Fatigue Testing of Stiffened Traffic Signal Structures
Publication: Journal of Structural Engineering
Volume 136, Issue 10
Abstract
Based on in-service inspection of poles with traditional designs, the inventory of Wyoming Department of Transportation (WYDOT) exhibited approximately a one-third cracking rate. A ring-stiffened connection is presently used. Sixteen fatigue tests were performed on 12 ring-stiffened cantilevered traffic signal pole connections to quantify the fatigue resistance. Two pole sizes were tested in three loading configurations: in plane, out of plane, and diagonal. Cyclic loading was applied to produce stress ranges (SRs) at several levels up to 16 ksi in the main member, more than six times the SR observed during monitoring an in-service pole. The WYDOT stiffened connection appears to be adequate to resist Wyoming’s sustained winds that average approximately 12 mph in many locations. The possibility of using this connection with longer mast arms exists. Connection bolt fatigue failures were observed and may be the limiting fatigue design feature and important for inspection.
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Acknowledgments
The support of WYDOT engineers Gregg Fredrick, Paul Huck, and Jeff Booher is appreciated. They provided significant help in the design of the test matrix, setting the SR levels, and providing background and documentation on WYDOT design practice. Additionally, Gregg Fredrick was helpful in specification interpretations and background as part of AASHTO SCOBS T-12. Mr. Carl Macchietto and Valmont provided the test specimens at cost. The writers are responsible for the content of this paper.
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Information & Authors
Information
Published In
Journal of Structural Engineering
Volume 136 • Issue 10 • October 2010
Pages: 1205 - 1214
Copyright
© 2010 ASCE.
History
Received: Jun 30, 2009
Accepted: Apr 5, 2010
Published online: Apr 9, 2010
Published in print: Oct 2010
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