DESIGNING AND DETAILING OF BUILDING SYSTEMS. MECHANICS IN CIVIL ENGINEERING

Methods of calculating the bearing capacity of eccentrically compressed concrete elements and suggestions for its improvement

Vestnik MGSU 3/2014
  • Starishko Ivan Nikolaevich - Vologda State University (VoGTU) Candidate of Technical Sciences, Associate Professor, Department of Motor Roads, Vologda State University (VoGTU), 15 Lenina str., Vologda, 160000, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 107-116

The proposed calculation method is specific in terms of determining the carrying capacity of eccentrically compressed concrete elements, in contrast to the calculation by error method, as in the existing regulations, where in the result of the calculation is not known what is the limit load the eccentric compression element can withstand. The proposed calculation method, the publication of which is expected in the next issue of the "Vestnik MGSU" the above mentioned shortcomings of the existing calculation methods, as well as the shortcomings listed in this article are eliminated, which results in the higher convergence of theoretical and experimental results of eccentrically compressed concrete elements strength and hence a high reliability of their operation.

DOI: 10.22227/1997-0935.2014.3.107-116

References
  1. SNiP 2.03.01—84*. Betonnye i zhelezobetonnye konstruktsii [Construction Norms and Regulations 2.03.01—84*. Concrete and Reinforced Concrete Structures]. Moscow, 2002, 76 p.
  2. SP 52-101—2003. Betonnye i zhelezobetonnye konstruktsii bez predvaritel'nogo napryazheniya armatury [Regulations 52-101—2003. Concrete and Reinforced Concrete Structures without Prestress of the Reinforcement]. Moscow, 2004, 53 p.
  3. Posobie po proektirovaniyu betonnykh i zhelezobetonnykh konstruktsiy iz tyazhelykh i legkikh betonov bez predvaritel'nogo napryazheniya armatury (k SNiP 2.03.01—84) [Guidebook on Concrete and Reinforced Concrete Structures Design Made of Heavy and Light Concretes without Prestress of the Reinforcement (to Construction Norms and Regulations 2.03.01—84)]. TsNIIPromzdaniy, NIIZhB Publ. Moscow, Stroyizdat Publ., 1986, 192 p.
  4. Posobie po proektirovaniyu betonnykh i zhelezobetonnykh konstruktsiy iz tyazhelogo betona bez predvaritel'nogo napryazheniya armatury (k SP 52-101—2003) [Guidebook on Concrete and Reinforced Concrete Structures Design Made of Heavy Concrete without Prestress of the Reinforcement (to Regulations 52-101—2003]. Moscow, TsNIIPromzdaniy Publ., 2005, 214 p.
  5. Baykov V.N., Sigalov E.E. Zhelezobetonnye konstruktsii. Obshchiy kurs [Reinforced Concrete Structures. Guidelines]. 6th edition. Moscow, BASTET Publ., 2009, 766 p.
  6. Bondarenko V.M., Bakirov R.O., Nazarenko V.G., Rimshin V.I. Zhelezobetonnye i kamennye konstruktsii [Reinforced Concrete and Masonry Structures]. 5th edition. Moscow, Vysshaya shkola Publ., 2008, 886 p.
  7. Tal' K.E., Chistyakov E.A. Issledovanie nesushchey sposobnosti gibkikh zhelezobetonnykh kolonn, rabotayushchikh po pervomu sluchayu vnetsentrennogo szhatiya [Research of the Bearing Capacity of Bending Reinforced Concrete Columns, Working on the First Case of Eccentric Compression]. Raschet zhelezobetonnykh konstruktsiy: trudy NIIZhB [Reinforced Concrete Structures Calculation: Works of the Scientific and Research Institute of Concrete and Reinforced Concrete]. Moscow, Gosstroyizdat Publ., 1963, no. 23, pp. 127—196.
  8. Chistyakov E.A. Osnovy teorii, metody rascheta i eksperimental'nye issledovaniya nesushchey sposobnosti szhatykh zhelezobetonnykh elementov pri staticheskom nagruzhenii: dissertatsiya doktorara tekhnicheskikh nauk [Fundamentals of the Theory, Calculation Methods and Experimental Research of the Bearing Capacity of the Compressed Reinforced Concrete Elements in Case of Static Loading. Dissertation of the Doctor of Technical Sciences]. Moscow, 1988, pp. 73—155.
