremely simple. it

  • a frame, the main element of which are shed trusses, which are responsible for the stability and strength of the structure;
  • coating. It is made of slate, polycarbonate, glass or profiled sheet;
  • additional elements. As a rule, these are elements of decoration that are placed inside the structure.

  The design is quite simple, besides it weighs a little, so it can be assembled with your own hands right on the site.

  However, in order to get a practical, correct canopy, first of all, you need to ensure its strength and long-term operation. To do this, you should know how to calculate a farm for a shed, make it yourself and weld or buy ready-made.

  Metal trusses for awnings

  

  This design consists of two belts. The upper chord and the lower chord are connected through braces and vertical posts. She is able to withstand significant loads. One such product weighing from 50-100 kg can replace three times larger metal beams. With the correct calculation, a metal truss in, channels, or does not deform and does not bend when exposed to loads.

  The metal frame is subjected to several loads at the same time, so it is so important to know how to calculate a metal truss in order to accurately find the equilibrium points. Only in this way will the structure be able to withstand even very high influences.

  How to choose material and cook them correctly

  

  The creation and self-installation of canopies is possible with a small structure. Trusses for sheds, depending on the configuration of the belts, can be made of profiles or steel corners. For relatively small structures, it is recommended to choose shaped pipes.

  This solution has several advantages:

  • The bearing capacity of a profile pipe is directly related to its thickness. Most often, a material with a square of 30-50x30-50 mm in cross-section is used to assemble the frame, and pipes of a smaller cross-section are suitable for structures of a small size.
  • Metal pipes are characterized by great strength and at the same time that they weigh much less than a solid bar of metal.
  • Pipes are bent - a quality necessary when creating curved structures, for example, arched or domed.
  • The price of a farm for sheds is relatively small, so it will not be difficult to buy them.

  On a note

  The metal frame will last much longer if it is protected from corrosion: primed and painted.

  • On such a metal frame, you can conveniently and quite simply lay almost any crate and roof.

  Profile connection methods

  How can you weld a canopy

  Among the main advantages of profile pipes, the bezel-less connection should be noted. Thanks to this technology, a truss for spans not exceeding 30 meters is structurally simple and relatively inexpensive. If its upper belt is rigid enough, then the roofing material can be supported directly on it.

  A bezel-less welded joint has a number of advantages:

  • the weight of the product is significantly reduced. For comparison, we note that riveted structures weigh 20%, and bolted ones - 25% more.
  • reduces labor and manufacturing costs.
  • the cost of welding is small. Moreover, the process can be automated if you use machines that allow you to feed the welded wire without interruption.
  • the resulting seam and the attached parts are equally strong.

  Of the minuses, it should be noted the need for experience in welding.

  Bolt-on

  Bolted connection of profile pipes is not so rare. It is mainly used for collapsible structures.

  The main advantages of this type of connection include:

  • Simple assembly;
  • No need for additional equipment;
  • Possible dismantling.

  But at the same time:

  • The weight of the product increases.
  • Additional hardware will be required.
  • Bolted connections are less strong and reliable than welded ones.

  

  How to calculate a metal truss for a canopy from a profile pipe

  

  The structures to be erected must be sufficiently rigid and durable to withstand various loads, therefore, before installing them, it is necessary to calculate the truss from a profile pipe for the shed and draw up a drawing.

  When calculating, as a rule, they resort to the help of specialized programs taking into account the requirements of SNiP ("Loads, impacts", "Steel structures"). You can calculate a metal truss online using a metal profile canopy calculator. If you have the appropriate engineering knowledge, the calculation can be done with your own hands.

  On a note

  If you know the main design parameters, you can search for a suitable ready-made project among those posted on the Internet.

  

  Design work is performed on the basis of the following initial ones:

  • Drawing. The configuration of the frame belts depends on the type of roof: single or gable, hipped or arched. The simplest solution can be considered a single-pitched truss from a profile pipe.
  • Dimensions of the structure. The larger the pitch the trusses are installed, the greater the load they can withstand. The angle of inclination is also important: the larger it is, the easier it will be for snow to melt from the roof. For the calculation, you will need data on the extreme points of the slope and their distance from each other.
  • Sizes of elements of roofing material. They play a decisive role in determining the pitch of the trusses for a canopy, say. By the way, this is the most popular coating for structures built on their own sites. they are easily bent, so they are suitable for the device of curved coverings, for example, arched. All that matters is how it is right. calculate a canopy made of polycarbonate.

