USA Banner
  U.S. flag
              An official website of the United States government Here's how you knowOfficial US Government Icon
              **Official websites use .gov**A **.gov** website belongs to an official government organization in the United States.
            Secure Site Icon
              **Secure .gov websites use HTTPS**
                  A **lock** ( A locked padlock ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites. 
 U.S. Department of Transportation Icon United States Department of Transportation
 Search DOT
            Search
                    About FHWAFHWA Organization
                Headquarters Offices
                Field Offices
                Strategic Plan
                Business Opportunities
                Staff Directories
                Careers
                Highway History
                Contact UsProgramsAcquisition Management
                Civil Rights
                Federal Lands Highway
                Infrastructure
                Innovative Program Delivery
                Operations
                Planning, Environment, and Realty
                Policy
                Research, Development, and Technology
                Safety
                Browse by TopicsResourcesCore Highway Topics
                Federal Aid Essentials
                Automation
                Complete Streets
                Laws and Regulations
                Policy & Guidance Center
                Section 508
                Publications and Statistics
                Professional Development
                National Highway Institute
                Resource Center
                Accessibility Resource Library
                FHWA Research LibraryNewsroomPress Releases
                Speeches & Testimony
                Photos
                Videos
                Media ContactsMenu FHWA Highway Safety Programs Home
                        Safety
                        Roadway Departure Safety
                        Reduce Crash Severity
                        Hardware Eligibility Letters


            
            In This Section
        Roadway Departure Safety
                Strategic Approach
                                Strategic Plan
                Crash Emphasis Brochures
                Focused Approach
                Noteworthy Practices
                Partner Resources
                Keep Vehicles on the Road
                                Pavement Friction
                Horizontal Curve Safety
                Rumble Strips and Rumble Stripes
                Nighttime Visibility
                Provide for a Safe Recovery
                                SafetyEdge
                Clear Zones
                Reduce Crash Severity
                                Overview
                Hardware Eligibility Letters
                Focus on Reducing Rural Roadway Departures (FoRRRwD)
                                Overview
                All Public Roads
                Proven Countermeasures
                Systemic Approach
                Safety Action Plans
                FoRRRwD Resources
                
                Safety Eligibility Letter B-228
  
  **Hardware Type:**
            Longitudinal Barriers and Bridge Rails
                          **Code:**
            B-228
                          **Date:**
            12/19/2011
                          **Testing Criteria:**
            MASH
                          **Manufacturer:**
            MWRSF
                          **Device Description:**
            31 in Midwest Guardrail System (MGS) Bridge Rail
                          **View PDF:**
            b228.pdf (859.47 KB)
    
    "FHWA Logo"

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

November 18, 2011

In Reply Refer To:
HSST/B-228

Mrs. Karla A. Lechtenberg
Midwest Roadside Safety Facility
130 Whittier Research Center
P. O. Box 830853
Lincoln, NE  68583-0853

Dear Mrs. Lechtenberg:

This letter is in response to your request for the Federal Highway Administration (FHWA) to review a roadside safety system for eligibility for reimbursement under the Federal-aid highway program.

Name of system:
			31-inch (787-millimeter) Midwest Guardrail
			System (MGS) Bridge RailType of system:
			Permanent Bridge BarrierTest Level:
			AASHTO Manual for Assessing Safety Hardware, TL-3Testing conducted by:
			Midwest Roadside Safety FacilityDate of request:
			July 20, 2011Task Force 13 Designator:
			SBW04cBased on a review of crash test results submitted by the manufacturer certifying the device described herein meets the crashworthiness criteria of the American Association of State Highway and Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH), the device is eligible for reimbursement under the Federal-aid highway program.  Eligibility for reimbursement under the Federal-aid highway program does not establish approval or endorsement by FHWA for any particular purpose or use.

The FHWA, the Department of Transportation, and the United States Government do not endorse products or services and the issuance of a reimbursement eligibility letter is not an endorsement of any product or service

**Decision**
The following device is eligible, with details provided below:

31-inch (787-millimeter) Midwest Guardrail System (MGS) Bridge Rail**Requirements**
Roadside safety devices should meet the guidelines contained in the American Association of State Highway and Transportation Officials' Manual for Assessing Safety Hardware (MASH).  The FHWA Memorandum "Identifying Acceptable Highway Safety Features" of July 25, 1997 provides further guidance on crash testing requirements of longitudinal barriers.

**Description**
The test installation consisted of 68 feet 9 inches (21.0 meters) of bridge rail installed between two approach sections of MGS measuring 50 feet (15.2 meters) and 56 feet 3 inches (17.1 meters) in length, for a total system length of 175 feet (53.3 meters).  Standard 12-gauge (2.66 millimeters thick) W-beam guardrail was used throughout, and no approach guardrail transition sections were used at the guardrail-to bridge rail interfaces.  All lap-splice connections in the W-beam rail were configured to reduce vehicle snag at the splice during the test.

The MGS was constructed in two sections with a total of seventeen guardrail posts.  Post nos. 3 through 8 and 32 through 38 were galvanized ASTM A36 steel W6x8.5 (W152x12.6) sections measuring 72 inches (1,829 millimeters) long, as shown in Figures 86 through 88.  Post nos. 1, 2, 39, and 40 were timber posts measuring 51⁄2 inches wide × 71⁄2 inches deep × 46 inches long (140 millimeters × 191millimeters × 1,168 millimeters) and were placed in 72 inches (1,829 millimeters) long steel foundation tubes.  The timber posts and foundation tubes are used on many tangent guardrail terminals. Post nos. 1 through 8 and 32 through 40 were spaced 75 inches (1,905 millimeters) on center with a soil embedment depth of 40 inches (1,016 millimeters).  The posts were placed in a compacted, coarse, crushed limestone material that met Grading B of AASHTO M147-65 (1990) as described in MASH.  For post nos. 3 through 8 and 32 through 38, 6 inches wide × 12 inches deep × 141⁄4 inches long (152 millimeters × 305 millimeters × 362 millimeters) wood spacer blockouts were used to block the rail away from the front face of the steel posts.

