BUCKLING STRESS FORMULAS FOR OVERHEAD SIGN BRIDGE SUPPORTS

CONTEMPORARY FREEWAY OPERATIONS REQUIRE LARGE SIGNS OVER TRAFFIC LANES. THESE SIGNS ARE USUALLY ATTACHED TO TRUSSES MOUNTED ON VERTICAL SUPPORTS WHICH ARE RESTRAINED CANTILEVER BEAMS. THE 1968 AASHO SPECIFICATIONS REQUIRE THAT THE CRITICAL BUCKLING STRESS BE LIMITED BY A FORMULA BASED ON THEORETICAL AND EXPERIMENTAL INVESTIGATIONS OF A SIMPLE BEAM SUBJECTED TO LOADS PRODUCING PURE BENDING. THE PURPOSE IS TO EXAMINE THIS FORMULA TO DETERMINE ITS APPLICABILITY TO HIGHWAY SIGN SUPPORTS, AND TO DEVELOP A SUITABLE ALTERNATE REQUIREMENTS. RIGOROUS ADHERENCE TO THE PRESENT AASHO REQUIREMENT RESULTS IN UNECONOMICAL OPEN SECTIONS FOR OVERHEAD SIGN BRIDGE SUPPORTS WHICH ARE FIXED AT THE BASE, RESTRAINED FROM LATERAL MOVEMENT AT THE TOP, AND ARE SUBJECTED TO WIND AND DEAD LOADS WHICH PRODUCE LATERAL, TRANSVERSE, AXIAL, AND MOMENT FORCES. THE SAME CONDITIONS EXIST ON ROADSIDE SIGNS WITH TWO OR MORE SUPPORTS, BUT THE CRITICAL BUCKLING STRESS REQUIREMENT DOES NOT GREATLY AFFECT THE SELECTION OF ECONOMICAL FLANGED SHAPES FOR SUCH SUPPORTS. A FORMULA IS DEVELOPED FOR CRITICAL BUCKLING STRESS, AND IT IS SHOWN THAT THIS FORMULA IS IN AGREEMENT WITH AVAILABLE TEST RESULTS. COMPARISONS OF OTHER THEORETICAL BUCKLING FORMULAS WITH TEST DATA ARE ALSO PRESENTED. /AUTHOR/

• Record URL:
  • http://onlinepubs.trb.org/Onlinepubs/hrr/1971/346/346-002.pdf
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0309019575
• Supplemental Notes:
  • Sponsored by Committee on Traffic Safety Barriers and Sign, Signal and Lighting Supports and presented at the 50th Annual Meeting. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
• Authors:
  • Gunderson, R H
  • Cetiner, A
  • Olson, R M
• Conference:
  • 50th Annual Meeting of the Highway Research Board
  • Location: Washington District of Columbia, United States
  • Date: 1971-1-18 to 1971-1-22
• Publication Date: 1971

Media Info

• Media Type: Print
• Features: Appendices; Figures; References; Tables;
• Pagination: pp 11-22
• Monograph Title: Design of Sign Supports and Structures
• Serial:
  • Highway Research Record
  • Issue Number: 346
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Beams; Bridges; Buckling; Cantilevers; Economics; Formulas; Overhead traffic signs; Specifications; Stresses; Structural supports; Traffic signs
• Identifier Terms: American Association of State Highway Officials
• Old TRIS Terms: Supports
• Subject Areas: Bridges and other structures; Design; Economics; Highways;

Filing Info

• Accession Number: 00203579
• Record Type: Publication
• ISBN: 0309019575
• Files: TRIS, TRB
• Created Date: Sep 13 1971 12:00AM