DESIGNING AND DETAILING OF BUILDING SYSTEMS. MECHANICS IN CIVIL ENGINEERING

TRIANGULAR TRUSSES FOR ROOFS (FLOORS) AND OPTIMIZATION OF THEIR DEPTHS

Vestnik MGSU 2/2017 Volume 12
  • Marutyan Aleksandr Surenovich - Institute of Service, Tourism and Design (ISTD), Branch of North Caucasus Federal University (NCFU) in Pyatigorsk Candidate of Technical Sciences, Associate Professor, Department of Construction, Institute of Service, Tourism and Design (ISTD), Branch of North Caucasus Federal University (NCFU) in Pyatigorsk, 56 40 Let Oktyabrya prospekt, Pyatigorsk, 357500, Russian Federation.
  • Orobinskaya Valeriya Nikolaevna - Institute of Service, Tourism and Design (ISTD), Branch of North Caucasus Federal University (NCFU) in Pyatigorsk Candidate of Technical Sciences, Leading Researcher, Department of Planning and Organization of Research Work, Institute of Service, Tourism and Design (ISTD), Branch of North Caucasus Federal University (NCFU) in Pyatigorsk, 56 40 Let Oktyabrya prospekt, Pyatigorsk, 357500, Russian Federation.

Pages 172-183

New technical solutions relating to triangular (three-chord) trusses for roofs (floors) are presented. In one of them for compressed-flexural elements of chords, Z-shaped built-up sections made of paired angle bars of assortment of structures of the TsNIISK, Moskva types are used instead of double-tee sections. In another solution, for gussetless nodal connections of rectangular tubes, the centering of these nodes on the ribbing of elements of chords with a V-shaped preparation of tip edges of elements of webs is used. For steel triangular roof trusses, optimal dimensions of their depths for which the usage of constructional material is minimal are given. These dimensions are 1/20...1/12 of the span and are obtained from the equality of masses of chord and web elements, taking into account the optimal inclination angles of braces. Acceptable convergence of the obtained results confirmed by the experience in the design of prestressed truss structures and optimization of structural designs of the TsNIISK type, taking into account new changes of boundary conditions, is shown. Sphere of effective application of the considered structures is defined. Thus, it can be concluded that the proposed technical solutions as to the triangular trusses for roofs (floors) are quite rational and promising for use in load-bearing structures of buildings and installations, and the optimization of depths of such trusses generalizes, to a certain extent, the widespread practice of calculating and designing thereof. The sphere of effective application of the considered triangular trusses can include lightweight metallic structures made of closed roll-welded sections (shaped tubes), rolled shapes and slender galvanized sections. Constituent part of this sphere can be presented by triangular (three-chord) trusses, shaping space frame systems in a form of space frames (see Fig. 1, а ) or crossed (see Fig. 5, в ) structures, and the technical and economic characteristics of these structures can be significantly improved due to rigid discs made of composite (steel reinforced concrete) slabs with permanent formwork and external reinforcement.

DOI: 10.22227/1997-0935.2017.2.172-183

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