Canopies 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 canopy over the entrance. By turning to professionals, you will get any canopy you want. But many can handle the installation work themselves. True, you will need an accurate calculation of the truss from profile pipe. You cannot do without the appropriate equipment and materials. Of course, welding and cutting skills are also required.
The basis of canopies 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 light, but durable. In cross-section it looks like:
When welding trusses from a profile pipe, they often choose a square or rectangular section. These profiles are easier to process.
Variety of pipe profiles
Permissible loads depend on the wall thickness, metal grade, and manufacturing method. The material is often high-quality structural steel (1-3ps/sp, 1-2ps(sp)). For special needs, low-alloy alloys and galvanization are used.
The length of profile pipes usually ranges from 6 m for small sections to 12 m for large sections. 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 above. Products maximum dimensions(300×300×12 mm and more) are more suitable for industrial buildings.
As for the parameters of frame elements, there are the following recommendations:
They call it a farm rod system, basis building structure. It consists of straight elements connected at nodes. For example, we are considering the design of a truss made of a profile pipe, in which there is no misalignment of the rods and no extra-nodal loads. Then only tensile and compressive forces will arise in its components. The mechanics of this system allows it to maintain geometric invariance when replacing rigidly mounted units with hinged ones.
The farm consists of the following elements:
The lattice system can be triangular, diagonal, semi-diagonal, cross. For connections, scarves, paired materials, rivets, and welds are used.
Mounting options in nodes
Making trusses from a profile pipe involves assembling a belt with a certain outline. By type they are:
Some systems are easier to install, others are more economical in terms of material consumption, and others are easier to construct support units.
The choice of design for canopy trusses made from profile pipes is related to the slope of the structure being designed. There are three possible options:
At a minimum angle (6°-15°), trapezoidal contours of the belts are recommended. To reduce weight, a height of 1/7 or 1/9 is allowed total length span. Designing a complex canopy geometric shape, you need to lift it in the middle part above the supports. Take advantage of Polonso farms, recommended by many experts. They are a system of two triangles connected by tightening. 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 length. The latter reaches 20 m. To increase the structure, the lower belt is made broken. Then the increase will be up to 0.23 span lengths. To calculate the required parameters, use tabular data.
Slope determination table rafter system
For slopes greater than 22°, calculations are carried out using special programs. Awnings of this kind are more often used for roofing 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 span length.
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 increasing its height. For additional strength, additional stiffening ribs are provided.
To understand how to calculate a truss from a profile pipe, it is necessary to find out the parameters of the basic units. For example, span dimensions should usually be specified in terms of reference. The number of panels and their dimensions are pre-assigned. Let's calculate optimal height(H) in the middle of the span.
The grille braces should have an inclination of approximately 45° (within 35°-50°).
Take advantage of the ready-made standard project, then you won’t have to do the calculation
In order for the canopy to be reliable and last a long time, its design requires precise calculations. After the calculation, materials are purchased, and then the frame is installed. There is a more expensive way - to purchase ready-made modules and assemble the structure on site. Another more difficult option is to do the calculations yourself. Then you will need data from special reference books on SNiP 2.01.07-85 (impacts, loads), as well as SNiP P-23-81 (data on steel structures). You need to do the following.
Among the methods for calculating statically determinate trusses, one of the simplest is considered to be cutting out nodes (areas where the rods are hingedly connected). Other options are the Ritter method, the Henneberg rod replacement method. As well as a graphical solution by drawing up a Maxwell-Cremona diagram. In modern computer programs The method of cutting out knots is more often used.
For a person who has knowledge of mechanics and strength of materials, calculating all this is not so difficult. 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 errors. It may be better to turn to specialists. Or choose an option from ready-made design solutions, where you can simply substitute your values. When it is clear what type of roof truss made from a profile pipe is needed, a drawing for it will probably be found on the Internet.
If the canopy belongs to a house or other building, it will require official permission, which will also have to be taken care of.
First, the site where the structure will be located is selected. What does this take into account?
The characteristics of the soil and the influence of nearby buildings are also important. The designer must take everything into account significant factors and clarifying coefficients that are included in the calculation algorithm. If you plan to carry out calculations on your own, use 3D Max, Arkon, AutoCAD or similar programs. There is a calculation option in online versions of construction calculators. Be sure to find out for the intended project the recommended spacing between load-bearing supports and sheathing. As well as parameters of materials and their quantities.
An example of a software calculation for a canopy covered with polycarbonate
The assembly of a frame from metal profiles should only be carried out by a welding specialist. This important task requires knowledge and skillful handling of the tool. You not only need to understand how to weld a truss from a profile pipe. It is important which units are best assembled on the ground, and only then lifted onto supports. If the structure is heavy, equipment will be required for installation.
Typically the installation process takes place in the following sequence:
Taking advantage finished project, you will quickly start assembling the canopy
Experts advise performing such responsible work only if you have 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, House master takes risks. The canopy will fold and collapse. Everything underneath it will suffer - cars or people. So take this knowledge to heart!
Today, profile pipe trusses are rightfully considered an ideal solution for the construction of a garage, residential building and garden buildings. Strong and durable, such designs are inexpensive, quick to implement, and anyone with at least a little understanding of mathematics and cutting and welding skills can handle them. And now we will tell you in detail how to choose the right profile, calculate the truss, make jumpers in it and install it. For this we have prepared for you detailed master classes making such farms, video tutorials and valuable advice from our experts!
Stage I. Designing the farm and its elements
So what is a farm? This is a structure that ties the supports together into one cohesive whole. In other words, the truss is a simple architectural structure, among the valuable advantages of which we highlight the following: high strength, excellent performance, low cost and good resistance to deformation and external loads.
Due to the fact that such trusses have a high load-bearing capacity, they are placed under any roofing materials, regardless of their weight.
The use of metal trusses from new or rectangular closed profiles in the construction is considered one of the most rational and constructive solutions. And for good reason:
Rafter trusses differ in the outline of the belts, the type of cross-section of the rods and the types of lattice. And with the right approach, you can independently weld and install a truss from a profile pipe of any complexity! Even this one:
Stage II. We purchase a high-quality profile
So, before drawing up a project for future farms, you first need to decide on the following important points:
Remember one simple thing: a profile pipe frame has so-called balance points, which are important to determine for the stability of the entire farm. And it is very important to choose high-quality material for this load:
Trusses are built from profile pipes of the following types of sections: rectangular or square. These are produced different sizes cross-section and diameter, with different wall thicknesses:
The stability of the entire structure is directly proportional to the thickness of the profile, so for the manufacture of trusses, do not use pipes that are intended only for welding racks and frames - these have different characteristics. Also pay attention to which method the product was manufactured: electric welded, hot-formed or cold-formed.
