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MODIFIED CAM-CLAY MODELS FOR DYNAMIC ANALYSIS OF GRANULAR METAMATERIALS IN EARTHQUAKE ENGINEERING

https://doi.org/10.34031/2618-7183-2021-4-3-54-60
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 54-60 p.
Abstract
the problem of protecting buildings and structures from vibrations of natural and artificial nature is important for modern construction. One of such modern methods of protection is seismic pads. The purpose of this work was to study the effect of adding a layer of granular metamaterial under a slab foundation on the vibration of a building under the influence of seismic shear waves (S-waves). To achieve this objective, the finite element method (FEM) was used in combination with Cam-Clay models. The FE model consists of a ten-story superstructure rested on the slab foundation, under which there is a layer of granular metamaterials. 16 models were created taking into account changes in the values of these parameters (pad thickness; density; cohesion; critical state strength parameter (M); Young's modulus-Poisson's ratio). The dynamic analysis performed using the software package Abaqus/CAE showed the effectiveness of granular metamaterials in their ability to dissipate seismic energy and significantly reduce vibration transmitted from the ground to the building.
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DRUCKER-PRAGER MODELS FOR DYNAMIC ANALYSIS OF GRANULAR METAMATERIALS IN EARTHQUAKE ENGINEERING

https://doi.org/10.34031/2618-7183-2021-4-2-5-11
 5-11 p.
Abstract
Problem of developing methods for protecting buildings and structures from the vibrations transmitted to them from the soil under the action of seismic effects is extremely important to date. One of these modern methods is seismic pads. The purpose of this work was to study the effectiveness of adding a pad of granular metamaterials under the foundation of the building to decrease influence of seismic shear waves. The Finite Element Analysis of Mohr-Coulomb models was used to achieve this goal. The FE model consists of a ten-story superstructure rested on the slab foundation, under which there is a layer of granular metamaterials. The values of five variables that affect the mechanical properties of these metamaterials were analyzed (density – cohesion – internal friction angle – Young's modulus – Poisson's ratio) for two different pad thicknesses. The dynamic analysis performed using the software package Abaqus/CAE showed the effectiveness of the granular metamaterials in their ability to significantly reduce magnitudes of displacements, velocities and accelerations in the building compared to the same values in the absence of these metamaterials. The analysis also revealed that among the studied variables, the cohesion is the parameter most influencing the effectiveness of metamaterials in their ability to dissipate seismic waves, while no significant effect was observed for the other parameters.
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AN EFFECTIVE WAY TO RECYCLE 3D PRINTING CONCRETE SCRAP

https://doi.org/10.34031/2618-7183-2021-4-2-12-18
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 12-18 p.
Abstract
The article proposes a rational method for processing 3D printing concrete scrap using vibration equipment, which allows obtaining a multicomponent building material with minimal electricity consumption. As a criterion for the degree of grinding of concrete scrap, it is proposed to use the specific surface area of the finely dispersed part of concrete scrap, which should correspond to 400-500 m2/kg. The possibility of reusing the resulting product instead of the traditional fine aggregate of quartz sand is shown. It was found that the concrete scrap without the addition of Portland cement hardens, reaching up to 48% of the compressive strength of the control samples by 28 days. When 10% of the binder CEM I 42.5 N was added to the concrete scrap processing product, the compressive strength of fine-grained concrete increased by 106.6%, and 20% of Portland cement - by 112.2 %, compared to the strength of control samples of a similar composition on traditional quartz sand after 28 days of hardening. It is noted that this is primarily due to the weak contact zone of quartz sand and the cement matrix of concrete. The use of the product of processing concrete scrap allows obtaining building composites based on it with the complete exclusion of natural raw materials.
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WORLD EXPERIENCE IN THE CONSTRUCTION OF GRAVITY DAMS FROM A PARTICULARLY LEAN CONCRETE MIX