  The calculation of a metal truss from a profile pipe for a canopy is performed in a certain sequence:

  • determine the size of the span corresponding to the terms of reference;
  • to calculate the height of the structure, according to the presented drawing, the dimensions of the span are substituted;
  • perform the slope task. According to the optimal shape of the roof of the structure, the contours of the belts are determined.

  On a note

  The maximum possible pitch of trusses for a canopy when using a profile pipe is 175 cm.

  How to make a polycarbonate truss

  

  The first step in making do-it-yourself trusses from a profile pipe for a canopy is to draw up a detailed plan, which should indicate the exact dimensions of each element. In addition, it is advisable to prepare an additional drawing of structurally complex parts.

  As you can see, before making your own farms, you need to be well prepared. We note again that while aesthetic considerations are guided when choosing the shape of the product, a calculation path is required to determine the design type and number of constituent elements. When checking the strength of a metal structure, it is imperative to take into account the data on atmospheric loads in this region.

  The arc is considered an extremely simplified version of the truss. This is one profiled pipe with a round or square cross section.

  Obviously, this is not only the simplest solution, it is also cheaper. Nevertheless, polycarbonate canopy arches have certain disadvantages. In particular, this concerns their reliability.

  

  arched awnings photos

  Let's analyze how the load is distributed in each of these options. The structure of the truss ensures an even distribution of the load, that is, the force acting on the supports will be directed, one might say, strictly downward. This means that the support pillars perfectly resist compressive forces, that is, they can withstand the additional pressure of the snow cover.

  Arcs do not possess such rigidity and are not able to distribute the load. To compensate for this kind of impact, they begin to unbend. The result is a force imposed on the supports at the top. If we take into account that it is attached to the center and directed horizontally, then the slightest error in calculating the base of the pillars, at least, will cause their irreversible deformation.

  An example of calculating a metal truss from a profile pipe

  The calculation of such a product assumes:

  • determination of the exact height (H) and length (L) of the metal structure. The latter value must exactly correspond to the length of the span, that is, the distance overlapping the structure. As for the height, it depends on the projected angle and the features of the contour.

  In triangular metal structures, the height is 1/5 or ¼ part of the length, for other types with rectilinear belts, for example, parallel or polygonal - 1/8 part.

  • The angle of the lattice braces ranges from 35–50 °. On average, it is 45 °.
  • It is important to determine the optimal distance from one node to another. Usually the gap you are looking for matches the width of the panel. For structures with a span of more than 30 m, it is necessary to additionally calculate the building lift. In the process of solving the problem, you can get the exact load on the metal structure and select the correct parameters of the shaped pipes.

  

  As an example, consider the calculation of trusses of a standard single-slope structure 4x6 m.

  The design uses a 3 x 3 cm profile, the walls of which are 1.2 mm thick.

  The lower belt of the product has a length of 3.1 m, and the upper one - 3.90 m. Between them, vertical posts made of the same profile pipe are installed. The largest of them has a height of 0.60 m. The rest are cut in descending order. You can limit yourself to three racks, placing them from the beginning of a high slope.

  

  The sections that are formed in this case are reinforced by installing diagonal jumpers. The latter are made from a thinner profile. For example, a pipe with a cross section of 20 by 20 mm is suitable for these purposes. At the point of convergence of the belts, stands are not needed. On one product, you can limit yourself to seven braces.

  Five similar structures are used for 6 m of the canopy length. They are laid with a step of 1.5 m, connected with additional cross-sections made of a profile with a section of 20 by 20 mm. They are fixed to the upper belt, we will arrange them with a step of 0.5 m. Polycarbonate panels are attached directly to these jumpers.

  Arched truss calculation

  

  The manufacture of arch trusses also requires precise calculations. This is due to the fact that the load imposed on them will be distributed evenly only if the created arched elements have ideal geometry, that is, the correct shape.

  Let's take a closer look at how to create an arched frame for a canopy with a span of 6 m (L). The distance between the arches will be 1.05 m. With a product height of 1.5 meters, the architectural structure will look aesthetically pleasing and will be able to withstand high loads.

  When calculating the length of the profile (mn) in the lower chord, the following formula for the sector length is used: π R α: 180, where the parameter values ​​for this example in accordance with the drawing are respectively: R = 410 cm, α ÷ 160 °.

