Snow load on the canopy. Calculation and production of a metal truss for a canopy. Farms come in several forms

After your house is built, you need to move on to a new stage - the exterior and interior decoration of the premises. This is necessary not only to decorate the facade or interior using a variety of decorative materials, but also to protect the building from all sorts of adverse influences. This applies to protection from winds, from excessive precipitation, from excessive humidity and exposure to sunlight. In addition to the fact that finishing and decorative details can protect the interior and some of its external elements, they can also protect a person from the same influences. One of these elements is a canopy, which is erected over the entrance to the house in order to prevent precipitation from falling on the path leading to the house.

These structures are quite easy to install with your own hands, especially from wooden materials. First of all, in order for the complete structure (canopies, rafters, and sheathing) to be strong and durable, as well as beautiful and neat, it is necessary to calculate the canopy structure in advance. As you know, a wooden canopy remains a fairly popular element both among owners of small country houses and among those who have a mansion or cottage at their disposal.

How to calculate a canopy?

So, an awning is an amazing way to protect your home and its occupants from sun, rain, hail, snow, icicles and more. In addition, a canopy turns out to be a wonderful way to construct the most original building. It helps to emphasize the special style of your home, as well as give it individuality.

Return to contents

What canopy designs can you build yourself?

There are a large number of varieties of awnings. They differ in size, shape and material from which they are constructed. According to the second principle, canopies are:

• wooden;
• metal.

The most reliable and therefore popular material for sheathing a canopy is metal. Usually the same material is chosen for the canopy that is used to cover the roof. Either stainless steel or a metal profile is suitable for this. It's inexpensive and practical. The installation of a wooden canopy is resorted to when it is necessary to emphasize the style of the house in this way. After all, if a canopy made of polycarbonate or metal is built against the background of a wooden house, then it will look at least funny.

In addition to this classification, canopies are also divided according to where they are used. Here you can select country sheds, garden sheds, summer sheds, car sheds, and entrance sheds. At first glance, it seems that there is no difference between them. However, a carport cannot be used for decorative covering in any way. But at the same time, the summer canopy can be used both as a car and garden canopy.

According to the distribution of canopies by method and material for covering, the following types are distinguished:

• cellular or monolithic polycarbonate floors;
• glass;
• metal;
• canopy made of corrugated sheets;
• canopy made of soft roofing materials.

Depending on the area of ​​use of the canopies, their roofing material is also selected.

So, a glass canopy will be an excellent option for decorating the local area and decorating a flower bed in this way.

Metal roofing is used in most cases for carports to protect the entrance to the house. As for the plastic canopy, polycarbonate is usually used here. You can give it absolutely any shape you want. Compared to a metal canopy, a plastic canopy is somewhat heavier, so you will need to build a stronger frame for it.

Return to contents

Calculation of a canopy made of wood

Regardless of what kind of canopy you plan to build and what materials you choose for the roof, the canopy must be supported by supports. Pillars are used for this purpose: either metal or wood. And their number depends on the type of canopy. So, you may need 2, 3 or even 10 pillars. They must be dug into the ground to a depth of at least 1/3 of the height that will remain on the surface of the earth, then concreted. Next, it is necessary to install a roof frame on these supporting structures, which will be sheathed with one or another material.

In order to build this structure, 320 cm long and 250 cm wide, you will need:

• timber (25*20 cm);
• 8 racks with a cross section of 5*10 cm;
• 2 wooden boards at least 120 cm long;
• nails;
• screws;
• hammer.

Return to contents

Assembling a canopy structure with your own hands

In order to install support pillars, it is necessary to dig recesses for them. As already mentioned, they are buried 1/3 of the length that will be on the surface. Therefore, if your canopy should be approximately 200-250 cm in height, then the holes will be dug at least 70 cm deep. After this, the treated bars can be immersed in these depressions. They need to be temporarily secured with something perpendicular to the surface of the earth. Otherwise, your canopy will turn out crooked. You can measure verticality using a plumb line. Next, you need to concrete these pillars. To do this you will need:

• sand;
• crushed stone;
• cement;
• water.

From 1 part of water and the same amount of sand, added to them 3 parts of crushed stone and sand, it is necessary to replace the solution, which is immediately poured into the hole. This solution dries in about 1 day, so you won’t have to do anything in this place until tomorrow. After this, you can fasten the rafters and proceed to covering the completed frame with boards. To do this, you need 4 boards that will go on both sides of the canopy in its upper part, and 3 more boards attached to the ridge of the rafters. If you carry out all the steps in accordance with these calculations, the frame will be as solid as possible.

