Stochastic method for the assessment of concrete bridges with SCC sensitive prestressing steel

Matthias Wild, Oliver Fischer

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

In the 1960’s and 1970’s many bridges were built in Germany using different types of prestressing steel. Some of them later were found to be sensitive to stress corrosion cracking (SCC). In these steels cracks and ruptures can occur very brittle without any notice at the concrete surface. In order to prevent sudden failures of bridges due to SCC, an analytical assessment method on basis of discrete cross-sections was developed. With this analytical approach it is checked if there will be a crack formation at the visible concrete surface before a sudden failure of the bridge could occur (prior warning). In this analysis it is often found that in case of unnoticed proceeding of the stress corrosion process, in some cross-sections a sudden failure has to be expected. Hence a system based stochastic method was introduced, by which the probability that failure might occur without prior warning can be assessed. These methods are state-of-the-art to estimate the probability of sudden failures in longitudinal direction of concrete bridges. The transverse direction of concrete bridges has an unfavourable ratio of visible to invisible concrete surfaces in the tension zone. Thus the stochastic evaluation method mentioned above cannot be used. A failure of the bridge will not be noticed by visible cracks until the bridge could be in a critical state. Therefore a new stochastic method was developed to evaluate the risk of brittle failure of the bridge in transverse direction. This approach allows combining already gained information on SCC behavior in longitudinal direction with system relevant parameters in transverse direction. The result of this stochastic method is the evaluation of risk of brittle failure in transverse direction. The method is an important step towards the sustainable use of existing concrete bridges which are sensitive to SCC by calculations, without mayor strengthening of the object.

Original languageEnglish
Title of host publicationConcrete structures for resilient society - Proceedings of the fib Symposium, 2020
EditorsBin Zhao, Xilin Lu
Publisherfib. The International Federation for Structural Concrete
Pages1825-1832
Number of pages8
ISBN (Print)9782940643042
StatePublished - 2020
EventInternational fib Symposium on Concrete structures for resilient society, 2020 - Virtual, Online
Duration: 22 Nov 202024 Nov 2020

Publication series

Namefib Symposium
ISSN (Print)2617-4820

Conference

ConferenceInternational fib Symposium on Concrete structures for resilient society, 2020
CityVirtual, Online
Period22/11/2024/11/20

Keywords

  • Bridge assessment
  • Prestressing steel
  • Stochastic
  • Stress corrosion cracking
  • Sustainability

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