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Federal Highway Administration |
400 Seventh St., S.W. Washington, D.C. 20590 |
November 21, 2007
In Reply Refer To: HSSD/B-134C
Mr. Barry D. Stephens, P.E.
Sr. Vice President Engineering
Energy Absorption Systems, Inc.
3617 Cincinnati Avenue
Rocklin, CA 95678
Dear Mr. Stephens:
Thank you for your October 19 letter requesting the Federal Highway Administration’s (FHWA) acceptance of your company’s unanchored Vulcan, a Vulcan-to-CMB Transition and a new Vulcan component called a Hinge segment as test level 3 (TL-3) devices for use on the National Highway System (NHS). In our November 17, 2005, letter B-134A, we accepted the use of Vulcan barrier to be used in conjunction with transitions in runs of CMB. Your current request is an extension of this previous design. You requested that we find these devices acceptable for use on the NHS under the provisions of National Cooperative Highway Research Program (NCHRP) Report 350 “Recommended Procedures for the Safety Performance Evaluation of Highway Features.”
On October 19, 2007, you provided my staff with test results from a crash test conducted on a run of unanchored Vulcan, a Vulcan-to-CMB Transition and a new Vulcan component called a Hinge segment. You requested FHWA’s acceptance of this specific design which is referred to as the Vulcan Gate. The test results of the NCHRP Report 350 for test 3-21 are documented in E-TECH Testing Services’ summary dated August 2007. For this test, five (5) freestanding Vulcan segments were pinned together and the upstream and downstream ends were pinned to unanchored Hinge segments which were pinned to anchored Vulcan-to-PCMB Transition segments to provide longitudinal tension. The impact point was the first Vulcan segment ahead of the new Hinge segment. The 2000p vehicle was redirected and the reported occupant risk values were acceptable. The Crash Data Summary Sheet, as well as drawings for the devices are enclosed for reference
The principle modification is the addition of a short steel, Vulcan-shaped segment that can act as a lateral hinge mechanism. The Vulcan, when configured with this new hinge section, is referred to as the “Vulcan Gate” and hereafter is referred to as VG. Energy conducted capacity test 3-21 to ensure the integrity of this new configuration under TL-3 impact conditions.
A typical VG system is comprised of existing Vulcan segments, two tested and accepted Transitions to CMB, and two new Hinge Segments. The system configuration is depicted in attached drawings V2000 and V6000. The new Hinges may also be used in a run of Vulcan barrier to create a gate opening. The Hinge is constructed of two thrie-beam panels integrated into side panels which identically match the cross-section of the Vulcan. The side panels are attached to the Hinge mid-frame by inserting tabs through slots on the Hinge mid-frame and then pinning the two side panels in place. Pinning is accomplished using (2) 48 mm diameter (OD) steel pins per side panel. The Hinge is also connected to the end Transitions and Vulcan sections with 48 mm diameter (OD) steel pins. When both Hinge side panels are manually removed, the Vulcan sections are able to pivot around the remaining 48 mm diameter (OD) steel pin. To minimize corrosion, all Vulcan components, including the new Hinge segment, are hot dipped galvanized.
Based upon the submitted test results, we concur that the Vulcan Gate meets NCHRP Report 350 evaluation criteria and may be used on the NHS as a TL-2 or 3 longitudinal barrier under the range of conditions tested, when proposed by a State or local transportation agency. We also agree that the successful results support the acceptance of this design using any number of Vulcan segments to configure a Vulcan Gate.
Please note the following standard provisions that apply to the FHWA letters of acceptance:
Sincerely yours, George E. Rice, Jr. |