The success of this event lies in the accuracy of the preparation of all components, which should result in a reliable and durable canopy. As for the canopy, the boards can be nailed to it closely or at some distance from each other. In the future, you can apply some other materials (iron, soft roofing, etc.) to this sheathing. It is imperative to remember that it is unacceptable to fasten the canopy (sheathing) before the frame structure itself is firmly fixed. Otherwise, this can lead, at a minimum, to the fact that some part of the structure will be shifted, and, at a maximum, to the fact that the builder (perhaps it will be you) will receive damage due to the instability of the structure.

That is why the entire canopy structure is calculated in advance before all materials are prepared. If the installation is not of a wooden, but of a metal canopy, then more durable materials will be required, and, accordingly, other tools. In order to connect these parts, they often resort to the services of a professional welder. It is in this way that both the frame and the metal canopy itself are installed. This way you can carry out all the necessary activities for assembling the canopy structure directly on the workbench. The main thing is not to make mistakes in the calculations and do everything so that the canopy dug into the ground fits perfectly both the house and the elements surrounding it.

Calculation of metal structures has become a stumbling block for many builders. Using the example of the simplest trusses for a street canopy, we will tell you how to correctly calculate the loads, and also share simple methods for self-assembly without the use of expensive equipment.

General calculation methodology

Trusses are used where using a solid load-bearing beam is impractical. These structures are characterized by lower spatial density, while maintaining the stability to absorb impacts without deformation due to the correct arrangement of parts.

Structurally, the truss consists of an external chord and filling elements. The essence of the operation of such a lattice is quite simple: since each horizontal (conditionally) element cannot withstand the full load due to its insufficiently large cross-section, two elements are located on the axis of the main influence (gravity) in such a way that the distance between them ensures a sufficiently large cross-section of the entire structure . It can be explained even more simply as follows: from the point of view of load absorption, the truss is treated as if it were made of solid material, while the filling provides sufficient strength based only on the calculated applied weight.

Structure of a truss made of a profile pipe: 1 - lower chord; 2 - braces; 3 - racks; 4 - side belt; 5 - upper belt

This approach is extremely simple and is often more than enough for the construction of simple metal structures, but the material consumption in a rough calculation turns out to be extremely high. A more detailed consideration of the current influences helps to reduce metal consumption by 2 or more times; this approach will be most useful for our task - to design a light and fairly rigid truss, and then assemble it.

The main profiles of trusses for a canopy: 1 - trapezoidal; 2 - with parallel belts; 3 - triangular; 4 - arched

You should start by determining the overall configuration of the farm. It usually has a triangular or trapezoidal profile. The lower element of the belt is placed mainly horizontally, the upper one is inclined, ensuring the correct slope of the roofing system. The cross-section and strength of the belt elements should be chosen close to such that the structure can support its own weight with the existing support system. Next, vertical jumpers and oblique connections are added in an arbitrary quantity. The design must be displayed on a sketch to visualize the mechanics of interaction, indicating the actual dimensions of all elements. Next, Her Majesty Physics comes into play.

Determination of combined influences and support reactions

From the statics section of the school mechanics course, we will take two key equations: the equilibrium of forces and moments. We will use them to calculate the reaction of the supports on which the beam is placed. For simplicity of calculations, we will consider the supports to be hinged, that is, not having rigid connections (embedding) at the point of contact with the beam.

Example of a metal truss: 1 - truss; 2 - sheathing beams; 3 - roofing

On the sketch, you must first mark the pitch of the roofing system sheathing, because it is in these places that the points of concentration of the applied load should be located. Usually, it is at the points of application of the load that the convergence nodes of the braces are located, this makes it easier to calculate the load. Knowing the total weight of the roof and the number of trusses in the canopy, it is not difficult to calculate the load on one truss, and the covering uniformity factor will determine whether the applied forces at the concentration points will be equal or different. The latter, by the way, is possible if in a certain part of the canopy one covering material is replaced by another, there is a passage ladder or, for example, an area with an unevenly distributed snow load. Also, the impact on different points of the truss will be uneven if its upper beam has a rounding; in this case, the points of application of the force must be connected by segments and the arc should be considered as a broken line.

