Vol.7, No 1, 2009 pp. 1 - 18
UDC 624.012-3(045)
DOI: 10.2298/FUACE0901001F
DURABILITY DESIGN OF CONCRETE STRUCTURES - PART 1: ANALYSIS FUNDAMENTALS
Radomir Folić
Faculty of Technical Sciences, 21000 Novi Sad, Trg D. Obradovića 6, Serbia
E-mail: folic@uns.ac.rs
Concrete structures (CS) are designed so that they can satisfy requirements regarding safety, serviceability, durability and aesthetics throughout their design service life. Present design procedures regarding CS required by national or international codes and standards such as Model Code Euro International Committee of Concrete (1993) now Federation Internationale du Beton (FIB), Eurocodes, ACI, RILEM, etc. are predominantly based on strength principles and limit state formulation. The durability aspect is a natural extension of the classical resistance verification where deterioration effects are normally neglected. The reliability is assessed through the given performance that must be delivered within the design service life, the so-called performance-based design. This approach can be adopted for a performance based on service life design. In the recent years design is related to durability through the analysis of carbonation, resistance to chloride ingress, improved freezing and thawing resistance, etc. The review of literature and some recommendations are presented referring to the design of structures aiming to attain greater durability of CS. The accent is put on the theory of reliability, failure probability and service life probability. The basics of this analysis are given through the principles of performances and service life, and deterministic and scholastic methods using the lifetime safety factor.
Key words: Concrete structures, service life, reliability, durability, failure, deterministic analysis, stochastic analysis
PROJEKTOVANJE BETONSKIH KONSTRUKCIJA SA ASPEKTA TRAJNOSTI - DEO 1: OSNOVNE ANALIZE
Betonske konstrukcije (BK) se projektuju tako da zadovolje zahteve sigurnosti, upotrebljivosti, trajnosti i estetike u eksploatacionom veku. Aktuelni postupci proračuna BK, koji se zahtevaju nacionalnim i međunarodnim tehničkim propisima kao što su: Model propisa Evro-internacionalnog komiteta za beton (iz 1993.) sada Međunarodna federacija za beton (FIB), Evrokodovi, Američki institut za beton, RILEM (Udruženje za istraživanje materijala i konstrukcija) i dr., zasnivaju se na proveri nosivosti i graničnih stanja. Aspekt trajnosti predstavlja prirodan nastavak provere klasične otpornosti pri čemu se efekti deterioracije zanemaruju. Pouzdanost se procenjuje preko obezbeđenja performansi BK tokom eksploatacionog veka (SL), tzv. projektovanje zasnovano na performansama. Ovaj pristup se može usvojiti za neku performansu zasnovanu na projektovanju eksploatacionog veka. Poslednjih godina proračun trajnosti vezuje se za analizu karbonizacije, otpornosti na dejstvo hlorida, na naizmenično zamrzavanje i otapanje i dr. U ovom radu dat je pregled literature i nekih preporuka sa ciljem postizanja veće trajnosti BK. Naglasak je na Teoriji pouzdanosti i verovatnoći otkaza i analizi eksploatacionog veka. Prikazane su osnove ove analize koristeći princip performansi i eksploatacionog veka, i metode: deterministička, stohastička i korišćenjem faktora sigurnosti.
Ključne reči: Betonske konstrukcije, eksploatacioni vek, pouzdanost, trajnost, otkaz, analiza, deterministička, stohastička