Investigating correlations between crack width, corrosion level and anchorage capacity

Tahershamsi, Mohammad; Fernandez, Ignasi; Lundgren, Karin; Zandi, Kamyab

doi:10.1080/15732479.2016.1263673

Cited by 52 publications

(44 citation statements)

References 41 publications

(49 reference statements)

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“…At the same time, accurate estimation of the corrosion level is difficult to obtain from non-destructive testing on existing structures. It is possible to quantify based on measurements of crack widths [37], but the results in the literature are scattered. An understanding can also be formed if the corrosion rate is monitored using, say, an electrochemical technique [38], with additional assumptions regarding the onset time of corrosion and previous corrosion rate.…”

Section: Discussionmentioning

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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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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Section: Discussionmentioning

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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“…The extracted steel was cut into suitable parts with a length of 300 mm, and the bars were cleaned by using the following three most common methods found in literature: metallic bristle brushing, acid immersion, and sandblasting. Metallic bristle brushing is the most commonly used cleaning method [27,30,31]; this is mainly because it entails a low number of requirements for its use. Conversely, immersion in an acid solution is less common [7,15,32,33].…”

Section: Removal Of Corrosion Products and Assessment Of The Corrosiomentioning

confidence: 99%

“…A method that was developed in a previous study [27] was used to determine the corrosion level variation along a bar based on the scanning measurements:…”

Section: Evaluation Of the Level Of Corrosion Using Scanning Techniquesmentioning

confidence: 99%

“…Nevertheless, all the aforementioned techniques are yet strongly dependent on the cleaning methods performed on the steel bars. A recent study by Tahershamsi et al [27] pointed out significant discrepancies between obtained results using three-dimensional optical measurement (3D scanning) and weight loss measurement following metallic brush cleaning of naturally corroded steel bars. There is a paucity of similar studies that relate and compare different cleaning methods and corrosion level measurement techniques.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of corrosion level of naturally corroded bars using different cleaning methods, computed tomography, and 3D optical scanning

2018

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Reliable methods are necessary to assess the corrosion level to establish links between structural performance and reinforcement corrosion in concrete structures. Hence, in this study, a set of naturally corroded bars were subjected to metallic brushing, acid immersion, and sandblasting for rust removal. Additionally, 3D optical, CT scanning, and weight loss measurements were used to evaluate the levels of corrosion. The results indicate that sandblasting is an optimal cleaning method. Weight loss measurements are sufficient when detailed information about corrosion is not required, and 3D scanning is preferred if information on corrosion variation along the bar is needed.

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“…When the concrete is uncracked, the steel reinforcement is protected by passivation in the alkaline environment within the hardened concrete, and the corrosion problem is minimal. Once the concrete is cracked, the cracks provide channels for ingress of moisture and deleterious chemicals that eventually depassivate the steel and accelerate corrosion [3,4].…”

Section: Introductionmentioning

confidence: 99%

Strengthening of Fibre Reinforced Concrete Elements: Synergy of the Fibres and External Sheet

Gribniak

Tamulenas

et al. 2019

Sustainability

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In structural rehabilitation and strengthening, the structural members are often required to cope with larger design loading due to the upgrading of building services and design standard, while maintaining the member size to preserve the architectural dimensions and headroom. Moreover, durability enhancement by mitigating or eliminating the reinforcement corrosion problem is often desired. Concrete cracking is a major initiating and accelerating factor of the corrosion of steel reinforcement. The application of fibres is a prominent solution to the cracking problem. Furthermore, the fibres can increase the mechanical resistance of the strengthening systems. This study reveals the synergy effect of the combined application of steel fibres and external carbon fibre-reinforced polymer (CFRP) sheets. The investigation encompasses the use of fibre-reinforced polymer (FRP) reinforcing bars, discrete steel fibres, externally bonded and mechanically fastened FRP sheets in different combinations. It is discovered that the steel fibres can help to control concrete cracking and eventually alter the failure mode and enhance the flexural resistance. The FRP reinforcement system, together with the steel fibres, radically resolves the structural safety problem caused by corrosion of the steel bar reinforcement. Finally, the impact of the external sheet on the fire limit state performance needs to be resolved, such as by adopting fire protection rendering for the finishes layer.

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Investigating correlations between crack width, corrosion level and anchorage capacity

Abstract: Highlights • Steel reinforcement corrosion level characterized through optical 3D scanning • Relations between corrosion induced crack and corrosion level • Relations between average bond, corrosion induced crack width and corrosion level

Cited by 52 publications

References 41 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

Evaluation of corrosion level of naturally corroded bars using different cleaning methods, computed tomography, and 3D optical scanning

Strengthening of Fibre Reinforced Concrete Elements: Synergy of the Fibres and External Sheet

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