DYNAMIC EVALUATION OF TIMBER POSTS FOR HIGHWAY GUARDRAILS

AN EXPERIMENTAL PROGRAM WAS PERFORMED ON GUARDRAIL POSTS TO LEARN THE MORE SIGNIFICANT DYNAMIC PROPERTIES. A SPECIAL PENDULUM IMPACT FACILITY WAS USED TO SUBJECT TEST SPECIMENS TO DYNAMIC LOADING THAT SIMULATED A VEHICLE-GUARDRAIL INSTALLATION COLLISION. ONE HUNDRED SPECIMENS OF DOUGLAS FIR, SOUTHERN PINE, RED OAK, AND RED PINE WOOD WERE EVALUATED; FOR COMPARISON 6B8.5 AND 315.7 STEEL MEMBERS WERE TESTED. SIZES OF WOOD POSTS RANGED FROM 4 BY 4 IN. TO 8 BY 8 IN. IN CROSS SECTION. THE POST SPECIMENS WERE RIGIDLY SECURED IN A BASE FIXTURE, AND THE DYNAMIC LOAD WAS APPLIED 24 IN. ABOVE GRADE. BASIC TEST DATA INCLUDE A COMPLETE LOAD RESISTANCE-POST DEFLECTION DETERMINATION FOR EACH SPECIMEN. THE DYNAMIC PROPERTIES OF PEAK RESISTANCE FORCE, AVERAGE RESISTANCE FORCE, AND FRACTURE ENERGY ARE REPORTED FOR WOOD SPECIES AND STEEL MEMBERS. TEST RESULTS SHOW THAT, WHILE DATA SCATTER EXIST WITHIN A WOOD SPECIES AND SIZE TEST GROUP, THE AVERAGE VALUES OF SUCH GROUPS CAN BE PLOTTED IN A MANNER TO GIVE MEANINGFUL TRENDS. PEAK FORCE, AVERAGE FORCE, AND FRACTURE ENERGY ARE SHOWN TO BE A DIRECT AND LINEAR FUNCTION OF MOMENT OF INERTIA. /AUTHOR/

• Record URL:
  • http://onlinepubs.trb.org/Onlinepubs/hrr/1971/343/343-003.pdf
• Supplemental Notes:
  • Sponsored by Committee on Traffic Safety Barriers and Sign, Signal and Lighting Supports and presented at the 59th 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:
  • Michie, Jarvis D
  • Gatchell, Charles J
  • Duke, Theodore J
• 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 19-33
• Monograph Title: Design of traffic safety barriers
• Serial:
  • Highway Research Record
  • Issue Number: 343
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Crashes; Deflection; Dynamic loads; Dynamics; Experiments; Force; Fracture mechanics; Guardrails; Moments of inertia; Posts; Steel; Timber construction; Vehicles
• Uncontrolled Terms: Fracture energy
• Old TRIS Terms: Moment of inertia; Resistance; Timber guardrails
• Subject Areas: Design; Highways; Vehicles and Equipment;

Filing Info

• Accession Number: 00203547
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: Jul 25 1971 12:00AM