If you undertake to make such trusses yourself, then take square-section blanks - they are the easiest to work with. Purchase a square profile 3-5 mm thick, which will be strong enough and its characteristics are close to metal bars. But if you are making a truss just for a visor, then you can give preference to a more budget-friendly option.
Be sure to consider snow and wind loads in your area when designing. After all great importance when choosing a profile (in terms of the load on it), the angle of inclination of the trusses is:
You can more accurately design a truss from a profile pipe using online calculators.
Let us only note that the simplest structure of a truss made from a profile pipe consists of several vertical posts and horizontal levels onto which rafters for the roof can be attached. You can purchase such a frame ready-made yourself, even to order in any city in Russia.
Stage III. We calculate the internal stress of farms
The most important and responsible task is to correctly calculate the truss from a profile pipe and select the desired format of the internal lattice. To do this, we will need a calculator or similar other software, as well as some tabular data of SNiPs, which for this:
Please review these documents if possible.
Roof shape and angle
What specific roofing needs a truss? Single-pitch, gable, dome, arched or hipped? The simplest option, of course, is to make a standard lean-to canopy. But you can also calculate and manufacture quite complex trusses yourself:
A standard farm consists of the following important elements, such as the upper and lower chords, racks, braces and auxiliary struts, which are also called trusses. Inside the trusses there is a system of gratings; welds, rivets, special paired materials and gussets are used to connect the pipes.
And, if you are going to make a complex-shaped roof, then such trusses will become suitable for it ideal option. It is very convenient to make them according to a template directly on the ground, and only then lift them up.
Most often, when building a small country house, garage or shed, so-called polonceau trusses are used - a special design of triangular trusses connected by ties, and the lower chord here comes out raised.
Essentially, in this case, in order to increase the height of the structure, the lower belt is made broken, and it then amounts to 0.23 of the flight length. It is very convenient for the interior space.
So, there are three main options for making a truss, depending on the slope of the roof:
What's the difference you ask? For example, if the angle of the structure is small, up to only 15°, then it is rational to make the trusses trapezoidal in shape. And at the same time, it is quite possible to reduce the weight of the structure itself, taking the height from 1/7 to 1/9 of the total flight length.
Those. follow this rule: the less the weight, the greater the height of the truss should be. But if we already have a complex geometric shape, then you need to choose a different type of truss and gratings.
Types of trusses and roof shapes
Here is an example of specific trusses for each type of roof (single, gable, complex):
Let's look at the types of farms:
Here is an example of making trusses from a profile pipe as a universal option that is suitable for any garden buildings. It's about about triangular trusses, and you've probably already seen them many times:
A triangular truss with a crossbar is also quite simple, and is quite suitable for building gazebos and cabins:
And here arched farms are already much more complicated to manufacture, although they have a number of valuable advantages:
Your main task is to center the metal truss elements from the center of gravity in all directions, saying in simple language, minimize the load and distribute it wisely.
Therefore, choose the type of farm that is more suitable for this purpose. In addition to those listed above, scissor trusses, asymmetrical, U-shaped, double-hinged, trusses with parallel chords and attic trusses with and without supports are also popular. And also an attic view of the farm:
You will be interested to know that a certain design of internal truss gratings is not selected for aesthetic reasons, but for quite practical ones: to suit the shape of the roof, the geometry of the ceiling and the calculation of loads.
You need to design your farm in such a way that all forces are concentrated specifically at the nodes. Then there will be no bending moments in the belts, braces and trusses - they will work only in compression and tension. And then the cross-section of such elements is reduced to the required minimum, while significantly saving on material. And you can easily make the truss itself hinged.
Otherwise, the force distributed over the rods will constantly act on the truss, and a bending moment will appear, in addition to the total stress. And here it is important to correctly calculate the maximum bending values for each individual rod.
Then the cross-section of such rods should be larger than if the truss itself were loaded with point forces. To summarize: trusses on which the distributed load acts uniformly are made of short elements with hinged joints.
Let's figure out what the advantage of this or that type of grid is in terms of load distribution:
We have prepared an illustration for you where we have collected all types of trusses and their gratings together:
Here is an example of how a triangular lattice truss is made:
Making a truss with a diagonal lattice looks like this:
It cannot be said that one type of truss is definitely better or worse than another - each of them is valuable due to its lower consumption of materials, lighter weight, load-bearing capacity and method of fastening. The drawing is responsible for what load pattern will act on it. And the chosen type of lattice will directly determine the weight of the truss, the appearance and labor intensity of its manufacture.
Let us also note this unusual option for making a truss, when it itself becomes a part or support for another, wooden one:
Stage IV. We manufacture and install trusses
We will give you some valuable tips on how to independently weld such trusses right on your own site without much difficulty:
Here, for example, is a good video tutorial on how to lengthen a pipe by welding and achieve ideal geometry:
Here is also a very useful video on how to cut a pipe at a 45° angle:
So, now we come directly to the assembly of the trusses themselves. The following step-by-step instructions will help you cope with this:
What else do those who make such farms at home face? First, think in advance about the support tables on which you will place the truss. Far from it the best option throw it on the ground - it will be very inconvenient to work.
Therefore, it is better to install small bridge supports that will be slightly wider than the lower and upper chords of the truss. After all, you will manually measure and place jumpers between the belts, and it is important that they do not fall to the ground.
The next important point: trusses made from profile pipes are heavy in weight, and therefore you will need the help of at least one more person. In addition, it wouldn’t hurt to have help with such tedious and painstaking work as sanding metal before cooking.
Also in some designs it is necessary to combine different types trusses to attach the roof to the wall of the building:
Also keep in mind that you will need to cut a lot of trusses for all the elements, and therefore we advise you to either purchase or build homemade machine similar to the one in our master class. Here's how it works:
So, step by step, you will draw up a drawing, calculate the truss lattice, make blanks and weld the structure on site. Moreover, you will also be using up the remains of the profile pipes, therefore, you will not need to throw anything away - all this will be needed for minor parts of the canopy or hangar!
Stage V. Clean and paint the finished trusses
After you install the trusses in their permanent place, be sure to treat them with anti-corrosion compounds and paint them with polymer paints. Paint that is durable and UV resistant is ideal for this purpose:
That's all, the profile pipe farm is ready! Only finishing work for covering the trusses from the inside with finishing and outside with roofing material:
Believe me, making a metal truss from a profile pipe will actually not be difficult for you. A huge role is played by a well-drawn drawing, high-quality welding of a truss from a profile pipe and the desire to do everything correctly and accurately.
