Polycarbonate is an ideal material for the construction of canopies. It allows you to get a light structure with a transparent roof through which sunlight penetrates. As a rule, the frame is made of profiled pipes. For the entire structure to be durable, it is necessary to correctly calculate the polycarbonate canopy.
What the frame consists of
Before starting the calculation of the canopy, you must clearly understand what elements it consists of. And there are only a few.
Racks, as the name implies, are the elements on which the entire canopy rests. As a rule, this is a profiled pipe 2.2-2.8 meters high. Its height depends on the mounting method. If it is attached by anchors to a mortgage, concreted in the ground, then its height is taken 2.2 meters. In cases where the stand is concreted or buried, then the height is taken 2.8 meters.
To strengthen the canopy are arches and farms. The latter are most often set by two. But the exact number of arches will tell only the calculation of the canopy. This value depends on the dimensions of the structure.
A truss is a structural element connecting support pillars and logs.
Polycarbonate sheets are attached to structural elements called guides. Thermowells are used for this. Their location and step frequency depend on the distance between the bearing supports and the type of polycarbonate (its thickness).
Canopy Mounting Steps
In order to correctly calculate the canopy from the profile pipe, it will be useful to understand the whole process. It consists of several stages. Arches are mounted on fixed racks. In this case, the angle between them must be exactly ninety degrees. The resulting sections are attached to mortgage anchors. Farms are attached to these supports. The angle between trusses and arches is also straight (i.e. ninety degrees). The final stage in the manufacture of the frame is the fixing of the guides. They are attached to the top of the arches. On this frame is ready. After painting, you can fix the polycarbonate sheets.
Construction errors to consider when calculating
Construction of canopies is often performed with errors. They affect not only the choice of type of construction, but also the calculation of the metal canopy carried out as a result of this .
A common mistake is choosing a sloping canopy. Often make a structure on two pillars and tilted to the windward side. This is far from the best option for permanent use (for example, for parking a car). Danger awaits if the wind changes direction. The canopy in this case can be compared with the wing of an airplane. Between it and the ground a lifting force is formed, which can easily carry a canopy. Even if there are four pillars, this will not always save.
Inclined canopies are suitable for situations when the structure is attached to the building. Free-standing inclined canopies must be done with roundings. Moreover, the convex part is oriented "towards" the wind.
Types of Canopies
Depending on the supporting elements, several types of canopies are distinguished:
- Standing apart. They have vertical supports installed around the entire perimeter.
- Beam-supporting, which are attached to the building on one side. They have one side held by support pillars. The second rests on a beam attached to the wall of the building.
- Cantilever-supporting. They differ from the previous view in that here brackets or mortgages are attached to the wall.
- Cantilever, which are held entirely by mortgages. Usually these are small visors above the door.
Calculation of the canopy of each type is carried out according to different schemes.
Types of Canopies
By their design, the outboard structures can be of three types:
- Pitched, in which the roof is tilted in one direction.
- Gable with two slope directions.
- Arched, in which the roof is made in the form of a semicircle (arc).
Data collection
The calculation of the canopy from the profile pipe must begin with the collection of necessary information. It should include the following data:
- Characteristics of the material.
- The purpose of the structure.
- Data on wind and snow loads (they are presented in special tables for each specific region).
The calculation of the canopy is carried out taking into account the above information. It includes formulas and calculations. Not everyone can understand them. The best option is to use special programs and calculators. Today there are plenty of them on the Internet.
Visors above an entrance console
Awnings of cantilever type depend on the size of the porch. In accordance with the requirements of regulatory documents, the platform in front of the door should be one and a half times the width of the door. The average door width is 0.9 meters. It turns out that the minimum size of the upper platform is 1.35 m (0.9 x 1.5 = 1.35). This value is equal to the recommended depth of the canopy.
As for the width of the visor, everything is simple here. It is made 0.6 meters more than the width of the door. On each side, the visor should protrude 0.3 meters.
In such a simple way canopies are calculated. Structural analysis at standard values leads to the following result: depth - 0.9-1.35 m, width - 1.4-1.8 m.
Console support canopies over a door
These types of visors are arranged over the entire platform with the capture of steps. The calculation of the depth of the canopy above the site is calculated similarly to the previous option. A part above the steps is added to it. It directly depends on their quantity. For each step, about 0.25-0.32 m is added.
The width depends on the width of the stairs, on both sides of which 0.3 meters are added. If the standard width of the steps in front of the door is 0.8-1.2 meters, then we get the width of the canopy 1.1-1.5 meters.