When all the effective forces are indicated on the sketch of the truss, we proceed to calculate the reaction of the support. With respect to each of them, the farm can be represented as nothing more than a lever with the corresponding sum of influences on it. To calculate the moment of force at the fulcrum point, you need to multiply the load at each point in kilograms by the length of the arm of application of this load in meters. The first equation states that the sum of the influences at each point is equal to the support reaction:

• 200 1.5 + 200 3 + 200 4.5 + 100 6 = R 2 6 - equilibrium equation of moments about the node A, where 6 m is the length of the arm)
• R 2 = (200 1.5 + 200 3 + 200 4.5 + 100 6) / 6 = 400 kg

The second equation determines equilibrium: the sum of the reactions of the two supports will be exactly equal to the applied weight, that is, knowing the reaction of one support, you can easily find the value for the other:

• R 1 + R 2 = 100 + 200 + 200 + 200 + 100
• R1 = 800 - 400 = 400 kg

But make no mistake: the rule of leverage also applies here, so if the truss has a significant extension beyond one of the supports, then the load in this place will be higher in proportion to the difference in distances from the center of mass to the supports.

Differential calculation of forces

Let's move from the general to the specific: now it is necessary to establish the quantitative value of the forces acting on each element of the farm. To do this, we list each belt segment and filling inserts in a list, then consider each of them as a balanced flat system.

For ease of calculation, each connecting node of the truss can be represented in the form of a vector diagram, where the vectors of influences lie along the longitudinal axes of the elements. All you need for calculations is to know the length of the segments converging at the node and the angles between them.

You need to start from the node for which, during the calculation of the support reaction, the maximum possible number of known values ​​was established. Let's start with the outermost vertical element: the equilibrium equation for it states that the sum of the vectors of converging loads is zero, respectively, the resistance to the force of gravity acting along the vertical axis is equivalent to the reaction of the support, equal in magnitude but opposite in sign. Note that the obtained value is only part of the total support reaction acting for a given node; the rest of the load will fall on the horizontal parts of the belt.

Knot b

• -100 + S 1 = 0
• S 1 = 100 kg

Next, let's move on to the lowest corner node, where the vertical and horizontal segments of the belt, as well as the inclined brace, converge. The force acting on the vertical segment was calculated in the previous paragraph - this is the pressing weight and the reaction of the support. The force acting on an inclined element is calculated from the projection of the axis of this element onto the vertical axis: we subtract the effect of gravity from the reaction of the support, then divide the “net” result by the sin of the angle at which the brace is inclined to the horizontal. The load on a horizontal element is also found by projection, but on the horizontal axis. We multiply the just obtained load on the inclined element by cos of the angle of inclination of the brace and obtain the value of the impact on the outermost horizontal segment of the belt.

Knot a

• -100 + 400 - sin(33.69) S 3 = 0 - equilibrium equation for the axis at
• S 3 = 300 / sin(33.69) = 540.83 kg - rod 3 compressed
• -S 3 cos(33.69) + S 4 = 0 - equilibrium equation for the axis X
• S 4 = 540.83 cos(33.69) = 450 kg - rod 4 stretched

Thus, sequentially moving from node to node, it is necessary to calculate the forces acting in each of them. Please note that counter-directed vectors of influence compress the rod and vice versa - stretch it if they are directed oppositely from each other.

Definition of section of elements

When all the effective loads are known for the farm, it is time to determine the cross-section of the elements. It does not have to be equal for all parts: the belt is traditionally made from rolled products with a larger cross-section than the filling parts. This ensures a safety margin for the design.

Where: F tr is the cross-sectional area of ​​the stretched part; N— force from design loads; Ry γ s

If everything is relatively simple with breaking loads for steel parts, then the calculation of compressed rods is carried out not for strength, but for stability, since the final result is quantitatively less and, accordingly, is considered a critical value. You can calculate it using an online calculator, or you can do it manually, having previously determined the length reduction coefficient, which determines over what part of the total length the rod is capable of bending. This coefficient depends on the method of fastening the edges of the rod: for end welding it is unity, and in the presence of “ideally” rigid gussets it can approach 0.5.

Where: F tr is the cross-sectional area of ​​the compressed part; N— force from design loads; φ — longitudinal bending coefficient of compressed elements (determined from the table); Ry— calculated resistance of the material; γ s— coefficient of working conditions.

You also need to know the minimum radius of inertia, defined as the square root of the axial moment of inertia divided by the cross-sectional area. The axial moment is determined by the shape and symmetry of the section; it is better to take this value from the table.