https://doi.org/10.34031/2618-7183-2021-4-2-19-28
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 19-28 p.
Abstract
The article discusses the main aspects of the construction of dams with a symmetrical profile from the material "solid embankment" or other names ("lean" concrete, cemented "sand and gravel mixture" CSG). The design of typical profiles of dams of implemented projects is considered, and information regarding the characteristics and methods of production of this material is provided. The main properties of this material and the principle of its preparation are considered. The work in this area of engineers from Russia, Japan, Iran, Korea, China, and Turkey is analyzed. These dam structures are characterized by high reliability and efficiency, but also, most importantly, by a much higher adaptability or high speed of construction, which is little dependent on local natural factors than traditional rolled concrete dams.
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NONLINEAR TRANSVERSE VIBRATIONS OF COMPOSITE RODS UNDER THE ACTION OF A STATICALLY APPLIED TRANSVERSE LOAD

https://doi.org/10.34031/2618-7183-2021-4-2-29-37
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 29-37 p.
Abstract
Nonlinear transverse vibrations of composite rods pre-loaded with lagging arranged symmetrically on both sides of the axis of the composite rod under the action of a statically applied transverse load are investigated. The cases of attaching the lagging only to the ends of the composite rod, as well as when the laggings are continuously attached to the composite rod along its entire length, are considered. The results of the study of nonlinear transverse vibrations of composite rods under the action of a statically applied transverse load are presented. When conducting studies of transverse vibrations of composite rods, solutions of differential equations of vibration of prestressed through beams and stiffening cores of high-rise buildings are obtained. The obtained differential equations of vibration of composite rods allow us to determine the dynamic characteristics of prestressed through beams under various linear and boundary conditions. A method for composing differential equations of free and forced oscillations of prestressed through beams and stiffening cores of high-rise buildings and solving differential equations under various linear and nonlinear boundary conditions is developed.
Expressions are given for determining the longitudinal forces and torques at the ends of the rod at any location of the lagging from the axis and at any different stiffness of the lagging.
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UTILIZATION OF GYPSUM-BEARING WASTES IN MATERIALS OF THE CONSTRUCTION INDUSTRY AND OTHER AREAS

https://doi.org/10.34031/2618-7183-2021-4-1-5-17
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 5-17 p.
Abstract
Rational environmental management is one of the priorities of the technological development of the Russian Federation and most countries of the world. Particularly important in this area is the work undertaken with previously generated and accumulated waste, a whole group of which is gypsum-bearing wastes (GBW), which includes by-products of various industries: phosphogypsum, borogypsum, chlorogypsum, ferrogypsum, citrogypsum, vitamin gypsum, etc. GBW features are similar compositions, prevalence, perennial volumes of stored reserves with stable dynamics of annual growth. This determines the relevance of research on the development of a unified methodology for converting GBW of various types into target products particularly for construction purposes, providing maximum energy efficiency and minimal generation of secondary waste. The starting point of the research is the monitoring of approaches developed by the scientific community which are presented in the article. It is shown that researchers are exploring several main areas of GBW conversion: components of Portland cement and clinker; single and multicomponent binders; direct raw materials for the production of building materials; and road construction. The latter two directions have the greatest potential capacity for the consumption of GBW. The general level of research on the issue is not exhaustive, but has the potential to improve on existing methods of processing and application and promote the search for new and more efficient methods.
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COMPARISON OF CAD AND BIM TECHNOLOGY EFFICIENCY WITH THE USE OF A MATHEMATICAL MODEL

https://doi.org/10.34031/2618-7183-2021-4-1-18-26
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 18-26 p.
Abstract
The article reveals definitions and the entity of computer-aided design and building information modeling. The content and effect of using information modeling at various phase of the life cycle of a real estate object are described in the article. The level of BIM applying in Russia is analyzed, data is obtained that the majority of AEC organizations do not use information modeling. A comparative evaluation of the applying of various CAE systems using mathematical modeling in the MATLAB environment using the Fuzzy Logic Toolbox extension package is carried out. Based on the obtained results, we can make a conclusion about the effectiveness of using building information modeling. The information in this article is relevant for designers, real estate investors, and leaders of AEC organizations. The obtained evaluation of project technology is able to induce stakeholders to analyze alternative technology of project and estimate the expediency of Russian enterprise's transition to the use of BIM technology.
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ANALYSIS OF THE INFLUENCE OF INDUSTRIAL WASTE IN THE FORM OF CERAMIC CHIPS CRUSHING DROPOUTS ON THE MAIN PROPERTIES OF CEMENT COMPOSITES

