Vol 18, No 2 (2022)

Articles

State Prize of the Russian Federation to the scientist Vladimir Ilyich Travush

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Structural Mechanics of Engineering Constructions and Buildings. 2022;18(2):91-92
91-92

Analysis and design of building structures

Nonlinear and linear analysis of the overall stability of the load-bearing system of a high-rise building with a load-bearing trunk

Inozemtseva O.V., Inozemtsev V.K.

Abstract

The results of numerical calculations can and should be verified, but testing a complex and detailed computational model is problematic. This possibility is provided by simplified models represented by simple computational schemes that are available for qualitative analysis, and the numerical results obtained are predictable. Such calculation schemes, as a rule, describe individual calculation tasks facing designers. For example, linear stability analysis is offered by the American Institute of Steel Structures (AISC). One of these models is discussed. The model under consideration is based on a linear analysis of the stability of a cantilever rack, which can be considered as a simple model of the bearing trunk of a high-rise building. A comparison of critical loads based on nonlinear and linear analysis of the stability of the cantilever rack is carried out. It is concluded that the considered linear model makes it possible to obtain a preliminary estimate of the critical load to verify the results of computer calculations using more complex models of the general stability of the equilibrium of the bearing trunk of a high-altitude object.

Structural Mechanics of Engineering Constructions and Buildings. 2022;18(2):93-103
93-103

Forced oscillations of a multimodular beam on a viscous elastic base

Rzayev N.S.

Abstract

The aims of the research are to obtain and to solve equations of forced oscillations of beams made of different modular materials and located on a viscous elastic base. It is assumed that the beam, which has different resistance to expansion and compression and which is continuous and heterogeneous by thickness and length, performs forced oscillations under the action of a force that varies according to the cross-harmonic law. When solving the problem, the resistance of the environment is taken into account. Since the equation of motion is a complicated differential equation with partial derivatives with respect to bending, it is solved by approximate analytical methods. At the first stage, decomposition into variables is used, and at the second stage, the Bubnov - Galerkin orthogonalization method is used. Equations of dependence between the circular frequency and parameters characterizing the resistance of the external environment and heterogeneity are obtained. Calculations were carried out for the specific values of characteristic functions. Results are represented in the form of tables and curves of the corresponding dependencies. It is clear from the obtained equations that serious errors are made in solving problems of oscillating motion without taking into account the resistance of the environment and different modularity. In addition to this, as the values of parameters that determine the heterogeneity of the density increase, the value of the frequency difference changes significantly. The results can be used in reports on solidity, stability and gain-frequency characteristic of different modular beams, boards and cylindrical coatings, taking into account the resistance of the environment.

Structural Mechanics of Engineering Constructions and Buildings. 2022;18(2):104-110
104-110

Optimization of channels and I-shaped bended closed profiles with perforated walls

Marutyan A.S.

Abstract

The article presents a continuation of the optimization of channel and I-shaped bended closed profiles (BCP) with tubular flanges and perforated walls made of rolled sheet products of both equal and different thicknesses. Such profiles are designed for light steel thin-walled structures (LSWS), which are distinguished by improved technical and economic indicators and mass demand in industrial and civil construction, which confirms the relevance of their further development. The purpose of the study is to show that the characteristics of LSWS can be further improved by shaping profiles, combining straight and round outlines of closed and open contours in a composite section, including their perforation. Through experimental design studies, solving optimization problems and variant design of the BCP, their design sections with a maximum margin of bending strength with a minimum mass have been refined. The originality of technical solutions is confirmed by patent examination. The channel BCP has extreme weight and strength with a relative height of cutouts in the wall of 1/1.87 and a ratio of width and height dimensions of 1/4.32. When the thickness of the shelves is 2 times the wall thickness, the strength and mass of the I-shaped BCP are extreme at a relative height of cutouts of 1/1.23 and a ratio of dimensions of 1/4.17, and when the thickness of the shelves is 0.6 of the wall thickness, the strength and mass of the BCP are extreme with a cutout height of 1/1.73 and a size ratio of 1/5.22. If the thicknesses of the shelves and the wall are equal, then the strength and mass of the BCP is extreme at a cutout height of 1/1.46 and a size ratio of 1/3.17.

Structural Mechanics of Engineering Constructions and Buildings. 2022;18(2):111-139
111-139

Theory of thin elastic shells

Tangential developable surfaces and their application in real structures

Krivoshapko S.N., Gil-oulbé M.

Abstract

A class of developable surfaces contains cylindrical, conical, and tangential developable surfaces. Tangential developable surfaces are ruled surfaces of zero Gaussian curvature with cuspidal edges. They give great opportunities to architects and engineers for realization of their creative projects. Both the theoretical researches in the area of geometry of torses and strength analysis of shells and the influence of these researches on the application of torses in practice are shown. A presented research demonstrated that torses found the application in shipbuilding, aircraft construction, mechanical engineering, in architecture and building, engineering equipment and communications, in road building, in anti-erosive banks, topography, and cartography, clothing articles of light industry, in sculptural forms, and in modelling with developable surfaces. It was confirmed by the references on great number of published works on the subject, real examples from practice, and by handing in 14 illustrations of real objects.

Structural Mechanics of Engineering Constructions and Buildings. 2022;18(2):140-149
140-149

Theoretical and experimental modeling of deformation of a cylindrical shell made of 45 steel under complex loading

Cheremnykh S.V.

