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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:
SP275-40
Date:
March 1, 2011
Author(s):
Guillermo D. Huaco, James O. Jirsa, and Oguzhan Bayrak
Publication:
Symposium Papers
Volume:
275
Abstract:
Different strategies can be used to repair, rehabilitate and strengthen existing structures. Techniques based on Fiber Reinforced Polymer (FRP) materials appear to be innovative alternatives to traditional solutions because of their high tensile strength, lightweight, and ease of installation. One of the most common and useful FRPs is Carbon Fiber Reinforced Polymer (CFRP) sheets and anchors attached to strengthen the section through addition of tensile capacity. The purpose of this study was to develop a technique for assessing the strength of anchors for quality control. A method for assessing the quality of CFRP anchor installation was developed using plain concrete beams reinforced externally with CFRP sheets attached with epoxy and CFRP anchors. Under loading on the beam, a tensile force was developed in the CFRP sheets and a shear force on the CFRP anchors. The forces in the CFRP anchors were defined by the load applied to the beam and compared with forces based on measured stress in CFRP sheets.
DOI:
10.14359/51682450
SP275-41
W. T. Jung, Y. H. Park, and J. S. Park
The application of the conventional anchoring system used for steel wires is likely to reduce the efficiency of the CFRP tendon. Therefore, need is to develop anchor appropriate to CFRP tendon. This study selected the compression-type anchor among the three types of anchor. Tapered section was adopted for the external diameter of the sleeve to alleviate the concentration of stress occurring under compression, and the performance of the anchor was observed with respect to the length of the taper. The experimental results showed that the performance of anchors is sensitive to dimensions of the sleeve and the compression force. The sleeve presenting stress softening section was seen to reduce the concentration of stress. The finite element analysis and experimental results enabled to derive dimensions of the sleeve improving the efficiency of CFRP tendon, and dimensions of the sleeve enhancing the anchor performance of CFRP tendons with different diameters are proposed.
10.14359/51682451
SP275-36
Yungon Kim, Kevin T. Quinn, Christopher N. Satrom, Wassim M. Ghannoum, and James O. Jirsa
Several tests were conducted to evaluate the shear performance of beams strengthened externally with carbon fiber reinforced polymer (CFRP) laminates and CFRP anchors. Results are presented for five tests conducted on 24-in.(610-mm) deep reinforced concrete T-beams constructed and tested at Phil M. Ferguson Structural Engineering Laboratory at the University of Texas at Austin. Monotonically increasing load was applied to the reinforced concrete members at a shear span-to-depth ratio of three (a/d = 3) until failure. Overall, a 40-45% increase in shear strength was observed when anchored CFRP laminates were installed on the RC members. In all cases, CFRP anchors prevented a premature de-bonding failure in the CFRP laminates, thus increasing the useable capacity of the CFRP laminates. Theoretical calculations predicting the shear strength of the retrofitted concrete members were carried out and compared with the measured strengths of the members.
10.14359/51682446
SP275-37
K. Gordon and L. Cheng
This paper presents the results evaluating the empirical fatigue-life relation-ships currently available for predicting the fatigue life of reinforced concrete beams strengthened with fiber reinforced polymers. Derived from individual studies, each relationship is used to generate predictions for sets of test data that are reported in the open literature. The predictions are then analyzed for accuracy and investigated for factors that may lead to improved fatigue-life models. Analyses of data using currently available models indicate that much improvement is needed. The improvements should not only address individual factors that can affect fatigue life, but should also result in accurate predictions across multiple sets of data.
10.14359/51682447
SP275-38
Fadi Oudah, and Raafat El-Hacha
A flexural fatigue strength prediction model of prestressed Near Surface Mounted (NSM) Carbon Fiber Reinforced Polymer (CFRP) strengthened beams has been developed in this paper. The prediction model is based on the degradation of the concrete compressive block and the degradation of the bond between the tension reinforcements, prestressed CFRP and steel reinforcements, and the surrounding concrete during the fatigue life. A parametric study using the developed model was conducted on reinforced concrete (RC) beam strengthened with prestressed NSM-CFRP reinforcement. It was concluded that the degradation of the concrete stress-strain relationship has a minor effect on the ultimate capacity of the beam as compared with the effect of bond breakdown.
10.14359/51682448
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