Reliability‐based evaluation of bond strength for tensed lapped joints and anchorages in new and existing reinforced concrete structures

al (2018) Partial safety factors for the anchorage capacity of corroded reinforcement bars in concrete Engineering Structures, 181: 579-588 http://dx. ABSTRACTMany reinforced concrete bridges in Europe and around the world are damaged by reinforcement corrosion and the annual maintenance costs are enormous. It is therefore important to develop reliable methods to assess the structural capacity of corroded reinforced concrete structures and avoid unnecessary maintenance costs. Although there are advanced models for determining the load carrying capacity of structures, it is not obvious how they should be used to verify the performance of existing structures. To confidently assess the bond of corroded reinforcement in concrete, for example, the calculation model must give a sufficient safety margin. When designing new structures, semi-probabilistic approaches (such as the partial safety factor method) are adopted to achieve the target reliabilities specified in structural design codes. This paper uses probabilistic methods to develop partial factors for application in an existing bond model, to assess the safety of corroded reinforced concrete structures. The response of the bond model was studied using Monte Carlo (MC) simulations for several design cases, with probability distributions fitted to the results. Partial factors were then derived, based on these distributions. Furthermore, an MC-based simulation technique called "importance sampling" was used to study the reliability of several deterministic bond assessments conducted using these partial factors. The results show that deterministic assessments which use the proposed partial factors lead to a safety level at least equal to the target value. The results presented in this paper will support the assessment of reinforced concrete structures with anchorage problems and give a reasonable approximation of the anchorage capacity with sufficient safety margin. When generalised to cover other failure modes and structural configurations, this will enable better utilisation of damaged structures and lead to major environmental and economical savings for society. 1.

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“…Note that the model uncertainty is dependent on the specific mechanical model used, and the domain of the input parameters c.f. [17,20].…”

Section: Model Uncertaintymentioning

confidence: 99%

“…For the case of uncorroded reinforcement, cf. Mancini et al work on reliability-based bond evaluation of tensed lapped joints or anchorages [17]. The availability to engineers of a calculation model which leads to an appropriate safety level will allow better assessment of corrosion-damaged RC structures.…”

Section: Introductionmentioning

confidence: 99%

Partial safety factors for the anchorage capacity of corroded reinforcement bars in concrete

Blomfors

Ivanov

Honfí

et al. 2019

Engineering Structures

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“…This database contains 807 results from laps splices and anchorages tests. The mean value μ ϑ and the coefficient of variation V ϑ are evaluated and listed in Table according to the statistical investigation proposed by Reference . According to References 4,6, and 15, ϑ can be described by means of a log‐normal distribution.…”

Section: Application Example: Tensile Strength Of Laps and Anchoragesmentioning

confidence: 99%

Framework for definition of design formulations from empirical and semi‐empirical resistance models

Castaldo

Gino

Carbone

et al. 2018

Structural Concrete

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The study proposes a framework based on the Monte Carlo method for the probabilistic calibration of empirical and semi‐empirical resisting models. The resisting models adopted in engineering practice may be based both on physical laws, such as equilibrium of forces, and on semi‐empirical or empirical formulations. Precisely, empirical or semi‐empirical resisting models are calibrated in order to fit experimental data and the direct application of partial safety factors to material properties does not allow a proper estimation of the structural reliability. For this reason, a probabilistic definition of design expressions from empirical or semi‐empirical resisting models should be preferred to define a final formulation in agreement with a specific level of reliability. After a detailed description of the framework, its application to the probabilistic calibration of the semi‐empirical model proposed by fib Model Code 2010 for the estimation of tensile strength of laps and anchorages in reinforced concrete structures is proposed.

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“…In particular, existing bridges and viaducts are extensively exposed to environmental actions, time dependent phenomena (e.g., creep, shrinkage, prestressing steel relaxation), degradation (e.g., corrosion due to carbonation and/or chloride penetration), and increasing magnitude of traffic loads. For these reasons, several investigations have been devoted to define methodologies to assess efficiently existing structures and infrastructures also including refined analysis methods . Moreover, national Authorities are strongly interested in the assessment of existing structures, with particular care for existing bridges and viaducts, due to the high costs for maintenance, interventions and upgrading.…”

Section: Introductionmentioning

confidence: 99%

“…For these reasons, several investigations have been devoted to define methodologies to assess efficiently existing structures and infrastructures also including refined analysis methods. [1][2][3][4][5][6] Moreover, national Authorities are strongly interested in the assessment of existing structures, with particular care for existing bridges and viaducts, due to the high costs for maintenance, interventions and upgrading.…”

Section: Introductionmentioning

confidence: 99%

Partial factor methods for existing structures according to fib Bulletin 80: Assessment of an existing prestressed concrete bridge

Gino

Castaldo

Bertagnoli

et al. 2019

Structural Concrete

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The assessment of existing reinforced concrete structures is one of the major aspects for engineers and practitioners. In particular, existing infrastructures, as bridges and viaducts, are extensively exposed to environmental actions, materials aging, degradation, and variation of magnitude of traffic loads during their service life. Hence, the assessment of existing structural systems assuming the same criteria conceived for the design (i.e., partial factor method—EN 1990) can be too conservative and, sometimes, may lead to unnecessary and expensive structural interventions. In this context, fib Bulletin 80 defines the partial factor methods suitable for the assessment of existing reinforced concrete structures accounting for their residual service life, information from in situ and laboratory tests, measurements of variable actions and reduced target reliability levels according to both economical and human safety criteria. The methodologies proposed in fib Bulletin 80 have been applied to assess the safety of an existing prestressed reinforced concrete bridge built in 90s and located in Italy. The results are compared to the outcomes from the assessment performed according to EN1990 and, finally, limits and advantages of the methodologies proposed by fib Bulletin 80 are discussed.

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Reliability‐based evaluation of bond strength for tensed lapped joints and anchorages in new and existing reinforced concrete structures

Cited by 22 publications

References 16 publications

Partial safety factors for the anchorage capacity of corroded reinforcement bars in concrete

Partial safety factors for the anchorage capacity of corroded reinforcement bars in concrete

Framework for definition of design formulations from empirical and semi‐empirical resistance models

Partial factor methods for existing structures according to fib Bulletin 80: Assessment of an existing prestressed concrete bridge

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