When the area of the structure is large enough, the issue of ensuring the reliability and strength of the structure becomes particularly important. There is a need to strengthen the rafter system, the rafters of which could cover fairly long spans.
Trusses made from profile pipes are metal structures assembled using lattice rods. Manufacturing metal trusses is a more labor-intensive process than in the case of solid beams, but more economical. Used in production paired material, and as a connecting part - scarves. The entire structure is assembled using welding or riveting.
With their help, you can cover spans of any length, however, it is worth noting that for correct installation competent calculation is required. Then, provided that the welding work is carried out with high quality, all that remains is to move the pipe assemblies upstairs and install them according to top harness, according to the markup.
Load-bearing trusses made of profile pipes have many undeniable advantages:
The division of these structures into specific types is based on different parameters. Let's start with the main thing -
There are:
According to the first parameter, they distinguish:
According to the contour, there are:
For spans longer than 14 m, braces are used, which are installed from top to bottom. A panel (about 150 – 250 cm in length) is placed along the upper belt. Thus, with these initial data we have a design that includes two belts. The number of panels is even.
If the span exceeds 20 m, then there is a need for a sub-rafter metal structure connected by supporting columns.
The so-called Polonso farm deserves special mention. It consists of two triangular systems connected to one another through a tie. This design solution avoids the installation of long braces in the middle panels, which leads to a significant reduction in overall weight.
Attention!
Trusses made of profile pipes for a pitched roof with a slope angle of 6–10° should have an asymmetrical shape.
Heights are determined by dividing the span length into seven, eight or nine parts, taking as a basis the features of a given structure.
The calculations are based on the requirements of SNiP:
A mandatory component of any calculation and subsequent installation of a structure is a drawing.
A diagram is prepared indicating the relationship between the length of the metal structure and the roof slope.
For truss lengths exceeding 36 m, the construction lift is additionally calculated.
Calculations are carried out taking into account the fact that an increase in height leads to an increase in load-bearing capacity. Snow cover will not linger on such a canopy. One way to strengthen trusses from a profile pipe is to install several strong stiffeners.
To determine the dimensions of metal structures for canopies, follow the following data:
When calculating the pitch, it is necessary to take into account that the greatest possible distance from one canopy support to another is 1.7 m. If this limitation is violated, the strength and reliability of the structure will be in question.
When the necessary parameters are completely obtained, the corresponding design diagram is obtained using formulas and special programs. Now all that remains is to think about how to weld the truss correctly.
On a note
The calculations should take into account:
Making metal trusses for a canopy on video.
© 2018 stylekrov.ru
A canopy made of pipes and polycarbonate is becoming an increasingly popular architectural form on a personal plot. No wonder, because this building can perform many functions, ranging from an open garage for a car, a wood warehouse, an indoor playground and ending with a recreation area with a barbecue and soft chairs.
The key advantage is the ability to make such a design with your own hands. This article will provide recommendations on the choice of material, examples of calculations of supports and trusses, and how to weld a canopy from a profile pipe.
The length of the rafter depends on the angle of inclination of the truss. For different angles, it is optimal to use different roofing materials:
Single-pitch canopy made of profile pipe, photo of a structure with a roof made of corrugated sheets
Calculation of a canopy made of polycarbonate from a profile pipe is carried out in accordance with SNiP P-23-81 “Steel Structures” and SNiP 2.01.07-85 “Loads and Impacts”.
The technological requirements for the farm and the calculation sequence are as follows. In accordance with the technical specifications, the required span is determined. Using the presented diagram, we substitute the dimensions of the span and determine the height of the structure. The angle of inclination of the truss and the optimal shape of the canopy roof are set. The contours of the upper and lower chords of the truss, the general outlines and type of roofing are determined accordingly.
Important! The maximum distance at which trusses are placed when making a canopy from a profile pipe is 1.75 m.
Diagram of the dependence of the length of the rafters on the angle of the roof when calculating a truss from a profile pipe for a canopy
As a material for assembling a truss, you can use channels, tees, angles and other profiled products made from steel grade St3SP or 09G2S (in accordance with GOST). However, all these materials have a significant drawback compared to profiled pipes - they are much heavier and thicker with comparable strength characteristics.
The dimensions of the frame elements for a canopy made from a profile pipe depend on the dimensions of the building. In accordance with GOST 23119-78 and GOST 23118-99 to create a canopy from square pipe with their own hands they use the following materials:
Before you begin assembling a canopy from a profile pipe with your own hands, you need to draw a detailed plan of the entire structure indicating the exact dimensions of all elements. This will help calculate the exact amount of materials of each type and calculate the cost of construction.
Drawing of a canopy made from a profile pipe indicating the main overall dimensions
In addition, it is advisable to do additional drawing the most complex designs. In this case, it is a single-pitched truss and the fastening points of its main elements.
Scheme for making a truss from a profile pipe for a canopy with the main fastening units
One of the main advantages of a profile pipe is the possibility of a faceless connection. This is manifested in the simplicity of the design and low cost of the truss with a length of rafter spans of up to 30 m. In this case, the roofing material can rest directly on the upper chord of the truss, provided it is sufficiently rigid.
Fastening points for assembling a canopy from a profile pipe with your own hands, in the photo a - a triangular lattice, b - a support lattice, c - a diagonal lattice
The advantages of a bevelless welded connection are:
Disadvantages include:
Bolted connections in the production of products from profile pipes are quite common. They are usually used in collapsible canopies made of profile pipes or in products produced for mass consumption.
Bolted connections are the simplest for installing a canopy from a profile pipe with your own hands, photo of the attached frame element
The main advantages of such connections are:
Flaws:
The article examined the design and methods of making the simplest single-pitch canopy from a profile pipe with your own hands, however, profiled pipe is a rather “flexible” material from which complex and aesthetically attractive structures can be made.
A complex design for creating a canopy from a corrugated pipe with your own hands, photo of a lean-to, dome structure
Canopies 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 canopy over the entrance. By turning to professionals, you will get any canopy you want. But many can handle the installation work themselves. True, you will need an accurate calculation of the truss made from a profile pipe. You cannot do without the appropriate equipment and materials. Of course, welding and cutting skills are also required.
The basis of canopies 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 light, but durable. In cross-section it looks like:
When welding trusses from a profile pipe, they often choose a square or rectangular section. These profiles are easier to process.
