STATIONARY VIBRATIONS OF A SYSTEM WITH AN IMPACT ABSORBER SUBJECTED TO PERIODIC IMPULSES OF FINITE DURATION

Vestnik MGSU 4/2012
  • Dukart Adam Vilebal'dovich - Moscow State University of Civil Engineering (MSUCE) Professor, Doctor of Technical Sciences, Department of Structural Mechanics, Moscow State University of Civil Engineering (MSUCE), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Thanh Binh Pham - Moscow State University of Civil Engineering (MSUCE) graduate student, Department of Structural Mechanics, Moscow State University of Civil Engineering (MSUCE), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 44 - 50

Impulsive loadings, or repetitive brief impacts, produced by machines and mechanisms of the shock action, are widely spread in the engineering practice. In many cases, trustworthy results of their dynamic analyses can be obtained by taking account of the shape and duration of their impulses.
In the paper, the periodic mode of the system motion and the parameters of the impact absorber applicable to one-sided periodic impulses of rectangular form are examined. The structure to be protected and the absorber are simulated as a system of a single collision of masses. The impacts are accepted to be instantaneous and taken into account by means of the coefficient of restitution. The damping properties of the protected structure and the absorber are considered on the basis of the viscid friction hypothesis; therefore, the damping properties of the whole system are disproportionate.
The relations identified in the course of the research are used to find the impulse frequency characteristics (IFC) of the protected structure to identify the absorber parameters. The affect of duration of external impulses produced onto the IFC, characterized by the drastic increase in the amplitudes as compared to that in the case of a single impulse of the same magnitude, is the subject of research. It is proven that the maximal ordinates of IFC decrease slightly against the increase in the duration of external impulses; therefore, the efficiency of the impact absorber changes insignificantly, and it is equivalent to that of a dynamic absorber. It is noteworthy that if the duration of external impulses is under 10 % of the duration of the period, they may be replaced by instantaneous impulses.

DOI: 10.22227/1997-0935.2012.4.44 - 50

References
  1. Dukart A.V. Zadachi teorii udarnykh gasiteley kolebaniy [Objectives of the Theory of the Impact Vibration Damper]. Moscow, ASV Publ., 2006.
  2. Korenev B.G., Rabinovich I.M., editors. Dinamicheskiy raschet zdaniy i sooruzheniy: spravochnik proektirovshchika [Dynamic Analysis of Buildings and Structures: Designer’s Reference Book]. Moscow, Stroyizdat Publ., 1981.
  3. Sorokin E.S. Osnovnye predposylki rascheta sooruzheniy na impul'sivnye nagruzki [Main Preconditions for Calculation of Structures Exposed to Impulsive Loads]. Voprosy prikladnoy mekhaniki [Problems of Applied Mechanics]. Moscow, Stroyizdat Publ., 1968, no. 260, pp. 5—37.
  4. Goldsmith V. Udar. Teoriya i fizicheskie svoystva soudaryaemykh tel [Impact. Theory and Physical Properties of Colliding Bodies]. Moscow, Stroyizdat Publ., 1965.
  5. Dukart A.V. K opredeleniyu ustanovivshikhsya kolebaniy sistemy s dvumya stepenyami svobody pri deystvii periodicheskikh impul'sov konechnoy prodolzhitel'nosti [About the Identification of Stationary Vibrations of a System That Has Two Levels of Freedom Exposed to Periodic Impulses of Finite Duration]. Izvestiya vuzov. Stroitel'stvo. [News of Higher Educational Institutions. Construction]. 2012, no. 1, pp. 3—13.

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SNOW ON TRANSLUCENT ROOFS OF HEATED BUILDINGS

Vestnik MGSU 4/2012
  • Konstantinov Aleksandr Petrovich - Moscow State University of Civil Engineering (MSUCE) postgraduate student, Department of Architecture of Civil and Industrial Buildings, Moscow State University of Civil Engineering (MSUCE), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Plotnikov Aleksandr Aleksandrovich - Moscow State University of Civil Engineering (National Research University) (MGSU) Candidate of Technical Sciences, senior research worker, Professor, Department of Civil and Industrial Buildings Architecture, Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Boriskina Irina Vasil'evna - Moscow State University of Civil Engineering (MSUCE) Candidate of Technical Sciences, Senior Researcher, Department of Testing of Structures, Moscow State University of Civil Engineering (MSUCE), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 51 - 55

The article covers the influence of the snow cover on the behaviour of translucent roofs acting as envelope structures. The authors note that the influence of the snow cover accumulated on the surfaces of translucent roofs is the least favourable influence produced on these structures, as any cover deprives translucent structures of their principal function; that is, admitting the sunlight and providing the natural illumination of the under-roof space. One of the actions aimed at prevention of the snow accumulation on the surfaces of translucent roofs represents the right choice of glazing, mode of heating and the roofing inclination angle, so that the snow could melt away within hours after a snowfall. However, this method requires a thorough research of the snow melting process typical for translucent roofs.
The authors provide the field data and describe the experiments involving the accumulation and melting of the snow on the surface of the roof glazing, given different angles of inclination. On the basis of the above, the authors propose a snow melting model that is based on the dynamic behaviour of the snow cover in the course of melting. This model may be used to resolve a wide range of problems that consist in the identification of the time period while the snow cover may rest on translucent roofs of different inclination angles, as well as the identification of the maximal amount of snow accumulated on translucent roofs without melting.
Numerical methods were applied to identify the time periods in the course of which the snow cover retained on the glass roofs that had different inclination angles. The snow melting model developed by the authors was used for the above purpose.

DOI: 10.22227/1997-0935.2012.4.51 - 55

References
  1. Konstantinov A.P., Plotnikov A.A., Boriskina I.V. Snezhnyy pokrov na steklyannykh kupol'nykh pokrytiyakh otaplivaemykh zdaniy (na primere g. Moskva) [Snow Cover Accumulated on Glass Domeshaped Roofings of Heated Buildings (as Exemplified by Moscow)]. Vestnik MGSU [Proceedings of Moscow State University of Civil Engineering]. 2011, no. 1, vol. 1, pp. 120—126.

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RESEARCH OF SWELLING OF SUZAKH CLAYS

Vestnik MGSU 4/2012
  • Kubetskiy Valeriy Leonidovich - Scientific Research Institute of Moscow Construction (NII Mosstroi) , Scientific Research Institute of Moscow Construction (NII Mosstroi), 8 Vinnitskaya St., Moscow, 119192, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 56 - 62

In the course of construction of Sangtudinsky hydropower plant-1 on the River Vakhsh, it was deemed necessary to identify clay swelling properties in the event of alterations of the humidity mode of fructured half-rock soils, or the Suzakh clay, that accommodated tunnel-shaped water outlets within a section that was 75 meters long. The depth of tunnels was about 100 m. Any interaction with swelling soils could lead to destruction of the tunnel lining. Suzakh clays demonstrated the following physical and mechanical properties: density of particles of soil ρ= 2,69 g/cm; soil density ρ = 2.40-2.47 g/cm; porosity of 8.2-10.8 %; ultimate resistance to uniaxial compression = 13.1-31.0 MPa. Water saturated clay samples disintegrated into cloddy fragments; the rate of a longitudinal ultrasonic wave in the area of unaltered soils was equal to = 2500 m/c; repulse coefficient k was equal to 15 MPa/m; solidity coefficient (according to Protodyakonov) was equal to 1,5; modulus of deformation in the massif was equal to 0.23 х10 MPa. The author proposed a methodology and designed a pilot set of equipment units designated for the identification of the swelling properties of fractured half-rock soils. Results of the pilot unit operation are presented in the article. Swelling properties are based on the monolith testing results. The programme contemplated a set of experiments held in various limit states on the surface of monoliths. Dependence between the swelling pressure and the swelling deformation in the course of water saturation was identified. The experiment demonstrates that alterations of the humidity mode of free surface Suzakh clays cause the relative deformation of swelling up to 1.1 %, and if the lining is rigid, the swelling pressure can exceed 4 MPa.

DOI: 10.22227/1997-0935.2012.4.56 - 62

References
  1. Sonin S.D., Sheykhet M.N., Chernyak I.L., Lukichev V.S. Bor'ba s pucheniem porod v gornykh vyrabotkakh [Control of Soil Heaving in Mine Openings]. Moscow, Nedra Publ., 1966.
  2. Sorochan E.A. Stroitel'stvo sooruzheniy na nabukhayushchikh gruntakh [Building of Structures on Swelling Soils]. Moscow, Stroyizdat Publ., 1989.
  3. Kubetskiy V.L., Sapegin D.D., Krivonogova N.F. Rekomendatsii po opredeleniyu kharakteristik reologicheskikh svoystv skal'nykh i poluskal'nykh gruntov metodom kol'tsevogo nagruzheniya [Recommendations Regarding Identification of Characteristics of Rheological Properties of Rocks and Half-rocks by Means of Circular Loading]. VNIIG Publ., 1990.
  4. Kubetskiy V.L. Rezul'taty issledovaniya reologicheskikh svoystv suzakskikh glin [Results of Research of Rheological Properties of Suzakh Clays]. Dushanbe, Tadjikistan, 2005.
  5. GOST 24143—80. Grunty. Metody laboratornogo opredeleniya kharakteristik nabukhaniya i usadki [State Standard 24143—80. Soils. Methods of Laboratory-based Identification of Characteristics of Swelling and Shrinkage Properties]. Moscow, 1987.