  9. Baykov V.N., Gorbatov S.V. Nekotorye predposylki k raschetu zhelezobetonnykh elementov pri deystvii vnetsentrennogo szhatiya i poperechnogo izgiba v ortogonal'nykh ploskostyakh [Some Prerequisites to the Reinforced Concrete Elements Calculation under the Action of Eccentric Compression and Lateral Bending in Orthogonal Planes]. Zhelezobetonnye konstruktsii promyshlennogo i grazhdanskogo stroitel'stva: sbornik trudov Moskovskogo inzhenerno-stroitel'nogo instituta im. V.V. Kuybysheva [Reinforced Concrete Structures of Industrial and Civil Engineering: Collection of the Works of Moscow Engineering and Construction Institute named after V.V. Kuybyshev]. Moscow, 1981, no. 185, pp. 95—99.
  10. Rudakov V.N. Povyshenie nadezhnosti elementov konstruktsiy pri osevom i radial'nom szhatii [Raising the Reliability of the Structure's Elements in Case of Axial Compression and Radial Compression]. Ekspluatatsiya i remont zdaniy i sooruzheniy gorodskogo khozyaystva: sbornik nauchykh trudov [Operation and Repairs of the Buildings of the Municipal Services]. Kiev, ICDO Publ., 1994, pp. 157—165.
  11. Veretennikov V.I., Bulavitskiy M.S. Utochnenie kriteriya massivnosti sterzhnevykh elementov iz tyazhelogo betona s uchetom izmeneniya ikh masshtabnogo faktora k nachalu ekspluatatsii zdaniy i sooruzheniy [Refi nement of the Solidness Criteria of the Axial Elements Made of Heavy Concrete with Account for their Size Factor Change before the Beginning of the Buildings and Structures Operation]. Beton i zhelezobeton [Concrete and Reinforced Concrete]. 2013, no. 1, pp. 27—30.
  12. Bulavytskyi M., Veretennykov V., Dolmatov A. Technological Factors, Arising under Vertical Members of the Skeleton-type In-situ Buildings Production and Infl uence of Some Onto Strength and Deformation Characteristics of Concrete. Beton — zhizneutverzhdayushchiy vybor stroitel'stva: sbornik dokladov 7-go Mezhdunarodnogo Kongressa [Concrete — Reassuring Choice of Construction: Collection of the Reports of the 7th International Congress]. Dundee, Scotland, 8-10 July 2008, p. 10.
  13. Veretennikov V.I., Bulavits'kiy M.S. Doslidzhennya neodnoridnosti betonu po ob’ºmu vertikal'nikh monolitnikh elementiv [Research of Concrete Inhomogeniety in Size of the Vertical Monolithic Elements]. Resursoekonomni materiali, konstruktsi¿, budivli ta sporudi: zbirnik naukovikh prats' [Resource Saving Materials, Constructions, Buildings and Structures: Collection of Scientific Works]. Rovno, 2008, no. 18 part 1. Nats. univ. vodnogo gospodarstva ta prirodokoristuvannya Publ., p. 142—147.
  14. Veretennykov V.I., Yugov A.M., Dolmatov A.O., Bulavytskyi M.S., Kukharev D.I., Bulavytskyi A.S. Concrete Inhomogeneity of Vertical Cast-in-Place Elements in Skeleton-Type Buildings. Proceedings of the 2008 Architectural Engineering National Conference “Building Integration Solutions”. September 24-27, 2008, Denver, Colorado, USA., AEI of the ASCE.
  15. Starishko I.N. Varianty i sluchai, predlagaemye dlya raschetov vnetsentrenno szhatykh elementov [Variants and Cases, Offered for the Calculations of the Eccentric Compressed Elements]. Beton i zhelezobeton [Concrete and Reinforced Concrete]. 2012, no. 3, pp. 14—20.
  16. Starishko I.N. Sovershenstvovanie teorii raschetov vnetsentrenno szhatykh zhelezobetonnykh elementov putem sovmestnogo resheniya uravneniy, otrazhayushchikh ikh napryazhenno-deformirovannoe sostoyanie [Improving Theory of Eccentrically Compressed Concrete Elements Calculations by Solving the Equations that Refl ect their Stress-strain State]. Vestnik grazhdanskikh inzhenerov [Proceedings of Civil Engineers]. 2012, no. 5(34), pp. 72—81.
  17. Toryanik M.S., editor. Primery rascheta zhelezobetonnykh konstruktsiy [Examples of the Calculation of Reinforced Concrete Structures]. Moscow, Stroyizdat Publ., 1979, 240 p.

