NOVE TENDENCIJE U PROJEKTOVANJU TRAJNOSTI BETONSKIH KONSTRUKCIJA

U poslednje vreme ostvaren je značajan napredak u redefinisanju projektovanja trajnosti betonskih konstrukcija. Ovo nije samo rezultat zahteva za održivošću, već i potrebe da se preskriptivni koncept iz važećih normi zameni pristupom baziranim na performansama.

U Evrokodovima druge generacije usvojen je pristup klasa otpornosti na izloženost (ERC), definisan u EN 206-1, kao osnova za projektovanje trajnosti. ERC predstavlja klasifikacioni sistem za označavanje nivoa trajnosti i otpornosti betonskih konstrukcija na faktore sredine, u zavisnosti od njihove predviđene namene i specifičnih uslova kojima će biti izložene tokom projektnog eksploatacionog veka. Sistem obezbeđuje okvir za specificiranje prilagođenih mešavina betona na osnovu čvrstoće pri pritisku, obradivosti i kategorije izloženosti. Prednosti ovakvog pristupa su brojne: postizanje željenih nivoa zaštite čak i u agresivnim sredinama, smanjeno održavanje, poboljšana sigurnost, efikasnija upotreba materijala, kao i nove i optimizovane kombinacije projektovanja mešavina. Međutim, prelazak na specifikaciju baziranu na performansama neće biti jednostavan, ne samo zbog konzervativnosti industrije vezane za betonske konstrukcije, već i zbog nedostatka brzih i pouzdanih postupaka ispitivanja trajnosti.

Pored mešavine betona, zaštitni sloj je ključni faktor u obezbeđivanju zaštite konstrukcije, s obzirom na to da utiče na trajanje kako perioda inicijacije, tako i perioda propagacije oštećenja. U novom predlogu propisa, debljina zaštitnog sloja se određuje kao funkcija proračuna eksploatacionog veka, uz pretpostavku kompatibilnosti sa zajedničkom ciljnom pouzdanošću. Na taj način, zaštitni slojevi betona su prilagođeni u okviru ERC koncepta.

U radu je prikazan sažet pregled novih dostignuća u oblasti projektovanja trajnosti, sa posebnim osvrtom na preporuke propisa. Naglasak je dat na aspekt projektovanja zaštitnog sloja betona za trajnost..

KEYWORDS / KLJUČNE REČI: 

Trajnost; Betonske konstrukcije; Klase otpornosti na izloženost (ERC); Klase izloženosti; Zaštitni sloj betona

ACKNOWLEDGEMENT / PROJEKAT:

REFERENES / LITERATURA:

• Geiker, M.R., Hendriks, M.A.N., Elsener, B. [2021]: Durability-based design: the European perspective, Sustainable and Resilient Infrastructure, 8:2, 169-184.
• Swamy [2008]: Sustainable Concrete for the 21st Century Concept of Strength through Durability. Japan Society of Civil Engineers Concrete Committee Newsletter, 13.
• fib [2013]: fib Model Code for Concrete Structures 2010, Ernst &
• Ojha, P.N., Kaura, P., Singh, B. [2022]: Durability Design of Concrete Structures: National and international Scenario, Sustainable and Green Construction, Civil Engineering and Construction Review, April 2022.
• Folić, R. [2009]: Durability design of concrete structures – Part 1: Analysis fundamentals, FACTA Universitatis, Series: Architecture and Civil engineering, Vol. 7, No 1, pp. 1-18.
• Sarja, A., Vesikari, E. (editors) [1996]: Durability design of concrete structures, RILEM report 14, E & FN Spon.
• CEN [2021]: European Standard prEN 1990:2021. Eurocode – Basis of structural and geotechnical design, September 2021, European Committee for Standardization.
• CEN [2013, 2021]: European standard EN 206:2013 + A2:2021. Concrete – Specification, performance, production and conformity, European Committee for Standardization.
• CEN [2004]: European standard EN 1992-1-1. Eurocode 2: Design of concrete structures – Part 1.1: General rules and rules for buildings, European Committee for Standardization.
• ACI [2016]: ACI 201.2R-16: Guide to durable concrete, ACI Committee 201, American Concrete Institute.
• ACI [2017]: ACI 365.1R-17: Report on service life prediction, ACI Committee 365, American Concrete Institute.
• fib [2006]: Model Code for Service Life Design, Bulletin 34, Federation international du beton (fib), February 2006, Switzerland.
• fib [2013]: fib Model Code for concrete structures 2010, Ernst & Sohn, October
• fib [2016]: Partial factor methods for existing concrete structures, Recommendation, Task group 3.1, Federation international du beton (fib), December 2016.
• Pivot Engineers [2020]: Literature review of concrete durability and service life requirements in global codes and standards, Submitted in fulfilment of ACI Foundation agreement 7-18-18, 10 August 2020.
• Helland, S. [2022]: The implementation of a performance and probabilistic based durability concept in revised European concrete standards, Key note, fib Congress, Oslo 2022.
• Hooton, R.D. [2019]: Future directions for design, specification, testing, and construction of durable concrete structures, Cement and Concrete Research 124 (2019).
• Horakova, A., Broukalova, I., Kohoutkova, A., Vaskova, J. [2017]: Sustainability and durability analysis of reinforced concrete structures, IOP Conference Series: Materials Science and Engineering, Volume 246, FIBRE CONCRETE 2017 13–16 September 2017, Prague, Czech Republic.
• Alexander, M., Bentur, A., Mindess, S. (editors) [2017]: Durability of Concrete – Design and construction, Modern concrete technology Series 20, Taylor & Francis.
• Helland, S. [2012]: Design for service life: implementation of fib Model Code 2010 rules in the operational code ISO 16204, Structural Concrete, Journal of the fib, Volume 14, March 2013.
• CEN [2023]: European Standard FprEN 1992-1-1:2023. Eurocode 2 – Design of concrete structures – Part 1-1: General rules and rules for buildings, bridges and civil engineering structures, April 2023, European Committee for Standardization.
• CEN [2023]: Background document to FprEN 1992-1-1:2023-04, Formal-Vote-Draft: Eurocode 2 – Design of concrete structures – Part 1-1: General rules and rules for buildings, bridges and civil engineering structures, CEN/TC 250/SC 2 N2087, March 2023.
• Folić, R., Stojković, N., Brujić, Z. [2022]: Service life and durability of concrete structure – sustainable construction, Proceedings, GNP 2022, University of Montenegro, Kolašin, March 2022, pp. 445-454.
• CEN [2021]: European standard prEN 206-100 (draft 10). Concrete – Specification, performance, production and conformity. European Committee for Standardization.
• Moraru, C., Adelina, A., Dan, G. [2020]: Freeze-thaw resistance classes of concretes, Romanian Journal of Transport Infrastructure, Vol.9, 2020, No.2.
• CEN [2009]: EN 13670: Execution of concrete structures, European Committee for
• Folić, R. Brujić, Z.: New tendencies in designing durabilty of concrete structures, Maced. Assoc. of Struct. Enginiers, 20th Symposium „Resilient structures“, 28-29. September 2023..
• A. Behnia, H.K Chai, M. Yorikawa, S. Momoki, M. Terazawa, and T. Shiotani, Integrated non-destructive assessment of concrete structures under flexure by acoustic emission and travel time tomography, Construction and Building Materials, 2014, vol. 67, pp.202–215