EXPERIENCE OF DESIGNING STEEL TRUSSES FROM RECTANGULAR HOLLOW SECTIONS ACCORDING TO EN 1993-1 REQUIREMENTS

Abstract

The history of using steel trusses is several hundred years. Modern construction prac-
tice has shown that steel welded trusses made of rectangular pipes are the most economical due to 
their manufacturability and relatively low material consumption. Currently, in the Republic of Bela-
rus, depending on the design assignment, the calculation of  steel structures is allowed to be per-
formed both in accordance with the requirements of SNiP II-23, and according to the EN 1993-1 
TRC. The article presents a comparison of structural solutions of trusses made of rectangular pipes 
with faceless nodes, designed according to the EN 1993 and SNiP II-23, and applied at various fa-
cilities in the Republic of Belarus. The analysis of the most common errors in their design is per-
formed. 
The cross section of the bent-welded profile is ideal for a three-sided prismatic rod structure in 
terms of ease of organization of the nodal spatial connection. The EN 1993-1-8 provides the ability 
to calculate and design spatial faceless nodes: type KK, TT and XX. The use of triangular trusses 
with such nodes in the frames of buildings allows you to reduce the cost of the device in the struc-
ture of the coating connections or completely eliminate cross-links on the coating.   
It is found that the Eurocode provides more options for designing nodes from rectangular pipes: 
a greater range of pipe thicknesses and angles of inclination of the grid to the belt, the possibility of 
calculating and designing spatial nodes. Tap EN 1993-1-8 contains more variants of destruction of 
nodes from rectangular pipes, but not all schemes of destruction are given the corresponding calcu-
lation formulas, which is often ignored by designers. 
The paper presents a design solution developed and implemented by the authors of a structural 
solution for strengthening a monolithic ribbed attic floor with the use of spatial three-sided trusses 
made of bent-welded profiles, designed using the EN 1993-1. 
The main idea of strengthening the attic floor, which is in an emergency, was to hang it to inde-
pendent  load-bearing structures  in the  form of three-sided trusses,  based on  vertical  load-bearing 
elements. Inclusion in the work of the entire structure of the reinforcement is made by stretching the 
suspensions, which are suspended unbroken main beam of the monolithic ribbed attic floor.