https://doi.org/10.34031/2618-7183-2021-4-1-27-34
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 27-34 p.
Abstract
During the implementation of the program to restore the housing stock of the Chechen Republic, as well as during the planned demolition of dilapidated housing, significant volumes of technogenic raw materials were generated, in particular, large volumes of brick and concrete scrap. Enterprises for the production of building materials and products also produce significant volumes of production defects, which accumulate over the years at landfills. Ceramic broken brick and broken brick dropouts are used to fill the roadbed, and the main part still goes to the dump and landfill, which is also an environmental problem. One of the promising ways to use dropouts and broken brick itself is to use them as secondary aggregates in concrete and mortars. This article discusses the issues of improving the quality of ceramic concrete mixtures, choosing the optimal composition and technology for mixing concrete mixtures using dust fractions of dropouts for crushing ceramic brick bricks.
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DETERMINATION OF THE TRANSSHIPMENT CAPACITY OF THE RAILWAY STATION AND MEASURES TO ENSURE IT IN THE REQUIRED VOLUME BY INSTALLING TEMPORARY LOADING AND UNLOADING DEVICES

https://doi.org/10.34031/2618-7183-2021-4-1-35-44
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 35-44 p.
Abstract
In view of the fact that recently the economic cooperation between Russia and Iran in a number of production areas of the raw materials sector is expanding its program, the provision of mineral extraction with specialized and auxiliary equipment is being carried out. The paper deals with the organization of the delivery of cranes of Russian production on the automobile base of the type "Ivanovets" KS-6476 in the composition of 40 units to the objects of ore mining. Transportation of cranes by rail on the route: St. Petersburg (Russia)-Julfa (Azerbaijan) – Bandar Abbas (Iran) is justified. For transportation on the railways of Russia, the paper considers long-wheelbase platforms of model 13-491, on bogies of 1520 mm gauge. In order to comply with the dimensions on the railways of Iran, the transporters with a reduced floor level of the model 14-T116 on trolleys of 1435 mm gauge were selected. The reloading of equipment is planned to be carried out at the Julfa railway station of the Azerbaijan Railway. The results of the research, in our opinion, are certainly of practical importance for the transport industry, as the developed and proposed designs of loading and unloading devices allow for the reloading of equipment without the use of crane equipment using always available stocks of materials at cargo stations.
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INCREASING IN IMPACT VISCOSITY OF FIBER-ASH-CONCRETE

https://doi.org/10.34031/2618-7183-2020-3-6-5-16
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 5-16 p.
Abstract
The trend in building materials science is to replace the different proportions of Portland cement in the binder. Therefore, the paper proposes the principles of controlling the static and dynamic strength of fiber-reinforced concrete, consisting in the complex effect of the hydro-removed ash and slag mix and basalt fiber on the processes of structure formation of the cement composite. A four-stage purification system for the hydro-removed ash and slag mixture has been developed, including disintegration, flotation and two-stage magnetic separation. It was found that the density of the fresh mix from the dose behaves naturally, and the density of solid samples at low doses slightly decreases. High early strength of the developed composites is noted, in particular, for specimens with ASM, one and a half increase in compressive strength is traced in comparison with non-additive specimens. Combinations of "fiber + ASM" with a quadrupling of strength have a significant effect on bending strength. Successful approximations of the compressive strength and bending strength on the ASM dose for different ages (1, 7, 28 days) are traced with the regular behavior of the coefficients in the power dependences. Revealed a multiple increase in the impact strength of the developed compositions. The use of the results will lead to the possibility of designing high-strength concretes, including for special structures.
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