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INFLUENCE OF A ROUND CAP ON THE BEARING CAPACITY OF A LATERALLY LOADED PILE

Vestnik MGSU 4/2012
  • Buslov Anatoliy Semenovich - Gersevanov Research Institute of Bases and Underground Structures (NIIOSP) Doctor of Technical Science, Professor, Advisor Russian Academy of Architecture and Construction Sciences, chief research worker, Gersevanov Research Institute of Bases and Underground Structures (NIIOSP), 59 Ryazanskiy pr-t, Moscow, 109428, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Bakulina Aleksandra Aleksandrovna - Ryazan' Branch, Moscow State Open University named after V.S. Chernomyrdin , Ryazan' Branch, Moscow State Open University named after V.S. Chernomyrdin, 26/53 Pravo-Lybedskaya St., 390000, Ryazan', Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 63 - 68

Foundations of laterally loaded single piles are widely used as part of power transmission lines, wind power stations, highway structures, etc. Ongoing pressure applied to a laterally loaded pile, particularly at the ground level, causes the soil deformation characterized by the bulging of the soil surface.
In the majority of cases, the deformation strength of a pile depends on the front-face soil resistance, Horizontal beams, ground caps or rigid plates are used to increase the pile resistance. An effective method of pressure reduction contemplates the use of a rigid round cap at the front-face or upper level of the soil.
In this paper, the authors analyse the data to examine how a round cap installed at the ground level impacts the bearing capacity of a single pile.
This research based on the methodology developed by the authors demonstrates that a laterally loaded pile, supported by a rigid cap at the ground level, is exposed to increased resistance due to the following factors, including the passive pressure along the cap side that creates an unloading effect for a horizontally-loaded pile. The cap acts as a vertical soil rebuff creating an additional resistance moment; the horizontal shear of the cap causes supplementary lateral resistance of a pile.
The following initial geometric and elastic material properties of the single pile are applied: total length = 5.0 meters (3.0 m above and 2.0 m below the ground surface); pile diameter = 40 centimeters; circle plates of various diameters = 60; 70; 80 and 100 cm and their thickness = 20 cm. A lateral load is applied at various heights, , of 0.2; 1.0; 2.0 and 3.0 meters above the ground level.
Elastic properties of the soil are assumed to be constant at each point below the surface of the ground, they are listed below: bulk modulus of soil E=20 MPa; Poisson's ratio μ=0,37; unit Weight γ=18,5 kN/m; cohesion =0,05 MPa; angle of internal friction φ=20°.
The data has proven that cap-covered piles are substantially more economical (over 40 %) in terms of materials consumption rate if compared to constant cross-section piles (cap-free or broadening piles), all other factors being equal.

DOI: 10.22227/1997-0935.2012.4.63 - 68

References
  1. Normy proektirovaniya kontaktnoy seti [Overhead Contact System Design Standards]. 141-99. MPS RF. Moscow, 2001.
  2. Matus N.Yu. K raschetu gorizontal'no nagruzhennoy svai-kolonny s nizkim rostverkomogolovkom [About the Design of a Laterally Loaded Pile-Column with Deep Grid Pile Foundation]. OOO HT Project — Ukraina, Odessa, 8 p.
  3. Buslov A.S., Tulakov E.S. Raschet gorizontal'no nagruzhennykh odnostoechnykh opor po ustoychivosti [Stability Design of Laterally Loaded Single Footings]. Osnovaniya, fundamenty i mekhanika gruntov [Beddings, Foundations, and Soil Mechanics]. Moscow, 2004, no. 3, pp. 6—9.

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СOMPUTATIONAL MODEL OF PILE FOUNDATIONS WITH ACCOUNTFOR THE EFFECT OF THEIR INTERACTION WITH THE SOIL MEDIA

Vestnik MGSU 4/2012
  • Sargsyan Akop Egishovich - Design and Development Institute, Joint Stock Company (JSC AEP) Candidate of Technical Sciences, Professor, Head of Department of Dynamics and Earthquake Resistance, Atomenergoproekt Research, Design and Development Institute, Joint Stock Company (JSC AEP), 7 Bakuninskaya st., Moscow, 105005, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Gerashchenko Vitaliy Sergeevich - Joint Stock Company (JSC AEP) engineer, Atomenergoproekt Research, Design and Development Institute, Joint Stock Company (JSC AEP), 7 Bakuninskaya st., Moscow, 105005, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Shaposhnikov Nikolay Nikolaevich - Moscow State University of Roads (MSUCE) Doctor of Technical Sciences, Associate Member of the Russian Academy of Architectural and Civil Engineering Sciences, Professor, Department of Systems of Computer-Aided Design of Transportation Structures and Constructions 8 (903) 786-53-64, Moscow State University of Roads (MSUCE), Office 7720, 2 Minaevskiy pereulok, Moscow, Russia; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 69 - 72

The authors of the paper present computational models of pile foundations with account for the effect of their interaction with the soil media, as well as the design parameters of integral stiffness of the soil environment contacting the pile sole surface that has round or rectangular caps.
The authors' assumptions that serve as the basis for the identification of the integrated response of the soil media to the contact surface of the pile are as follows:
there is no full soil-to-pile contact whenever tensile stresses are formed on the walls of the side surface of a pile, as the soil does not work in tension;
in the course of the vertical travel of piles along their longitudinal axis over the perimeter of their side surface, soils are subjected to simple shear, whereas the pile sole is subjected to compression;
in the course of the travel of piles having rectangular cross sections in the horizontal direction in the soil media, soil shear is formed in the two opposite side surfaces. The front wall of the side surface is subjected to compression in the direction of the pile travel, while soil is separated from the opposite side surface of the pile shaft;
the pile travel in the horizontal direction causes simple shear of the pile sole.

DOI: 10.22227/1997-0935.2012.4.69 - 72

References
  1. Sargsyan A.E., Gerashchenko V.S. Razrabotka staticheskoy i dinamicheskoy raschetnoy modeli svaynykh fundamentov s uchetom effekta ikh vzaimodeystviya s gruntovoy sredoy [Development of Static and Dynamic Computational Model of Pile Foundations with Account for the Effect of Their Interaction with the Soil Environment]. Vestnik CNIISK V.A. Kucherenko [Journal of Central Scientific Research Institute for Building Structures named after V.A. Koucherenko], Moscow, 2010.
  2. SP 50-102—2003. Proektirovanie i ustrojstvo svajnyh fundamentov [Construction Rules 50-102-2003. Design and Construction of Pile Foundations]. Moscow, Federal State Unitary Enterprise “Center for Design Products in the Construction Industry”, 2004, 83 р.

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GOALS AND OBJECTIVES OF GAS DISTRIBUTION NETWORKS OPTIMIZATION

Vestnik MGSU 4/2012
  • Tabunschikov Yuriy Andreevich - Moscow Architectural Institute (MARKHI) Doctor of Technical Sciences, Professor, Chair, Department of Engineering Systems of Buildings, Moscow Architectural Institute (MARKHI), 11 Rozhdestvenka St., Moscow, 107031, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Prokhorov Vitaly Ivanovich - Moscow State University of Civil Engineering (MSUCE) +7 (499) 183-26-92, Moscow State University of Civil Engineering (MSUCE), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.
  • Bryukhanov Oleg Nikolaevich - Moscow State University of Civil Engineering (MSUCE) : 8 (499) 183-26-92, Moscow State University of Civil Engineering (MSUCE), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.
  • Zhila Victor Andreevich - Moscow State University of Civil Engineering (MSUCE) Candidate of Technical Sciences, Professor, Department of Heating Facilities and Heat/Gas Supply, +7 (499) 183-26-92, Moscow State University of Civil Engineering (MSUCE), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Klochko Alexey Konstantinovich - Moscow State University of Civil Engineering (MSUCE) assistant lecturer, Department of Heating Facilities and Heat/Gas Supply, Moscow State University of Civil Engineering (MSUCE), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 73 - 77

Presently, no uniform methodology of identification of optimal costs of construction of gas distribution networks is available. The amount of work, and, hence, its cost, are identified empirically; therefore, they are insufficiently substantiated by feasibility studies. At best, the problem of optimization is reduced to simple examination of various options.
The problem to be resolved by the method of search optimization may be stated in the following manner:
Two consumers are to obtain access to the gas supply. Their positions in the arbitrary coordinate system are available (; ). The high pressure gas distribution line of a gas distribution network is located at some distance from the aforementioned consumers. It can be represented as follows: = +. Gas control unit installation is required to assure gas pressure reduction.
Goal 1: positioning of a gas control unit to assure the lowest possible cost of the gas distribution network construction.
Goal 2: solution to the above problem turns more complicated, if the line of the gas distribution network required to connect the designed gas pipeline extension is long. In this case, besides the identification of the optimal coordinates of a gas control unit, it is also necessary to find the point of connection to the gas control unit, for the cost of the gas distribution network to be as low as possible.
Goal 3: some sections of gas distribution networks pass through or over natural or artificial barriers. In the event of such restrictions, the search for the optimal point of connection to the gas control unit turns more labor-intensive and challenging.
To sum up the above statements, the authors demonstrate that rational design of gas distribution networks brings essential economic benefits.