Abstract

Thin-walled cylindrical shells are used in elements of highly loaded products of mechanical engineering and energy. Along with their frequent use in production, experimental research in laboratories is also carried out constantly. This allows to simulate the behavior of the shell when exposed to external forces. But sometimes conducting an experiment becomes little possible due to the limitation of the power of the experimental apparatus when modeling the corresponding conditions of exposure to the shell in practice, therefore, improving theoretical methods for calculating the limiting states of shells when working in the elastoplastic region is relevant. The purpose of the study is to verify the conformity of the results of the experiment conducted on a thin-walled cylindrical shell made of steel 45 (GOST 1050-2013) when exposed to the sample by stretching, compression and torsion forces with theoretical calculations based on the equations of the theory of elastic-plastic processes by A.A. Ilyushin. The equations of the defining relations of the theory of elastic-plastic processes by A.A. Ilyushin for arbitrary trajectories of complex loading and deformation of materials in the deviatory deformation space Э1-Э3 are presented. All theoretical results are checked for compliance with the experiment, the reliability of the existing theory of stability is assessed. The solution is presented in the form of graphs of the dependence of the vector and scalar properties of the material on the length of the arc of the deformation trajectory and other parameters. Numerical values are selectively presented for different loading stages.

Structural Mechanics of Engineering Constructions and Buildings. 2022;18(2):150-160
150-160

Seismic resistence

Macroseismic intensity-based catalogue of earthquakes in Ecuador

Cajamarca-Zuniga D., Kabantsev O.V., Marin C.

Abstract

Earthquake magnitude catalogues and peak ground acceleration (PGA) maps for Ecuador may be found in several studies, however, there are rare works on the characterisation of the epicentral macroseismic intensities associated with earthquakes. In view of the concept that macroseismic intensity enables us to categorise the extent and severity of damage to buildings and structures caused by an earthquake, this study aims to compile a macro-seismic intensity-based catalogue of earthquakes in Ecuador, characterise the epicentral macroseismic intensities associated to seismogenic sources and perform a comparison with the National Seismic Hazard Map. This paper is the first that presents a catalogue of earthquakes with macroseismic intensities ≥VII and a series of maps of earthquake epicentres according to intensity, focal depth, data and magnitude of seismic events in Ecuador, based on the study of historical and instrumental records from 1900 to 2021. The obtained data shows that 95% of the territory of Ecuador has a PGA > 0.1 g, which corresponds to seismic intensities greater than VII, while regions with seismicity>VIII (ag = 0.2 g) constitute 86%, and 3.8% of the territory of Ecuador has very high seismicity (>IX), where the PGA exceeds 0.5 g. This information suggests that the normative National Seismic Hazard Map of Ecuador underestimate the hazard mainly in the south-east and in the Central Andes of Ecuador, and require an actualization.

Structural Mechanics of Engineering Constructions and Buildings. 2022;18(2):161-171
161-171

Reviews

Problems and benefits of implementing BIM in the construction industry

Iushkin I.I., Alamedy S.G., Stashevskaya N.A.

Abstract

The construction industry is one of the important pillars of the economy. Building Information Modeling (BIM) is a set of technologies that aims to enhance collaboration across the architecture, engineering, and construction industries to improve the productivity and quality of the design, construction, and maintenance phases of a building. Rethinking construction is the key to increasing productivity. However, BIM has not been widely adopted in the construction industry. It is necessary to understand the main problems hindering the implementation of BIM, consider the appropriate strategies that can be applied to gain a deeper understanding of BIM, conduct a comprehensive and systematic analysis of the factors influencing the implementation of BIM. Based on a literature review, a questionnaire survey and the collection of statistical data, factors of a negative impact on the implementation of BIM were identified. The results show that key factors influencing BIM adoption include a lack of trained professionals, of investment in staff training, of BIM standardization, as well as the position of leadership in organizations. This article puts forward some proposals to promote the implementation of BIM and specific measures to implement the widespread use of BIM technology in the construction industry.

Structural Mechanics of Engineering Constructions and Buildings. 2022;18(2):172-181
172-181

Properties of dispersed fibers for efficient concrete reinforcement

Markovich A.S., Miloserdova D.A.

Abstract

The question of increasing the reliability and durability of reinforced concrete structures is a priority. One of the ways to increase the strength of concrete is using of dispersed reinforcement. The interest of using of fiber-reinforced concrete in Russia, as well as in Europe, Asia and the USA has increased significantly in recent ten years. The improvement of the physical and mechanical properties of concrete is noted to depend on the reinforcement parameters, such as the volume content of the fiber, the characteristics of the dispersed reinforcement, the structure of the concrete matrix, etc. Authors consider various types of fibers for dispersed concrete reinforcement, specifically polypropylene, polyethylene, nylon, acrylic, polyester, cotton, asbestos, glass, basalt, steel, carbon. Description of the main advantages and disadvantages of each type of fiber is given. Comparative characteristics are presented in terms of density, tensile strength, modulus of elasticity, elongation at fracture of the materials used to manufacture the fiber. The influence of fibers on crack strength of fiber-reinforced concrete under impact loads is studied. Analytical review of existing works found that it is possible to achieve a significant increase of strength of fiber-reinforced concrete in axial compression, tension, tension in bending, shear compared to ordinary heavy concrete.

Structural Mechanics of Engineering Constructions and Buildings. 2022;18(2):182-192
182-192