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August 12, 2017 18:07

Production of metal trusses : drawings and instructions .

Purpose and material metal trusses

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Metal Farm - a finished or assembled on-site welded (rarely bolted assembly, riveting) Truss.In conventional treatments of metallic triangular trusses called planar element that includes only details of the future support of the roof (actually bearing flanks, legs, struts, girders, etc.).According to another version - the same hard rafter triangle attached to the lower belt, defined braces and struts.

Actually, the purpose of these structures is easy to read in their definition.Quick installation of the roof of any industrial building or residential home with minimal effort on the layout and construction of roof system.With the proper calculation of the metal truss of the shaped tube and quality performance of welding further roofing work are minimized: flat tube assembly need only pick up on the upper harness constructions and set the markup.

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The basic material is most often chosen in black or galvanized steel in the following versions rental:

  • shaped tubes of excellent mechanical properties we mentioned separately;choice of square or rectangular cross-section for the farm depends on how well it was possible to calculate;
  • T-bar rental, a channel for the roof with special loads;the weight of all-metal assemblies are much larger, so the scope of application is limited to the production of construction;
  • Area: opposite option for the manufacture of metal trusses or temporary outbuildings (sheds, garages, hozblok, etc.), which can perform, and with his hands in the presence of welding equipment.

For the manufacture of ready-farms for lightweight roof coatings, for example, polycarbonate, aluminum profiles are sometimes used, which greatly simplifies the installation of the finished product.


How to calculate and choose a metal farm

should first refer to the technical conditions of use of roof systems, which are the two most important defining parameters, angle and width of the span.Depending on these values ​​is chosen not only carrying pipe section, but metal species.Entrust the design and manufacture of such serious structural elements we recommend a professional, but have about them the most common presentation is necessary.

main structural variants metal gable roof trusses are only four:

  • classic triangle on the roof thrust;
  • triangular design on the frontal notching;
  • pentagonal element segment with additional stiffening ribs;
  • polygonal design for spans over 24 meters with a potentially high external loads.

Accordingly, the choice of scheme is defined project task.

  1. slope of the gable roof 22-30o - an ideal option, which allows without too much trouble to install the product of the first category in the size 6 - 12 m. Height and width ratio of 1/5 is taken.
  2. slope roofing should be reduced to 15-22o at the same posting metal trusses in length: the problem to be solved by the broken line of the lower zone and a corresponding increase in stiffness rafter element.
  3. For small slopes of the roof should be applied lean-trapezoidal farm, the height of which the top edge should be calculated from the ratio 1/7 or even 1/9 of the width of the covering of the room.

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design flaw of steel shaped tube

It is clear that the production of steel trusses on the set by you or calculated by the architect parameters Built undertake such products manufacturers, the market conditions they can offer a range of services,from which dizzy.But the product without hidden flaws do not exist, these are the laws of the market.

What we have in real life:

  • Metal farm even in the manufacture of thin-walled steel profiles on the ceiling of 15 m can weigh up to 5 tons.Recalculate on the size of your house and think about shipping.At the same time, consider the linear dimensions of the product.Professional calculation, assembly, transportation and loading and unloading of steel structural elements comes at a price.
  • Installing roof system: no special lifting equipment and welding equipment can not do, and the good people still have to search.
  • Finally, no special anti-corrosion treatment of metal girders of square profiled steel pipe in two to three years will begin to rust from elementary accumulation of condensation in the attic area.

But spoonful of honey is still there: these rafters for any external and internal environments will survive not only you, but your home.

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