November 4, 2002
Owen S. Denman, P.E.
President, Barrier Systems, Inc.
180 River Road
Rio Vista, CA 94571-1208
Dear Mr. Denman:
In your October 4 letter to Mr. Frederick Wright, former Director of the Federal Highway Administration's Office of Safety, you requested formal review and acceptance of a new longitudinal barrier named the SafeGuard Link System. To support this request, you also sent copies of a September 30, 2002 test report entitled "Barrier Systems, Inc. SafeGuard Link System" prepared by Safe Technologies, Inc. and videotapes of the crash tests that you conducted.
The SafeGuard Link System is a longitudinal barrier constructed from 8-gauge A36 galvanized steel panels assembled in 8-meter segments. These segments are hinged at both ends and contain caster wheel/jack assemblies so individual segments can be released and removed or swung open to allow temporary access through the barrier. Likewise, an entire installation can be pulled to a new location without requiring disassembly of the individual segments. The hinge assemblies are shielded from direct impact by a removable aluminum cover and the segments are connected with a 28.6-mm diameter ASTM C1018 steel pin. The effective length (including the hinge) of each segment is 8.5 m and its overall height is 847 mm. Its base width is 727 mm and the width of its "T" top section is 513 mm. Each segment weighs approximately 1525 kg. Selected design details are shown in Enclosures 1 through 3. The SafeGuard Link System can be used as a "stand alone" temporary barrier or as a removable gate within a run of portable concrete barrier. A transition design was developed and tested for the latter application and is shown in Enclosure 4.
A 68-m long test section (eight 8-m long segments) of the SafeGuard Link System was impacted at 100 km/h with an 820-kg car at 20 degrees and with a 2000-kg pickup truck at 25 degrees. Maximum deflection (with the truck) was reported to be 1920 mm. All NCHRP Report 350 evaluation criteria were met in both tests. Summary reports are shown in Enclosures 5 and 6. You also conducted a test with the pickup truck at 70 km/h into an installation that was 34-m long (four 8-m long segments). Under these test level 2 (TL-2) impact conditions, the dynamic deflection was 1040 mm. Enclosure 7 is the summary data for that test. Finally, you tested the SafeGuard Link System at its critical impact point when three 8-m long segments were inserted into a run comprised of 6-m long portable concrete barrier segments, with three on the upstream end of the test installation and four on the downstream end. The results of this test are shown in Enclosure 8.
Based on the information you submitted, I agree the SafeGuard Link System, as tested, meets NCHRP Report 350 evaluation criteria and may be used on the National Highway System (NHS) as a test level 2 (TL-2) barrier when a minimum of two 8-m segments are upstream from the length of need point and as a test level 3 (TL-3) barrier when a minimum of four segments precede the length of need point. Designers must, of course, remain aware that impacts nearer to either end of an unanchored installation will result in greater deflections and possible penetration into the area behind the barrier. The ends of a SafeGuard Link installation will need to be shielded if located within the design clear zone on projects on the NHS.
The SafeGuard Link System may also be used as a TL-3 barrier to create a temporary opening in a portable concrete barrier when it is inserted into a run of temporary concrete barrier. Based on review of the videotape of the test that was conducted, the concrete barrier segments on either end of the SafeGuard Link System should be 6-m long segments, but the remaining segments may be any length or design that have met Report 350 evaluation criteria.
Since the SafeGuard Link System is both a steel product and is proprietary, the provisions of Title 23, Code of Federal Regulations Sections 635.410 and 635.411 are applicable.
(original signed by Harry W. Taylor)
Carol H. Jacoby, P.E.
Director, Office of safety Design