  

  After substitution, we have:

  3.14 410 160: 180 = 758 (cm).

  The structural units should be located on the lower chord at a distance of 0.55 m (rounded) from each other. The position of the extreme is calculated individually.

  In cases where the span length is less than 6 m, welding of complex metal structures is often replaced with a single or double beam, bending the metal profile under a given radius. Although there is no need to calculate the arched frame, the correct selection of a profiled pipe is still relevant. Indeed, the strength of the finished structure depends on its section.

  Calculation of an arch truss from a profile pipe online

  How to calculate the arc length for a polycarbonate canopy

  The length of the arc of an arch can be determined using the Huygens formula. The middle is marked on the arc, denoting it with a point M, which is located on the perpendicular CM, drawn to the chord AB, through its middle C. Then it is necessary to measure the chords AB and AM.

  The arc length is determined by the Huygens formula: p = 2l x 1/3 x (2l - L), where l is the AM chord, L is the AB chord)

  The relative error of the formula is 0.5% if the arc AB contains 60 degrees, and with a decrease in the angular measure, the error drops significantly. For an arc of 45 degrees. it is only 0.02%.

Metal roof trusses are one of the most basic structures. They are often erected in summer cottages and the territories of country houses. These are simple structures from a frame, cover and additional elements. From them you can make a canopy that covers the space allocated for storing things, or create a mini-parking for a car. The entire assembly can be done independently, but in order for the farm to be strong and durable, correct calculations are necessary.

Carports are designed to provide space for storing things or erecting a mini-parking for a car

Types of structures

Trusses are made from rectangular profiles or metal corners. The material is chosen depending on the type of construction and the type of belts. The belts are the basis of the truss, they are located below and above the structure and form its spatial outline. For the manufacture of small structures, profile pipes are used.

Farms take several forms:

1. Polygonal. This type of truss is designed to be installed on spans of 10 meters or more. If you install a canopy in a small area, then the structure is completed with additional parts, which complicates its assembly. Canopies made in production and having an arched shape are an exception.
2. Triangular. This is a gable canopy with a slope of 22-30 degrees. It is often installed in regions where there is a large amount of snowfall. The disadvantage of the product is a sharp knot at the base of the structure and long supports located in the center. These areas must be correctly calculated and marked on the drawing. Polycarbonate trusses for small sheds have proportions in relation to the height and width of no more than ¼, 1/5.

   

   There are many types of trusses for the frame, they differ in the complexity of construction and have a different number of advantages.

3. Parallel. According to the drawing, the slope of the finished product is no more than 1.5%. In this case, the ratio of height and length varies from 1/6 to 1/8. The product is used for a flat canopy, which is planned to be finished with roll cladding. The rods of the chords, which create a spatial lattice, have a uniform length, which results in a minimum of connecting nodes.
4. Arched. This is the most convenient truss design. It allows you to hide bending lines in the cross-sections of the framing. In addition, the arch material is under constant compression. Therefore, all calculations are carried out according to a simplified template, since the weight from the roof, mounting lathing and snow load will be equally distributed throughout the canopy.
5. Trapezoidal. The tilt angle of the frame is from 6 to 150 degrees. Moreover, its height and length are in proportions of 1/6. The product is characterized by a rigid frame.

This video shows how to draw up a drawing of a truss for a shed:

What level of load the structure can withstand depends on the thickness of the profile pipe. The thicker it is, the stronger the structure. For large structures, it is better to choose a square profile with a cross section of 30-50 × 30-50 mm. Pipes with a smaller cross-section are used for a small frame.

The metal profile has high strength and in comparison with a solid metal bar it weighs much less. The material is easy to bend, this allows you to create arched and domed structures.

Ready-made trusses for a canopy from a metal profile have an affordable price. In order for the material to last a long time, it is painted or coated with a primer that will protect it from corrosion.

Polycarbonate truss

To assemble a polycarbonate canopy truss, you need to draw up a detailed diagram. Each detail indicated in the diagram must be of exact dimensions. Details with a complex structure are drawn in an additional drawing.

To select the type of structure and the number of constituent parts, it is necessary to make calculations. Additionally, they study the level of precipitation in their region. This data will help to create the structure of the required strength. The most simplified type of truss is an arc (pipe) with a round or square cross section. Despite being the cheapest option of all, polycarbonate pipes are not very reliable.