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Constructing a deformation diagram of uniaxially compressed concrete

Vestnik MGSU 6/2015
  • Rimshin Vladimir Ivanovich - Moscow State University of Civil Engineering (MGSU) Doctor of Technical Sciences, Professor, corresponding member of Russian Academy of Architecture and Construction Sciences, Department of Housing and Utility Complex, 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 .
  • Krishan Anatoliy Leonidovich - Nosov Magnitogorsk State Technical University (MGTU) Doctor of Technical Sciences, Professor, chair, Department of postgraduate student, Department of Building and Engineering Structures Design, Nosov Magnitogorsk State Technical University (MGTU), 38 Prospekt Lenina, Magnitogorsk, Chelyabinsk Region, 455000, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Mukhametzyanov Al’bert Il’darovich - Nosov Magnitogorsk State Technical University (MGTU) student, Department of Building and Engineering Structures Design, Nosov Magnitogorsk State Technical University (MGTU), 38 Prospekt Lenina, Magnitogorsk, Chelyabinsk Region, 455000, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 23-31

At the present time the nonlinear deformation model based on deformation diagrams of the materials is believed to be the most promising for estimation of stress-strain state of reinforced concrete elements at different stages of their compression: before crack formation, in the process of crack formation, at the stage of cracked element operation, at destruction stage. Reliability of estimates depends largely on accuracy of analytical description of curvilinear diagram of concrete deformation. On the other hand we should remember that the calculated construction may be subject to different loading modes: short-term, long-term or competitive. In this regard the universal character is required from the used deformability diagrams. They should be easily transformed for calculation with different modes.The authors suggest methods of constructing such a deformation diagram using elasticity coefficient. Using the corresponding elasticity coefficients in calculations it is possible to account for different loading modes of structures (for example long-term loading). Such an analytical representation of concrete deformation diagram is more generalpurpose as compared to dependence on European standards.

