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Home > Publications > International Concrete Abstracts Portal
The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.
Showing 1-5 of 73 Abstracts search results
Document:
SP275-35
Date:
March 1, 2011
Author(s):
Alex S. Larkin, Jovan Tatar, and Charles W. Dolan
Publication:
Symposium Papers
Volume:
275
Abstract:
A four-point Iosipescu shear test is used to evaluate the effects of CFRP reinforcement on crack width development and the corresponding stress of the internal steel reinforcement. The test program indicates that the steel reinforcement yields following cracking in a concrete beam test specimen containing a No. 10 (No. 3) 71 mm2 (0.11 in2)-420 MPa (60 ksi) yield strength reinforcing bar in most cases; however, some CFRP reinforced specimens have a steel strain as low as 45 percent of the yield strain prior to the failure between the CFRP and the concrete surface. The research conducted a parametric study and provides a correlation between CFRP shear reinforcement ratios, crack width, and internal steel reinforcement stress. The results are found by testing several shear friction type specimens where the CFRP varies in size while the internal steel reinforcement is held constant.
DOI:
10.14359/51682445
SP275-30
Rajan Sen, Gray Mullins, Julio Aguilar and Danny Winters
The poor performance of conventional chip and patch methods for repairing corrosion damaged piles has led to renewed interest in the use of fiber reinforced polymers (FRP). Over the past decade, laboratory research complemented by numerous field demonstration projects has led to improvements in the design, construction and monitoring of FRP pile repair. The two principal areas of advancement were in the development of techniques borrowed from the composites industry for improving FRP-concrete bond and in the incorporation of a sacrificial anode cathodic protection system within a FRP wrap. Both developments enhance the competitiveness of FRP pile repair. This paper provides an overview of laboratory and field demonstration studies in recent years that led to these advancements.
10.14359/51682440
SP275-31
Hiran D. Yapa and Janet M. Lees
External, prestressed carbon fiber reinforced polymer (CFRP) straps can be used to enhance the shear strength of existing reinforced concrete beams. In order to effectively design a strengthening system, a rational predictive theory is required. The current work investigates the ability of the modified compression field theory (MCFT) to predict the behavior of rectangular strap strengthened beams where the discrete CFRP strap forces are approximated as a uniform vertical stress. An unstrengthened control beam and two strengthened beams were tested to verify the predictions. The experimental results suggest that the MCFT could predict the general response of a strengthened beam with a uniform strap spacing < 0.9d. However, whereas the strengthened beams failed in shear, the MCFT predicted flexural failures. It is proposed that a different compression softening model or the inclusion of a crack width limit is required to reflect the onset of shear failures in the strengthened beams.
10.14359/51682441
SP275-32
Amir Mofidi and Omar Chaallal
This paper deals with the shear strengthening of reinforced concrete (RC) beams using externally bonded (EB) fiber-reinforced polymers (FRP). The parameters that have the greatest influence on the shear behavior of RC members strengthened with EB FRP and the role of these parameters in current design codes are reviewed. The effect of transverse steel on the shear contribution of FRP was found significant and yet is not captured by any existing codes or guidelines. Therefore, a new design method is proposed, which considers the effect of transverse steel as well as to other influencing factors on the shear contribution of FRP (Vfrp). The accuracy of the proposed equations is verified by predicting the shear strength of experimentally tested RC beams using data collected from literature.
10.14359/51682442
SP275-27
A. Bilotta, F. Ceroni, E. Nigro, and M. Pecce
This paper deals with the assessment of a design formulation to predict the end debonding load in reinforced concrete (RC) elements strengthened with externally bonded reinforcement (EBR) in fiber reinforced polymer (FRP). The debonding loads recorded during several bond tests have been collected and the reliability of three relationships furnished by literature and codes to calculate the end plate debonding load has been assessed. Then, the experimental data have been used to assess a new relationship for the end plate debonding load according to the ‘design by testing’ procedure suggested in European codes. In particular, numerical factors for calculating mean values and percentiles for the end plate debonding load have been calibrated. Moreover, different factors have been assessed for the preformed and cured in-situ EBR FRP systems that have been distinguished in order to better exploit the performance of the latter ones.
10.14359/51682437
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