Load distribution:

1. All the load acts on the structural supports and is directed downward. Because of this, it is evenly distributed. Consequently, the support pillars have good compression resistance. This allows it to support the additional weight from the snow cover.
2. Since the arcs are less rigid, the load is unevenly distributed. Because of this, under the influence of load, they unbend. As a result, a force appears that acts on the supports located at the top of the structure.

Incorrect calculation of the truss for the canopy threatens that the bases of the pillars will begin to bend and deform.

When calculating a polycarbonate truss, take into account the height and length of the frame, as well as the angle of inclination of the lattice and the distance between the modules. Calculation example:

1. The length of the frame must exactly match the span length (spacing overlapping the profile).
2. Depending on the developed angle and characteristics, the outlines determine the height of the structure. If the structure is triangular, then its height varies from 1/5 or ¼ of the length. The ratio of the straight roof is 1/8.
3. The angle of inclination of the lattice to the belt varies from 35 to 50 degrees. The average is 45 degrees.
4. The width of the panel will help you correctly calculate the spacing between the nodes. They are always identical. If the frame has a long span (25-30 meters or more), then a building lift is required for it. It is calculated additionally. These calculations will help determine the load level and select the appropriate size for the profile pipes.

For example, the calculation for a single-pitched frame with a size of 4 × 6 m is as follows. The structure is created from a 3 × 3 cm profile. Its thickness is 0.12 cm. The length of the lower belt is 310 cm, and the upper one is 390 cm. Vertical supports are mounted between the belts. The height of the largest will be 60 cm, the other three are evenly shortened. After installing the supports, places appear that need to be strengthened. They are equipped with diagonal bridges (thin profile with a section of 2 × 2 cm). In the places where the belts are connected, the racks are not installed.

If the canopy is long (6-7 meters), then 5 such structures are installed. They are positioned with a distance of 1.5 m. Each module is secured with transverse bridges. A profile with a cross section of 2 × 2 cm is used as jumpers.

It is placed at a distance of 50 cm from each other and fixed on the upper belt. The polycarbonate sheathing is attached to the lintels.

Arched frame

Due to the special structure, the arched truss for the canopy also needs accurate calculations. They are necessary so that the acting load is evenly distributed over the entire surface. And this is possible only due to the correct and even shape of the frame.

Arched frame making 6 meters long:

1. In order for the structure to have a beautiful appearance and at the same time withstand high loads, the distance between the arches is 105 cm.The height of the structure will be 150 cm.
2. The sector length formula π × R × α ÷ 180 will help to calculate the length of the profile along the lower chord. According to the drawing: R = 410 cm, α ÷ 160 °. Substituting the numbers, it turns out: 3.14 × 410 × 160 ÷ 180 = 758 (cm).
3. Frame nodes are placed on the lower chord. The distance between them must be at least 55 cm. To install the extreme nodes, an individual calculation is required.

A canopy is a simple architectural structure that can be used for a wide variety of purposes. In most cases, it is made in the absence of a covered garage in the country or in order to protect the recreation area from the strong rays of the sun. To ensure the reliability and strength of such a small building, you will need to calculate the canopy. Ultimately, it will be possible to obtain data that can show which farms will be used and how they will need to be brewed.

The fixing diagram of the shaped pipes can be seen in Fig. 1.

Figure 1 shows a diagram of pipe fastening

How to calculate do-it-yourself canopy trusses?

In order to calculate a similar structure for a canopy, you will need to prepare:

• Calculator and special software;
• SNiP 2.01.07-85 and SNiP P-23-81.

When carrying out calculations, you will need to perform the following steps:

1. First of all, you need to choose a farm layout. For this, future contours are determined. The outlines must be chosen based on the basic functions of the canopy, material and other parameters;
2. After that, it will be necessary to determine the dimensions of the structure being manufactured. The height will depend on the type of roof and the material used, weight and other parameters;
3. If the span dimensions exceed 36 m, it will be necessary to calculate the construction lift. In this case, we mean the reverse damped bending from the loads on the truss;
4. It is necessary to determine the dimensions of the panels of the structure, which must correspond to the distances between the individual elements, which ensure the transfer of loads;
5. At the next stage, the distance between the nodes is determined, which is most often equal to the width of the panel.

