Federal Highway Administration
400 Seventh St., S.W.
Washington, D.C. 20590
May 8, 2007
In Reply Refer To: HSSD/B-158
Mr. Owen S. Denman, P.E.
President and CEO
Barrier Systems Inc.
180 River Road
Rio Vista, CA 94571-1208
Dear Mr. Denman:
Thank you for your letter of December 18, 2006, requesting the Federal Highway Administration’s (FHWA) acceptance of the BarrierGuardTM 800 (BG 800) - Minimum Deflection System of Highway Care, Ltd. and Laura Metaal Eygelshoven, BV, for use on National Highway System under the provisions of the National Cooperative Highway Research Program (NCHRP) Report 350 "Recommended Procedures for the Safety Performance Evaluation of Highway Features". Accompanying your letter was a report on testing of the BarrierGuardTM 800 - Minimum Deflection system prepared by Safe Technologies Inc, test videos, drawings and previously prepared crash test reports providing additional information and background, including report on crash testing of regular BarrierGuardTM 800 system of October 2004 and report on crash testing of BarrierGuardTM 800 with Intermediate Anchors of October 2005.
Longitudinal barrier systems should meet the guidelines contained in the NCHRP Report 350, "Recommended Procedures for the Safety Performance Evaluation of Highway Features". FHWA Memorandum “Action: Identifying Acceptable Highway Safety Features” of July 25, 1997 provides further guidance on crash testing of longitudinal barriers.
The previously approved BarrierGuardTM 800 system (acceptance letter HSA-10/B-131) is a high containment and low deflection steel barrier designed for both permanent applications and temporary use in roadwork situations, preventing penetration of errant vehicles into working areas. It is constructed from 5-mm (0.2”) thick A36 galvanized steel panels assembled in either 6-meter (19.7 ft) or 12-meter (39.4 ft) segments. Each segment is 800-mm (31.5”) high with a base width of 540 mm (21”) and a top width of 230 mm (9”). The BarrierGuardTM 800 has a sloped face with a "step" 255 mm (10”) above the ground. Each 12 meter segment weighs approximately 1080 kg (2381 lb). The system is anchored at each end and at a point approximately 6 m (20 ft) in from each end. The test level 3 (TL-3) dynamic deflection of the BarrierGuardTM 800 system was reported to be 1000 mm (39.4”) for Test 3-21 conditions and estimated to be 1500 mm (78.8”) for Test 3-11 conditions.
The BarrierGuardTM 800 - Minimum Deflection system is a modification of the previously approved BarrierGuardTM 800 system designed to minimize the dynamic deflection of the system. Minimum Deflection systems are valuable in application where there is only limited space available, such as bridge deck repairs/replacement projects. To achieve this reduction in deflection, BarrierGuardTM 800 - Minimum Deflection system incorporates the following modifications to the standard BarrierGuardTM 800:
Drawings of the BarrierGuardTM 800 - Minimum Deflection system are provided in Enclosure 1.
Test article installation
The barrier installation consisted of eight 6 meter (20ft) sections for a total length of 48 meters (157 ft). The test article configuration and layout, including points of intersection, anchorage and impact, are summarized in the drawing provided in Enclosure 1.
The NCHRP Report 350 requires that in order for the length-of-need of longitudinal barriers to meet the NCHRP Report 350 TL-3 criteria they must successfully pass tests 3-10 and 3-11 while test S3-10 is optional. However, since your company’s regular BarrierGuardTM 800 system (without intermediate anchors) was fully tested and approved before (acceptance letter HSA-10/B-131), you ran only test 3-11 on the BarrierGuardTM 800 - Minimum Deflection system. The assumption was that this test will be more critical than the test 3-10 since it will deliver the maximum load to the anchor point and connection and evaluate the strength of the system in containing and redirecting the 2000P test vehicle.
Taking into account that previous 3-10 comparable crash tests on regular BarrierGuardTM 800 system recorded occupant impact velocities and ridedown accelerations well below the maximum limits (6 m/s and 9.6 g, respectively), it can be reasonably assumed that while increase in lateral stiffness of the barrier provided by BarrierGuardTM 800 - Minimum Deflection system may lead to an increase in the occupant risk values, they will remain within the maximum NCHRP 350 limits. I therefore agree that test 3-10 on the BarrierGuardTM 800 - Minimum Deflection system is redundant and can be waived.
The full-scale NCHRP Report 350 Test 3-11 conducted on your company’s BarrierGuardTM 800 - Minimum Deflection system involved a 2000P vehicle impacting the device at 101.4 km/h and 25.0 deg. angle with the impact point 23 meters (76 ft) from the upstream end at a section joint and anchor point. The test vehicle impacted the article, was redirected away from the barrier, and lost contact with the barrier downstream from the impact point at a velocity of 72.4 km/h and an angle of 14 degrees.
The impacted and the downstream barrier sections received moderate damage at the T-top and anchor assembly. The barrier was dented in the impact area, but did not separate or tear. The anchors upstream and downstream from the impact did not lift or crack the concrete or asphalt. The total permanent deflection was 19mm (0.75") at the base and 203 mm (8") at the T- top and the total dynamic deflection was 76mm (3") at the base and 305 mm (12") at the T-top.
All occupant risk factors were within the limits specified in NCHRP Report 350. The theoretical occupant impact velocity values in the longitudinal and lateral directions were 5.9 and 6.5 m/s respectively and the theoretical occupant ridedown acceleration values in the longitudinal and lateral directions were 5.5 and 7.8 g’s respectively. A summary of the test results is provided in Enclosure 2.
