Evaluation of Anchor Bolts with Excessive Standoff in Cantilever Sign and Signal Structures
Publication: Practice Periodical on Structural Design and Construction
Volume 19, Issue 2
Abstract
AASHTO specifies a one-bolt-diameter cutoff for standoff distance to consider bending stresses in anchor bolts. When evaluating the strength of anchor bolts in accordance with these specifications, many cantilever-type support structures with a standoff distance of slightly more than one bolt diameter were determined to be structurally insufficient. In this paper, a comprehensive study on bending stresses of anchor bolts for cantilever-type structural supports was performed. Two finite-element models were developed, one using solid elements to model individual anchor bolts and the other using beam/plate elements to model an entire group of anchor bolts with a base plate. Parametric studies were carried out to investigate the effects of number of bolts, base plate thickness, and standoff distance on bending stresses. Based on ultimate strength theory, strength limit states for individual anchor bolts and entire groups of anchor bolts were derived to include the influence of local bending stresses. As an illustrative example, anchor bolts of an existing cantilever sign structure were evaluated in accordance with AASHTO and AISC. This example demonstrates advantages of the load and resistance factor design method over the allowable stress design (ASD) method.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The author expresses his sincere thanks to Mr. Josh Plummer, SE, and Mr. Matt Brown, PE, of RISA Technologies, for their valuable help in RISA-3D modeling.
References
AASHTO. (2001). Standard specifications for structural supports for highway signs, luminaires, and traffic signals, 4th Ed., Washington, DC.
AASHTO. (2009). Standard specifications for structural supports for highway signs, luminaires, and traffic signals, 5th Ed., Washington, DC.
AASHTO. (2012). LRFD bridge design specifications, 6th Ed., Washington, DC.
AISC. (2011). Steel construction manual, 14th Ed., Chicago.
ASCE. (2005). “Minimum design loads for buildings and other structures.” SEI/ASCE 7-02, New York.
Cook, R. A. (2001). “Design guidelines for annular base plates.” Structures Research Rep. No. 716, Florida DOT, Gainesville, FL.
Cook, R. A., Doerr, G. T., and Klingner, R. E. (1989). “Design guide for steel-to-concrete connections.” Rep. No. FHWA/TX-89+1126-4F, Texas DOT, Austin, TX.
Cook, R. A. and Prevatt, D. O. (2012). “Base connections for signal/sign 542 structures.” Structures Research Rep. No. BDK75 977-32, Florida DOT, Gainesville, FL.
Cook, R. A. and Tia, M. (2000). “Use of grout pads for sign and lighting structures: Part 1—Structural evaluation.” Structures Research Rep. No. BB-512, Florida DOT, Gainesville, FL.
Foley, C. M., et al. (2004). “Structural analysis of sign bridge structures and luminaire supports.” Rep. No. 04-03, Wisconsin DOT, Madison, WI.
Fouad, F. H., et al. (2003). “Structural supports for highway signs, luminaires, and traffic signals.” NCHRP Rep. No. 494, Transportation Research Board, Washington, DC.
Garlich, M. J., and Thorkildsen, E. T. (2005). “Guidelines for the installation, inspection, maintenance and repair of structural supports for highway signs, luminaries, and traffic signals.” FHWA NHI 05-036, Federal Highway Administration, Washington, DC.
Mathcad 15.0 [Computer software]. Needham, MA, Parametric Technology.
RISA-3D 9.1 [Computer software]. Foothill Ranch, CA, RISA Technologies.
Information & Authors
Information
Published In
Copyright
© 2014 American Society of Civil Engineers.
History
Received: Oct 31, 2012
Accepted: Mar 25, 2013
Published online: Apr 1, 2013
Published in print: May 1, 2014
Discussion open until: Jul 10, 2014
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.