CFRP Tendons for the Repair of Posttensioned, Unbonded Concrete Buildings
Publication: Journal of Performance of Constructed Facilities
Volume 25, Issue 3
Abstract
The deterioration attributable to corrosion of concrete structures reinforced with unbonded, posttensioned tendons is a costly problem. Recent research has shown composite materials such as fiber-reinforced polymers (FRP) to be suitable alternatives to steel because they provide similar strength without susceptibility to electrochemical corrosion. Carbon-FRP (CFRP) in particular has great promise for prestressed applications because it shows resistance to corrosion in environments that might be encountered in concrete and experiences less relaxation than steel. This paper outlines the testing and implementation of a posttensioned system that uses CFRP tendons to replace corroded, unbonded posttensioned steel tendons. This system was then implemented in a parking garage in downtown Toronto. To the writers’ knowledge, this is the first example of an unbonded, posttensioned tendon replacement using FRP tendons. The system used split-wedge anchors designed specifically for CFRP tendons. The dead end was anchored by directly bonding the tendon to the concrete slab. The CFRP tendon was successfully inserted in the opening created by the removal of the corroded tendon and stressed. Although the system was shown to be feasible, the current anchorage configuration results in load losses of up to 60% during the transfer. Changing the orientation of the anchor was found to reduce the load loss to an acceptable range of 1–9%.
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References
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Information & Authors
Information
Published In
Journal of Performance of Constructed Facilities
Volume 25 • Issue 3 • June 2011
Pages: 149 - 157
Copyright
© 2011 American Society of Civil Engineers.
History
Received: Jun 9, 2009
Accepted: May 1, 2010
Published online: Jun 21, 2010
Published in print: Jun 1, 2011
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