Variety of pipe profiles
Permissible loads depend on the wall thickness, metal grade, and manufacturing method. The material is often high-quality structural steel (1-3ps/sp, 1-2ps(sp)). For special needs, low-alloy alloys and galvanization are used.
The length of profile pipes usually ranges from 6 m for small sections to 12 m for large sections. 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 above. Products of maximum dimensions (300×300×12 mm and more) are more suitable for industrial buildings.
Regarding the parameters of frame elements, there are the following recommendations:
A truss is a rod system, the basis of a building structure. It consists of straight elements connected at nodes. For example, we are considering the design of a truss made of a profile pipe, in which there is no misalignment of the rods and no extra-nodal loads. Then only tensile and compressive forces will arise in its components. The mechanics of this system allows it to maintain geometric invariance when replacing rigidly mounted units with hinged ones.
Example of a welded rod system
The farm consists of the following elements:
The lattice system can be triangular, diagonal, semi-diagonal, cross. For connections, scarves, paired materials, rivets, and welds are used.
Mounting options in nodes
Making trusses from a profile pipe involves assembling a belt with a certain outline. By type they are:
Types according to the outlines of the belts
Some systems are easier to install, others are more economical in terms of material consumption, and others are easier to construct support units.
The choice of design for canopy trusses made from profile pipes is related to the slope of the structure being designed. There are three possible options:
At a minimum angle (6°-15°), trapezoidal contours of the belts are recommended. To reduce weight, a height of 1/7 or 1/9 of the total span length is allowed. When designing a flat canopy of a complex geometric shape, it is necessary to raise it in the middle part above the supports. Take advantage of Polonso farms, recommended by many experts. They are a system of two triangles connected by tightening. 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 length. The latter reaches 20 m. To increase the structure, the lower belt is made broken. Then the increase will be up to 0.23 span lengths. To calculate the required parameters, use tabular data.
Table for determining the slope of the rafter system
For slopes greater than 22°, calculations are carried out using special programs. Awnings of this kind are more often used for roofing 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 span length.
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 increasing its height. For additional strength, additional stiffening ribs are provided.
To understand how to calculate a truss from a profile pipe, it is necessary to find out the parameters of the basic units. For example, span dimensions should usually be specified in the technical specifications. The number of panels and their dimensions are pre-assigned. Let's calculate the optimal height (H) in the middle of the span.
The grille braces should have an inclination of approximately 45° (within 35°-50°).
Use a ready-made standard project, then you won’t have to make calculations
In order for the canopy to be reliable and last a long time, its design requires precise calculations. After the calculation, materials are purchased, and then the frame is installed. There is a more expensive way - to purchase ready-made modules and assemble the structure on site. Another more difficult option is to do the calculations yourself. Then you will need data from special reference books on SNiP 2.01.07-85 (impacts, loads), as well as SNiP P-23-81 (data on steel structures). You need to do the following.
Among the methods for calculating statically determinate trusses, one of the simplest is considered to be cutting out nodes (areas where the rods are hingedly connected). Other options are the Ritter method, the Henneberg rod replacement method. As well as a graphical solution by drawing up a Maxwell-Cremona diagram. In modern computer programs, the method of cutting nodes is more often used.
For a person who has knowledge of mechanics and strength of materials, calculating all this is not so difficult. 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 errors. It may be better to turn to specialists. Or choose an option from ready-made design solutions, where you can simply substitute your values. When it is clear what type of roof truss made from a profile pipe is needed, a drawing for it will probably be found on the Internet.
If the canopy belongs to a house or other building, it will require official permission, which will also have to be taken care of.
First, the site where the structure will be located is selected. What does this take into account?
The characteristics of the soil and the influence of nearby buildings are also important. The designer must take into account all significant factors and clarifying coefficients that are included in the calculation algorithm. If you plan to carry out calculations on your own, use 3D Max, Arkon, AutoCAD or similar programs. There is a calculation option in online versions of construction calculators. Be sure to find out for the intended project the recommended spacing between load-bearing supports and sheathing. As well as parameters of materials and their quantities.
An example of a software calculation for a canopy covered with polycarbonate
The assembly of a frame from metal profiles should only be carried out by a welding specialist. This important task requires knowledge and skillful handling of the tool. You not only need to understand how to weld a truss from a profile pipe. It is important which units are best assembled on the ground, and only then lifted onto supports. If the structure is heavy, equipment will be required for installation.
Typically the installation process takes place in the following sequence:
By using a ready-made project, you will quickly begin assembling the canopy
Experts advise performing such responsible work only if you have the appropriate experience. It is not enough to know in theory how to properly weld a truss from a profile pipe. By doing something wrong, by ignoring the nuances, the home master takes risks. The canopy will fold and collapse. Everything underneath it will suffer - cars or people. So take this knowledge to heart!
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.
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.
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:
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:
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.
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
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
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.
When all the effective loads are known for the truss, 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 - area cross section 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.
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.
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.
By using a profile pipe to install trusses, you can create structures designed for high loads. Light metal structures are suitable for the construction of structures, arrangement of frames for chimneys, installation of roof supports and canopies. The type and dimensions of farms are determined depending on the specific use, be it household or industrial. It is important to correctly calculate a truss made from a profile pipe, otherwise the structure may not withstand operational loads.
Arch truss canopy
Metal trusses made from rolled pipes are labor-intensive to install, but they are more economical and lighter than structures made from solid beams. A profiled pipe, which is made from a round pipe by hot or cold processing, in cross section has the form of a rectangle, square, polyhedron, oval, semi-oval or flat-oval shape. It is most convenient to install trusses from square pipes.
A truss is a metal structure that includes an upper and lower chord, as well as a lattice between them. The lattice elements include:
Structural elements of a metal truss
Trusses are primarily designed to cover spans. Due to the stiffening ribs, they do not deform even when using long structures on structures with large spans.
The production of metal trusses is carried out on the ground or in production conditions. Elements made from profile pipes are usually fastened together using welding machine or rivets, scarves and paired materials can be used. To mount the frame of a canopy, canopy, or roof of a permanent building, the finished trusses are lifted and attached to the top frame according to the markings.
To cover spans they are used various options metal trusses. The design can be:
Triangular trusses made from profile pipes are used as rafters, including for the installation of a simple lean-to canopy. Metal structures in the form of arches are popular due to their aesthetic appearance. But arched structures require the most accurate calculations, since the load on the profile must be distributed evenly.