DOI: 10.22227/1997-0935.2012.4.73 - 77

References
  1. SNiP 42-01—2002. Gazoraspredelitel'nye sistemy. [Construction Rules and Regulations 42-01—2002. Gas Distribution Networks]. St. Petersburg, 2004, 80 p.

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GENERATION OF IRREGULAR HEXAGONAL MESHES

Vestnik MGSU 4/2012
  • Vlasov Aleksandr Nikolaevich - Sergeev Institute of Environmental Geoscience of the Russian Academy of Sciences (IEG RAS), Institute of Applied Mechanics of the Russian Academy of Sciences (IAM RAS) Doctor of Technical Sciences, Principal Researcher, +7 (495) 523-81-92, Sergeev Institute of Environmental Geoscience of the Russian Academy of Sciences (IEG RAS), Institute of Applied Mechanics of the Russian Academy of Sciences (IAM RAS), 32а Leninskiy prospekt, Moscow, 119334, Russian Federation Building 2, 13 Ulanskiy pereulok, 101000, Moscow, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Volkov-Bogorodskiy Dmitriy Borisovich - Institute of Applied Mechanics of the Russian Academy of Sciences (IAM RAS) Candidate of Physics and Mathematics, Senior Researcher, +7 (499) 160-42-82, Institute of Applied Mechanics of the Russian Academy of Sciences (IAM RAS), 32а Leninskiy prospekt, Moscow, 119334, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Znamenskiy Vladimir Valerianovich - Moscow State University of Civil Engineering (MGSU) Doctor of Technical Sciences, Professor, Professor, Department of Soil Mechanics, Beddings and Foundations, Moscow State University of Civil Engineering (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Mnushkin Mikhail Grigor'evich - Sergeev Institute of Environmental Geoscience Russian Academy of Sciences (IEG RAS) Candidate of Technical Sciences, Principal Researcher, Sergeev Institute of Environmental Geoscience Russian Academy of Sciences (IEG RAS), Building 2, 13 Ulanskiy pereulok, 101000, Moscow, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 78 - 87

In the paper, the authors propose original mesh generation solutions based on the finite element method applicable within the computational domain. The mesh generation procedure contemplates homeomorphic mapping of the initial domain onto the canonical domain. The authors consider mappings generated through the application of differential operators, including the Laplace operator (harmonic mappings) or the Lamé operator. In the latter case, additional control parameter ν is required The following domains are regarded as canonical: a parametric cube (or a square), a cylindrical layer, and a spherical layer. They represent simply connected or biconnected domains.
The above mappings are based on the parametric mesh generated alongside the domain boundary or boundaries dividing heterogeneous elements (inclusions). Therefore, generation of the above mappings is reduced to the resolution of the boundary problems by means of the Laplace or Lamé differential operators. Basically, the proposed approach represents the problem of the theory of elasticity with regard to the prescribed displacement. This problem may have two solutions. The first one is the analytical (meshless) least square solution, and the second one represents consequent mesh refining on the basis of the finite-element discretization of elasticity equations. The least square method assumes decomposition of the initial domain into the system of simply connected sub-domains. In every sub-domain, or a block, numerical/analytical approximation of homeomorphic mapping of the initial domain onto the canonical domain is performed with the help of local representations generated by means of systems of special functions.
Decomposition is performed in a constructive way and, as option, it involves meshless representation. Further, this mapping method is used to generate the calculation mesh. In this paper, the authors analyze different cases of mapping onto simply connected and bi-connected canonical domains. They represent forward and backward mapping techniques. Their potential application for generation of nonuniform meshes within the framework of the asymptotic homogenization theory is also performed to assess and project effective characteristics of heterogeneous materials (composites).

DOI: 10.22227/1997-0935.2012.4.78 - 87

References
  1. Haber R., Abel J.F. Numer. Meth. Eng., 1982, vol. 18, pp. 41—46.
  2. Volkov-Bogorodskiy D.B. Razrabotka blochnogo analitiko-chislennogo metoda resheniya zadach mekhaniki i akustiki [Development of the Block-based Analytical and Numerical Method of Resolution of Problems of Mechanics and Acoustics]. Collected papers, Composite Materials Workshop. Moscow, IPRIM RAN [Institute of Applied Mechanics of the Russian Academy of Sciences], 2000, pp. 44—56.
  3. Eells J., Sampson J. Harmonic Mappings of Riemannian Manifolds. Amer. J. Math., 1964, vol. 86, pp. 109—160.
  4. Thompson J.F., Soni B.K., Weatherill N.P., Harmonic Mappings. Handbook of Grid Generation. CRC Press, 1998.
  5. Godunov S.K., Prokopov G.P. Ob ispol'zovanii podvizhnykh setok v gazodinamicheskikh raschetakh [On the Use of Flexible Grids in Gas-Dynamic Calculations]. Vychislitel’naya matematika i matematicheskaya fizika [Computational Maths and Mathematical Physics]. 1972, vol. 12, no. 2, pp. 429—440.
  6. Spekreijse S.P. Elliptic Grid Generation Based on Laplace Equations and Algebraic Transformations. J. Comput. Phys., 1995, vol. 118, pp. 28—61.
  7. Novatskiy V. Teoriya uprugosti [Theory of Elasticity]. Moscow, Mir Publ., 1975, 872 p.
  8. Volkov-Bogorodsky D.B. On Construction of Harmonic Maps of Spatial Domains by the Block Analytical-Numerical Method. Proceedings of the minisymposium “Grid Generation: New Trends and Applications in Real-World Simulations”, International Conference “Optimization of Finite-Element Approximations, Splines and Wavelets”, St.Petersburg, 25—29 June 2001. Moscow, Computing Centre RAS, 2001, pp. 129—143.
  9. UWay Software. Certificate of State Registration of Software Programme no. 2011611833, issued on 28 February 2011. Compliance Certificate ROSS RU.SP15.N00438, issued on 27 October 2011.
  10. Kompozitsionnye materialy [Composite Materials]. Moscow, Mashinostroenie Publ., 1990, 511 p.
  11. Novikov V.U. Polimernye materialy dlya stroitel'stva [Polymeric Materials for Construction Purposes]. Moscow, Vysshaya Shkola Publ., 1995, 448 p.
  12. Obraztsov I.F., Yanovskiy Yu.G., Vlasov A.N., Zgaevskiy V.E. Koeffitsienty Puassona mezhfaznykh sloev polimernykh kompozitov [Poisson Ratios for Interphase Layers of Polymeric Composites]. Academy of Science Reports, 2001, vol. 378, no. 3, pp. 336—338.
  13. Bakhvalov N.S., Panasenko G.P. Osrednenie protsessov v periodicheskikh sredakh [Averaging of Processes in Periodic Media]. Moscow, Nauka Publ., 1984, 352 p.
  14. Vlasov A.N. Usrednenie mekhanicheskikh svoystv strukturno neodnorodnykh sred. [Averaging of Mechanical Properties of Structurally Heterogeneous Media]. Mekhanika kompozitsionnykh materialov i konstruktsiy [Mechanics of Composite Materials and Structures]. 2004, vol. 10, no. 3, pp. 424—441.

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BEARING CAPACITY AND SETTLEMENT OF BORED CAST-IN-SITU PILES FOR HIGH-RISE CONSTRUCTION IN CLAYEY SOILS WITH ACCOUNT FOR THE NEW REASONS OF THE FAILURE OF THEIR BEDDINGS

Vestnik MGSU 4/2012
  • Grigoryan Anaida Aleksandrovna - Scientific and Research Institute of Beddings and Subterranean Structures named after M.N. Gersevanov Professor, Doctor of Technical Sciences, Department of Structural Mechanics, Scientific and Research Institute of Beddings and Subterranean Structures named after M.N. Gersevanov, 6 2nd Institutskaya St., Moscow, 109428, Russian Federation.