DOI: 10.22227/1997-0935.2015.6.23-31

References
  1. Kaklauskas G., Ghaboussi J. Stress Strain Relations for Cracked Tensile Concrete from RC Beam Tests. ASCE Journal of Structural Engineering. January 2001, vol. 127, no. 1, pp. 64—73. DOI: http://dx.doi.org/10.1061/(ASCE)0733-9445(2001)127:1(64).
  2. Raue E. Non-linear Analysis of Composite Cross-Sections by Non-Linear Optimization. Modern Building Materials, Structures and Techniques. Abstracts of 9th Int. Conf. held in Vilnius on May 16—18, 2007. Vilnius, Technika, 2007, p. 434.
  3. Smith G., Young L. Ultimate Theory in Flexure by Exponential Function. Journal ACI. 1955, vol. 52, no. 11, pp. 349—359. DOI: http://dx.doi.org/10.14359/11605.
  4. Liebenderg A.C. Stress-Strain Function for Concrete Subjected to Short-Term Loading. Mag. of Concrete Research. 1962, vol. 14, no. 41, pp. 85—90. DOI: http://dx.doi.org/10.1680/macr.1962.14.41.85.
  5. Saennz L.P. Discussion of Equation to the Stress-Strain Curvier of Concrete By P. Desai and S. Krishnan. ACI Journal Proc. 1964, vol. 61, no. 9, pp. 1229—1235.
  6. Sinha B., Cerstle K., Tulin L. Stress-Strain Relations for Concrete under Cyclic Loading. Journal ACI. 1964, vol. 61, no. 2, pp. 195—211. DOI: http://dx.doi.org/10.14359/7775.
  7. Shah S., Winter G. Inelastic Behavior and Fracture of Concrete. Journal ACI. 1968, vol. 20, pp. 5—28.
  8. Bachinskiy V.Ya., Bambura A.N., Vatagin S.S. Svyaz’ mezhdu napryazheniyami i deformatsiyami betona pri kratkovremennom neodnorodnom szhatii [Connection between Stresses and Deformations of Concrete at Short-term Non-uniform Compression]. Beton i zhelezobeton [Concrete and Reinforced Concrete]. 1984, no. 10, pp. 18—19. (In Russian)
  9. Balan T.A. Model’ deformirovaniya betona pri kratkovremennom mnogoosnom nagruzhenii [Concrete Deformation Model at Short-Term Multiaxial Loading]. Stroitel’naya mekhanika i raschet sooruzheniy [Structural Mechanics and Calculation of Structures]. 1986, no. 4, pp. 32—36. (In Russian)
  10. Baykov V.N., Dodonov M.I., Rastorguev B.S., Frolov A.K., Mukhamediev T.A., Kunizhev V.Kh. Obshchiy sluchay rascheta prochnosti elementov po normal’nym secheniyam [Common Case of Strength Calculation of Elements Across Normal Sections]. Beton i zhelezobeton [Concrete and Reinforced Concrete]. 1987, no. 5, pp. 16—18. (In Russian)
  11. Krol’ I.S. Empiricheskoe predstavlenie diagramm szhatiya betona (obzor literaturnykh istochnikov) [Empiric Presentation of Concrete Compression Diagrams]. Issledovanie v oblasti mekhaniki izmereniy [Investigation in the Field of Measurement Mechanics]. Moscow, VNIIFTRI Publ., 1971, no. 8 (38), pp. 306—326. (In Russian)
  12. Zidonis I. A Simple-To-Integrate Formula of Stress as a Function of Strain in Concrete and Its Description Procedure. Mechanica. 2007, no. 4 (66), pp. 23—30.
  13. Židonis I. Strength Calculation Method for Cross-Section of Reinforced Concrete Flexural Member Using Curvilinear Concrete Stress Diagram of EN-2. 11th International Conference on Modern Building Materials, Structures and Techniques. MBMST 2013. Procedia Engineering. 2013, vol. 57, pp. 1309—1318. DOI: http://dx.doi.org/10.1016/j.proeng.2013.04.165.
  14. Murashkin G.V., Mordovskiy S.S. Primenenie diagramm deformirovaniya dlya rascheta nesushchey sposobnosti vnetsentrenno szhatykh zhelezobetonnykh elementov [Using Deformation Diagrams for Bearing Capacity Calculation of Off-Center Compressed Reinforced Concrete Elements]. Zhilishchnoe stroitel’stvo [Housing Construction]. 2013, no. 3, pp. 38—40. (In Russian)
  15. Karpenko N.I. Obshchie modeli mekhaniki zhelezobetona [General Models of Reinforced Concrete Mechanics] Moscow, Stroyizdat Publ., 1996, 416 p. (In Russian)
  16. Karpenko N.I., Karpenko S.N., Petrov A.N., Palyuvina S.N. Model’ deformirovaniya zhelezobetona v prirashcheniyakh i raschet balok-stenok i izgibaemykh plit s treshchinami [Reinforced Concrete Deformation Model in Incrementations and Calculations of Deep Beams and Bendable Plates with Cracks]. Petrozavodsk, PetrGU Publ., 2013, 156 p. (In Russian)
  17. Krishan A.L., Astaf’eva M.A., Narkevich M.Yu., Rimshin V.I. Opredelenie deformatsionnykh kharakteristik betona [Defining Deformation Properties of Concrete]. Estestvennye i tekhnicheskie nauki [Natural and Engineering Sciences]. 2014, no. 9—10 (77), pp. 367—369. (In Russian)
  18. Krishan A.L., Astaf’eva M.A., Rimshin V.I. Predel’nye otnositel’nye deformatsii tsentral’no szhatykh zhelezobetonnykh elementov [Ultimate Relative Strains of Axially Loaded Reinforced Concrete Elements]. Estestvennye i tekhnicheskie nauki [Natural and Engineering Sciences]. 2014, no. 9—10 (77), pp. 370—372. (In Russian)
  19. Krishan A.L., Zaikin A.I., Mel’nichuk A.S. Raschet prochnosti trubobetonnykh kolonn [Strength Calculation of Tube Confined Concrete Columns]. Stroitel’naya mekhanika inzhenernykh konstruktsiy i sooruzheniy [Construction Mechanics of Engineering Structures and Constructions]. 2010, no. 1, pp. 20—25. (In Russian)