Triangular truss for a lean-to structure
The choice of design for canopy trusses made from profile pipes, canopies, and rafter systems under the roof depends on the design operating loads. The number of belts varies:
In construction, you can use trusses with different contours:
Outlines of truss belts
In accordance with the angle of inclination, typical trusses are divided into the following types:
Before calculating the truss, it is necessary to select a suitable roof configuration, taking into account the dimensions of the structure, the optimal number and angle of inclination of the slopes. You should also determine which belt contour is suitable for the selected roof option - taking into account all operational loads on the roof, including precipitation, wind load, the weight of people carrying out work on arranging and maintaining a canopy from a profile pipe or roof, installation and repair of equipment on the roof.
To calculate a truss made from a profile pipe, it is necessary to determine the length and height of the metal structure. The length corresponds to the distance that the structure must cover, while the height depends on the designed angle of inclination of the slope and the selected contour of the metal structure.
Calculating a canopy ultimately comes down to determining the optimal spacing between the nodes of the truss. To do this, you need to calculate the load on the metal structure and calculate the profile pipe.
Incorrectly designed roof frames pose a threat to the life and health of people, since thin or insufficiently rigid metal structures may not withstand the loads and collapse. Therefore, it is recommended to entrust the calculation of a metal truss to professionals familiar with specialized programs.
If you decide to carry out the calculations yourself, you must use reference data, including information on the bending resistance of the pipe, and be guided by SNiP. It is difficult to correctly calculate a structure without the appropriate knowledge, so it is recommended to find an example of calculating a typical truss of the required configuration and substitute the necessary values into the formula.
At the design stage, a drawing of a truss from a profile pipe is drawn up. Prepared drawings indicating the dimensions of all elements will simplify and speed up the production of metal structures.
Drawing with dimensions of elements
We calculate a truss from a steel profile pipe
Manufacturing a structure from a profile pipe To ensure the necessary accuracy of calculations, use a construction calculator - a suitable special program. This way you can compare your calculations and the software calculations in order to avoid large discrepancies in sizes!
Arched structures: calculation example
To weld a truss for a canopy in the form of an arch using a profile pipe, it is necessary to correctly calculate the structure. Let's consider the principles of calculation using the example of a proposed structure with a span between supporting structures (L) of 6 meters, a pitch between arches of 1.05 meters, a truss height of 1.5 meters - such an arched truss looks aesthetically pleasing and can withstand high loads. The length of the boom of the lower level of the arched truss is 1.3 meters (f), and the radius of the circle in the lower chord will be equal to 4.1 meters (r). The magnitude of the angle between the radii: a=105.9776°.
Diagram with dimensions of the arched canopy
For the lower belt, the profile length (mн) is calculated using the formula:
mн – length of the profile from the lower chord;
π – constant value (3.14);
R – radius of the circle;
α is the angle between the radii.
As a result we get:
The structural nodes are located in sections of the lower chord with a step of 55.1 cm - it is allowed to round the value to 55 cm to simplify the assembly of the structure, but the parameter should not be increased. The distances between the extreme sections must be calculated individually.
If the span is less than 6 meters, instead of welding complex metal structures, you can use a single or double beam by bending the metal element at a selected radius. In this case, calculation of arched trusses is not required, but it is important to select the correct cross-section of the material so that the structure can withstand the loads.
Profile pipe for installation of trusses: calculation requirements
In order for finished floor structures, primarily large-sized ones, to withstand strength testing throughout their entire service life, pipe products for the manufacture of trusses are selected based on:
Data from these sources will allow you to familiarize yourself with the types of profile pipes and choose the best option, taking into account the cross-section configuration and wall thickness of the elements, and the design features of the truss.
Carport made from rolled pipes
It is recommended to make trusses from high-quality rolled pipes; for arched structures, it is advisable to choose alloy steel. In order for metal structures to be resistant to corrosion, the alloy must include a large percentage of carbon. Metal structures made of alloy steel do not require additional protective painting.
Helpful installation tips
Knowing how to make a lattice truss, you can mount a reliable frame under a translucent canopy or roof. It is important to take into account a number of nuances.
It is important to understand how to weld a truss from a profile pipe if the metal structure needs to be assembled directly at the construction site. If you do not have welding skills, it is recommended to invite a welder with professional equipment.
Welding of truss elements
The metal structure racks are mounted at a right angle, the braces are mounted at an angle of 45°. At the first stage, we cut elements from the profile pipe in accordance with the dimensions indicated in the drawing. We assemble the main structure on the ground and check its geometry. Then we weld the assembled frame, using corners and overlay plates where required.
We make sure to check the strength of each weld.. The strength and reliability of welded metal structures and their load-bearing capacity depend on their quality and accuracy of arrangement of elements. The finished trusses are lifted up and attached to the harness, observing the installation step according to the project.
Trusses from profile pipes: manufacturing, how to calculate and weld
The truss is a hanging structure, which consists of upper and lower chords, braces and racks, which is part of the overall rafter system of the roof of the house. Today it can be made from different material, but structures made of metal are beginning to become increasingly popular.
A roof truss can be made of various materials, but metal structures are becoming increasingly popular.
Design metal roofing performed using modern technology, which today is considered optimal for a wide variety of buildings. Frame houses made of lightweight metal structures resistant to various external conditions, they are durable and reliable.
The calculation of such rafter systems is carried out using special programs that take into account numerous factors, which makes the entire structure very reliable.
Metal trusses were previously used wherever high structural strength was needed; today the advantage of using such structures is also used for private construction, and not only for the construction of industrial enterprises. Today, metal trusses are in demand, which can be divided into two groups: spatial and flat.
Flat structures are distinguished by the fact that each metal rod is located in only one plane. Spatial structures form beams that perfectly withstand loads from all sides. This is similar to the design of a tower crane, which is resistant to fairly strong, prolonged loads during use.
The main elements of a metal truss are the rafter belt and gratings; the belt accounts for the longitudinal force and moment, and the lattice accounts for the transverse force. The space that is located between them is usually called a panel, the free gap between the trusses is the span, the space between the axes of the chords is the height.
Types of metal trusses.
The metal trusses used today can be very different, which greatly distinguishes them from others. They differ in the shape of the belts, spans, sizes, and manufacturing patterns. Thus, static trusses can be frame, beam, cable-stayed, arched. Beams in this case are distinguished by more economical consumption of materials, lighter weight than others, they can be used for the manufacture of structures that require resistance to large, constant loads. Arched ones are used to create unusual, attractive roof shapes, but during their construction the consumption of building materials is slightly increased.
In addition, combined patterns are used, polygonal, segmented, triangular, trapezoidal, with parallel belts. All of them are distinguished by great strength, low weight, and stability. The high quality of installation of the rafter system is ensured by the fact that any calculation for such a structure is carried out using special programs.
