International Concrete Abstracts Portal

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: 

SP275-37

Date: 

March 1, 2011

Author(s):

K. Gordon and L. Cheng

Publication:

Symposium Papers

Volume:

275

Abstract:

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.

DOI:

10.14359/51682447


Document: 

SP275-38

Date: 

March 1, 2011

Author(s):

Fadi Oudah, and Raafat El-Hacha

Publication:

Symposium Papers

Volume:

275

Abstract:

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.

DOI:

10.14359/51682448


Document: 

SP275-33

Date: 

March 1, 2011

Author(s):

Rajai Alrousan, Mohsen A. Issa, Thilan Ovitigala and Moussa A. Issa

Publication:

Symposium Papers

Volume:

275

Abstract:

Several reinforced lightweight concrete beams were cast with and without CFRP shear strips. The objective of this research is to investigate the shear contribution of the CFRP strips to the ultimate shear strength of the beams. To make full use of the CFRP strips, anchorage at the top sides of the beam webs was provided in the form of CFRP strips along the shear span length. This solution works well with beams with monolithic slabs and T-beams. The test variables were the orientation of CFRP composites, width of longitudinal shear strip to total beam depth (wt /h), shear span to depth ratio (a/d), and concrete compressive strength (fc΄). The experimental and FEA results indicated that the anchoring of the shear strips with longitudinal CFRP strips on both top sides of the beam increases the shear capacity and it was found to be a very efficient and economical method.

DOI:

10.14359/51682443


Document: 

SP275-34

Date: 

March 1, 2011

Author(s):

Vincenzo Bianco, J.A.O. Barros and Giorgio Monti

Publication:

Symposium Papers

Volume:

275

Abstract:

A three dimensional mechanical model was recently developed to simulate the shear strength contribution provided by a system of Near Surface Mounted (NSM) Fiber Reinforced Polymer (FRP) strips to a Reinforced Concrete (RC) beam throughout its loading process. It was developed fulfilling equilibrium, kinematic compatibility and constitutive laws of both materials, concrete and FRP, and local bond between themselves. In the present paper, that model is first appraised on the basis of some of the most recent experimental results and then is applied to carry out parametric studies. The influence of each of the involved parameters on the contribution provided by a system of NSM FRP strips to the shear strength of a RC beam is investigated. The results of those studies are presented along with the main findings.

DOI:

10.14359/51682444


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


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