Pages 88 - 97

The author of the article considers it necessary to perform a bearing capacity analysis to ensure the safety of high-rise structures in the medium of loose clayey soils. The author proposes a new mechanism of the soil failure prevention that illustrates the nature of the bearing capacity. The soil medium is considered to be discrete rather than solid. The distribution of stresses in the core sections and in the base of long vertically loaded bored cast-in-situ piles is identified on the basis of field tests. Effectiveness of several actions aimed at the increase of the point resistance of piles is the subject of the research.

DOI: 10.22227/1997-0935.2012.4.88 - 97

References
  1. Grigoryan A.A. O bezopasnosti stroitel'stva na glinistykh gruntakh po 1-mu predel'nomu sostoyaniyu [About the Safety of Construction Works in Clayey Soils based on the First Limit State]. OFMG Publ., 2006, no. 5, pp. 24—29.
  2. Tertsagi K. Teoriya mekhaniki gruntov [Theory of Soil Mechanics]. Moscow, Gosstroyizdat Publ., 1961, 506 p.
  3. Meyerhof G.G. The Ultimate Bearing Capacity of Foundations. Geotechnique, vol. 2, 1951, no. 4. pp. 301—332.
  4. Grigoryan A.A. Svaynye fundamenty zdaniy i sooruzheniy na prosadochnykh gruntakh [Pile Foundations of Buildings and Structures in Collapsing Soils]. Moscow, Stroyizdat Publ., 1984, 162 p.
  5. Grigorian A.A. Pile Foundations for Buildings and Structures in Collapsible Soils. Oxford IBH Publishing Co. Pvt. Ltd., 1997, 153 p.
  6. Grigoryan A.A. O novom mekhanizme razrusheniya osnovaniya na glinistykh gruntakh pod fundamentami sooruzheniy [About the New Mechanism of Destruction of Beddings in Clay Soils Underneath Foundations of Structures]. OFMG Publ., 2009, no. 3, pp. 10—14.
  7. Grigoryan A.A., Khabibullin I.I. Eksperimental'noe issledovanie raspredeleniya napryazheniy v buronabivnykh svayakh znachitel'nykh razmerov [Experimental Research of Distribution of Stresses Inside Big Bored Cast-in-Situ Piles]. OFMG Pibl., 1980, no. 3, pp. 11—13.
  8. Grigoryan A.A., Chinenkov Yu.A. Iz opyta stroitel'stva na svayakh bol'shoy dliny s ushirennymi pyatami v prosadochnykh gruntakh [The Experience of Construction Based on Long Piles That Have Extended Feed Pads in Collapsing Soils]. OFMG Publ., 1990, no. 4, pp. 2—5.
  9. Dzagov A.M., Sidorchuk V.F. O napryazhennom sostoyanii osnovaniya pri ustroystve i nagruzhenii buronabivnoy svai v glinistykh gruntakh [About the Stress State of the Bedding in the Course of Construction and Loading of a Bored Cast-in-Situ Pile in Clayey Soils]. OFMG Publ., 2002, no. 3, pp. 10—15.
  10. Rekomendatsii po proektirovaniyu i ustroystvu buronabivnykh svay s uplotneniem grunta v zaboe skvazhin [Recommendations for Design and Construction of Bored Cast-in-Situ Piles and Soil Compaction in the Area of Pile Toes]. Moscow, All-Union Scientific and Research Institute of the State Committee in charge of Construction of the Council of Ministers of the USSR, 1982, 24 p.
  11. Brandle N. An Innovative Method of Minimizing Pile Settlements. Proceedings of the 4th International Conference on Deep Foundation Practice. Singapore, 1999, 12 p.
  12. Grigorian A.A., Ivanov E.S. Bearing Capacity and Method of Penetration of Piles in Loose Soils. Proceedings of the 8th International Conference on Soil Mechanics and Foundation. Moscow, 1973, vol. 3, pp. 125—130.
  13. Gotman A.L. Svaynye fundamenty. Obzorno-analiticheskaya lektsiya [Pile Foundations. An Analytical Review Lecture]. Proceedings of the Jubilee Conference Commemorating the 50th Anniversary of the Russian Society in charge of Soil Mechanics, Geotechnics and Foundations “Russian Geotechnics: a Step into the 21st Century”. 2007, vol. 1, pp. 37—52.

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IDENTIFICATION OF EQUIVALENT STATIC FORCES AS PART OF ANALYSIS OF SYSTEMS THAT HAVE DISRUPTABLE CONSTRAINS

Vestnik MGSU 4/2012
  • Chernov Yuriy Tikhonovich - Central Scientific Research Institute for Building Structures named after V.A. Kucherenko (V.A. Kucherenko CSRIBS) Doctor of Technical Sciences, Professor, Central Scientific Research Institute for Building Structures named after V.A. Kucherenko (V.A. Kucherenko CSRIBS), 6 2nd Institutskaya St., Moscow, 109428, Russian Federation.
  • Petrov Ivan Aleksandrovich - Moscow State University of Civil Engineering (MSUCE) postgraduate student, Department of Structural Mechanics, Moscow State University of Civil Engineering (MSUCE), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 98 - 101

The algorithm of analysis of systems that have disruptable constrains is described in the article. The algorithm is based on the joint solving of two linear systems. The first linear system is the one that describes the processes before constraints get disrupted; the second linear system represents the system describing the processes in the aftermath of disruption of constrains with account for the influence of free vibrations. Free vibrations are caused by disrupted constraints. The proposed approach is more effective, if applicable to the systems that have their constraints disrupted only once. Also, the method describing disrupted constraints is considered as a special case of physical nonlinearity. Physical non-linearity adds some fictitious load to regular loads.
Formulas of equivalent static loads, with the help of which the systems are analyzed when constraints are disrupted, are generated. No inertial force is to be derived to obtain equivalent static loads. This is important in view of their application in dynamic analyses .
Analysis of the static system in the event of disrupted constraints is based on the equations derived by the authors. The result of the analysis represents an inverse linear relation of static loading and relative stiffness of the system with disrupted constraints. This means that the lower the stiffness of the system, the higher the static loading.

DOI: 10.22227/1997-0935.2012.4.98 - 101

References
  1. Chernov Yu.T. Vibratsii stroitel'nykh konstruktsiy [Vibrations of Engineering Structures]. Moscow, ASV Publ., 2011, 382 p.
  2. Timoshenko S.P., Yang D.Kh., Univer U. Kolebaniya v inzhenernom dele [Vibrations in Engineering]. Мoscow, Mashinostroenie [Machine Building],1985, 472 p.
  3. Chernov Yu.T. K raschetu sistem s vyklyuchayushchimisya svyazyami [About the Analysis of Systems That Have Disruptable Constraints]. Stroitel'naya mekhanika i raschet sooruzheniy [Structural Mechanics and Analysis of Structures]. 2010, no. 4, pp. 53—57.

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APPLICATION OF GENERALIZED EQUATIONS OF THE FINITE DIFFERENCE METHOD AS PART OF THE ANALYSIS OF SLABS RESTING ON ELASTIC FOUNDATIONS

Vestnik MGSU 4/2012
  • Gabbasov Radek Fatykhovich - Moscow State University of Civil Engineering (National Research University) (MGSU) Doctor of Technical Sciences, Professor, Construction and Theoretical Mechanics Departmenе, Moscow State University of Civil Engineering (National Research University) (MGSU), .
  • Uvarova Nataliya Borisovna - Moscow State University of Civil Engineering (MSUCE) Candidate of Technical Sciences, Professor, Department of Structural Mechanics, Moscow State University of Civil Engineering (MSUCE), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 102 - 107

Generalized equations of the finite difference method are used to analyze bended slabs resting on elastic foundations. The algorithm makes it possible to take account of the finite discontinuity of the function, its first derivative and the right part of the differential equation without getting any points outside of the contour or a fine grid involved in the analysis. The examples have proven the high accuracy of the proposed analysis that employs a coarse grid and a simple algorithm.
It is noteworthy that the algorithm of the analysis is developed with a view to the employment of computer-aided methods and with due account for a substantial number of subsettings. The examples provided in the article are solely designated to illustrate the operation of the proposed algorithm. They demonstrate that even if the number of subsettings is minimal, generalized equations of the method of finite differences are capable of generating the results that make it possible to assess the stress-strained state of a slab.

DOI: 10.22227/1997-0935.2012.4.102 - 107

References
  1. Gabbasov R.F., Mussa Sali. Obobshchennye uravneniya metoda konechnykh raznostey i ikh primenenie k raschetu izgibaemykh plastin peremennoy zhestkosti [Generalized Equations of the Method of Finite Differences and Their Application to Analysis of Bent Slabs of Variable Rigidity]. Izvestiya VUZov, Stroitel'stvo [News of Higher Education Institutions. Construction]. 2004, no. 5, pp. 17—22.
  2. Timoshenko S.P., Voynovskiy-Kriger S. Plastinki i obolochki [Plates and Envelopes]. Moscow, Nauka Publ., 1966
  3. Gabbasov R.F., Gabbasov A.R., Filatov V.V. Chislennoe postroenie razryvnykh resheniy zadach stroitel'noy mekhaniki [Numerical Structure of Discontinuous Solutions of Problems of Structural Mechanics]. Moscow, ASV Publ., 2008, 277 p.