The materials used for the manufacture of metal trusses are lightweight galvanized metal profiles (the so-called LSTC, that is, light steel thin-walled structures), fastened with self-tapping screws and special bolts, or special steel beams for which welded joints are used.
Calculating metal roof trusses is a procedure that requires special knowledge. Typically, such calculations are performed by designers using special programs, taking into account numerous factors. This calculation makes metal structures as reliable as possible. When calculating the rafter system, it is necessary to take into account the following factors:
Diagram of snow load on the roof.
Snow load is calculated using the formula: N= Q*k
It is worth taking into account wind loads, which include data on the maximum wind speed in the area, the number of storeys of the building, the design features of the roof, and its area.
Only a specialist can make an accurate calculation of metal trusses; you should not try to do this yourself!
Installation of metal roof trusses should only be carried out by professionals. All fastenings are carried out only according to the project. These are bolted and welded fastenings (for various types material). Installation rules depend not only on the type of structure, but also on its specification; for spans greater than 4.5 m, it is recommended to pre-install additional supports for any type of truss.
Choosing a coating depending on the angle of the roof
All metal rafters, or rather their type and design, largely depend on the roof slope angle. Let's consider options for installing rafter systems:
For large buildings, where the span length is from 20 to 35 meters, it is necessary to use the so-called Polonceau trusses, that is, a metal structure that consists of two triangular trusses connected by ties. This makes it possible to remove the long braces for the middle panels to reduce weight. In this case, the upper belt must be divided into 12-16 panels each 2-2.75 meters long. The calculation for lining the ceiling must take into account the presence of a tie of 4-6 panels, which is attached to the nodes of the upper chord.
The use of metal for the manufacture of rafter systems is not such a new thing. Such structures have been known since the end of the 19th century, although they were used extremely rarely, mainly for the construction of palaces and temples. Today, metal has found a second life; reliable and very durable buildings are made from it, residential buildings, industrial facilities.
The calculation of such structures should be carried out only by specialists; there are special programs for this. Fastenings of metal trusses can be different, as well as the material of manufacture: these are welded steel structures, lightweight galvanized ones, which are fastened with self-tapping screws and bolts. The type of trusses themselves and their dimensions largely depend on what roof slope will be made and what loads are expected.
Metal roof truss
Trusses are structural elements that, having absorbed the load in the span, transfer it to the supports. Metal trusses have the form of a lattice through structure made of rectangular rods “assembled” together into nodes. The choice of their design for a particular roof determines the location of the attic floor, the roof slope and the required span length.
Metal trusses are mainly made from steel profiles, often from angle steel. For heavier structures, the profile has a T-section or I-beam section, and for hydraulic structures– round, profile pipe. Steel roof trusses are widely used in structures for roofing and covering buildings, most often with spans greater than 24 m.
The strength and rigidity of these elements of the supporting structure is ensured by their shape. The classic version of a metal truss consists of rods - two parallel and one between them, welded in a zigzag manner. Thanks to this arrangement, even with relatively low material consumption, the resistance of the metal structure increases.
Main structural elements:
The nodal connection of the elements is carried out by direct adjoining one to the other. The lattice rods are fixed to the belts either by welding or by means of shaped elements. In addition to rafters, there may also be sub-rafters. They are used as supports for load-bearing structures and floors if the distance between the columns exceeds the pitch of the beams or the columns have unequal pitch.
They are classified according to the geometry of the belts and the type of lattice.
According to the outline of the belt
Grid systems
When calculating, the requirements of SNiP for “Steel Structures” and “Loads and Impacts” are taken into account. Correctly calculating metal rafter systems is possible only with special knowledge. In this case, numerous factors are taken into account, so designers, as a rule, turn to the help of special programs when making calculations.
What is the basis for calculating a triangular truss: an example
Trusses are under constant influence of loads such as the weight of the roof, lanterns, suspended drainage systems, fans, the dead weight of the supporting structure and others. Temporary loads include wind pressure, snow pressure, the weight of people on the roof, and suspended vehicles.
Special or periodic loads, such as seismic, hurricane, etc., are also taken into account.
Some device rules
The type and design of metal rafters largely depends on the slope of the roof. Let's consider the relationship between the roof slope and the design of rafter systems:
Series 1.263.2-4. Issue 1. Trusses with spans of 18, 21 and 24 m from rolled angles. KM drawings(7.1 MiB, 368 hits)
1.263-2-4.1KM-4 Diagrams of trusses with markings of nodes. Breakdown of farms into shipping marks
1.263-2-4.1KM-5 Layout of trusses with a span of 18 m and connections
1.263-2-4.1KM-6 Layout of trusses with a span of 21 m and connections
1.263-2-4.1KM-7 Layout of trusses with a span of 24 m and connections
1.263-2-4.1KM-8 Diagram of trusses with markings of elements
1.263-2-4.1KM-9 Assortment of trusses with span L=18 m and H=1.2 m
1.263-2-4.1KM-10 Assortment of trusses with span L=18 m and H=1.8 m
1.263-2-4.1KM-11 Assortment of trusses with span L=21 m and H=1.8 m
1.263-2-4.1KM-12 Assortment of trusses with span L=24 m and H=1.8 m
1.263-2-4.1KM-13 Schemes of vertical connections V-1, V-2
1.263-2-4.1KM-14 Unit 1
1.263-2-4.1KM-15 Unit 2.3
1.263-2-4.1KM-16 Unit 4
1.263-2-4.1KM-17 Unit 5
1.263-2-4.1KM-18 Unit 6
1.263-2-4.1KM-19 Unit 7
1.263-2-4.1KM-20 Unit 8
1.263-2-4.1KM-21 Unit 9
1.263-2-4.1KM-22 Unit 10
1.263-2-4.1KM-23 Unit 11
1.263-2-4.1KM-24 Unit 12-15
1.263-2-4.1KM-25 Instructions for calculating welds of truss units