When making calculations, follow these tips:

1. You will need to calculate all the values ​​exactly. You should be aware that even the slightest flaw will lead to errors in the process of performing all the work on the manufacture of the structure. If you are not confident in your own abilities, it is recommended to immediately contact professionals who have experience in carrying out such calculations;
2. To facilitate the work, you can use ready-made projects, into which you just have to substitute the existing values.

This photo shows a metal shelter.

In the process of calculating the truss, it should be remembered that in the case of its increasing height, the bearing capacity will also increase. In the winter season, snow on such a canopy will practically not accumulate. In order to increase the strength of the structure, several strong stiffeners should be installed.

For the construction of a truss, it is best to use an iron pipe, which is light in weight, high strength and stiffness. In the process of determining the dimensions for such an element, you will need to take into account the following data:

1. For structures of small sizes, the width of which is up to 4.5 m, you will need to use a metal pipe 40x20x2 mm;
2. For structures with a width of less than 5.5 m, you need to use a pipe with dimensions of 40x40x2 mm;
3. If the width of the truss is more than 5.5 m, it is best to use a pipe of 60x30x2 mm or 40x40x3 mm.

In the process of planning the pitch of the trusses, it should be borne in mind that the maximum possible distance between the canopy pipes is 1.7 m. Only in this case it will be possible to save the reliability and strength of the structure.

An example of calculating trusses for a canopy

1. As an example, we will consider a canopy with a width of 9 m with a slope of 8 °. The span of the structure is 4.7 m. Snow loads for the region are at 84 kg / m²;
2. The weight of the truss is approximately 150 kg (a small margin of strength should be taken). The vertical load is 1.1 t per rack with a height of 2.2 m;
3. At one end, the truss will rest on the wall of the brick building, and at the other end, on the column to support the canopy with the help of anchor bolts. For the manufacture of the truss, a square pipe 45x4 mm is used. It should be noted that it is quite convenient to work with such a device;
4. It is best to make trusses with parallel chords. The height of each of the elements is 40 cm. A pipe with a section of 25x3 mm is used for the braces. For the lower and upper chord, a 35x4 mm pipe is used. Visors and other elements will need to be welded together, so the wall thickness will be 4 mm.

Ultimately, you can get the following data:

• Design resistance for steel: Ry = 2.45 T / cm²;
• Reliability factor - 1;
• Farm span - 4.7 m;
• Truss height - 0.4 m;
• The number of panels for the upper belt of the structure - 7;
• The corners will need to be cooked through one.

All the necessary data for calculations can be found in special reference books. However, professionals recommend making calculations of this type using software. If a mistake is made, the manufactured trusses will be formed under the influence of the loads of snow and wind.

How to calculate a polycarbonate canopy truss?

The canopy is a complex structure, therefore, an estimate will be needed before purchasing a certain amount of material. The support frame must be able to withstand any loads.

In order to make a professional calculation of a polycarbonate structure, it is recommended to seek help from an engineer with experience in such work. If the canopy is a separate structure, and not an extension to a private house, then the calculations will become more complicated.

Street roofing consists of posts, logs, trusses and coverings. It is these elements that will need to be calculated.

If you plan to make an arched-type polycarbonate canopy, then you will not be able to do without the use of trusses. Trusses are fixtures that connect joists and support posts. The size of the canopy will depend on such elements.

Polycarbonate canopies, which are based on metal trusses, are quite difficult to manufacture. The correct frame will be able to distribute the load over the support posts and lags, while the structure of the canopy will not collapse.

For the installation of polycarbonate, it is best to use profile pipes. The main calculation of the truss is material and slope accounting. For example, an irregular truss shape is used for a single-slope hinged structure with a small slope. If the structure has a small angle, then trapezoid-shaped metal trusses can be used. The larger the radius of the arch structure, the less there is a possibility of trapping snow on the roof. In this case, the load-bearing capacity of the truss will be large (Fig. 2).

Figure 2 shows the future canopy covered with polycarbonate

If a simple farm with a 6x8 m house is used, then the calculations will be as follows:

• The step between the posts for the support is 3 m;
• Number of metal posts - 8 pcs;
• The height of the trusses under the slings is 0.6 m;
• For the device of the roof sheathing, you will need 12 profile pipes with dimensions of 40x20x0.2 cm.