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SIMULATION OF THE stress-strain state of excavation BOUNDARIES in fractured massifs

Vestnik MGSU 4/2012
  • Nizomov Dzhahongir Nizomovich - Academy of Sciences of the Republic of Tajikistan Institute of Geology, Antiseismic Construction and Seismology, 8 (992) 919-35-57-34, Academy of Sciences of the Republic of Tajikistan, ushanbe, Republic of Tajikistan; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Hodzhiboev Abduaziz Abdusattorovich - Tajik Technical University named after academic M.S. Osimi 8 (992) 918-89-35-14, Tajik Technical University named after academic M.S. Osimi, 10 Akademikov Radzhabovyh St., 734042, Dushanbe, Republic of Tajikistan; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Hodzhiboev Orifdzhon Abduazizovich - Academy of Sciences of the Republic of Tajikistan Institute of Geology, Antiseismic Construction and Seismology 8 (992) 918-72-08-44, Academy of Sciences of the Republic of Tajikistan, Dushanbe, Republic of Tajikistan; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 108 - 115

The authors have applied the method of boundary equations to resolve the problem of numerical calculation of the stress-strain state of arbitrary boundaries of excavation works in fractures massifs, if subjected to various impacts.
Benchmarking of the results have proven that the proposed model based on the method of boundary integral equations may be used to identify the concentrated stresses that the loose excavation boundaries in fractured massifs are exposed to.
The authors have developed an algorithm and a calculation pattern through the application of the method of boundary integral equations to calculate the values of stresses concentrated around arbitrary shape openings under impacts of various origins.
Any limiting process, namely, if or and any results are in line with the isotropic medium.
The proposed algorithm and calculation pattern may be used to research the concentrated stresses alongside the boundaries of hydrotechnical engineering facilities.

DOI: 10.22227/1997-0935.2012.4.108 - 115

References
  1. Lehnickiy S.G. Anizotropnye plastinki [Anisotropic Plates]. Moscow – Leningrad, Gosudarstvennoe izdatel'stvo tekhniko-teoreticheskoy literatury [State Publishing House of Theoretical Technical Literature]. 1947, 355 p.
  2. Lehnickiy S.G. Teoriya uprugosti anizotropnogo tela [Theory of Elasticity of Anisotropic Bodies]. Moscow – Leningrad, Gosudarstvennoe izdatel'stvo tekhniko-teoreticheskoy literatury [State Publishing House of Theoretical Technical Literature]. 1950, 299 p.
  3. Ruppeneyt K.V. Deformiruemost' massivov treschinovatykh gornykh porod [Deformability of Fractured Rock Massifs]. Moscow, Nedra Publ., 1975, 223 p.
  4. Roza S.A., Zelenskiy B.D. Issledovanie mehanicheskikh svoystv skal'nykh osnovaniy gidrotehnicheskikh sooruzheniy [Research of Mechanical Properties of Bedrock Foundations of Hydrotechnical Engineering Facilities]. Moscow, Jenergiya Publ., 1967. 392 p.
  5. Baklashov I.V. Deformirovanie i razrushenie porodnykh massivov [Deformation and Collapse of Rock Masses]. Moscow, Nedra Publ., 1988, 271 p.
  6. Baklashov I.V., Kartoziya B.A. Mehanicheskie processy v porodnykh massivakh [Mechanical Processes in Rock Masses]. Moscow, Nedra Publ., 1986, 272 p.
  7. Baklashov I.V., Kartoziya B.A. Mekhanika gornykh porod [Rock Mechanics]. Moscow, Nedra Publ., 1975, 271 p.
  8. Zelenskiy B.D. O metode ucheta vliyaniya treschinovatosti na deformacionnye svoystva skal'nykh massivov [About the Method of Analysis of the Impact of Fractures onto Deformation Properties of the Rock Massif]. Works of Leningrad Institute of Engineering and Economics. 1967, Issue No. 68, pp. 62—70.
  9. Zelenskiy B.D. Osnovnye napravleniya issledovaniy informaciy skal'nykh porod kak osnovaniy betonnykh plotin [Principal Lines of Information Research of Rock Massifs as Bedrocks of Concrete Dams]. Problemy inzhenernoy geologii v stroitel'stve [Problems of Engineering Geology in Construction]. Moscow, Gostrojizdat Publ., 1961, pp. 143—156.
  10. Krauch S., Starfild A. Metody granichnykh elementov v mekhanike tverdogo tela [Method of Finite Elements in Mechanics of Rigid Body]. Moscow, Mir Publ., 1987, 328 p.
  11. Kuznecov Ju.I., Pozinenko B.V., Pylaeva T.A. Ob anizotropii uprugikh svoystv treschinovatykh gornykh porod [About the Anisotropy of Elastic Properties of Fractured Rocks]. Academic Papers of Leningrad State University, Series of Physical and Geological Sciences. 1966, Issue no. 16, № 329, pp. 94—106.
  12. Pancini M. Result of the First Series of Tests Performed on a Model Reproducing the Actual Structure of the Abutment Rock of the Vaiont Dam. Geologie und Bauwesen Publ., H. 3, 4, 1962, pp. 105—119.
  13. Tokano M. Rupture Studies on Arch Dam Foundation by Means of Models. Geologie und Bauwesen Publ., H. 3, 4, 1961, pp. 99—121.
  14. Walsh J.B. The Effect of Cracks on the Uniaxial Elastic Compression of Rocks. Journal of Geophysical Research. Issue no. 70, №. 2, 1965, pp. 399—411.
  15. Nizomov Dzh.N. Metod granichnykh uravneniy v reshenii staticheskikh i dinamicheskikh zadach stroitel'noy mekhaniki [Method of Boundary Equations Used to Solve Static and Dynamic Problems of Structural Mechanics]. Moscow, ASV Publ., 2000, 283 p.
  16. Myuller L. Inzhenernaya geologiya. Mekhanika skal'nykh massivov [Engineering Geology. Mechanics of Rock Massifs]. Moscow, Mir Publ., 1971, 255 p.

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VIBRATIONS OF A DEEP HEAVY FOUNDATION RESTING ON WEIGHTY MULTILAYER SOILS

Vestnik MGSU 4/2012
  • Ter-Martirosyan Zaven Grigor'evich - Moscow State University of Civil Engineering (MSUCE) , Moscow State University of Civil Engineering (MSUCE), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Jaro Mokhammed Nazeem - Moscow State University of Civil Engineering (MSUCE) postgraduate student, Department of Soil Mechanics, Beddings and Foundations, Moscow State University of Civil Engineering (MSUCE), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 116 - 120

The authors present analytical and numerical solutions to the problem of vibrations of deep foundations caused by dynamic loads, if the foundations rest on multilayer soils. It is proven that the friction force that influences the foundation, the weighty nature of the bedding, and the visco-elastic properties of soils affect the amplitude and the frequency of vibrations.
The authors present an approach to the calculation of vibrations of deep foundations resting on multilayer soils. The proposed approach takes account of the side surface friction of the foundation and the soil and elastic and viscous properties of soils. The soil is presented as a multilayer substance, and all of its layers are connected to one another by elastic-viscous elements. In this case, each layer of soil vibrates independently and provides multiple degrees of freedom to the system.
A mathematical description of vibrations requires the identification of the coefficient of stiffness for each layer of soil, as well as the weight, the average per-layer stress and the angle of distributed static stress.
The results have proven that the weight of the bedding, the friction of a deep foundation, and elastic and viscous properties of soil affect the behavior of the amplitude and the frequency of foundation vibrations and the accumulation of residual settlements.

DOI: 10.22227/1997-0935.2012.4.116 - 120

References
  1. Voznesenskiy E.A. Dinamicheskaya neustoychivost' gruntov [Dynamic Instability of Soils]. Moscow, Editorial Publ., 1999, 264 p.
  2. Krasnikov N.D. Dinamicheskie svoystva gruntov i metody ikh opredeleniya [Dynamic Properties of Soils and Methods of Their Identification]. Leningrad, Stroyizdat Publ., 1970, 239 p.
  3. Savinov O.A. Sovremennye konstrukyii fundamentov pod mashiny i ikh raschet [Modern Structures of Foundations to Accommodate Machinery and Analysis of Structures]. Leningrad – Moscow, Stroyizdat Publ., 1974, 279 p.
  4. Ter-Martirosyan Z.G. Mekhanika gruntov [Soil Mechanics]. Moscow, ASV Publ., 2009, 552 p.
  5. Ukhov S.B., Semenov V.V, Znamenskiy V.V., Ter-Martirosyan Z.G., Chernyshev S.H. Mekhanika gruntov. Osnovaniya i fundamenty [Soil Mechanics. Beddings and Foundations], 2007, 561 p.
  6. Braja M. DA. Fundamentals of Soil Dynamics, ed. ELSEVIER, New York, Amsterdam, Oxford, 1983, p. 399.

