Links are necessary and important parts of the steel frame. They fulfill the following functions:
At local loads, the links ensure the joint operation of the transverse frames.
Links take various loads and transfer them to the foundations, for example, wind loads, loads from cranes, etc.
Links provide the best stability of the elements of the entire frame, as well as the constancy of its spatial system.
In order to ensure optimum operating conditions, communications contribute to the creation of the necessary rigidity of the framework.
Provide the most optimal conditions and convenience for a qualitative installation of the frame.
For example, between the columns links are necessary to ensure that during the installation and operation the frame does not change its geometric shape, and also that the load-carrying capacity of the carcass remains unchanged in the longitudinal direction.
Links are differentiated depending on the destination in two types: the connection between the columns and the connection between the truss or the so-called connection of the tent.
The system of links between the trusses provides the framework with a general spatial stiffness. Due to this type of links, local loads are redistributed from one of the frames to adjacent frames, as well as receiving and transferring all kinds of loads to the columns. The links between the trusses, as a rule, are responsible for preserving the geometry of the whole frame, as well as for the good stability of the compressed bolt elements from the truss plane. In addition, the links between the trusses ensure the convenience of installing the frame itself.
In light roofing metal structures, so-called purlins are often used as auxiliary beams.
The main function of the purlins is to transfer the load to the roof truss structures from the roof.
Purlins are divided into two main types: lattice runs and runs of solid cross-section.
For the production of continuous purlins, as a rule, rolled channel bars and I-beams are used. In the purlins, bends are arranged, since manufacturers, first of all, need to ensure the best stability of the shelves. Lattice purlins are much lighter weight than solid ones. However, the manufacture and installation of continuous runs is an easier process than the production and installation of latticework.