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Monolithic construction in the Republic of Bashkortostan: from theory to practice

Vestnik MGSU 10/2013
  • Bedov Anatoliy Ivanovich - Moscow State University of Civil Engineering (National Research University) (MGSU) Candidate of Technical Sciences, Professor, Department of Reinforced Concrete and Masonry Structures, 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 .
  • Babkov Vadim Vasil’evich - Ufa State Petroleum Technological University (UGNTU) Doctor of Technical Sciences, Professor, Department of Building Structures, Ufa State Petroleum Technological University (UGNTU), Office 225, 195 Mendeleeva St., Ufa, 450062, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Gabitov Azat Ismagilovich - Ufa State Petroleum Technological University (USPTU) Doctor of Technical Sciences, Professor, Department of Building Structures, Ufa State Petroleum Technological University (USPTU), 195 Mendeleeva str., Ufa, 450062, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Sakhibgareev Rinat Rashidovich - Ufa State Petroleum Technological University (UGNTU) Doctor of Technical Sciences, Associate Professor, Department of Building Structures, Ufa State Petroleum Technological University (UGNTU), Office 225, 195 Mendeleeva St., Ufa, 450062, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Salov Aleksandr Sergeevich - Ufa State Petroleum Technological University (USPTU) Candidate of Technical Sciences, Associate Professor, Department of Highways and Technology of Construction Production, Ufa State Petroleum Technological University (USPTU), 195 Mendeleeva str., Ufa, 450062, Russian Federation; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 110-121

In the article the dependences of concrete compression strength from fluidity of concrete and water cementitious ratio for non-modified and modified concrete with superplasticizing and organo-mineral admixtures are cited and analyzed. The problems of application efficiency assessment of concrete and reinforcing steel of high classes of strength in reinforced concrete elements are examined. Calculating algorithms are presented with the use of an economic-mathematical method, which allow to improve calculation and designing of a monolithic reinforced concrete framework. Results of the researches are applied in the process of designing some objects in Ufa. The article presents design solutions using concrete and reinforcing steel of higher strength classes.The co-authors present the generalizing approach to the solution of the problems of optimized application of high-strength concrete and efficient armature classes in bendable ferroconcrete elements. The decision is made by the criteria of reducing reinforced concrete and concrete consumption.The methods of analysis offered and developed by the authors are widely used in the Republic of Bashkortostan and allow to reveal effective fields of application of the effective classes of concrete and reinforcement steel in reinforced concrete elements with evaluating expediency at the design stage and in order to estimate their efficiency. That is especially important in the process of choosing modified concrete and modern steel for building frame and monolithic structures.