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INTERACTION BETWEEN FINITE STIFNESS STRUCTURES WITH THE DOUBLE-LAYERED SOIL BEDDING IN THE COURSE OF SEISMIC LOADS

Vestnik MGSU 4/2012
  • Ter-Martirosyan Zaven Grigor'evich - Moscow State University of Civil Engineering (MSUCE) , Moscow State University of Civil Engineering (MSUCE), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Jaro Mokhammed Nazeem - Moscow State University of Civil Engineering (MSUCE) postgraduate student, Department of Soil Mechanics, Beddings and Foundations, Moscow State University of Civil Engineering (MSUCE), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 121 - 125

In the paper, the authors present their research of the stress-strain behavior of the doublelayered soil bedding interacting with structures in the course of seismic excitation by taking account of elastic and plastic properties of the soil. Seismic excitation of soil causes irreversible residual stresses and settlements, local failure zones, cracks in the soil surface and structures that interact with it. The analysis of residual stresses and settlements caused by the seismic excitation is one of relevant problems of soil dynamics.
The factors that boost stresses and settlements in the course of seismic excitation include the intensity of the earthquake, the amplitude and frequency of vibrations of structures. In some cases, seismic excitation leads to resonance that may cause failure of the structure. The use of the elastic and plastic model makes it possible to identify the local zone of structural failure and residual deformations. The important factor of projecting the stress-strain state of soil during seismic excitation is the boundary condition of the model used for the analysis purposes. It is clear that the model used for seismic analysis purposes must be bigger than the one used for static analysis purposes. The results have proven that heterogeneous stresses and deformations originate in the soil bedding, and the heavier the structure, the longer the period of decay of vibrations.

DOI: 10.22227/1997-0935.2012.4.121 - 125

References
  1. Ishikhara K. Povedenie gruntov pri zemletryaseniyakh [Soil Behaviour in the course of Earthquakes]. St.Petersburg, NPO «Georekonstruktsiya-Fundament-Proekt» [Research and Production Association “Geological Structures — Foundations - Designs]. 2006, 384 p.
  2. SNiP II-7—81* Stroitel'stvo v seysmichnykh rayonakh. Normy proektirovaniya [Construction Norms and Rules II-7—81*. Construction in Seismic Areas. Norms of Design]. Moscow, Stroyizdat Publ., 1982.
  3. Stavnitser L.R. Seysmostoykost' osnovaniy i fundamentov [Seismic Resistance of Beddings and Foundations]. Moscow, ASV Publ., 2010, 446 p.
  4. Ter-Martirosyan Z. G. Mekhanika gruntov [Soil Mechanics]. Moscow, ASV Publ., 2009, 552 p.
  5. Chopra A.K. and Gutierrez J.A. Earthquake Response Analysis of Multistory Buildings including Foundation Interaction. Journal of Earthquake Engineering and Structural Dynamics, 1974, vol. 3, pp. 65-77.
  6. Lysmer J., Kuhlmeyer R.L. Finite Dynamic Model for Infinite Media. ASCE. J. of the Eng. Mech. Div., 1969, pp. 859-877.
  7. Naylor D.J. and Pande G.N. Finite Elements in Geomechanics. Pineridge Press Limited, 1981.

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ASSESSMENT OF RELIABILITY OF OVERLAPPINGS IN THE COURSE OF THE WAREHOUSE RECONSTRUCTION

Vestnik MGSU 4/2012
  • Dolganov Andrey Ivanovich - Zhilekspertiza Limited Liability Company lead engineer, Zhilekspertiza Limited Liability Company, 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Kaleev Denis Ivanovich - Zhilekspertiza Limited Liability Company lead engineer, Zhilekspertiza Limited Liability Company, Building 2, 21 Yablochkova St., Moscow, 127322, Russian Federation.

Pages 126 - 130

In the article, the authors perform the assessment of the reliability of overlappings of a warehouse building owned by Vysokovol'tnyy Kabel' Open Joint Stock Company. The assessment is performed in 25-38/А-D axes on the basis of the bearing capacity criterion. The authors have assessed the compliance of the condition of the restructured building with the regulatory requirements issued by the Federal Service in charge of Ecological, Technological and Nuclear Supervision, Federal Law № 116-FZ On Industrial Safety of Hazardous Industrial Facilities, issued on July 21, 1997, and Federal Law № 384-FZ Technical Regulations of Safety of Buildings and Structures, issued on December 30, 2009, in terms of the assurance of safe maintenance of the above industrial building.
The warehouse building is located within the area occupied by the Moscow cable factory. It occupies a two-aisle section of a single-storied industrial building in 25-38/А-D axes. The climatic area represents Area II, the subsection of the climatic zone is 2B. The warehouse has a metal frame; it is made of I-shaped steel columns and beams that have reinforced concrete floor slabs resting on them. The foundations are made of reinforced concrete posts resting on the concrete foundation mat.
As a result of a specialized analysis, the authors have identified that the probability of compliance of the steel beams with the requirements of the first group of limit states, with account for the identified damages, is equal to 5σ. The analysis of the structure of the overlapping and the columns demonstrates that their bearing capacity and rigidity are sufficient to resist the principal combinations of load, including the loads that come from the two allied loaded loaders of Doosan series (48B AC) that represent a short term load.

DOI: 10.22227/1997-0935.2012.4.126 - 130

References
  1. Augusti G., Baratta A., Kashiati F. Veroyatnostnye metody v stroitel'nom proektirovanii [Probability Methods in Structural Design]. Moscow, Stroyizdat Publ., 1988, 584 p.
  2. Dolganov A.I. Nadezhnost' sterzhnevykh zhelezobetonnykh konstruktsiy [Reliability of Reinforced Concrete Framing Structures]. Magadan, OAO "MAOBTI", 2007, 209 p.
  3. Dolganov A.I. Otsenka nadezhnosti monolitnykh mnogoetazhnykh zdaniy [Assessment of Reliability of Monolithic Multi-storied Buildings]. Promyshlennoe i grazhdanskoe stroitel'stvo [Industrial and Civil Engineering]. 2010, no. 8, pp. 50—51.

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Geoecological conditions of THE territory OF Tomsk and their influence on URBAN CONSTRUCTION AND DEVELOPMENT

Vestnik MGSU 4/2012
  • Ol'khovatenko Valentin Egorovich - Tomsk State University of Architecture and Building (TSUAB) Professor, Doctor of Geological and Mineralogical Sciences, Chair, Department of Engineering Geology and Geoecology, Tomsk State University of Architecture and Building (TSUAB), 2 Solyanaya sq., Tomsk, 634003, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Lazarev Vladimir Mikhaylovich - Tomsk State University of Architecture and Building (TSUAB) Candidate of Technical Sciences, Associated Professor, Chair, Department of Geodesy, Tomsk State University of Architecture and Building (TSUAB), 2 Solyanaya sq., Tomsk, 634003, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Filimonova Irina Sergeevna - Tomsk State University of Architecture and Building (TSUAB) Senior Lecturer, Department of Engineering Geology and Geoecology, Tomsk State University of Architecture and Building (TSUAB), 2 Solyanaya sq., Tomsk, 634003, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 131 - 139

Geoecological conditions, natural and anthropogenic factors that boost hazardous processes in the territory of Tomsk are considered in the paper. The algorithm of research of geoecological conditions of urban territories is proposed by the authors. The authors have also identified the reasons of hazardous processes and development patterns typical for them; the authors also break the territory into zones on the basis of the level of hazards and risks that the urban development is exposed to. The authors provide their recommendations in respect of the engineering protection of urban lands on the basis of the zoning of the territory of Tomsk.
Comprehensive geoecological research was performed in furtherance of the algorithm proposed by the authors. The research undertaking made it possible to identify the patterns of hazardous processes, to assess the state and sustainability of natural and technological systems in the zones of geoecological risks, to compile a map of urban zones based on the intensity of geoecological risks that challenged the urban development, and to develop a set of actions to assure the engineering protection of the territory, its buildings and structures.

DOI: 10.22227/1997-0935.2012.4.131 - 139

References
  1. Ol'khovatenko V.E., Rutman M.G., Lazarev V.I. Opasnye prirodnye i tekhnoprirodnye protsessy na territorii goroda Tomska i ikh vliyanie na ustoychivost' prirodno-tekhnicheskikh sistem [Hazardous Natural and Technological-Natural Processes in the Territory of Tomsk and Their Influence on the Sustainability of Natural and Technological Systems]. Tomsk, Pechatnaya Manufaktura Publ., 2005, 152 p.