Consider the option with a staircase of three steps and a platform of standard sizes. The depth will be about 1.65-2.31 meters (0.9 + 3 x 0.25 or 1.35 + 3 x 0.32). Width under the same conditions - 1.4-1.8 meters. It is calculated as follows: 0.8 + 0.3 + 0.3 or 1.2 + 0.3 + 0.3. Two calculation options consider the minimum and maximum value of standard parameters.
Sheds adjacent to the building
Calculation of a single-pitched canopy, which is adjacent to the house on one side, is carried out with a minus of half the vertical supports. Another important point: the joints of the sheets should be above the profile. This means that between the profiles a distance of 1260, 2050 or 2100 millimeters must be maintained, corresponding to the size of the polycarbonate sheet. The average width of the canopy is three meters. With this size, there is enough space even for a car. On polycarbonate at this width will bend. He needs a rafter system.
First, the material is calculated. A canopy attached to the house, with such dimensions, will have six vertical risers. They will all be located on one side. If the structure is free-standing, then the supports are needed twice as much (that is, twelve, six on each side). For each rafter leg, a support is installed.
Shed freestanding canopy
The calculation of a stand-alone structure should take into account the load that rainfall carries. The design will be as rigid as possible if it is made in the shape of a triangle.
Calculation of the canopy is carried out taking into account conventionally accepted values. With a polycarbonate sheet size of 2.1 x 0.6 m, the roof width is taken to be six meters, and the length is 10.6 meters. The most optimal option: the height of the ramp is 2.4 meters and 11 rafter sections. In such a situation, six profiles (standard length of six meters) will be required. Instead of eleven, you can make only two triangles. This will reduce the amount of consumed materials. This option is suitable for regions with average rainfall.
Calculation of a gable canopy
The principle of calculation is similar to single-slope structures. The main thing is to achieve structural rigidity. And this is done at the expense of the same triangles. Their optimal number is calculated as follows. Each running meter of a canopy is divided by a vertical profile. The resulting rectangle is divided into two triangles.
Calculation of arched structures
Arched type canopies are the most complex structures. The need for material is directly dependent on the bulge of the roof. This means that the steeper the bulge, the more materials you have to spend.
In this case, you can save only on the rafter system. With the previously considered dimensions of the canopy (10.6 x 6 meters), two or three systems (two at the edges, one in the middle) will be enough. The remaining “legs” will be arcs. Their ends are optional. The metal profile that is used to make the truss is quite durable. It will be enough to provide the necessary rigidity. The main thing is that the farm is firmly attached to the risers.
If you make an arch canopy with such dimensions (for example, for a car), then you will need the following materials:
- Six profiles, curved in the shape of an arc, with a length of six meters. The ends of three of them are connected by a jumper. It is recommended that they also be divided into several triangles to increase the rigidity of the structure.
- For each arc, two supports are required (under each edge). That is, all of them need twelve (2 x 6).
- Along the edges, along the pillars and along the roof, longitudinal beams are attached. In total, six will be required.
Calculation of the main structural elements
The calculation of the cross section of the pipe for the canopy depends on the height of the structure itself and the number of columns. If the size of the structure does not exceed five meters, the pipe is selected with a cross section of 6-8 centimeters. With large sizes, the number of risers should be increased. To avoid this, you can select a profile with a large cross section. For example, 10 centimeters.
The size of the crate will depend on the thickness of the polycarbonate and the size of the canopy. If the plastic sheet has a thickness of one centimeter, and the canopy has dimensions of 6 x 8 meters, then the crate will be collected in increments of one meter. These values are in accordance with the loads. For this, there are special tables that take into account the magnitude of the load and the thickness of the polycarbonate. An example of this table can be seen in the photo below. It is designed for polycarbonate with a thickness of six, eight, ten and sixteen millimeters.
The calculation of the arch canopy involves the calculation of farms and their number. It is the sizes of the farms that determine the width of the entire canopy. To determine them, you need to know the following information:
- The size of the material (polycarbonate).
- The method of fastening elements (welding, bolting, and so on).
- The value of the loads (in accordance with regulatory documents).
- Steel structures according to SNiP.
The size of the canopy is selected according to the size of the materials. If a polycarbonate sheet is six meters in length, then it is either used whole or cut into two parts. Of course, you can cut into more parts. But this will lead to waste. Thus, the roof will be either six-meter or three-meter. Any length can be chosen, depending on personal preference.