1.263-2-4.1KM-26 Marking holes along the upper chords of trusses for fastening ties
1.263-2-4.1KM-27 Layout diagram of reinforced concrete slabs and details of their welding to truss chords
1.263-2-4.1KM-28 Specification of steel trusses with a span of 18 m
1.263-2-4.1KM-29 Specification of steel trusses with a span of 21 m
1.263-2-4.1KM-30 Specification of steel trusses with a span of 24 m
Approved: State Committee for Civil Engineering and Architecture under the USSR State Construction Committee 10/13/1982
Series 1.263.2-4. Issue 2. Trusses with a span of 27, 30 and 36 m from rolled angles. KM drawings(8.8 MiB, 129 hits)
1.263-2-4.2KM-2 Diagrams of trusses with markings of nodes. Breakdown of farms into shipping marks
1.263-2-4.2KM-3 Layout of trusses with a span of 27 m and connections
1.263-2-4.2KM-4 Layout of trusses with a span of 30 m and connections
1.263-2-4.2KM-5 Layout of trusses with a span of 36 m and connections
1.263-2-4.2KM-6 Truss diagrams with element markings
1.263-2-4.2KM-7 Assortment of trusses with a span of L=27 m; H=1.8 m
1.263-2-4.2KM-8 Assortment of trusses with a span of L=27 m; H=2.1 m
1.263-2-4.2KM-9 Assortment of trusses with a span of L=30 m; H=1.8 m
1.263-2-4.2KM-10 Assortment of trusses with a span of L=30 m; H=2.1 m
1.263-2-4.2KM-11 Assortment of trusses with a span of L=36 m; H=2.1 m
1.263-2-4.2KM-12 Assortment of trusses with span L=36 m; H=2.4 m
1.263-2-4.2KM-13 Schemes of vertical connections V-1, V-2; V-3
1.263-2-4.2KM-14 Unit 1
1.263-2-4.2KM-15 Unit 2.3
1.263-2-4.2KM-16 Unit 4
1.263-2-4.2KM-17 Unit 5
1.263-2-4.2KM-18 Unit 6
1.263-2-4.2KM-19 Unit 7
1.263-2-4.2KM-20 Unit 8
1.263-2-4.2KM-21 Unit 9
1.263-2-4.2KM-22 Unit 10-13
1.263-2-4.2KM-23 Instructions for the calculation of welds in truss joints
1.263-2-4.2KM-24 Marking holes along the upper chords of trusses for fastening ties
1.263-2-4.2KM-25 Layout diagram of reinforced concrete slabs and details of their welding to truss chords
1.263-2-4.2KM-26 Specification of steel trusses with a span of L=27 m; N=1.8 m
1.263-2-4.2KM-27 Specification of steel trusses with a span of L=27 m; N=2.1 m
1.263-2-4.2KM-28 Specification of steel trusses with a span of L=30 m; N=1.8 m
1.263-2-4.2KM-29 Specification of steel trusses with a span of L=30 m; N=2.1 m
1.263-2-4.2KM-30 Specification of steel trusses with a span of L=36 m; N=2.1 m
1.263-2-4.2KM-31 Specification of steel trusses with a span of L=36 m; N=2.4 m
Accepted: MADI Ministry of Higher Education of the USSR (Moscow Automobile and Highway Institute)
Accepted: President of Russian Federation
Accepted: CITP Gosstroy USSR
Approved: State Committee for Civil Engineering and Architecture under the USSR State Construction Committee 01/04/1983
Series 1.263.2-4. Issue 3. Trusses with a span of 18, 21, 24, 27, 30 and 36 m from rolled angles under a lightweight roof(11.6 MiB, 80 hits)
1.263-2-4.1KM-2 Diagrams of trusses with markings of nodes. Breakdown of farms into shipping marks
1.263-2-4.1KM-3 Layout of trusses with a span of 18 m, purlins and connections
1.263-2-4.1KM-4 Layout of trusses with a span of 21 m, purlins and connections
1.263-2-4.1KM-5 Layout of trusses with a span of 24 m, purlins and connections
1.263-2-4.1KM-6 Layout of trusses with a span of 27 m, purlins and connections
1.263-2-4.1KM-7 Layout diagrams for trusses with a span of 30 m, purlins and connections
1.263-2-4.1KM-8 Layout of trusses with a span of 36 m, purlins and connections
1.263-2-4.1KM-9 Diagram of trusses with markings of elements
1.263-2-4.1KM-10 Assortment of trusses with a span of L=18 m; H=1.2 m
1.263-2-4.1KM-11 Assortment of trusses with a span of L=18 m; H=1.8 m
1.263-2-4.1KM-12 Assortment of trusses with a span of L=21 m; H=1.8 m
1.263-2-4.1KM-13 Assortment of trusses with a span of L=24 m; H=1.8 m
1.263-2-4.1KM-14 Assortment of trusses with a span of L=27 m; H=1.8 m
1.263-2-4.1KM-15 Assortment of trusses with a span of L=27 m; H=2.1 m
1.263-2-4.1KM-16 Assortment of trusses with a span of L=30 m; H=1.8 m
1.263-2-4.1KM-17 Assortment of trusses with a span of L=30 m; H=2.1 m
1.263-2-4.1KM-18 Assortment of trusses with span L=36 m; H=2.1 m
1.263-2-4.1KM-19 Assortment of trusses with span L=36 m; H=2.4 m
1.263-2-4.1KM-20 Schemes of vertical connections V-1…V-4
1.263-2-4.1KM-21 Unit 1
1.263-2-4.1KM-22 Unit 2.3
1.263-2-4.1KM-23 Unit 4
1.263-2-4.1KM-24 Unit 5
1.263-2-4.1KM-25 Unit 6
1.263-2-4.1KM-26 Unit 7
1.263-2-4.1KM-27 Unit 8
1.263-2-4.1KM-28 Unit 9
1.263-2-4.1KM-29 Unit 10
1.263-2-4.1KM-30 Unit 11
1.263-2-4.1KM-31 Unit 12-15
1.263-2-4.1KM-32 Instructions for calculating welds of truss units
1.263-2-4.1KM-33 Marking holes along the upper chords of trusses L=18-24 m for fastening ties
1.263-2-4.1KM-34 Marking holes along the upper chords of trusses L=27-36 m for fastening ties
1.263-2-4.1KM-35 Tables for selecting purlin brands and flooring size profiles
1.263-2-4.1KM-36 Specification of steel trusses with a span of L=18 m; N=1.2 m; N=1.8 m
1.263-2-4.1KM-37 Specification of steel trusses with a span of L=27 m; L=24 m; H=1.8 m
1.263-2-4.1KM-38 Specification of steel trusses with a span of L=27 m; N=1.8 m; N=2.7 m
1.263-2-4.1KM-39 Specification of steel trusses with a span of L=30 m; N=1.8 m; N=2.1 m
1.263-2-4.1KM-40 Specification of steel trusses with a span of L=36 m; N=2.1 m
1.263-2-4.1KM-41 Specification of steel trusses with a span of L=36 m; N=2.4 m
Approved: State Committee for Civil Engineering and Architecture under the USSR State Construction Committee 05/06/1983
Series 1.263.2-4. Issue-4. Trusses with a span of 15, 18, 21, 24, 27 and 30 m from welded curved closed profiles (with reduced height)(6.8 MiB, 139 hits)
1.263-2-4.4-01КМ Truss diagrams with node markings. Breakdown of farms into starting marks
1.263-2-4.4-02KM Layout of trusses with a span of 15.18 m and connections
1.263-2-4.4-03КМ Layout of trusses with a span of 21.24 m and connections
1.263-2-4.4-04KM Layout of trusses with a span of 27.30 m and connections
1.263-2-4.4-05KM Truss diagrams with element markings
1.263-2-4.4-06KM Assortment of trusses with a span of 15,18,21 m
1.263-2-4.4-07KM Assortment of trusses with a span of 24 m
1.263-2-4.4-08KM Assortment of trusses with a span of 27 m
1.263-2-4.4-09KM Assortment of trusses with a span of 30 m
1.263-2-4.4-10KM Geometric diagrams of shipping marks for roof trusses
1.263-2-4.4-11KM Unit 1.2
1.263-2-4.4-12KM Node 3…8
1.263-2-4.4-13KM Truss support units (options)
1.263-2-4.4-14KM Fragments of the flooring plan with the location of fastenings
1.263-2-4.4-15KM Permissible design load on the deck
1.263-2-4.4-16KM Tie fastening unit
1.263-2-4.4-17KM Truss welds
1.263-2-4.4-18KM Details D-1…D-3