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IMPACT OF VARIOUS ADDITIVES ONTO MORPHOLOGY OF GYPSUM CRYSTALS

Vestnik MGSU 4/2012
  • Ustinova Yuliya Valer'evna - Moscow State University of Civil Engineering (MSUCE) +7 (499) 183-32-92, Moscow State University of Civil Engineering (MSUCE), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Sivkov Sergey Pavlovich - D. Mendeleyev University of Chemical Technology of Russia (MUCTR) 8 (495) 496-92-38, D. Mendeleyev University of Chemical Technology of Russia (MUCTR), 20 Geroev Panfilovtsev str., Moscow, 125047, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Barinova Ol'ga Pavlovna - D. Mendeleyev University of Chemical Technology of Russia (MUCTR) +7 (495) 496-93-40, D. Mendeleyev University of Chemical Technology of Russia (MUCTR), 20 Geroev Panfilovtsev str., Moscow, 125047, Russian Federation; opbar@rambler.ru; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Sanzharovskiy Aleksandr Yur'evich - D. Mendeleyev University of Chemical Technology of Russia (MUCTR) +7 (495) 496-93-40, D. Mendeleyev University of Chemical Technology of Russia (MUCTR), 20 Geroev Panfilovtsev str., Moscow, 125047, Russian Federation.

Pages 140 - 144

Nowadays, functional additives represented by multiple classes of substances and compounds, including polymers of different origin, are available for introduction into dry mixtures based on gypsum binders. However, their impact onto the growth and formation of calcium sulfate dihydrate (CaSO∙2HO) crystals generated in the course of hardening of gypsum binders is not quite clear. Therefore, the objective of the research was to analyze the processes of growth and formation of calcium sulfate dihydrate crystals caused by functional additives based on polymers of different origin. The analysis was composed of three stages.
At the first stage, both pure and modified calcium sulfate dihydrate crystals were synthesized. Super plasticizers based on sulfonated melamine-formaldehyde resin, methylcellulose (MC) and redispersible polymer powder based on copolymer of vinyl acetate, ethylene and vinyl chloride (VAEVC) were applied as additives. At the second stage, the objective was to identify the influence of polymer additives on the shape and size of calcium sulfate dihydrate crystals; therefore, an X-ray analysis of synthesized crystals was performed. Following the X-ray analysis data and with the help of a special software programme, possible combinations of simple forms of CaSO∙2HO were simulated, and the habitus of generated crystals was also studied. At the third stage, the objective was to validate the models of calcium sulfate dihydrate crystals by means of an electron-microscopic analysis.
The following conclusions were made upon completion of the research:
A. It has been identified that additives based on polymers of different origin affect the processes of crystallization, the size and shape of gypsum crystals. The presence of the super plasticizer based on sulfonated melamine-formaldehyde resin, methylcellulose and redispersible polymer powder based on a copolymer of vinyl acetate, ethylene and vinyl chloride, causes reduction of the size of crystals, while the crystals turn elongated. The crystal-to-crystal contact area increases; therefore, it is likely that the strength of the hardening agent goes up.
B. It has been demonstrated that the X-ray analysis can be applied to simulate the shape and habitus of crystals.

DOI: 10.22227/1997-0935.2012.4.140 - 144

References
  1. Korneev V.I., Zozulya P.V., Medvedeva I.N., Bogoyavlenskaya G.A., Nuzhdina N.I. Retsepturnyy spravochnik po sukhim stroitel'nym smesyam [Book of References and Recipes of Dry Building Mixtures]. St. Petersburg, Kvintet Publ., 2010, 308 p.
  2. Izotov V.S. Khimicheskie dobavki dlya modifikatsii betona [Chemical Additives to Modify the Concrete]. Moscow, Paleotip Publ., 2006, 244 p.
  3. Mishra R.K., Flatt R.J., Heinz H. Molecular Understanding of Directional Surface and Interface Tensions of Gypsum and Calcium Sulfate Hemihydrate. Proceedings of the XIII ICCC International Congress on the Chemistry of Cement, Madrid, Spain, 3-8 July, 2011.
  4. Kristallograficheskaya i kristallokhimicheskaya baza dannykh dlya mineralov i ikh struk-turnykh analogov [Crystallographic and crystal-chemical database of minerals and their structural counterparts]. Available at: http://database.iem.ac.ru/mincryst/rus. Date of access: 04.02.2012.

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COMPUTER-AIDED FLOW METER APPLICABLE TO LOOSE MATERIALS IN THE COURSE OF PNEUMATIC TRANSPORTATION

Vestnik MGSU 4/2012
  • Gulyaev Valeriy Genrihovich - Nizhniy Novgorod State University of Architecture and Civil Engineering (NNSUAC) , Nizhniy Novgorod State University of Architecture and Civil Engineering (NNSUAC), 65 Ilyinskaya Str., Nizhniy Novgorod, 603950, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 145 - 148

The article covers the issues of development and the results of the pilot testing of the contact-free meter of the two-phase flow of loose construction materials in the course of their pneumatic transportation. The flow meter designed by the author is based on the method of registration of polarization currents caused by the motion of the dielectric material within the electric field of a measurement unit integrated into the pneumatic transportation line. The registration unit is the implementation of the original technology. Its functional concept is based on the Pockels transverse effect inside the lithium niobate crystal. This electro-optical effect is characterized by minimal persistence, as the phase of the optical wave varies within the time period of 10 second, and this effect makes it possible to improve the accuracy of measurements. The flow rates is identified on the basis of one variable integral parameter, the intensity of an optical wave passing through the Pockels cell simulated by the currents of polarization of the material. The paper contains the structural pattern of the computer-aided meter of loose dielectric materials in the course of their pneumatic transportation, the system of visualization of the mass flow, and the results of the pilot testing of the proposed meter. The proposed system may represent an unbiased system of management of construction materials, consumption procedures, and warehouse processing of materials.

DOI: 10.22227/1997-0935.2012.4.145 - 148

References
  1. Plotnikov N.M., Gulyaev V.G., Kirgizov A.M. Razrabotka izmeritelya rashoda dvuhfaznogo potoka sypuchikh stroitel'nykh materialov pri pnevmotransportirovanii [Development of the Two-Phase Flow Meter of Loose Building Materials in the Course of Pneumatic Transportation]. Nizhniy Novgorod University of Architecture and Civil Engineering (NNUACE), Privolzhskiy nauchnyy zhurnal [Privolzhsky Scientific Journal], no. 3, Nizhniy Novgorod, 2010, pp. 105—111.
  2. Plotnikov N.M., Gulyaev V.G. Izmeritel' rashoda sypuchikh dielektricheskikh materialov, transportiruemykh vozduhom v zakrytykh truboprovodakh [Meter of the Flow of Loose Dielectric Materials Transported by the Compressed Air in Closed Pipelines]. Pribory [Devices], no. 1 (127), Moscow, 2011, pp. 35—39.

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COMPOSITE POLYMERICADDITIVESDESIGNATED FORCONCRETEMIXES BASED ONPOLYACRYLATES, PRODUCTS OF THERMAL DECOMPOSITION OF POLYAMIDE-6 AND LOW-MOLECULAR POLYETHYLENE

Vestnik MGSU 4/2012
  • Polyakov Vyacheslav Sergeevich - Ivanovo State University of Chemistry and Technology (ISUCT) Director, "Polymer" Research and Production Laboratory, Ivanovo State University of Chemistry and Technology (ISUCT), 7 Prospekt Engelsa, Ivanovo, 153000, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Padokhin Valeriy Alekseevich - Institute of Machine Science named after A.A. Blagonravov of the Russian Academy of Sciences (IMASH RAN) Doctor of Technical Sciences, Professor, Principal Researcher, Institute of Machine Science named after A.A. Blagonravov of the Russian Academy of Sciences (IMASH RAN), 4 Malyy Khariton'evskiy per., Moscow, 101990, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Akulova Marina Vladimirovna - - Ivanovo State University of Architecture and Civil Engineering (ISUACE) Doctor of Technical Sciences, Professor, Chair, Department of Construction Materials, Ivanovo State University of Architecture and Civil Engineering (ISUACE), 20 8th March St., Ivanovo, 153037, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 149 - 154