In some cases, savings can be made by reducing the amount of material. For example, instead of 8 racks, you can install 6. You can also cut the frame crate. However, it is not recommended to allow a loss of stiffness, as this can lead to the destruction of the structure.

Detailed calculation of the truss and the arch for the canopy

In this case, the calculation of the canopy will be carried out, the trusses of which are installed in increments of 1 m. The load on such elements from the crate is transferred exclusively to the nodes of the truss. The roofing material is corrugated board. The height of the truss and the arc can be any. If it is a canopy that is adjacent to the main building, then the main constraint is the shape of the roof. In most cases, it will not work to make the height of the truss more than 1 m. Taking into account the fact that it will be necessary to make the girder between the columns, the maximum height will be 0.8 m.

The canopy scheme for farms can be seen in Fig. 3. The beams of the sheathing are indicated in blue, the truss that will need to be calculated is in blue. Beams or trusses on which the columns will be supported are indicated in purple.

In this case, 6 triangular trusses will be used. The load on the extreme elements will be several times less than on the others. In this case, the metal trusses will be cantilever, that is, their supports are located not at the ends of the trusses, but in the nodes shown in Fig. 3. This scheme allows you to evenly distribute the loads.

Figure 3 shows the scheme of the shelter by farms

The design load is Q = 190 kg, while the snow load is 180 kg / m². Thanks to the sections, it is possible to calculate the forces in all the bars of the structure, while taking into account the fact that the truss and the load on this element are symmetrical. Therefore, not all trusses and arcs will need to be calculated, but only some of them. In order to freely navigate in a large number of rods during the calculation process, rods and nodes are marked.

Formulas that you need to use when calculating

You will need to determine the efforts in several truss members. For this, the static equilibrium equation should be used. There are hinges at the nodes of the elements, therefore the value of the bending moments at the nodes of the truss is 0. The sum of all forces with respect to the x and y axis is also 0.

You will need to draw up an equation of moments with respect to point 3 (d):

М3 = -Ql / 2 + N2-a * h = 0, where l is the distance from point 3 to the point of application of the force Q / 2, which is 1.5 m, and h is the shoulder of the force N2-a.

The truss has a design height of 0.8 m and a length of 10 m. In this case, the tangent of the angle a will be tga = 0.8 / 5 = 0.16. Angle value a = arctga = 9.09 °. Ultimately h = lsina. From this follows the equation:

N2-a = Ql / (2lsina) = 190 / (2 * 0.158) = 601.32 kg.

In the same way, you can determine the value of N1-a. To do this, you need to draw up an equation of moments in relation to point 2:

M2 = -Ql / 2 + N1-a * h = 0;

N1-a = Q / (2tga) = 190 / (2 * 0.16) = 593.77 kg.

You can check the correctness of the calculations by drawing up the equation of forces:

EQy = Q / 2 - N2-asina = 0; Q / 2 = 95 = 601.32 * 0.158 = 95 kg;

EQx = N2-acosa - N1-a = 0; N1-a = 593.77 = 601.32 * 0.987 = 593.77 kg.

The conditions of statistical equilibrium are fulfilled. Any of the force equations that were used during the verification process can be used to determine the forces in the members. Further calculation of the trusses is done in the same way, the equations will not change.

It is worth knowing that the design scheme can be drawn up so that all longitudinal forces are directed from the cross sections. In this case, the "-" sign in front of the force index, which was obtained in the calculations, will show that such a rod will work in compression.

In order to determine the force in the rod h-i, you will first need to determine the value of the angle y: h = 3siny = 2.544 m.

A do-it-yourself canopy farm is easy to calculate. You just need to know the basic formulas and be able to use them.

Video on how to use the calculator:

The profile of the pillars is selected depending on the width of the canopy (from the side of the truss, below in the sketch by dimension "B")

For canopy width:

up to 4000 mm profile of pillars 60x60x2.5

over 4000 mm up to 6000 mm pillar profile 80x80x3

over 6000 mm up to 8000 mm profile 100x100x3

over 8000 mm up to 10000 mm profile 120x120x4

Determination of the crossbar for strength:

The calculator will show a positive number as a percentage of the safety factor if the profile is selected correctly and a negative safety factor for a profile that cannot be used.

