Polycarbonate is becoming an increasingly popular material, including for arranging canopies. They, like any other structure, must first be designed. And before you mount the frame for a polycarbonate canopy with your own hands, it should be calculated.
The supporting structure must be able to easily withstand the pressure loads from the roof, as well as the effects of wind and snow masses.
Components of the skeleton
The "skeleton" of the canopy can be assembled from wood or metal, based on the strength requirements of the project.
- For example, a small structure for recreation, a barbecue can be assembled from a bar, an analogue for a playground, playground, parking for a car, a pool - from pipes.
- The metal frame is more durable and reliable. But for its installation, you will need a welding machine and the skills of such work, and its price is higher.
- Manufacturers now offer prefabricated bolted frames. They are slightly more expensive than simple profile designs.
Note!
For metal supports, a square profile with a cross section of 60 × 60 mm to 100 × 100 mm is required, based on the design loads.
Pipes 40 × 40 or 60 × 60 go under the runs; for the crate, buy analogues 20 × 20 or 40 × 20.
Welded construction
- The main advantages of welded metal bases are strength, durability, ease and speed of installation.
- They can be installed on elementary strip, slab and pile / column foundations.
- The material for the construction can be shaped pipes, corners, channels.
- It consists of both upper and lower trims, support posts between them, as well as metal rafters and roof sheathing.
Supports of the structure
When calculating the racks, the height of the building and the number of supports themselves should be taken into account.
- For example, if a hammock is designed with a frame and a 2/5 m canopy, you can use thick-walled pipes with a section of 60/80 mm.
- If the structure is large, then in order not to increase the number of supports, you can use pipes with a cross section of 100 ×
roof lathing
When the frame of the canopy is placed under polycarbonate, the pitch and thickness of the roof sheathing should be calculated:
- So, if the structure is 8 m long, 6 m wide, and the plastic will have a thickness of 1 cm, then a crate is needed in increments of 1 m.
- The distance between its profiles is calculated based on the magnitude of the impacts and the choice of their cross section.
- Calculating the pressure on the supports and the truss of the building will help make it more stable in winter, when snow presses on the roof with a force of up to 3.5 tons.
Below is a table of the crate step for cellular polycarbonate. The letter "A" in it means the width of the cells, and "B" - their length in centimeters.
| Size 6 mm 8 mm 10 mm 16 mm |
| A B A B A B A B |
| 100/kg2 105 79 120 90 132 92 125 95 |
| 90 90 95 95 100 100 110 110 |
| 82 103 90 110 90 115 95 120 |
| 160/kg2 88 66 100 75 105 75 115 90 |
| 76 76 83 83 83 83 97 97 |
| 70 86 75 90 75 95 85 105 |
| 200/kg2 80 60 85 65 95 70 110 85 |
| 69 69 76 76 78 78 88 88 |
| 62 78 65 85 70 85 75 95 |
Snow and wind load on the structure
Before the frame canopy is built, it is necessary to calculate the loads on it. Basically, this is the effect of weather conditions on the skeleton and roof: winds, snow and other precipitation.
The amount of snow loads
The pressure on the structure is calculated by hand, according to the formula: S = λ∙Sg.
In it:
- Sg is the weight of snow on each square meter of the roof, in different regions of Russia this figure ranges from 0.8 kg to 5.6;
- λ is the conversion factor from the snow load on the ground to its effect on roof roof, it is from 3% to 20.
In the Central zone of the Russian Federation, these indicators are such that the best option is to weld a frame from a metal profile.
Note!
For example, if a snow mass of 4 kg presses on the "square" of the roof, and the transition coefficient is 15%, then the sum of the loads on the horizontal floors is 60.
This value corresponds to the optimal use of metal or reinforced concrete supports.
wind effect
To determine whether the frame is optimal for polycarbonate - for a canopy from this particular material, wind loads should also be calculated.
For the calculation, you will need the following data.
- The standard value of wind pressure in your area (V0). It can be numbers from 17 to 85.
- The coefficient of change in air pressure, depending on the height of the building (q). Based on the characteristics of the region, it is 0.4/2.75.
- Aerodynamic coefficient (c) equal to 2.
The formula for calculating the effect of wind on a building looks like this:
Vн=V0∙q∙c.
If your area is mountainous, then the local air pressure parameter is determined separately:
V0=0.61∙F0∙2. Here F0 means wind speed in meters per second.
Conclusion
The basis of any structure before its construction must be designed. Otherwise, the structure may not withstand the weight of the roof and climatic loads on it. The video in this article will complement the agreed information.
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