DOI: 10.22227/1997-0935.2013.10.110-121

References
  1. Braun V. Raskhod armatury v zhelezobetonnykh elementakh [Consumption Rate of Reinforcing Steel in Reinforced Concrete Elements]. Moscow, Stroyizdat Publ., 1993, 144 p.
  2. Shah S.P., Ahmad S.H. High Performance Concrete: Properties and Applications. McGraw-Hill, Inc., 1994, 403 p.
  3. Balageas D., Fritzen C.P., Guemes A. Structural Health Monitoring. ISTE Ltd, London, 2006, 496 p.
  4. Posobie po proektirovaniyu betonnykh i zhelezobetonnykh konstruktsiy iz tyazhelogo betona bez predvaritel’nogo napryazheniya armatury (k SP 52-101—2003) [Handbook of Design of Concrete and Reinforced Concrete Structures Made of Heavy Concrete without Prestressing of the Reinforcement (based on Construction Rules 52-101—2003)]. TsNIIPromzdaniy [Central Scientific and Research Institute of Industrial Buildings]. Moscow, 2005, 214 p.
  5. Kaprielov S.S., Travush V.I., Karpenko N.I., Sheynfel'd A.V. and others. Modifitsirovannye betony novogo pokoleniya v sooruzheniyakh MMDTs «Moskva-Siti». Chast' I [New Generation of Modified Concrete in the Buildings of "Moscow-City". Part 1]. Stroitel'nye materialy [Building materials]. 2006, no. 10, pp. 13—17.
  6. Beddar M. Fiber Reinforced Concrete: Past, Present and Future. Scientific works of the 2nd International Conference on Concrete and Reinforced Concrete. 2005, vol. 3. pp. 228—234.
  7. Salov A.S., Babkov V.V., Sakhibgareev R.R. Raschet effektivnogo raskhoda armaturnoy stali dlya variantnogo secheniya izgibaemogo zhelezobetonnogo elementa: Svidetel’stvo o gosudarstvennoy registratsii programmy dlya EVM ¹ 2010610325 [Calculation of Efficient Consumption of Reinforcing Steel for Varying Sections of a Bendable Reinforced Concrete Element: Certificate of State Registration of Software Program no. 2010610325]. Right holder: Ufa State Petroleum Technological University. Patent application filed: 17.11.2009; Patent registered: 11.01.2010.
  8. Bedov A.I., Babkov V.V., Gabitov A.I., Salov A.S. Ispol'zovanie betonov i armatury povyshennoy prochnosti v proektirovanii sbornykh i monolitnykh zhelezobetonnykh konstruktsiy [Use of Heavy Duty Concretes and Reinforcement in Design of Prefabricated and Monolithic Reinforced Concrete Structures]. Vestnik MGSU [Proceedings of Moscow State University of Civil Engineering]. 2012, no. 8, pp. 76—84.
  9. Ovchinnikov I.I., Migunov V.N. Dolgovechnost' zhelezobetonnoy balki v usloviyakh khloridnoy agressii [Durability of a Reinforced Concrete Beam under Conditions of Chloride Aggression]. Stroitel'nye materialy [Building materials]. 2012, no. 9, pp. 61—67.
  10. Eksperimental'nye issledovaniya prostranstvennoy raboty stalezhelezobetonnykh konstruktsiy [Experimental Research of Three-dimensional Performance of Composite Steel and Concrete Structures]. Vestnik MGSU [Proceedings of Moscow State University of Civil Engineering]. 2012, no. 12, pp. 53—60.
  11. Ses'kin I.E., Baranov A.S. Vliyanie superplastifikatora S-3 na formirovanie prochnosti pressovannogo betona [Influence of Superplasticizer C-3 on the Formation of the Pressed Concrete Strength]. Stroitel'nye materialy [Building materials]. 2013, no. 1, pp. 32—33.
  12. Bazhenov Yu.M., Lukuttsova N.P., Karpikov E.G. Melkozernistyy beton, modifitsirovannyy kompleksnoy mikrodispersnoy dobavkoy [Fine-grained Concrete Modified by Integrated Mikro-dispersive Additive]. Vestnik MGSU [Proceedings of Moscow State University of Civil Engineering]. 2013, no. 2, pp. 94—100.
  13. Andreev V.I., Barmenkova E.V. Raschet dvukhsloynoy plity na uprugom osnovanii s uchetom sobstvennogo vesa [Calculation of a Two-layer Slab Bending on an Elastic Basis with Consideration of Dead Weight]. Computational Civil and Structural Engineering. 2010, vol. 6, no. 1—2, pp. 33—38.
  14. Panibratov Yu.P., Seko E.V., Balberov A.A. Ekonomicheskaya otsenka rezul'tatov energosberegayushchikh meropriyatiy v stroitel'stve [Economic Evaluation of Energy Saving Measures in Construction]. Academia. Arkhitektura i stroitel'stvo [Architecture and Construction]. 2012, no. 2, pp. 123—127.

