Behavior of FRP-Retrofitted Joints Built with Plain Bars and Low-Strength Concrete
Publication: Journal of Composites for Construction
Volume 15, Issue 3
Abstract
Two series of tests on eight full-scale exterior beam-column joint subassemblages built with plain bars and low-strength concrete were conducted. No transverse reinforcement was present in the joint cores. In the first series of tests, which included three specimens, the behavior of joints before fiber-reinforced polymer (FRP) retrofitting was investigated. In the second series, which included five specimens, the behavior of the FRP-retrofitted joints was investigated. The six specimens consisted of a column, an in-plane beam, a transverse beam, and a slab part, and two specimens were plane members without transverse beams and slabs. The utilized retrofitting scheme is easily applicable for actual exterior beam-column joints, even in the presence of a transverse beam and a slab. Two types of strength limitation were observed for specimens in the first series. The strength of the specimen with beam longitudinal bars sufficiently anchored to the joint core was limited by the shear strength of the joint. The strengths of the other two specimens were limited by the slip of the beams’ longitudinal bars at their anchorages. In the second series of tests, significantly better performance was obtained both in terms of shear strength and ductility, provided that the slip of the beam bars was prevented. Furthermore, by using a simple theoretical algorithm based on truss analogy, the strength and deformability characteristics of the tested reference and FRP-retrofitted joints are predicted with reasonable accuracy. The same algorithm is used for predicting the joint shear strength of specimens tested by other researchers, and satisfactory agreement is obtained between the predictions and test results.
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Acknowledgments
This study is a part of an extensive project funded by the Scientific and Technological Research Council of Turkey (TUBITAK), project number UNSPECIFIED106M054, and Istanbul Technical University, project number UNSPECIFIED31811 and UNSPECIFIED32002 (supervised by A. Ilki). The in-kind contributions provided by UNSPECIFIEDISTON and BETONSA Ready Concrete Companies and UNSPECIFIEDBASF Chemical Company, are also gratefully acknowledged. So is the assistance of Mr. C. Asan, A. Nart, O. Incecik, K. Kolcu, and the valuable contribution of Salih Usta, who helped in the construction of the specimens and, unfortunately, passed away recently.
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Published In
Journal of Composites for Construction
Volume 15 • Issue 3 • June 2011
Pages: 312 - 326
Copyright
© 2011 American Society of Civil Engineers.
History
Received: Feb 2, 2010
Accepted: Jul 14, 2010
Published online: Jul 17, 2010
Published in print: Jun 1, 2011
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