DESIGNING AND DETAILING OF BUILDING SYSTEMS. MECHANICS IN CIVIL ENGINEERING

MODELING OF RAILWAY TRACK OPERATION AS A SYSTEM OF QUASI-ELASTIC ORTHOTROPIC LAYERS

Vestnik MGSU 3/2016
  • Sycheva Anna Vyacheslavovna - Moscow State University of Railway Engineering (MIIT) Candidate of Technical Sciences, Associate Professor, Department of Buildings and Structures on the Transport, Moscow State University of Railway Engineering (MIIT), 22/2 Chasovaya str., Moscow, 125993, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Sychev Vyacheslav Petrovich - Moscow State University of Railway Engineering (MIIT) Doctor of Technical Sciences, Professor, Department of Transport Construction, Moscow State University of Railway Engineering (MIIT), 22/2 Chasovaya str., Moscow, 125993, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Buchkin Vitaliy Alekseevich - Moscow State University of Railway Engineering (MIIT) Doctor of Technical Sciences, Professor, Department of Railway Design and Construction, Moscow State University of Railway Engineering (MIIT), 22/2 Chasovaya str., Moscow, 125993, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Bykov Yuriy Aleksandrovich - Moscow State University of Railway Engineering (MIIT) Doctor of Technical Sciences, Professor, Department of Railway and Track Economy, Moscow State University of Railway Engineering (MIIT), 22/2 Chasovaya str., Moscow, 125993, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 37-46

In this paper the authors give a solution to the problem of the impact of a rolling stock on the rail track on the basis of modeling a railway track as a multi-layered space, introducing each of the layers is a quasi-elastic orthotropic layer with cylindrical anisotropy in the polar coordinate system. The article describes wave equations, taking into account the rotational inertia of cross sectional and transverse shear strains. From the point of view of classical structural mechanics train path can be represented as a multilayer system comprising separate layers with different stiffness, lying on the foundation being the elastic-isotropic space. Winkler model provides that the basis is linearly deformable space, there are loads influencing its surface. These loads are transferred through a layered deformable half-space. This representation is used in this study as an initial approximation. For more accurate results of the deformation of a railway track because of rolling dynamic loads it is proposed to present a railway track in the form of a layered structure, where each element (assembled rails and sleepers, ballast section, the soil in the embankment, basement soils) is modeled as a planar quasi-elastic orthotropic layer with cylindrical anisotropy. The equations describing the dynamic behaviour of flat element in a polar coordinate system are hyperbolic in nature and take into account the rotational inertia of the cross sectional and the transverse shear strains. This allows identifying the impact on the final characteristics of the blade wave effects, and oscillatory processes. In order to determine the unknown functions included in the constitutive equations it is proposed to use decomposition in power series in spatial coordinate and time. In order to determine the coefficients of ray series for the required functions, it is necessary to differentiate the defining wave equations k times on time, to take their difference on the different sides of the wave surface, and apply the consistency condition for the transition from the jump of the derivative of a function in the coordinate to the jump of the derivative of a sought function in time of higher order. The proposed approach allows considering the whole structure of the railway track in the form of a set of layers, making for each layer (rail - sleeper; sleeper - ballast; ballast - ballast bed) a system of equations and solving them. Therefore it is possible to vary the characteristics of different layers and their modules of elasticity, determining the optimal thickness of the ballast layer or oversleeper and undersleeper strips.

DOI: 10.22227/1997-0935.2016.3.37-46

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Efficiency of fiber reinforced concrete application in structures subjected to dynamic effects

Vestnik MGSU 3/2014
  • Morozov Valeriy Ivanovich - Saint-Petersburg State University of Architecture and Civil Engineering (SPbGASU) Doctor of Technical Sciences, Professor, head, Department of Reinforced Concrete and Masonry Structures, corresponding member of Russian Academy of Architecture and Construction Sciences, Saint-Petersburg State University of Architecture and Civil Engineering (SPbGASU), 4, 2 Krasnoarmeiskaya St., 190005, St. Petersburg, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Pukharenko Yuriy Vladimirovich - Saint-Petersburg State University of Architecture and Civil Engineering (SPbGASU) Doctor of Technical Sciences, Professor, head, Department of Building Materials Technology and Metrology, councilor of Russian Academy of Architecture and Construction Sciences, Saint-Petersburg State University of Architecture and Civil Engineering (SPbGASU), 4, 2 Krasnoarmeiskaya St., 190005, St. Petersburg, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 189-196

Fiber reinforced concretes possess high strength under dynamic loadings, which include impact loads, thanks to their high structural viscosity. This is the reason for using them in difficult operating conditions, where increasing the performance characteristics and the structure durability is of prime importance, and the issues of the cost become less significant. Applying methods of disperse reinforcement is most challenging in case of subtle high-porous materials on mineral binders, for example foamed concrete. At the same time, the experiments conducted in Russia and abroad show, that also in other cases the concrete strength resistance several times increases as a result of disperse reinforcement. This doesn't depend on average density of the concrete and type of fiber used. In the article the fibre reinforced concrete impact resistance is analysed. Recommendations are given in regard to fibre concrete application in manufacture of monolithic floor units for industrial buildings and precast piles.