Where: i x— radius of gyration of the section; J x— axial moment of inertia; F tr is the cross-sectional area.

Thus, if you divide the length (taking into account the reduction coefficient) by the minimum radius of gyration, you can obtain a quantitative value for flexibility. For a stable rod, the condition is met that the quotient of the load divided by the cross-sectional area should not be less than the product of the permissible compressive load and the buckling coefficient, which is determined by the flexibility of a particular rod and the material of its manufacture.

Where: l x— design length in the plane of the truss; i x— minimum radius of gyration of the section along the x axis; l y— estimated length from the plane of the truss; i y— minimum radius of gyration of the section along the y-axis.

Please note that it is in the calculation of the compressed rod for stability that the whole essence of the operation of the truss is reflected. If the cross-section of an element is insufficient to ensure its stability, we have the right to add finer connections by changing the fastening system. This complicates the truss configuration, but allows for greater stability with less weight.

Making parts for the farm

The accuracy of the truss assembly is extremely important, because we carried out all the calculations using the vector diagram method, and a vector, as we know, can only be absolutely straight. Therefore, the slightest stresses arising due to curvature due to improper fitting of the elements will make the truss extremely unstable.

First you need to decide on the dimensions of the outer belt parts. If everything is quite simple with the lower beam, then to find the length of the upper one you can use either the Pythagorean theorem or the trigonometric ratio of sides and angles. The latter is preferable when working with materials such as angle steel and profile pipe. If the angle of the truss slope is known, it can be made as a correction when trimming the edges of parts. Right angles of the belt are connected by trimming at 45°, inclined ones by adding to 45° the angle of inclination on one side of the joint and subtracting it from the other.

The filling details are cut out by analogy with the belt elements. The main catch is that the truss is a strictly standardized product, and therefore its manufacture will require precise detailing. As with the calculation of impacts, each element must be considered individually, determining the toe-in angles and, accordingly, the cutting angles of the edges.

Quite often, trusses are made with radius trusses. Such structures have a more complex calculation method, but greater structural strength due to a more uniform load perception. There is no point in making the filling elements rounded, but for belt parts this is quite applicable. Typically, arched trusses consist of several segments that are connected at the convergence points of the infill braces, which must be taken into account during the design.

Assembly on hardware or welding?

In conclusion, it would be nice to outline the practical difference between the methods of assembling a truss by welding and using detachable connections. We should start with the fact that drilling holes for bolts or rivets in the body of an element has virtually no effect on its flexibility, and therefore is not taken into account in practice.

When it came to the method of fastening the truss elements, we found that in the presence of gussets, the length of the section of the rod capable of bending is significantly reduced, due to which its cross-section can be reduced. This is the advantage of assembling the truss on gussets, which are attached to the side of the truss elements. In this case, there is no particular difference in the assembly method: the length of the welding seams will be guaranteed to be sufficient to withstand concentrated stresses in the nodes.

If the truss is assembled by joining elements without gussets, special skills are required. The strength of the entire truss is determined by its least strong unit, and therefore a defect in the welding of at least one of the elements can lead to the destruction of the entire structure. If welding skills are insufficient, it is recommended to assemble with bolts or rivets using clamps, corner brackets or overlay plates. In this case, each element must be attached to the assembly at at least two points.

X

Y

Z

Width of visor material– allows you to determine the width of the required covering material to cover a semicircular canopy or canopy. Using the function for calculating this parameter, you can select the optimal dimensions of the visor to maximize the use of factory-sized material. Knowing visor area, You will be able to purchase exactly as much material for covering the structure as you need and not overpay for excess. Please note that the calculator only calculates the parameters of the roofing material for the canopy and does not calculate what and how much is needed to make the frame and its fastening (metal profiles, boards, concrete, hardware).

X– the width of the canopy is the distance between its extreme points along the facade. To protect against precipitation, the width of the canopy should be chosen slightly larger than the size of the front door. If possible, you should make a canopy over the entire width of the porch with a margin of 500 mm on each side. However, it should be remembered that the larger the surface of the canopy, the more snow there will be on it in winter, which means the structure must be reliable. When choosing the width of the visor, it is necessary to take into account SP 20.13330.2011 “Loads and impacts”.

Y– the height of the canopy (this means the height of the segment of the semicircular canopy, and not the installation level relative to the threshold of the house), the larger this parameter, the greater the consumption of material for the covering.

