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:
SP275-32
Date:
March 1, 2011
Author(s):
Amir Mofidi and Omar Chaallal
Publication:
Symposium Papers
Volume:
275
Abstract:
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.
DOI:
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
SP275-22
Wolfgang Finckh and Konrad Zilch
When RC is strengthened by using externally bonded reinforcement (EBR) it is not sufficient to perform checks just for the end anchorages. The bond forces must be transferred where the load is applied. These bond forces may be transferred by the elements in between flexural cracks which are mainly influenced by the bond behavior of the internal and external reinforcement. Therefore the models which were derived from end anchorage tests must be expanded to include other effects as well. The here considered laboratory tests had shown that aside from the bond friction a self-induced contact pres-sure on the strip occurs as a result from the element's curving under load. This article presents a model for bond force transfer which includes the increased bond strength resulting from the positive curvature of structural elements. By considering the curvature for the bond force transfer strengthened elements can be design in a more economic and safe way.
10.14359/51682432
SP275-23
Ying-Wu Zhou, Yu-Fei Wu, Yan-chun Yun, Li-Li Sui, and Feng Xing
An analytical model is developed in this work to derive the bond-slip relationship at the reinforcement-substrate concrete interface (joint) for externally bonded FRP (EB-FRP). The model is generally applicable to both long joints (infinite bond length) and short joints. The bond-slip relationship for short joints with a limited bond length is a general model for EB-FRP joints. When the bond length approaches infinity, the model degenerates to a well-known existing analytical model. It is concluded from the modeling that the existing model for long joints is not applicable to short joints that have a bond length that is less than the effective bond length, or at locations in long joints that are closer than the effective bond length to the free end of the reinforcement. The bond-slip relationship is verified with test results.
10.14359/51682433
SP275-24
A. Bilotta, F. Ceroni, M. Di Ludovico, E. Nigro, M. Pecce, and G. Manfredi
The paper deals with the results of an experimental program aimed at the investigation of the bonding behavior of different types of FRP materials for strengthening: externally bonded carbon (EBR) plates, and bars or strips externally applied according to the Near Surface Mounted (NSM) technique. The overall experimental program consists of 18 bond tests on concrete specimens strengthened with EBR carbon plates and of 24 bond tests on concrete specimens strengthened with NSM systems (carbon, basalt and glass bars and carbon strips). The performances of each reinforcement system are presented, discussed and compared in terms of debonding load, load - slip relationship, and strain distribution; the failure mode of each system is also analyzed. The results of the experimental program allow a comparison of the effectiveness of the various EBR and NSM strengthening systems tested and evidence of some differences in the bond behavior.
10.14359/51682434
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