It is my understanding that you also intending to use the BarrierGuardTM 800 - Minimum Deflection system with the intermediate anchoring every 12 m instead of 6 m. In October 2005 you conducted test 3-11 on the similar system with intermediate anchors every 12 m, however without T-top. While all evaluation criteria were met, the pitch angle was somewhat higher than in free standing tests previously submitted. I therefore agree that if this system is used with the T-top, as BarrierGuardTM 800 - Minimum Deflection system with anchoring every 12 m, its performance will be acceptable. Of course, maximum permanent and dynamic deflection will increase compared to the BarrierGuardTM 800 - Minimum Deflection system anchored every 6 m. The estimated deflection for the system with a T-top and 12 m anchors is less than that observed in the 3-11 test conducted without the T-top, approximately 890 mm (35”).
From the documentation accompanying your request for acceptance it is clear that you also request the acceptance of applications where regular BarrierGuardTM 800 system (without intermediate anchors and T-top) and BarrierGuardTM 800 - Minimum Deflection system are used in combinations, provided that transitions are used. You specified that to provide such transitions T-top is to begin a min of 12 m (39.4 ft) prior to any anchor and run a minimum 12 m (39.4 ft) past anchors with T-top transition sections extending additional 1.5 m (4.9 ft). No specific tests were conducted to test these transitions, however test 3-21 on the regular BarrierGuardTM that you successfully conducted in October 2004 (acceptance letter HSA-10/B131) is relevant to predict crash performance of such transitions. In that test the impact point was selected 15 m (49.2 ft) from the downstream end of the system, which was anchored at two points - at the end and 6 m (20 ft) in from the end. Thus, this impact point was located at the transition from freestanding and anchored sections of the barrier. Taking into account that this 3-21 test was successful and that you also propose the use of T-top as an additional treatment smoothening stiffness changes in the transitions between freestanding and anchored sections, I agree that full crash testing of transitions between BarrierGuardTM 800 system (without intermediate anchors and T-top) and BarrierGuardTM 800 - Minimum Deflection systems would be redundant.
In summary I agree that BarrierGuardTM 800 - Minimum Deflection system, as described above, meets the appropriate evaluation criteria for the NCHRP 350 TL-3 longitudinal barriers and may be used at all appropriate locations on the NHS when selected by the contracting authority, subject to the provisions of Title 23, Code of Federal Regulations, Section 635.411 as they pertain to proprietary products. It can also be used with intermediate anchoring every 6m or 12 m when using the T-top adaptor and in combinations with regular BarrierGuardTM 800 provided that proper transitions are used and changes in deflections are taken into account. This acceptance is based on the reported crash performance of the BarrierGuardTM 800 - Minimum Deflection system. Further, I am assuming that production models will be identical to the prototype test units.
Please note the following standard provisions that apply to the FHWA letters of acceptance:
George E. Rice, Jr.
Title 23, Code of Federal Regulations
§ 635.410 Buy America requirements.
(a) The provisions of this section shall prevail and be given precedence over any requirements of this subpart which are contrary to this section. However, nothing in this section shall be construed to be contrary to the requirements of §635.409(a) of this subpart.
(b) No Federal-aid highway construction project is to be authorized for advertisement or otherwise authorized to proceed unless at least one of the following requirements is met:
(1) The project either: (i) Includes no permanently incorporated steel or iron materials, or (ii) if steel or iron materials are to be used, all manufacturing processes, including application of a coating, for these materials must occur in the United States. Coating includes all processes which protect or enhance the value of the material to which the coating is applied.
(2) The State has standard contract provisions that require the use of domestic materials and products, including steel and iron materials, to the same or greater extent as the provisions set forth in this section.
(3) The State elects to include alternate bid provisions for foreign and domestic steel and iron materials which comply with the following requirements. Any procedure for obtaining alternate bids based on furnishing foreign steel and iron materials which is acceptable to the Division Administrator may be used. The contract provisions must (i) require all bidders to submit a bid based on furnishing domestic steel and iron materials, and (ii) clearly state that the contract will be awarded to the bidder who submits the lowest total bid based on furnishing domestic steel and iron materials unless such total bid exceeds the lowest total bid based on furnishing foreign steel and iron materials by more than 25 percent.
(4) When steel and iron materials are used in a project, the requirements of this section do not prevent a minimal use of foreign steel and iron materials, if the cost of such materials used does not exceed one-tenth of one percent (0.1 percent) of the total contract cost or $2,500, whichever is greater. For purposes of this paragraph, the cost is that shown to be the value of the steel and iron products as they are delivered to the project.
(c)(1) A State may request a waiver of the provisions of this section if;
(i) The application of those provisions would be inconsistent with the public interest; or
(ii) Steel and iron materials/products are not produced in the United States in sufficient and reasonably available quantities which are of a satisfactory quality.
(2) A request for waiver, accompanied by supporting information, must be submitted in writing to the Regional Federal Highway Administrator (RFHWA) through the FHWA Division Administrator. A request must be submitted sufficiently in advance of the need for the waiver in order to allow time for proper review and action on the request. The RFHWA will have approval authority on the request.
(3) Requests for waivers may be made for specific projects, or for certain materials or products in specific geographic areas, or for combinations of both, depending on the circumstances.
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