Z– the length of the canopy – the distance from the facade can be different, depending on your wishes and the architecture of the house. The minimum length for protection against precipitation is 700 mm. You can focus on the dimensions of the porch with a small margin. Please note that if the length of the canopy exceeds 2000 mm, then additional supports must be placed under the free edge.

By checking the “Black and white drawing” option, you will receive a drawing close to GOST requirements and will be able to print it without wasting color paint or toner.

Calculation results and their use:

Width of visor material– allows you to determine the width of the required covering material to cover a semicircular canopy or canopy. Using the function for calculating this parameter, you can select the optimal dimensions of the visor to maximize the use of factory-sized material. Having calculated visor area, You will be able to purchase exactly as much material for the canopy arch as you need and not overpay for excess. Please note that the calculator only calculates the parameters of the roofing material for the canopy arch and does not calculate what and how much is needed to make the frame and its fastening (metal profiles, boards, concrete, hardware). If desired, you can specify a height equal to a small number, which will allow you to calculate a flat canopy.

Metal trusses for a canopy are one of the most basic structures. They are often erected on summer cottages and areas of country houses. These are simple structures made of a frame, covering and additional elements. You can use them to make a canopy that covers the space allocated for storing things, or to create a mini parking lot for a car. You can do the entire assembly yourself, but to make the truss strong and durable, correct calculations are necessary.

Sheds are designed to provide space for storing things or constructing a mini parking lot for a car.

Types of structures

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

Farms have several forms:

1. Polygonal. This type of trusses is designed for installation on spans of 10 meters or more in length. If you install a canopy in a small area, the structure is equipped with additional parts, which complicates its assembly. Canopies manufactured 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 the sharp knot at the base of the structure and the long supports located in the center. These areas must be correctly calculated and marked on the drawing. Polycarbonate trusses for canopies of small sizes have proportions in relation to height and width of no more than ¼, 1/5.

   

   There are many types of frame trusses, 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 belt rods that create the spatial lattice have a uniform length, which results in a minimum of connecting nodes.
4. Arched. This is the most convenient farm design. It allows you to hide bending lines in the cross sections of the frame. In addition, the arch material experiences constant compression. Therefore, all calculations are carried out according to a simplified template, since the weight from the roof, mounting sheathing and snow load will be equally distributed throughout the entire canopy.
5. Trapezoidal. The tilt angle of the frame ranges from 6 to 150 degrees. Moreover, its height and length have proportions of 1/6. The product is characterized by a rigid frame.

This video shows how to draw a truss drawing for a canopy:

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 is highly durable and compared to a solid metal bar it weighs much less. The material bends easily, this allows you to create arched and dome-shaped structures.

Ready-made metal profile canopy trusses have an affordable price. To ensure that the material lasts a long time, it is painted or coated with a primer, which will protect it from corrosion.

Polycarbonate truss

To assemble a polycarbonate canopy truss, you need to draw up a detailed diagram. Each part indicated in the diagram must have exact dimensions. Parts with a complex design are drawn in an additional drawing.

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

Load distribution:

1. The entire load acts on the supports of the structure and is directed downward. Because of this, it is evenly distributed. Consequently, the support pillars have good resistance against compression. This allows you to withstand the additional weight from snow cover.
2. Since the arches are less rigid, the load is distributed unevenly. 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 a truss for a canopy threatens that the bases of the pillars will become bent and deformed.

When calculating a polycarbonate truss, the height and length of the frame are taken into account, 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 length of the span (the interval overlapping the profile).
2. Depending on the developed angle and characteristics of the outline, the height of the structure is determined. If the structure is triangular, then its height varies from 1/5 or ¼ of the length. The ratio of straight roofing is 1/8.
3. The angle of inclination of the grille to the belt varies from 35 to 50 degrees. The average value is 45 degrees.
4. The width of the panel will help you correctly calculate the gap between the nodes. They are always identical. If the frame has a long span (25-30 meters or more), then it requires a construction lift. It is calculated additionally. These calculations will help determine the load level and select the appropriate size of profile pipes.

For example, the calculation for a single-pitched frame measuring 4 × 6 m is as follows. The structure is created from a 3x3 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 will be shortened evenly. After installing the supports, there are places that need to be strengthened. They are equipped with slanting lintels (thin profile with a cross-section of 2×2 cm). In places where the belts are connected, racks are not installed.

If the canopy is long (6-7 meters), then 5 such structures are installed. They are placed at a distance of 1.5 m. Each module is secured with transverse jumpers. 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 secured to the upper belt. The polycarbonate sheathing is attached to the lintels.

