Journal of Advanced Concrete Technology
Online ISSN : 1347-3913
ISSN-L : 1346-8014
Volume 14 , Issue 10
Showing 1-3 articles out of 3 articles from the selected issue
Scientific paper
  • Mohammad Mahdi Raouffard, Minehiro Nishiyama
    2016 Volume 14 Issue 10 Pages 625-633
    Published: October 19, 2016
    Released: October 19, 2016

    Estimating the residual strength of fire-exposed reinforced concrete (RC) structures is of great importance in determin-ing whether the cooled structure is safely functional or immediate repair is needed. This paper describes the results of experimental and numerical investigations on fire and post-fire structural responses of a 2-story moment-resisting RC frame test specimen. The lower story of the test specimen, which was subjected to service loads, was heated for 60 min-utes in accordance with the ISO-834 standard fire test. The test specimen exhibited a satisfactory structural performance during the fire course and considerably recovered much of its pre-fire deflection state when cooled. To investigate the re-serviceability and residual load bearing capacity of the cooled test specimen, a destructive cyclic vertical loading was conducted. A detailed 2D finite element model was developed as well. By comparing the test and analysis results, it was found that due to the fire damage the test specimen lost 30% of its load bearing capacity. The proposed numerical mod-elling approach in this study predicted considerably well the post-fire residual strength of the test specimen.

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  • Osamu Kontani, Naoki Ishitobi, Junya Kawada, Noriaki Taogoshi, Makoto ...
    2016 Volume 14 Issue 10 Pages 634-642
    Published: October 22, 2016
    Released: October 22, 2016

    The residual strength tests after cyclic loadings on concrete cylinder specimens and stud anchor specimens were performed to obtain data regarding effects of cyclic loadings on concrete and stud anchor specimens for proposing a new method capable of evaluating the soundness of equipment support using the S-N curves. More specifically, cyclic loadings may lead to a reduction in the strength and stiffness of concrete and also lead to the pullout and a reduction of the strength of stud anchor sections, which may reduce the rigidity of the equipment support, and this situation is not preferable from the viewpoint of long-term soundness evaluation. Then, in order to investigate whether or not cyclic loadings reduce the strength and the rigidity of the equipment support, cyclic compressive loadings with constant amplitude were applied to cylinder specimens, then static compression tests were performed. Also, cyclic tensile loadings with constant amplitude were applied to stud anchor specimens, then static pullout tests were performed. As a result, it was found that the cyclic loading would not lead to the pullout of stud anchor and a reduction of the strength of stud anchor if the maximum stress ratio is less than the long-term allowable stress.

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Technical report