PENDULUM TESTS OF TIMBER SIGN SUPPORTS

The attached report describes the results of eight pendulum tests on timber poles with four different drilled hole patterns used to reduce the impact resistance of the poles. The pendulum mass weighed 2250 lbs, was equipped with a crushable nose simulating a pre-1974 Chevrolet Vega, and had an impact speed of 20 mph. Only the drilled hole pattern used in Tests 7 and 8 was adequate to limit the change of momentum of the pendulum mass to values under 1100 lb-sec in both tests. This pattern consisted of two 4-inch-diameter holes, one each at 4 inches and 24 inches above-ground, connected with a vertical 3/8-inch-wide saw cut, all placed perpendicular to the pendulum line of approach. The purpose of the pendulum tests was to screen different drilled hole patterns before conducting more costly crash tests. The pendulum tests pointed up the fact that the dynamic strength of the wood poles can be very variable with 50 to 100% variations in the change of momentum from tests on two poles with identical drilled hole patterns. High speed cameras were used to film all eight pendulum tests. (FHWA)

  • Corporate Authors:

    Southwest Research Institute

    6220 Culebra Road, P.O. Drawer 28510
    San Antonio, TX  USA  78228-0510

    California Department of Transportation

    1120 N Street
    Sacramento, CA  USA  95814
  • Authors:
    • Kimball, C E
    • Deel, G W
  • Publication Date: 1980-3

Media Info

  • Pagination: 60 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00325366
  • Record Type: Publication
  • Source Agency: Federal Highway Administration
  • Report/Paper Numbers: FHWA/SWRI-80/01 Intrm Rpt., FCP 41V3-134
  • Contract Numbers: F78TL02
  • Files: TRIS, USDOT, STATEDOT
  • Created Date: Apr 15 1981 12:00AM