The goal of the present research is to develop polymeric additives based on aqueous dispersions of (meth)acrylic polymers, including polymethacrylates, polyacrylates, products of thermal decomposition of polyamide-6 in the vegetable oil media, and low-molecular polyethylene. Decomposition of polyamide-6 took 8…10 hours at the temperature of 245…275 °С. The mixture of low-molecular polyamides, the average molecular weight of which reached 3400…8600, was used both independently and as a constituent of a composite additive designated for Concrete Mix В 22,5 (М300). The choice of polymers is based on their availability, as they are produced by local manufacturers of chemicals. For example, low-molecular polyethylene is the by-product of high-capacity synthesis of high-pressure polyethylene. Besides low-molecular polyamides, additives may represent concentrated oligomers of ε-caprolactam generated in the course of synthesis of polyamide-6. Therefore, the problem of disposal of by-products generated by major producers of chemicals is resolved to some extent, while the cost of the feed stock required for the manufacturing of effective additives designated for concretes goes down. The above substances are non-toxic, they do not emit any hazardous fumes in the course of the concrete mixture preparation, further evaporation and dehydration of molded concrete and reinforced concrete products.
Therefore, the following conclusions can be made on the basis of the research of the influence of polymeric additives onto the properties of Concrete В 22,5:
1) polymeric additives 1, 2, 3, 4, 5 represent plasticizing additives that decelerate the hardening of concrete mixtures and reduce the water-cement ratio by 6.5 % (Additive 1) - 19.4 % (Additive 5);
2) Additives 1, 2, 3, 4, 5 added into the mixture in the amount of 0.5…0.7 % (weight share) improve the strength of Concrete В 22,5 samples, if tested on the 28 day of hardening (see Table 1) in the dry-hardening mode, if compared to the benchmark sample, by 0.6% (Additive 1),by 9.1% (Additive 2), by 22.4% (Additive 3), by 24.8% (Additive 4), and by28.2% (Additive 5);
3) polymeric additives improve the water resistance of Concrete В 22,5 by 2.56 times (Additive 1), by 7.5 times (Additive 2),by 26,2 times (Additive 4), by 191…195 times (Additive 5), if compared to the benchmark sample;
4) the optimal composite additive that increases the time period of stiffening of the cement grout , improves the water resistance and the compressive strength of concrete, represents the composition of polyacrylates and polymethacrylates, products of thermal decomposition of polyamide-6 and low-molecular polyethylene in the weight ratio of 1:1:0.5.

DOI: 10.22227/1997-0935.2012.4.149 - 154

References
  1. Rebinder P.A. Selected works. Poverkhnostnye yavleniya v dispersnykh sistemakh. Kolloidnaya khimiya [Surface Effects in Disperse Systems. Colloid Chemistry]. Moscow, Nauka Publ., 1978, 368 p.
  2. Bazhenov Yu.M. Tekhnologiya betona [Technology of Concrete]. Moscow, Stroyizdat Publ., 1987, 415 p.
  3. Ramachandran V., Feldman R., Boduen G. Nauka o betone. Fiziko-khimicheskoe betonovedenie [Science of Concrete. Physical and Chemical Studies of Concrete]. Moscow, Stroyizdat Publ., 1986, 278 p.
  4. Ratinov V.B., Ivanov F.M. Khimiya v stroitel'stve [Chemistry in Construction]. Moscow, Stroyizdat Publ., 1977, 380 p.

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MODELING AND OPTIMIZATION OF THE AEROCONCRETE TECHNOLOGY

Vestnik MGSU 4/2012
  • Zhukov Aleksey Dmitrievich - Moscow State University of Civil Engineering (MSUCE) C andidate o f Technical S ciences, A ssociated P rofessor, D epartment of Technology of Finishing and Insulating Materials, Moscow State University of Civil Engineering (MSUCE), 26 Yaroslavskoeshosse, Moscow, 129337, Russia; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Chugunkov Aleksandr Viktorovich - Moscow State University of Civil Engineering (MGSU) Director, Department of Examination of Buildings, postgraduate student, Department of Technology of Finishing and Insulation Materials, Moscow State University of Civil Engineering (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Gudkov Pavel Kirillovich - Moscow State University of Civil Engineering (MSUCE) Engineer, Web-editor, Editorial and Publishing Centre, Moscow State University of Civil Engineering (MSUCE), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 155 - 159

Heat-insulating cellular concrete manufactured in the variotropic pressure environment, may be used both for making single-piece products, and for monolithic construction purposes. Optimization of technology-related parameters prevents excessive consumption of principal components, while output products maintain pre-set characteristics. Both the product and the technology are based on the provisions of the general methodology of development of highly porous materials.
The technology is based on the principle of adjustable formation of the state of stress in the variotropic pressure environment. The state of stress maintained in the course of blowout contributes to formation of optimized cellular structure (in accordance with the criteria that include the shape, dimensions of pores, and characteristics of interpore partitions).
The process of manufacturing of the heat-insulating cellular concrete breaks down into the following stages: preparation of raw materials, preparation of the cellular concrete mixture, casting of products, thermal processing or ageing in the natural environment. Products are placed under heating domes, equipped with electric heaters, and exposed to heat treatment for six hours. Before the heat treatment, products are kept in their moulds for four hours. In the absence of heat treatment, products are kept on their pallets for 14 days.
Selection of the appropriate composition and optimal technological parameters is performed with the help of G-BAT-2011 software programme developed at MSUCE. The software is based on the methodology that is based on complete factorial experiments, experiments based on fractional replicates and testing of all essential statistical hypotheses. Linear, incomplete quadratic and quadratic equations generated as a result of experiments make it possible to design a model that represents natural processes in the adequate manner. The model is analytically optimized and interpreted thereafter.

DOI: 10.22227/1997-0935.2012.4.155 - 159

References
  1. Zhukov A.D., Chugunkov A.V. Lokal'naya analiticheskaya optimizatsiya tehnologicheskikh protsessov [Local Analytical Optimization of Technology-related Processes]. Vestnik MGSU [Proceedings of Moscow State University of Civil Engineering]. 2011, no. 1, vol. 2, pp. 273—278.
  2. Zhukov A.D., Chugunkov A.V. Rudnitskaya V.A. Reshenie tehnologicheskikh zadach metodami matematicheskogo modelirovaniya [Resolution of Technology-related Problems by Methods of Mathematical Modeling]. Moscow, MSUCE, 2011, 176 p.

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REINFORCING FIBRES AS PART OF TECHNOLOGY OF CONCRETES

Vestnik MGSU 4/2012
  • Zhukov Aleksey Dmitrievich - Moscow State University of Civil Engineering (MSUCE) C andidate o f Technical S ciences, A ssociated P rofessor, D epartment of Technology of Finishing and Insulating Materials, Moscow State University of Civil Engineering (MSUCE), 26 Yaroslavskoeshosse, Moscow, 129337, Russia; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Rudnitskaya Viktoriya Aleksandrovna - Moscow State University of Civil Engineering (MSUCE) master student, Department of Technology of Finishing and Insulation Materials, Moscow State University of Civil Engineering (MSUCE), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Smirnova Tat'yana Viktorovna - Moscow State University of Civil Engineering (MSUCE) ROCKWOOL postgraduate student Leading Specialist, Moscow State University of Civil Engineering (MSUCE) ROCKWOOL, 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 160 - 164

Methods of modification of the foamed fibre concrete technology and optimization of its parameters within the framework of methodologies of new construction materials developed by the specialists of Department of Technology of Finishing and Insulation Materials of MSUCE is considered in the paper. The methodology of highly porous materials is based on the research and modeling of their structure, and optimization of the process of their manufacturing. The core constituent of the proposed methodology is the identification of the markets for the designed products, as well as the pre-setting of their properties and assurance of their stability over the time.
The foamed fibre concrete technology represents modified procedures of preparation of the foam, the mineral component, and the basalt fiber, the blending of the components, their casting and heat treatment. The process-related parameters were subjected to double-staged analysis: Stage 1 represented an experiment encompassing the whole process. As a result of the experiment, factors of major impact (or control parameters) were identified. At Stage 2, factorial experiment was conducted to identify second-order mathematical dependencies. The results were subjected to analytical optimization, and graphical representation of dependencies was performed. Selection of the composition and optimal process parameters was performed with the help of G-BAT-2011 software programme developed at MSUCE.
It was identified that the basalt fibre consumption rate influences both the strength and the density of products made of cellular concrete. The length of the basalt fibre impacts the strength of products. A nomogram was developed to identify the consumption rate of the basalt fibre driven by the strength of products and the Portland cement consumption rate. The authors also studied the influence of the consumption rate of Portland cement and basalt fibre onto the structural quality ratio of the foamed fibre concrete.

DOI: 10.22227/1997-0935.2012.4.160 - 164

References
  1. Zhukov A.D., Chugunkov A.V. Rudnitskaya V.A. Reshenie tehnologicheskikh zadach metodami matematicheskogo modelirovaniya [Resolution of Technology-related Problems by Methods of Mathematical Modeling]. Moscow, MSUCE, 2011, 176 p.
  2. Zhukov A.D., Chugunkov A.V. Lokal'naya analiticheskaya optimizatsiya tehnologicheskikh protsessov [Local Analytical Optimization of Technology-related Processes]. Vestnik MGSU [Proceedings of Moscow State University of Civil Engineering]. 2011, no. 1, vol. 2, pp. 273—278.

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