## Magazine of Civil Engineering, No.1(61), 2016 Building structures. Structural mechanics

METHODS

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#### V.S. UtkinCalculation of the reliability of the earth foundations of buildings and structures according to the deformation criteria with limited information on the soils and loads (rus)

GOST R 54257–2010 recommends calculating the reliability of the earth foundations of structures by probabilistic methods with full statistical information about random quantities. Currently, there are no guidelines for calculating the reliabilityof earth foundations by the settlement with limited information about the parameters. The earth foundation (foundation bed) is a part of a mechanical system also including the foundation itself and the above-foundation construction.

#### I.N. Serpik, A.V. Alekseytsev Optimization of flat steel frame and foundation posts system (rus)

The development of effective design solutions for many construction projects requires taking into account the bearing capacity and the cost of manufacturing the superstructure and the foundation as a single system. We suggested an algorithm of complex optimal design of a steel flat frame for the building frame, and foundation posts under its columns on the natural foundation. It is proposed to minimize the cost of materials of basic variable parts of the structure.

CALCULATIONS

#### D.V. TinkovThe optimum geometry of the flat diagonal truss taking into account the linear creep (rus)

We have found the exact analytical expressions for the optimal geometry and minimum mass of a diagonal truss beam made of a material with properties of linear creep. We have derived simple analytical expressions for the deflection of the optimal weight of the truss. The deflection of the truss was calculated by the Maxwell - Mohr formula. We found solution generalizations for any number of panels by induction.

#### M.N. KirsanovThe exact formulas for calculating deflection and forces in the rods of the ’Molodechno’ truss with an arbitrary number of panels (rus)

We have obtained an analytical expression for the deflection and forces in the rods of a flat truss of beam type in the elastic stage. We found that the induction method, which has been tested for a wide class of two-dimensional elastic and regular trusses, does not yield a direct and compact result for trusses with an inclined upper chord.

#### A.A. KikotDesign of cold-formed tension members using the CFSteel software (rus)

A review of literature in research and calculate of cold-formed steel tension members with bolt attachments is presented. Limit States of such members may be: excessive elongation, a rupture in the weakened cross-section along the member, a rupture in the net cross-section with the holes at connection, bearing, block shear. A CFSteel software for calculation of the strength of tension members was developed.

STRUCTURES

#### A.B. Bondarev, A. YugovТhe method of calculating the accuracy of large-span metal rod systems (rus)

The article presents a method for calculating the accuracy of large-span metal rod systems and its mathematical model. The method takes into account the connectivity of hinged-rod metal shells, the technology of their construction and the gaps in the bolted joints. The latter are caused by the the center of the hole deviating from its designed position and by the actual shape of the holes for the bolts designing from the nominal form.

#### O.A. Sergeyev, V.G. Kiselev, S.A. SergeyevaOptimal design of 3d frame structures taking into account the stress and multiple natural frequency constraints (rus)

The problem of determining the optimal cross-sectional parameters and joint positions of linearly elastic space frames with imposed stress and multiple frequency constraints was considered. The frame was assumed to be acted on by different independent load systems, including temperature and self-weight loads. The stress-state analysis includes tension, bending, shear and torsion of beam elements.