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 United States 78228-0510

California Department of Transportation

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

Media Info

Pagination: 60 p.

Subject/Index Terms

TRT Terms: Boreholes; Crash tests; Momentum; Pendulum tests; Simulation; Strength of materials; Structural supports; Timber; Traffic signs
Old TRIS Terms: Supports; Timber (Structural)
Subject Areas: Geotechnology; Highways; Materials; Research; I35: Miscellaneous Materials;

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