This article presents the results of experimental study of the strength of wood and concrete specimens under local buckling by a flat die under short-term loading action. At joint operation of a reinforced concrete slab and a timber beam in the connection there is buckling of timber and concrete elements, therefore it is necessary to know values of strength at these types of loading of timber and concrete. The strength values of timber, concrete on expanded clay aggregate, compression and buckling strength ratios of materials, as well as physical properties of materials according to the requirements of normative documents have been determined. The values of timber deformation were obtained and the graph of deformation dependence on stresses and graphs of deformation growth were plotted; the coefficient of soil stiffness was obtained to determine the strength for local crushing of materials

Keywords: short-term loading, strength, flat die, compression, buckling, coefficient of subgrade reaction, timber, concrete

The article contains the methodology and results of theoretical and experimental studies of the stress-strain state of a conical radial-beam dome with triangular shell elements. The results obtained by various methods are analyzed and compared. The triangular membrane panel is part of the radial beam dome structure and consists of a support frame and a steel membrane in the shape of a triangle. The shape of the triangle forming the membrane panel can be different and depends on the number of ribs in the radial beam dome. The supporting contour is a compressed-bending element of the dome and is made, as a rule, from a rolled steel profile with a channel section. The membrane is made of thin steel sheet and attached to the upper flange of the channel with self-tapping screws or spot welding. To assess the strength and deformability of a steel membrane sheet, its operation under the action of a uniformly distributed snow load, an unevenly distributed snow load and a concentrated installation load was considered. Several options for nonlinear static calculations in various computer systems are shown.

Keywords: building structures, wooden structures, membrane panel, stress-strain state, radial beam dome, dome, membrane, design, experimental study

The factors affecting the strength of the interlayer bond of 3D concrete, as well as factors affecting the ability of the printer nozzle to produce a controlled concrete thread of a particular composition, which is being investigated in the process of 3D printing technology, the main characteristics of the suitability of compositions for printing on a 3D printer, requirements for rheology, hydration and strength in an uncured form, are considered 3D concrete, the main mechanical test methods for determining the adhesion strength in concrete printed on a 3D printer. The possible shapes and nominal sizes of the samples used in the methods for determining the strength of concrete are given.

Keywords: 3D concrete, anisotropy of mechanical properties, extrusion, cold connection, interfacial coupling, deflocation, thixotropy, initial static viscosity, curing, three-point bending

The article shows the possibility of producing a composite using carbon black as a filler. Trivalent chromium oxide was chosen not only as a pigment component, but also as a light stabilizer. The results obtained allow us to say that the dispersed composition is efficient. Compositions based on carbon black and containing trivalent chromium oxide in an amount of 1% exhibit electrically conductive properties.

Keywords: pyrolysis carbon, chemical composition, structural and morphological characteristics, elemental composition, energy dispersive spectrum, micrograph, epoxy binder, polyethylene polyamine, trivalent chromium oxide, thermal conductivity, electrical conductiv

The results of numerical modeling of wooden beams strengthened of composite materials based on carbon fiber are considered. Modeling of beams strengthened of composite material was carried out in the ANSYS software using deformation diagrams. The reliability of the modeling methodology was assessed by comparing the results of a numerical study with the results of a physical experiment obtained during testing of models of wooden beams strengthened of composite materials based on carbon fiber.

Keywords: carbon fiber, carbon composite materials, strengthening of wooden structures, external reinforcement of wooden beams

The article considers an experimental study of the stress-strain state of radial beam domes. The maximum stress values are fixed in stretched flexible elements with a peak value of 363.6 MPa. With the calculated resistance of the wire material Bp-I Rs = 410 MPa, there is a 12% load-bearing capacity margin. Note the high level of stresses in other flexible elements with values in the range from 141.4 to 274.72 MPa.

Keywords: radial beam dome, experimental studies, loading, strain gages, deformation