Refer to: HSA-10/WZ-100 Amendment #4
Mr. Bill Korman
Korman Signs, Incorporated
3029 Lincoln Avenue
Richmond, VA 23228
Dear Mr. Korman:
Thank you for your letter of January 7, 2004, requesting Federal Highway Administration (FHWA) acceptance of a modication to your company's crashworthy Type III Barricades as for use in work zones on National Highway System (NHS). Accompanying your letter were detailed drawings and descriptions of the Stub Tee Bracket and a Hinge Plate Bracket. You requested that we find these modified devices acceptance for use on NHS under the provisions of National Cooperative Highway Research Program (NCHRP) Report 350 "Recommended Procedures for the Safety Performance Evaluation of Highway Features."
The FHWA accepted your company's perforated square steel tube (PSST)-framed Type III Barricades via the original WZ-100 dated June 20, 2002. Further modifications to the devices in WZ-100 were made in three subsequent amendments. Your present request is to allow either a Stub Tee Bracket or a Hinge Plate Bracket to form the connection of the horizontal skid to the upright support. These connections are shown in the enclosed drawings for reference.
The Stub Tee Bracket functions like the generic welded stub based barricades described in WZ-85 where the upright tubes fit into a square tube welded to the ski. The Stub Tee Bracket is formed by welding two short sections of PSST together to form a "tee" which can be bolted to the skid. The Stub Tee Bracket may also be used to support the PSST to form the Stub Tee Bracket you can join various sizes of frame elements.
The Hinge Plate Bracket is a splice plate bracket consisting of one or two hinge plates that are bolted or welded to the horizontal skid. It may also be fastened to an upright in order to support a horizontal PSST stiffener. The hinge plates may also be welded to a short section of PSST that is used to fix the splice in place. When the barricade is struck the bolts slip up and out of the slot.
We concur that these two splice schemes are similar in nature to generic splice details that have already been found acceptable. Therefore, the Stub Tee Bracket and a Hinge Plate Bracket described abovd and detailed in the enclosed drawings are acceptable for use on NHS under the range of conditions tested, when proposed by a State.
Please note the following standard provisions that apply to FHWA letters of acceptance:
John R. Baxter, P.E.
Director, Office of Safety Design
Office of Safety