Methodology for Designing the Steel Frames of Variable Cross-Section from Rolled I-Beams

Introduction. The article tackles the problem of finding the most efficient in terms of metal consumption I-shaped crosssection for creating a frame of variable section. In this paper from various options of creating the variable in length frame elements the authors study the option of creating the elements from the ordinary I-beams by diagonal slitting followed by welding as one of the most technologically advanced one. To obtain the most efficient in terms of metal consumption cross-section, it is proposed to use a monosymmetric I-beam composed of two different assortment items.Materials and Methods. The review of scientific works related to the topic of designing structures from I-beams allowed the authors to compile a methodology for calculating the optimal section parameters. The implementation of this methodology makes it possible to draw the parameters for finding the most efficient for application cross-sections from the existing assortment of rolled I-beams.Results. The object considered in this study is a frame of a building designed as the braced frame structure from welded single-span frames with elements of variable cross-section (code 828KM). The calculation was made in accordance with the proposed methodology. The results of the calculation show that the use of a monosymmetrical I-beam, composed of two different I-beams, gives opportunity to use the load-bearing capacity of the section to the fullest extent.Discussion and Conclusions. In the result of implementation of the proposed methodology, it became possible to reduce the mass of an I-beam of a variable cross-section compared to the serial one used under similar loads. The result of the study allows us to conclude that the use of frames of variable section formed of I-beams of various cross-sections by diagonal slitting and subsequent welding in the construction of industrial frame buildings is highly perspective.