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

Abstract

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.

Investigating Partial Factors for the Assessment of Existing Reinforced Concrete Bridges

“…The first approach is traditionally adopted for shear and torsion resistance of RC members. It has been proposed for instance for columns under pure compression by Moccia et al (2021), for shear resistance by Bairán and Casas (2018), and for bond of reinforcement by Blomfors et al (2019), now being incorporated into prEN 1992-1-1 for bending and compression (Muttoni, 2021). The second approach is generally adopted in current codes, e.g.…”

Uncertainty in the Estimation of Partial Safety Factors for Different Steel-Grade Corroded Pipelines

“…Partial safety factors for structures undergoing corrosion are not frequently estimated and the literature is limited in this regard [28,29]. One recent study has proposed a safety factor estimation scheme based on risk factors for corroded pipelines and their range [29].…”

Resistance of corroded RC beams: Extending fib Model Code 2010 models

“…The application of the method for existing structures is discussed in ISO13822 20 and more recently in fib Commission 3 TG3.1. 21 An interesting development for anchorage capacity including deterioration has been proposed by Blomfors et al 22 The first part of the paper describes the experimental background, with the choice of tests for validation. Then the effects of corrosion for the material properties of steel, concrete, and bond strength are introduced.…”

“…The application of the method for existing structures is discussed in ISO13822 20 and more recently in fib Commission 3 TG3.1 21 . An interesting development for anchorage capacity including deterioration has been proposed by Blomfors et al 22 …”