Seismic Behavior and Retrofit of Outrigger Knee Joints
Publication: Journal of Bridge Engineering
Volume 12, Issue 5
Abstract
Experimental tests were conducted on six 1/3-scale specimens to define the vulnerabilities of existing outrigger bents under in-plane and out-of-plane seismic loading and to develop retrofit measures that address the identified vulnerabilities. The specimens represented knee joints in the SR 99 Spokane Street overcrossing in western Washington State but included deficiencies present in a number of older bridges. The as-built specimens failed at low ductility levels due to shear distress, low torsional strength of the outrigger beam, and reinforcement bond failures within the joint. Threshold principal tension stress values describing the expected condition of the joints were established and compared to values obtained by other researchers. Circular steel jackets were used to retrofit the as-built specimens. The retrofitted specimens developed plastic hinging in the column, with enhanced strength, energy, and ductility capacities. Design and detailing guidelines for retrofitting outrigger bents were proposed.
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Acknowledgments
The research presented in this paper was funded by the Washington State Department of Transportation. The assistance of the Washington State University engineering shops in making components for the retrofitted specimens is appreciated.
References
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Information & Authors
Information
Published In
Journal of Bridge Engineering
Volume 12 • Issue 5 • September 2007
Pages: 591 - 599
Copyright
© 2007 ASCE.
History
Received: Aug 30, 2004
Accepted: Jul 14, 2006
Published online: Sep 1, 2007
Published in print: Sep 2007
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