1.263-2-4.4-19KM Specification of steel trusses with a span of 15,18,21 and 24 m
1.263-2-4.4-20KM Specification of steel trusses with a span of 27 and 30 m
1.263-2-4.4-21KM Material consumption sheet
Approved: State Committee for Civil Engineering and Architecture under the USSR State Construction Committee 03/29/1984
Metal trusses: design calculation, manufacturing
Roof trusses for house construction are made mainly of wood, which is susceptible to environmental influences. In places where wood comes into contact with other materials, it is necessary to install gaskets that will serve as moisture insulation on the roof side and vapor barrier on the residential side. It is necessary to install ventilated gaps and treat them with fire retardants and antiseptics.
The roof truss carries all the structural loads of the roof, the weight of the roof, sheathing and resists external influences.
Roof truss made of metal structures is the most durable, reliable and high-quality material that is suitable for absolutely all types of buildings and has a wide range of operation in various climatic zones and weather conditions.
The MSL Consulting Group company offers you roofing trusses made of metal structures of the following types:
A rafter system made of metal, based on a triangle, is the most rigid and most economical structure, capable of evenly distributing loads on the load-bearing walls of the house and becoming a load-bearing roofing part. It is created on the basis of accurate calculations based on the requirements for roof construction. There are a number of structural elements, variations, the use of which affects the variety of types of structures of such trusses. There is a difference in the intersupport spans - hanging rafters rest on the outer supports, and inclined ones have additional support on the middle load-bearing wall.
An original rafter structure made of metal, where the lower plane consists of two segments (strings) that have a slope. The lower chord of the truss does not fill the under-roof space. In industrial buildings and many design projects no interfloor overlap is provided. This provides a number of aesthetic advantages. But to perform the main function of resisting the stretching of the rafters, it is necessary to ensure that the angle of inclination of the prefabricated tightening is no more than 2/3 of the angle of the rafters.
It is used for arranging a single-pitched roof or for a zone-like one, where several slopes are mounted at different levels. The desired location of the lower part is on the leeward side. As a rule, the angle of inclination is lower than that of multi-slope roofs. When the length of the rafter leg is more than 4.5 m, supports (stands, struts) are required.
They are used on flat or slightly sloping single-pitched roofs, for arranging soft roofs, for attic and interfloor ceilings, or to strengthen them. The triangle system lattice makes the truss unchangeable under any load. Suitable for ceilings and large spans, which makes it most popular in the field of industrial construction.
It is used as an attic truss when arranging a gable triangular roof. In this case, part of the rafter system is the attic frame. Metal interfloor beams can serve as a tie. It has a lot of design solutions based on the use of additional struts and girders.
They are used in the construction of a gable roof to equip part of the under-roof space as a living space, creating additional space if necessary. The structure has two parallel beams and horizontal braces that form the geometry of the living space. The strut system is made outside it.
A scissor-shaped truss, the middle segment of the lower plane of which has no slope and is made horizontally. The central post under the ridge girder transfers horizontal stress to the lower chord of the truss, reducing it to zero. Additional racks allow you to increase the width of the purlin, the struts form the same angles - the basis of a reliable structure and distribute the remaining load. The rafters have two outer supports.
Design with broken slopes for those cases when it is impossible to fit attic room into a simple triangular roof. When installing on a single-bay house, it is necessary to strengthen the contractions of the risers of the lower and upper chords (which serves interfloor covering). If there is additional support from interior wall, it's not obligatory. The living space here is formed by parallel contractions and racks. The truss has no central support and this gives room for an open loft layout.
The broken slopes form two angles of inclination - gentle and steep, which is ideal for arranging a spacious attic. There is no “dead” zone. The design feature of the truss is overhanging rafters, due to which the trusses rest through corner struts on longitudinal walls with a fixed mauerlat. The complex truss system at the top of the posts and struts that form the triangles requires precise calculation of the stress and load distribution. The high position of the tightening connecting the rafter legs determines high requirements to the fastenings and to the power of the tightening itself, since it reduces the bursting force of the metal rafters.
The metal trusses used today can be very different, which greatly distinguishes them from others. They differ in the shape of the belts, spans, sizes, and manufacturing patterns. Thus, static trusses can be frame, beam, cable-stayed, arched. Beams in this case are distinguished by more economical consumption of materials, lighter weight than others, they can be used for the manufacture of structures that require resistance to large, constant loads. Arched ones are used to create unusual, attractive roof shapes, but during their construction the consumption of building materials is slightly increased.
In addition, combined patterns are used, polygonal, segmented, triangular, trapezoidal, with parallel belts. All of them are distinguished by great strength, low weight, and stability. The high quality of installation of the rafter system is ensured by the fact that any calculation for such a structure is carried out using special programs.
The materials used for the manufacture of metal trusses are lightweight galvanized metal profiles (the so-called LSTC, that is, light steel thin-walled structures), fastened with self-tapping screws and special bolts, or special steel beams for which welded joints are used.
Before installation, the roof truss made of LGTS is assembled on the ground and raised to the required height in finished form, then the structure is fixed to the building frame.
Installation is carried out in several stages:
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