A tapadás hatása feszített vasbeton szerkezeti elemek erőtani viselkedésére (Influence of bond on the structural behaviour of prestressed concrete members)

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Nyilvántartási szám: 
18/69
Témavezető neve: 
Témavezető e-mail címe:
kovacs.tamas@emk.bme.hu
A témavezető teljes publikációs listája az MTMT-ben:
A téma rövid leírása, a kidolgozandó feladat részletezése: 

Composite action between concrete and embedded reinforcement is ensured by bond developing on the interface during the hardening process of concrete. Crack formulation and size and the consequent deformation of the whole member, anchorage of reinforcing bars as well as transfer of prestress from tendons to concrete are all governed by force transfer between reinforcement and concrete that is fundamentally affected by bond. Bond is physically described and can be characterized by the local bond stress-slip (b-s) relationship influenced not only by the surface and mechanical properties of the contacting materials, time dependency of their long-term deformation and degradation due to environmental exposure but also the cyclic character of loading and many other parameters. Although several local bond stress-slip models have been elaborated for ribbed reinforcing bars by deeply investigating its influencing parameters, surprisingly low number of experimental-based data are available in the literature on the bond behaviour of steel prestressing strands and especially of group of strands irrespectively of their wide use in the prefabrication industry. From analysis point of view bond is very rarely represented in numerical models of recent time; usually full bond (i.e. no slip) on the bar-concrete interface is assumed. Similarly to that, the available analytical procedures focusing on crack- and anchorage-related parameters consider bond in a relatively simple way. The aim of the current research is the elaboration of local bond stress-slip models for prestressing strands and for group of strands as well as their application in describing bond-sensitive processes (transfer of prestress, stress distribution and splitting of prestressed beam ends, cracking) of pre-tensioned concrete members. The PhD research shall complete an extensive literature review based on which a comparative analysis of existing bond models should be carried out especially focusing on classification, limits of applicability and level of standardization. The proposed research methodology includes: (i) experimental description of local bond stress-slip law on strands and group of strands by existing standardized or appropriately improved bond tests, (ii) numerical 3D modelling of bond (development of both surface and interface models), (iii) improvement of available calculation methods for pre-tensioned members based on bond as governing effect.

A téma meghatározó irodalma: 
    1. Tepfers, R. (1973) A Theory of Bond Applied to Overlapped Tensile Reinforcement Splices for Deformed Bars, Doctoral Thesis, Work No. 723, Publ. 73:2, Division of Concrete Structures, Chalmers University of Technology, Göteborg
    2. Gambarova, P., Giuriani, E. (1985) Fracture mechanics of bond in reinforced concrete, Journal of Structural Engineering, ASCE, Vol. 111.
    3. Reinhardt, H.W., Balázs, G.L. (1995) Steel-concrete interfaces: Experimental aspects, Mechanics of Geometrical Interfaces, (Ed.: Selvadurai, A.P.S. and Boulon, M.J.), Studies in Applied Sciences, Vol. 42., Elsevier
    4. Eligehausen, R., Bigaj, A. (2009) Bond behaviour and models, fib Bulletin 51 Structural Concrete, Textbook on behaviour, design and performance, Vol. 1, pp. 225-252.
    5. Bond and anchorage of embedded reinforcement: Backgrounf to the fib Model Code for Concrete Structures 2010 (2014) International Federation for Structural Concrete (fib), Lausanne, Switzerland
    6. Lachemi, M., Bae, S., Hossain. K.M.A., Sahmaran, M. (2009) Steel–concrete bond strength of lightweight self-consolidating concrete, Materials and Structures, Vol. 42 (7), pp. 1015–1023.
    7. Dybeł, P., Furtak, K. (2017) The influence of high-strength concrete – rebars bond conditions on the mechanism of its failure, Magazine of Concrete Research, Vol. 69 (4), pp. 163–174.
    8. Mancini, G., Carbone, V.I., Bertagnoli, G., Gino, D. (2017) Reliability‐based evaluation of bond strength for tensed lapped joints and anchorages in new and existing reinforced concrete structures, Structural Concrete, Vol. 19 (3), pp. 904-917.
A téma hazai és nemzetközi folyóiratai: 
    1. Vasbetonépítés, Concrete Structures
    2. Építés – Építészettudomány 
    3. Periodica Polytechnica Civil Engineering
    4. Structural Concrete
    5. Materials and Structures
    6. Engineering Structures
    7. Construction and Building Materials
    8. Journal of Materials in Civil Engineering
    9. Materials and Structures
    10. Magazine of Concrete Research
A témavezető utóbbi tíz évben megjelent 5 legfontosabb publikációja: 
    1. Kovács, T. (2010) Effect of deterioration-induced cracks on the modal properties of concrete beams, Proc. disk of The Third Int. fib Congress and Exhibition „Think globally, Build Locally”, ID 628, Washington, USA, May 29-June 2
    2. Kovács, T., Laczák, L. (2012) Integration of deck and pavement for superstructures of concrete bridges to reduce life-cycle cost, Concrete Structures, Vol.13., Special issue for fib 2012 Stockholm Symposium,  Budapest, pp. 54-60.
    3. Nagy R., Borosnyói A., Kovács T. (2013) Feszültségeloszlás modellezése fiatal betonban, Vasbetonépítés, XV. évf., 2013/4, Budapest, pp.105-111.
    4. Gulyás G., Kovács T., Nemes R. (2014) Feszítőpászma tapadása nagyszilárdságú normál- és könnyűbetonokban, Építés - Építészettudomány, 42 (3-4), Akadémiai Kiadó, Budapest, pp. 261-280., DOI: 10.1556/EpTud.42.2014.3-4.8
    5. Kovács, T., Nemes, R. (2015) Bond between strands and high-strength lightweight aggregate concrete, Innovative Concrete Technology in Practice, Proceedings of The 11th Central European Congress on Concrete Engineering (CCC2015), Hainburg, Austria, October 1-2, 2015 (365 p.), Austrian Society for Construction Technology, www.CCC2015.at, pp. 355-359. (ISBN 978-3-9502387-2-3)
A témavezető fenti folyóiratokban megjelent 5 közleménye: 
    1. Kovács, T., Farkas, Gy. (2002) Effect of cracking on the dynamic characteristics of concrete beams, Concrete Structures, Vol.3, Special issue for fib 2002 Osaka Congress, 2002, Budapest, pp. 64-69.
    2. Kovács, T., Farkas, Gy. (2005) Condition monitoring of a lightly reinforced concrete beam by dynamic measurements, Periodica Polytechnika Ser. Civ. Eng., Vol.49, No.1, pp. 27-46.
    3. Kovács, T., Laczák, L. (2012) Integration of deck and pavement for superstructures of concrete bridges to reduce life-cycle cost, Concrete Structures, Vol.13., Special issue for fib 2012 Stockholm Symposium,  Budapest, pp. 54-60.
    4. Nagy R., Borosnyói A., Kovács T. (2013) Feszültségeloszlás modellezése fiatal betonban, Vasbetonépítés, XV. évf., 2013/4, Budapest, pp. 105-111.
    5. Gulyás G., Kovács T., Nemes R. (2014) Feszítőpászma tapadása nagyszilárdságú normál- és könnyűbetonokban, Építés - Építészettudomány, 42 (3-4), Akadémiai Kiadó, Budapest, pp. 261-280., DOI: 10.1556/EpTud.42.2014.3-4.8
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A témavezető eddigi doktoranduszai

Alkurdi Zaher (2020//)
Státusz: 
elfogadott