Arch frame

Due to its special structure, an arched truss for a canopy also requires precise calculations. They are necessary to ensure that the acting load is distributed evenly over the entire surface. And this is only possible thanks to the correct and even shape of the frame.

Making an arched frame 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. In this case, the height of the structure will be 150 cm.
2. The sector length formula π × R × α ÷ 180 will help 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. The frame nodes are placed on the lower belt. The distance between them must be at least 55 cm. An individual calculation is required to install the extreme units.

Video on how to use the calculator:

The profile of the pillars is selected depending on the width of the canopy (from the truss side, below in the sketch according to dimension “B”)

For canopy width:

up to 4000 mm column profile 60x60x2.5

over 4000 mm to 6000 mm column profile 80x80x3

over 6000 mm up to 8000 mm profile 100x100x3

over 8000 mm to 10000 mm profile 120x120x4

Determination of crossbar strength:

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

Determination of the “noodle” part for strength:

the rectangular “noodle” part is taken into account in the “flat” position and not “on the edge”

Definition of a complex truss for strength:

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

Dimension "A" for any truss you have in mind, triangular, square, etc., is taken at the midpoint of the overall length of the truss between the top and bottom pipes.

Definition of a simple truss for strength:

The canopy truss can be made of one link - a corrugated pipe or an I-beam. The loads on this link are enormous due to the fallen snow. Checking the snow load is mandatory here!

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

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

Determining the strength of the system

transom + sub-transom truss

It often happens that the distance between the pillars needs to be increased, and the crossbar, no matter how powerful it is laid, does not pass the calculation of the snow load. This problem is solved by installing an additional sub-transom truss, and the pipes of the sub-transom truss can be made from a much smaller profile section. The problem arises - what profile parameter and what width of the crossbar truss should be in order to achieve sufficient strength without overpayments and without creating unnecessary clutter in the canopy. Of course, we are talking about a crossbar farm, filled with triangular shapes, as shown in the figure, and not in squares. The calculator will show the strength of the system by adding up the flexural resistance of the main transom plus the resistance of the sub-transom truss bottom tube up to the tensile yield point, rather than the flexural resistance of the sub-transom truss when it is incorrectly filled with square shapes, rendering the truss useless.

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

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

We do not fool the reader with phrases - “here we need to take into account...”, “calculate...”, “select from engineering tables...”, as is done on all sites! All formulas, accounting, selections, snips, state standards, assortments are hidden inside the calculator.

Here is your canopy - here are your planned dimensions! Enter your desired dimensions and the calculator will show you the safety factor of the selected professional pipes as a percentage. If the safety factor is positive, the canopy part will be considered calculated by the laws of strength of materials using all SNPs, GOSTs, assortments, and ifWhen ordering a product at our production site, we will confirm the results of this calculator with additional with a link to GOST assortments of professional pipes.

​

Our calculator is aimed at clients of gardening associations, cottage communities, and other private owners who need a quick, informed selection of corrugated pipes for sheds on outbuildings, car sheds, and extensions to buildings. Since often, in the absence of such a calculator, lack of experience, clients of "Garden and Vegetable Garden" undertake construction without any justification at all, either underestimating the strength, or, on the contrary, spending extra money, overestimating the strength. Therefore, the purpose of the calculator is only to guide 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 (in addition to taking into account the yield strength of tensile and bending in this calculator) for flexibility in compression and torsion, the parameter of which is taken into account before this link is used in the manufacture of the 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 safety margin yourself, for example 50%, 80%, choosing the strength yourself relative to your budget. For example, the trusses of our production workshop have a reserve of 80%, and can withstand not only snow, but also a crane beam that carries heavy loads. In any case, of course, you need to adhere to basic rules during construction, for example, you cannot use loads across the links, only along them. For example, in a truss, the place where it rests on the crossbar should not be empty, that is, without filling (that is, above the crossbar in the truss, there must be a link to fill the truss! Very often trusses break for this reason!). To install the “noodle” part, it is better to provide vertical filling links or the intersection of triangular fillings under it in the truss. It is better to make truss fillings from a thinner profile and more often than from a powerful one and rarely, since you should not forget that the load on the triangular filling links is along the axis and is insignificant, and the horizontal pipes of the trusses have a bending load component, and the loads on horizontal pipes huge, compared to the insignificant loads of the truss filling pipes.

​