Determination of the "noodle" part for strength:

detail "noodles" of rectangular cross-section is taken into account in the "flat" position, and not "on edge"

Definition of a complex truss for strength:

The weakest point of the truss is its middle, the trusses break down in the middle when the canopy cannot withstand the snow load, therefore, the calculator will show the tensile strength of the truss at a break in the middle of the truss. trouble spot

Dimension "A" for any truss you conceive, triangular, square, etc., is taken in the middle of the total truss length between the upper and lower tubes.

Definition of a simple truss for strength:

The canopy truss can be made of one link - a professional pipe or an I-beam. The loads on this link are colossal from the snow that has fallen. Checking the snow load is a must here!

We will consider an I-beam only in the position "like a rail to the ground"; its dimensions are in accordance with GOST 26020-83 (I-beam No. 10 is its height 100 mm, No. 14 is its height 140, etc.), and we will consider the professional pipes as "flat" and "on edge"

The angle of inclination is neglected, you can manually add a percentage of the angle of inclination, or leave it as it is, as it only affects the increase in strength.

Determination of system strength

girder + sub-girder

It often happens that the distance between the posts must be increased, and the crossbar, no matter how powerful it is, does not pass the calculation of the snow load. This task is solved by installing an additional underrun truss, and the underrun truss pipes can be made from a much smaller section of the profile. The task appears - what is the profile parameter and what should be the width of the underrun truss in order to keep within sufficient strength without overpayments without creating unnecessary heaps in the canopy. Of course, we are talking about a truss farm, filled with triangular shapes as shown in the figure, not in squares. The calculator will show the strength of the system by adding the flexural resistance of the main girder plus the resistance of the bottom girder to the tensile yield point, not the flexural resistance of the girder when it is incorrectly filled with square shapes, making the truss useless.

Note: in this section, the safety factor (1.3) has already been taken into account, that is, for example, the calculator showed a safety factor of 0%, which means that the truss is calculated normally, with a safety factor (1.3)..

Without using any formulas, engineering calculations, programs, tables!

We do not fool the reader with phrases - "here it is necessary to take into account ...", "calculate ...", "select from engineering tables ...", as is done on all sites! All formulas, accounting, selections, snips, guests, assortments are hidden inside the calculator.

Here's your canopy - here's your planned dimensions! Enter your desired dimensions and the calculator will show you in percentage the safety factor of the selected professional pipes. With a positive value of the safety factor, the canopy part will be considered calculated by the laws of resistance using all snips, GOSTs, assortments, and withordering a product from our factory, we will confirm the results of this calculator with additional with a link to GOST pipe assortments.

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Our calculator is aimed at clients of gardening associations, cottage settlements, and other private owners who need a quick, reasoned selection of professional pipes for sheds of outbuildings, carports, annexes to buildings. Since often, in the absence of such a calculator, lack of experience, clients of "Garden and Garden" undertake construction without any justification at all, either under-laying the strength, or vice versa, spending extra funds, re-laying the strength. Therefore, the purpose of the calculator is only to orient the client in the right direction. For the construction of industrial buildings and workshops, industrial hangars and other large structures, a more detailed calculation is required. For example, in an industrial structure, each link of a truss must be calculated (except for taking into account the tensile and bending yield strength in this calculator) for flexibility in compression and torsion, the parameter of which is taken into account before this link went into the manufacture of a truss, before rolling on a pipe bender, and filling with triangular elements and other parameters with their calculations. But in any case, if you want to build "something" relying only on "experience" and not on calculations, then it is better to use this calculator. Also, on this calculator, you can set the margin of safety yourself, for example 50%, 80%, by choosing the strength yourself relative to your budget. For example, the farms of our production workshop have a reserve of 80%, and they can withstand not only snow, but also a crane beam that carries heavy loads. In any case, of course, you need to adhere to elementary rules during construction, for example, you cannot use loads across the links, only along. For example, in a farm, the place with which it rests on the crossbar must not be empty, that is, without filling (that is, above the crossbar in the farm, there must be a farm filling link! Very often farms break for this reason!). To install the "noodles" part, it is better to provide vertical filling links or the intersection of triangular fillings under it in the farm. It is better to fill the truss from a thinner profile and more often than from a powerful one and rarely, since you should not forget that the load on the links of the triangular filling falls along the axis and it is insignificant, and the horizontal pipes of the trusses have a bending load component, and loads on horizontal pipes huge compared to the low loads of the truss filling pipes.

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