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FHWA Home / Safety / Roadway Departure / Safety Eligibility Letter B-134C

Safety Eligibility Letter B-134C

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U.S. Department of Transportation
Federal Highway Administration

1200 New Jersey Ave. S.E.
Washington, D.C. 20590

July 28, 2008

Reply Refer To: HSSD/B-134C

Mr. Barry Stephens
Sr. Vice President Engineering
Energy Absorption Systems, Inc.
3617 Cincinnati Avenue
Rocklin, CA. 95765

Dear Mr. Stephens:

This letter is in response to your request for Federal Highway Administration (FHW A) acceptance of a roadside safety system for use on the National Highway System (NHS).

Name of system: 12M Vulcan Barrier and Vulcan Barrier Anchor System
Manufacturer: Energy Absorption Systems, Inc. (EASI)
Type of system: Steel tlrie beam portable barrier system
Test Level: NCHRP Report 350 TL-3
Testing conducted by: E-Tech Testing Services, Inc.
Date of request: March 10, 2008
Date of completed package: March 10, 2008

You requested that we find this system 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."

Requirements

Roadside safety 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 requirements of longitudinal barriers.

Description

The 12-Meter Vulcan portable longitudinal barrier segment is shown in the enclosed drawing for reference. Each segment is 8 13 mm tall × 546 mm wide × 11 ,754 mm long (32 in × 21.5 in × 38.6 ft) and weighs 1185 kg (2612 pounds). The 12M Vulcan segments incorporate six thrie beam guardrail panels integrated into both sides at a height designed to optimize vehicle redirection. The design also incorporates a lower rub rail along the entire length to help redirect the wheels of impacting vehicles. Thirteen steel bulkheads are incorporated into each segment to help distribute impact loads from one side to the other. A lifting tab is built into the top of the center bulkhead to permit easy grappling and transport. The ends of each Vulcan incorporate tabs that allow the pinning together when segments are butted together. Pinning is accomplished using 48 mm (2 in) diameter (OD) steel pins with a wall thickness of 10 mm (0.39 in). To minimize corrosion, all Vulcan components are hot dipped galvanized. When installed in continuous straight segments, a gap-filling steel plate can be added which helps the pinned joint support a bending moment, thereby reducing lateral deflection. These gap-filling steel plates were used in the crash test you submitted for review. You noted that the 12M Vulcan's end bulkheads can also be used to connect an appropriate crash cushion to protect the exposed end of a run of 12M Vulcan.

You noted that the 12M Vulcan segments used in the crash test was restrained from moving laterally by a new Vulcan Barrier Anchoring System (VAS). This system consists of a 9.5 mm x 76.2 mm (0.37 in x 3 in) ASTM A-36 steel strap that can be inserted through the base of the 12M Vulcan and then anchored to a rigid surface using (2) two 19 mm diameter by 250 mm long (3/4 in x 10 in) threaded rods (made from ASTM A 193 steel) which are locked into their respective anchor holes using Energy's MP-3 anchoring compound.

Crash Testing

To test worst case impact conditions, NCHRP 350 test 3-11 was conducted into the 12M Vulcan Barrier anchored using the new VAS. The test system consisted of four freestanding 12M Vulcan segments pinned together and anchored with three VAS straps per 12M Vulcan section. Each VAS strap was held down with two MP-3 threaded rods embedded into concrete or asphalt at a depth that was appropriate per manufactures recommendations. The impact point for this test is identified and the test data summary page is enclosed for reference. The test was successful, with the 2000p vehicle being smoothly redirected at a shallow angle back into the traffic flow. Maximum dynamic deflection of the upper portion of the 12M Vulcan during this anchored test was 300 mm (12 in). You noted that the deflection at the base of the Vulcan Barrier was 76 mm (3 in). NCHRP Test 3-10 was waived as the original Vulcan Barrier was tested using the 820C vehicle.

Findings

Based upon the successful completion of the aforementioned 350 test, we concur that the Energy Absorption Systems' 12M Vulcan Barrier meets the NCHRP Report 350 criteria for Test 3-11. Successful completion of this test qualifies the 12M Vulcan for use on the NHS as TL-2 or TL-3 barrier under the range of conditions tested, when such use is acceptable to a highway agency. We also concur that the Vulcan Barrier Anchoring System is an acceptable anchoring system that can be used where lateral deflection of the barrier must be controlled, with lateral displacement at TL-3 impact conditions expected to range from 76 mm (3 in) to 300 nm1 (12 in). The freestanding, unshielded end of this design is not crashworthy and requires either shielding with a suitable impact attenuator or introduced outside the appropriate clear zone. However we do concur that since the 12M Vulcan has the same design characteristics and end features as the already accepted 4M Vulcan, the same end treatments are also acceptable (reference the FHW A acceptance letter B-134, dated February 14, 2005).

Please note the following standard provisions that apply to FHW A letters of acceptance:

This acceptance is limited to the crash worthiness characteristics of the systems and does not
cover their structural features, nor conformity with the Manual on Uniform Traffic Control
Devices.

 

Sincerely yours,

/* Signature of David A Nicol*/
David A. Nicol, P.E.
Director, Office of Safety Design
Office of Safety

2 Enclosures

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Diagram: Vulcan Barrier Anchoring System

General Information
   Test Agency E-TECH Testing Services, Inc
   Test Designation NCHRP 350 Test 3-11
   Test No. 0 1-8430-005
   Date 3/2/07
Test Article
   Type Vulcan™ Barrier with Concrete Anchoring System. Segments 12000 × 813 × 546 mm (L×H ×W). 1094 kg per Segment
   Installation Length (4) pinned Segments 48 m overall
   Material of key elements 12 Ga. AASHTO M180 galvanized steel
Panels, nom. 1-½" Sch 80 ASTM A53 pipe
Pins.9.5 × 76.2mm ASTMA36AnchorStraps
      Foundation and Anchoring Nominal 27.6 MPa concrete pad w/Vulcan
Strap Anchoring System (3) per 12 m Segment with (2) 250 mm long ASTM A 193 B7 Studs per strap at nominal 200 mm embedment using MP-3 Anchoring System
Test Vehicle
   Type Production Model
   Designation 2000P
   Model 1988 GMC C2500
   Mass
      Curb 1923
      Test inertial 1987
      Dummy N/A
      Gross Static 1987
Impact Conditions
   Speed (km/h)e 101.8
   Angle (deg) 25
   Impact Severity (kJ)e 141.8
Exit conditions
Speed (km/h) 56.6
Angle (deg - veh. e.g.) 4
Occupant Risk Values
Impact Velocity (m/s)
x-direction 5.5
y-direction 4.8
Ridedown Acceleration (g's)
x-direction -9.0
y-direction 13.2
European Committee for Normalization (CEN) Values
THIV 25.3
PHD (g's) 13.5
ASI 0.9
Test Article Deflections (m)
   Dynamic 0.3
   Permanent 0.3
Vehicle Damage (Primary Impact)
Exterior
VDS LFQ-4
CDC HLFEW1
Interior
VCDI LF0001000
Maximum Deformation 62
Post-Impact Vehicular Behavior (deg - rate gyro)
Maximum Roll Angle 31.5
Maximum Pitch Angle 16.7
Maximum Yaw Angle 38.2

Figure 1. Summary of Results – Vulcan Barrier Anchoring System NCHRP 350 Test 3-11

Page last modified on January 17, 2013.
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