Time-Dependent Reliability Analysis of Reinforced Concrete Beams Subjected to Uniform and Pitting Corrosion and Brittle Fracture

Abstract

Reinforced concrete (RC) beams are basic elements used in the construction of various structures and infrastructural systems. When exposed to harsh environmental conditions, the integrity of RC beams could be compromised as a result of various deterioration mechanisms. One of the most common deterioration mechanisms is the formation of different types of corrosion in the steel reinforcements of the beams, which could impact the overall reliability of the beam. Existing classical reliability analysis methods have shown unstable results when used for the assessment of highly nonlinear problems, such as corroded RC beams. To that end, the main purpose of this paper is to explore the use of a structural reliability method for the multi-state assessment of corroded RC beams. To do so, an improved reliability method, namely the three-term conjugate map (TCM) based on the first order reliability method (FORM), is used. The application of the TCM method to identify the multi-state failure of RC beams is validated against various well-known structural reliability-based FORM formulations. The limit state function (LSF) for corroded RC beams is formulated in accordance with two corrosion types, namely uniform and pitting corrosion, and with consideration of brittle fracture due to the pit-to-crack transition probability. The time-dependent reliability analyses conducted in this study are also used to assess the influence of various parameters on the resulting failure probability of the corroded beams. The results show that the nominal bar diameter, corrosion initiation rate, and the external loads have an important influence on the safety of these structures. In addition, the proposed method is shown to outperform other reliability-based FORM formulations in predicting the level of reliability in RC beams.

Developing a Fuzzy Expert System for Diagnosing Chemical Deterioration in Reinforced Concrete Structures

“…The study highlighted the importance of considering the cyclic behavior of corroded reinforced concrete in structural design and maintenance practices. The findings contribute to the understanding of the performance of deteriorated concrete structures in chloride-rich environments [13,14]. Moreover, artificial intelligence find extensive applications in the field of structural engineering, as demonstrated by numerous studies [15][16][17][18][19][20][21][22][23][24].…”

Probabilistic analysis of climate change impact on chloride-induced deterioration of reinforced concrete considering Nordic climate

“…3.5) [62]. In the current article, the effect of corrosion on the reinforcement yield strength is considered as follows [62,65]: with where δ Q cr is a model uncertainty factor, f y,0 is the initial yield strength before corrosion and f y (t) is the yield strength at age t . Although it is acknowledged that reinforcement corrosion has several other effects (e.g., reduction of concrete strength, reduction of steel-concrete bond strength, reduction of low cycle fatigue and buckling strength [29,64]), these effects are not considered in the current article.…”

“…As in previous studies, e.g., [65], the maximum bending moment at mid span is considered for assessing the flexural reliability of the beam. Although failure can occur at other sections along the beam due to pitting corrosion [44], this is not considered herein.…”

“…Although failure can occur at other sections along the beam due to pitting corrosion [44], this is not considered herein. The following limit state function is considered [65]: with where δ M R is the flexural resistance model uncertainty factor, d is the effective depth of the cross section [ mm ], K M R represents the flexural resistance ratio, b is the section width [ mm ], f c is the compressive strength of concrete [ MPa ], M S is the applied bending moment at midspan [ N • mm ], G is the dead load kN m , Q s is the sustained live load kN m , Q E is the extraordinary live load kN m , and L is the beam length [ mm ]. Failure is defined as the event that g(t) becomes less than or equal to zero (i.e., the beam flexural resistance is lower than or equal to the applied bending moment):…”

Reliability‑based probabilistic numerical plastically limited analysis of reinforced concrete haunched beams

“…Using this unique method, it was possible to get a versatile tool to aid decision-makers in planning maintenance interventions. Seghier et al 15 studied the use of a structural reliability methodology, especially the three-term conjugate map (TCM) relying on the first-order reliability method (FORM), for the multi-state assessment of corroded RC beams. Stewart 16 also developed a probabilistic model to evaluate immediate shrinkage deflections and creep.…”