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Steel Reinforcement (steel + reinforcement)

Distribution by Scientific Domains

Engineering	50%

Selected Abstracts

Corrosion of Steel Reinforcement in Concrete

MATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 2 2009
Michael Raupach
[source]

Effect of cumulative seismic damage and corrosion on the life-cycle cost of reinforced concrete bridges

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 7 2009
R. Kumar
Abstract Bridge design should take into account not only safety and functionality, but also the cost effectiveness of investments throughout a bridge life-cycle. This paper presents a probabilistic approach to compute the life-cycle cost (LCC) of corroding reinforced concrete (RC) bridges in earthquake-prone regions. The approach is developed by combining cumulative seismic damage and damage associated with corrosion due to environmental conditions. Cumulative seismic damage is obtained from a low-cycle fatigue analysis. Chloride-induced corrosion of steel reinforcement is computed based on Fick's second law of diffusion. The proposed methodology accounts for the uncertainties in the ground motion parameters, the distance from the source, the seismic demand on the bridge, and the corrosion initiation time. The statistics of the accumulated damage and the cost of repairs throughout the bridge life-cycle are obtained by Monte-Carlo simulation. As an illustration of the proposed approach, the effects of design parameters on the LCC of an example RC bridge are studied. The results are valuable in better estimating the condition of existing bridges and, therefore, can help to schedule inspection and maintenance programs. In addition, by taking into consideration the two deterioration processes over a bridge life-cycle, it is possible to estimate the optimal design parameters by minimizing, for example, the expected cost throughout the life of the structure. A comparison between the effects of the two deterioration processes shows that, in seismic regions, the cumulative seismic damage affects the reliability of bridges over time more than the corrosion even for corrosive environments. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Depassivation of steel reinforcement in case of pitting corrosion: detection techniques for laboratory studies

MATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 8 2009
L. Bertolini
Abstract Methods for service life prediction of reinforced concrete structures exposed to chloride-bearing environments require, amongst other parameters, the knowledge of the chloride threshold for pitting corrosion initiation (Clth). Nowadays, although the main factors influencing the chloride threshold are well known, it is often difficult to quantify a value of the chloride threshold, partly because of its intrinsic high variability, and partly because of the different test methods that have been used to measure it. All the experimental tests rely on the detection of steel depassivation and simultaneous measurement of chloride content or steel potential. This paper deals with the methods that can be used to detect steel depassivation in relation with the determination of the chloride threshold. Tests in concrete-pore-simulating solutions as well as tests in concrete will be considered, and advantages and limitations will be discussed. [source]

Verstärken von Stahlbetonstützen mit textilbewehrtem Beton

BETON- UND STAHLBETONBAU, Issue 10 2009
Regine Ortlepp Dr.-Ing.
Versuche; Bewehrung Abstract Der Aufsatz beschreibt die Ergebnisse experimenteller Untersuchungen zur Wirkung einer Textilbetonverstärkung an 2 m langen Stützen mit und ohne innen liegender Stahlbewehrung. Die Verstärkung mit textilbewehrtem Beton wurde auf zwei verschiedene Weisen ausgeführt, sowohl als vollständige Umwicklung über die gesamte Länge der Stützen als auch als teilweise Verstärkung über eine Länge von 30 cm in den Lasteinleitungsbereichen. Die einzelnen Anteile am Tragverhalten der verstärkten Stützen wurden untersucht. Ein einfaches Berechnungsmodell wird angegeben. Strengthening of Columns using Textile Reinforced Concrete (TRC) In the context of rehabilitation and repair works or in the course of usage changes of existing buildings the planning engineer frequently is confronted with the task of strengthening the loadbearing structure. This can become necessary, for example, if live loads are increased because of changes of use or if the structural safety of a building must be restored after a fire or earthquake. Particularly columns represent important components and elements of the static system for many buildings, whose main task is bearing normal forces. The results of experimental tests on the effect of a strengthening from textile reinforced concrete at 2 m long columns, both with and without internal steel reinforcement, are described in this article. The strengthening with textile reinforced concrete was made both wrapping round completely along the full height of the columns and partly wrapping round the columns along 300 mm in the load introduction ranges. Related to the unstrengthened reference columns ultimate load increasings by up to 85% could thereby be achieved. The individual components of the load bearing properties are analysed. A simple calculation model is indicated. [source]