DOI: 10.22227/1997-0935.2014.3.189-196

References
  1. Pukharenko Yu.V. Nauchnye i prakticheskie osnovy formirovaniya struktury i svoystv fibrobetonov: avtoreferat dissertatsii doktora tekhnicheskikh nauk [Scientific and Practical Fundamentals of Fiber Concrete Structure and Properties. Thesis Abstract of the Doctor of Technical Sciences]. Saint Petersburg, 2004, 46 p.
  2. Lobanov I.A., Pukharenko Yu.V., Gurashkin Yu.A. Udarostoykost' fibrobetonov, armirovannykh nizkomodul'nymi sinteticheskimi voloknami [Shock Resistance of Fiber Concretes, Reinforced by Low-modulus Synthetic Fibers]. Tekhnologiya i dolgovechnost' dispersno-armirovannykh betonov [Technology and Durability of Fiber Reinforced Concretes]. Leningrad, LenZNIIEP Publ., 1984, pp. 92—96.
  3. Rabinovich F.N. Kompozity na osnove dispersno-armirovannykh betonov. Voprosy teorii i proektirovaniya, tekhnologii, konstruktsii [Composites Based on Fibre Reinforced Concretes. Problems of Theory and Design, Technologies, Structures]. Moscow, ASV Publ., 2004, 560 p.
  4. Tefaruk Haktanir, Kamuran Ari, Fatih Altun, Cengiz D. Atis, Okan Karahan. Effects of Steel Fibers and Mineral Filler on the Water-tightness of Concrete Pipes. Cement and Concrete Composites. 2006, vol. 28, no. 9, pp. 811—816. DOI: 10.1016/j.cemconcomp.2006.06.002.
  5. Bhikshma V., Manipal K. Study on Mechanical Properties of Recycled Aggregate Concrete Containing Steel Fibers. Asian Journal of Civil Engineering (Building and Housing). 2012, vol. 13, no. 2, pp. 155—164.
  6. Bhikshma V., Singh J.L. Investigations on Mechanical Properties of Recycled Aggregate Concrete Containing Steel Fibers. Indian Concrete Institute Journal. 2010, no. 4—9 (10), pp. 15—19.
  7. Shah P.S., Rangan V.K. Effect of Fiber Addition on Concrete Strength. Indian Concrete Journal. 1994, vol. 5, no. 2—6, pp. 13—21.
  8. Rasheed M.H.F., Agha A.Z.S. Analysis of Fibrous Reinforced Concrete Beams. Engineering and Technical Journal. 2012, no. 30 (6), pp. 974—987.
  9. Morozov V.I., Opbul E.K. Raschet prochnosti izgibaemykh fi brozhelezobetonnykh elementov s vysokoprochnoy armaturoy bez predvaritel'nogo napryazheniya [Strength Calculation of Bending Fiber Reinforced Concrete Elements with High-strength Reinforcement without Preliminary Strain]. Doklad 62 nauchnnoy konferentsii [Report of the 62nd Scientific Conference]. Saint Petersburg, SPbGASU Publ., 2005, Part 1, pp. 210—214.
  10. RTM-17-01—2002. Rukovodyashchie tekhnicheskie materialy po proektirovaniyu i primeneniyu stalefi brobetonnykh stroitel'nykh konstruktsiy [RTM-17-01—2002. Technical Guides on Designing and Calculating Steel Fiber Reinforced Concrete Building Structures]. Moscow, 2003.
  11. Rodov G.S., Leykin B.V., Sterin V.S. Opyt primeneniya stal'nykh fibr diametrom 2 mm i fibr iz otrabotannykh trosov dlya proizvodstva zabivnykh svay: Ekspress-inform [Experience of Using Steel Fibers of 2 mm Diameter and Fibers Made of Used Wires for Producing Drive Piles: Express-Inform]. Stroitel'stvo v rayonakh Urala i Zapadniy Sibiri SSSR. Seriya: Sovershenstvovanie bazy stroitel'stva [Construction in the Regions of South Ural and Western Siberia of the USSR]. TsBNTI Publ. 1987, no. 1, pp. 31—33.

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OPERATING SAFETY OF FOUNDATIONS OF BUILDINGS AND STRUCTURES UNDER DYNAMIC IMPACT

Vestnik MGSU 5/2017 Volume 12
  • Ter-Martirosyan Armen Zavenovich - Moscow State University of Civil Engineering (National Research University) (MGSU) Doctor of Technical Sciences, Professor of the Department of Soil Mechanics and Geotechnics, Head of Research and Education Center «Geotechnics», Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.
  • Sobolev Evgeniy Stanislavovich - Moscow State University of Civil Engineering (National Research University) (MGSU) Candidate of Technical Sciences, Senior Lecturer, Department of Soil Mechanics and Geotechnics, researcher at the Research and education center «Geotechnics», Moscow State University of Civil Engineering (National Research University) (MGSU), 26 Yaroslavskoe shosse, Moscow, 129337, Russian Federation.

Pages 537-544

Ensuring the safe operation of buildings and structures of increased responsibility in complex engineering and geological conditions requires a special approach to engineering surveys and construction. When designing ground bases, it is necessary to take into account the dynamic effects of man-made or natural origin. In this case, it is necessary to provide for a complex of special studies of the foundation soils. The results of the investigations make it possible to obtain the mechanical properties of soils necessary for subsequent calculations. As a rule, calculations are performed in modern software systems by numerical simulation of the "foundation-construction" system. Forecasting the stress-strain state of the soil base, taking into account special studies of soils and numerical modeling, allows to ensure strength and stability, as well as safe operation of the proposed structure during its entire service life.

DOI: 10.22227/1997-0935.2017.5.537-544

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