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ESTIMATES OF PRESTRESS LOSSES AND FORCES SCATTER IN REINFORCEMENT OF SPAN REINFORCED CONCRETE STRUCTURES

Vestnik MGSU 6/2018 Volume 13
  • Ahaieva Olha - Odessa State Academy of Civil Engineering and Architecture (OSACEA) , Odessa State Academy of Civil Engineering and Architecture (OSACEA), 4 Didrikhsona st., Odessa, 65029, Ukraine.
  • Karpiuk Vasyl - Odessa State Academy of Civil Engineering and Architecture (OSACEA) , Odessa State Academy of Civil Engineering and Architecture (OSACEA), 4 Didrikhsona st., Odessa, 65029, Ukraine.

Pages 686-696

Subject: the article is devoted to investigation of prestress losses and force distribution in the reinforcement of span reinforced concrete structures. As the long-term studies have shown, these quantities are very unstable, which should be taken into account in structures design. However, the existing normative documents take into account the possible deviations of losses and forces in prestressed reinforcement from their design values in a fairly general form. Since each of the types of losses, according to the formulas, depends on one or several random factors, they should be considered from a probabilistic point of view. Research objectives: determine the scattering of different losses and acting forces in the prestressed reinforcement to identify the factors affecting its value. Materials and methods: in this work, we used the normative technique of prestress losses calculation and characteristics of the variability of physical and mechanical properties of concrete and reinforcement, obtained from the previous studies. The distribution laws of investigated parameters were assumed to be normal (the Gaussian law). To calculate the coefficients of variation, the method of statistical testing (the Monte-Carlo method) and the linearization method (the Taylor series expansion) implemented in MATLAB software package were applied. Results: in the process of numerical experiment, the values of prestress losses and forces scatter in the reinforcement were obtained for all prestressing methods stipulated by the current design codes. It was established that both values depend significantly on the method of reinforcement tensioning, its type and class, and also on the diameter of wire. Moreover, many concomitant factors affect the variability of the above-mentioned characteristics such as the plant-manufacturer, stability of technological process, qualification of the service staff, etc. Conclusions: the obtained data is recommended to be used to determine the accurate values of strength, deformability and crack resistance of span reinforced concrete structures as well as in probabilistic calculations related to the assessment of their reliability by various limit states. In particular, the described technique was applied in calculating the reliability of bent prestressed elements from the viewpoint of strength of oblique sections.

DOI: 10.22227/1997-0935.2018.6.686-696

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