Confinement Effectiveness of FRP in Retrofitting Circular Concrete Columns under Simulated Seismic Load
Publication: Journal of Composites for Construction
Volume 14, Issue 5
Abstract
The results of a research program that evaluated the confinement effectiveness of the type and the amount of fiber-reinforced polymer (FRP) used to retrofit circular concrete columns are presented. A total of 17 circular concrete columns were tested under combined lateral cyclic displacement excursions and constant axial load. It is demonstrated that a high axial load level has a detrimental effect and that a large aspect ratio has a positive effect on drift capacity. Compared with the performance of columns that are monotonically loaded until failure, three cycles of every displacement excursion significantly affect drift capacity. The energy dissipation capacity is controlled by FRP jacket confinement stiffness, especially under a high axial load level. The fracture strain of FRP material has no significant impact on the drift capacity of retrofitted circular concrete columns as long as the same confining pressure is provided, which differs from the common opinion that a larger FRP fracture strain is advantageous in seismic retrofitting. The amount of confining FRP greatly affects the length of the plastic hinge region and the drift capacity of FRP-retrofitted columns. A further increase in confinement after a critical value causes a reduction in the deformation capacity of the columns.
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Acknowledgments
The writers would like to acknowledge financial support from the National Basic Research Program of China (973 Program) (Grant No. UNSPECIFIED2007CB714200), the National Natural Science Foundation of China (Grant Nos. NNSFC50608015 and NNSFC50908102), and National Key Technology R&D Program of China in the 11th Five-Year Period (Grant No. UNSPECIFIED2006BAJ03B07). Supplementary support was provided by the Research Grants Council of the Hong Kong Special Administrative Region, China (Project No. UNSPECIFIEDCityU 122106), and the research fund of key laboratory of concrete and prestressed concrete structures of the Ministry of Education, Southeast Univ., China.
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Information & Authors
Information
Published In
Journal of Composites for Construction
Volume 14 • Issue 5 • October 2010
Pages: 531 - 540
Copyright
© 2010 ASCE.
History
Received: Aug 13, 2009
Accepted: Jan 25, 2010
Published online: Feb 3, 2010
Published in print: Oct 2010
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