APPENDIX B: CRASH TESTING OF RPC POSTS AND BLOCKOUTS
Report on the crash testing of RPC posts and blockouts at the
Federal Outdoor Impact Laboratory (FOIL) at TFHRC in McLean, Virginia.
Extract from reference McDevitt and Dutta (1993)
"In order to investigate the suitability of
was expected because wood posts also break
Rivenite posts and blockouts for guardrails, a 100-
under these test conditions. However, since the
ft- (30.5-m-) long test section of guardrail was con-
Rivenite posts are nonfibrous, they broke cleanly
structed at the Federal Outdoor Impact Labora-
in a horizontal plane at groundline. The test data
tory (FOIL) at TFHRC in McLean, Virginia. The
met all of the evaluation criteria in National
upstream end of the guardrail was anchored with
Cooperative Highway Research Program Report
a 37.5-ft- (11.4-m-) long BCT. A cable anchorage
No. 230 (Michie 1981). The maximum lateral
was used on the downstream end. The 6-in 8-in.
deflection of the guardrail was two ft (609 mm).
(152-mm 203-mm) Rivenite posts were driven
Under the same test conditions, a guardrail with
into the ground by a subcontractor that special-
wood posts and blockouts deflected ten in (254
izes in constructing guardrails. It was found that
mm) (AASHTO, 1977). This test indicates that the
the Rivenite posts could readily be driven, but they
Rivenite posts are not a one-for-one substitute
required about twice as many hammer blows as
for either the Douglas fir or the Southern Yellow
wood posts. This was due to the greater energy
Pine wood posts that are used in this guardrail
absorption of the Rivenite material. When driven,
system (AASHTO, 1977).
the posts retained their shape and did not mush-
Each guardrail system has its own characteris-
room out on the bottom end. In appearance, this
tic design deflection. For example, the G1 3-cable
guardrail looked very much like the G4 (2w)
guardrail has a design deflection of 11 ft (3.4 m)
W-beam on strong wood post guardrail used by
(AASHTO, 1977). This guardrail with Rivenite
many states (AASHTO, 1977 and 1989).
posts and blockouts can be thought of as a new
In October 1991, this guardrail was crash-tested
guardrail system that will have its own unique
with an 1,800-lb (816 kg) car at 60 mi/h (96.5
design deflection. However, since the FOIL facility
km/h) at an impact angle of 20. The test vehicle
does not have the capability to conduct tests with
was redirected parallel to the guardrail. Several
full-size sedans, the crash test needed to investi-
Rivenite posts were broken in the impact zone and
gate the strength of this guardrail and establish
flew away from the back of the guardrail. This
its design deflection has not yet been conducted."
Figure B1. Crash testing of RPC posts and blockouts at the FHWA FOIL
Laboratory.
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