Steel truss
A steel truss is a rather complex metal construction which consists of rod elements connected into nodes. The steel elements are usually attached by welding, but in some cases rivets are used. Such metal structures are lightweight, but at the same time they can withstand huge loads unlike other similar systems. In addition, installing precast truss is more profitable than monolithic metal or reinforced concrete structures. The rigidity of the trusses is achieved by a properly selected design. The trusses have upper and lower zones which are connected to each other by jumpers that increases the resistance of metal structures. The truss structure consists of belts, racks, braces and supporting braces or racks. It all depends on the operational purpose of the truss.
Purpose of steel trusses
These structures are designed for roof installation on buildings and structures where it is necessary to block large spans between the walls. Also spans of railway and automobile bridges are made from farms. Besides gantry and tower cranes are made from these metal structures. Nowadays trusses are widely used in the industrial construction due to the fact that they can cover large distances between walls and columns with reducing material costs and lightening the weight of structures. Steel farms are mainly in demand in the construction of industrial buildings, warehouses and sports facilities.
Materials for the production of steel trusses
As being trusses, profile pipes (square and rectangular) as well as an I-beam,T-profile, channel steel, corner etc. are used. Engineers evaluate which section of the elements is required for a particular truss as well as how many welds and rivets are needed,
Making a truss from metal
The farm configuration is selected depending on its purpose. If heavy loads are put on the truss, then I-beams and T-profiles are used. Belts with designs are made of profile pipes (rectangular or square). Standard trusses are made by using a corner which is a zigzag joined by welding. The frame of the truss is formed by the upper and lower zones, and the struts and braces in the form of a lattice imparting the strength and  load resistance.
Design features and types of truss structures:

  • Hanging
  • With interior supports;
  • Inclined.

By form they can be:

  • Arched
  • Rectangular
  • Double slope ;
  • Lean-to.

Along the outline  they can be:
  • With a parallel flange. More suitable for flat roofs. They band together quickly because all parts are of the same size.
  • Single-slope These trusses can withstand significant loads and require less material.
  • Polygonous They can withstand heavy loads, but they are more difficult to mount.
  • Three-angled These trusses are the best option for roofs with a high angle of inclination. The disadvantage of these structures is too many waste products.

Angle of dip:

  • 22-30. Such trusses are used in the construction of housing and outbuildings. The main plus is a small mass, and the three-angled forms are in a great demand.
  • 15-22. The approximate length is about 20 m. If the length is longer, then the lower belt is made broken.
  • 15 and less. Basically, such farms are trapezium-shaped and the use of racks increases the resistance to longitudinal loadings.

The advantages of truss structures:
  • Light weight
  • Long term operation
  • High stability to loads;
  • Complex configurations can be created
  • Reasonable price of materials and mechanical installation. Such trusses make it possible to build any type structure.