Standard 12-gauge (2.66 millimeters thick) W-beam rails with post bolt slots at 75 inches (1,905 millimeters) intervals were placed between post nos. 1 through 8 and 32 through 40.  The W-beam's top rail height was 31 inches (787 millimeters), with a 247⁄8 inches (632 millimeters) center mounting height. Rail splices were located at the center of the guardrail span locations.

The bridge rail was constructed with twenty-three guardrail posts.  Post nos. 9 through 31 were ASTM A36 steel S3x5.7 (S76x8.5) sections measuring 44 inches (1,118 millimeters) long.  Post nos. 9 through 31 were spaced 371⁄2 inches (953 millimeter) on center and mounted in steel socket assemblies.  A steel bolt was passed through the web of the post and both sides of the socket to support the bridge rail and posts.  The sockets were anchored to the deck with a through-deck bolt that passed through the upper strap of the socket and a lower angle plate which was bolted to the socket.

Standard 12-gauge (2.66 millimeters thick) W-beam rails with post bolt slots at 371⁄2 inches (953 millimeters) intervals were placed between post nos. 9 through 31.  The W-beam's top rail height was 31 inches (787 millimeters), with a 247⁄8 inches (632 millimeters) center mounting height. Rail splices were located at bridge rail post locations.  No blockouts were used with the bridge rail, and 6 inches (152 millimeters) long, 12-gauge (2.66 millimeters thick) W-beam backup plates were positioned between the bridge rail and bridge posts at both splice and non-splice locations.  The rail was connected to the posts with 5⁄16-inch (7.9 millimeters) diameter ASTM A307 Grade A bolts and nuts and 13⁄4 inches × 13⁄4 inches × 1⁄8 inches (44 millimeters × 44 millimeters × 3.2 millimeters) square washers that were positioned on the traffic-side face of the bridge rail.  A 75 feet long × 4 feet wide × 8 inches thick (22.86 meters × 1.22 meters × 203 millimeters) concrete bridge deck was designed and built for crash testing the bridge rail.

The thickness of the bridge deck was increased to 12 in. (305 mm) for a width of 12 in. (305 millimeters) adjacent to the rigid concrete surface and was anchored to the outer vertical edge of the rigid pavement. This deck was intended to simulate a slab-on-girder bridge deck. Anchorage consisted of bent no. 5 (16 millimeters diameter) upper dowels spaced 9 inches (229 millimeters) on center that were embedded in epoxy.  Additional no. 4 (13 millimeters diameter) lower dowels were spaced 18 inches (457 millimeters) on center.  All dowels and deck reinforcement were comprised of ASTM A615 steel.

The concrete deck was designed according to the Nebraska Department of Roads (NDOR) *Bridge Operations, Policies, and Procedures Manual* and the empirical design guidelines presented in the *AASHTO LRFD Bridge Design Specifications*.  A deck thickness of 8 inches (203 millimeters) was used with concrete having a minimum specified 28-day compressive strength of 4,000 psi (27.6 MPa).  Longitudinal reinforcement consisted of upper no. 4 (13 millimeters diameter) bars on 12 inches (305 millimeters) centers and lower no. 5 (16 millimeters diameter) bars on 12 inches (305-millimeters) centers, with the upper reinforcement offset 6 inches (152 millimeters) from the lower reinforcement. Transverse reinforcement consisted of upper no. 4 (13 millimeters diameter) bars on 12 inches (305 millimeters) centers and lower no. 5 (16 millimeters diameter) bars on 12 inches (305 millimeters) centers, with the upper and lower layers also offset 6 inches (152 millimeters). Top concrete clear cover was 21⁄2 inches (64 millimeters), edge concrete clear cover was 2 inches (51 millimeters), and bottom concrete clear cover was 1-inch (25 millimeters).

Details of this system are included in this correspondence as an enclosure.

**Crash Testing**
The barrier was crash tested at the test facilities at the Midwest Roadside Safety Facility. Longitudinal barriers, such as W-beam bridge rails, must satisfy the impact safety standards provided in MASH in order to be accepted by the Federal Highway Administration (FHWA) for use on National Highway System (NHS) new construction projects or as a replacement for existing designs not meeting current safety standards.   According to TL-3 of MASH, longitudinal barrier systems must be subjected to two full-scale vehicle crash tests. The two full-scale crash tests are as follows:

Test Designation 3-10 consisting of a 2,425-lb (1,100-kg) passenger car impacting the system at a nominal speed and angle of 62 mph (100 km/h) and 25 degrees, respectively.
	Test Designation 3-11 consisting of a 5,000-lb (2,268-kg) 4-door, half-ton pickup truck impacting the system at a nominal speed and angle of 62 mph (100 km/h) and 25 degrees, respectively.**Findings**
Test no. MGSBR-1 featured a 5,174-lb (2,347-kg) 4-door pickup truck that impacted the barrier at a speed of 61.9 mph (99.6 km/h) and at an angle of 24.9 degrees.  The bridge rail successfully redirected the vehicle while meeting all required safety criteria and sustaining a maximum deflection of 48.9 inches (1,242 millimeters), compared to 43.9 inches (1,114 millimeters) for MGS testing under similar impact conditions. In test no. MGSBR-2, a 2,585-lb (1,173-kg) small car impacted the barrier at a speed of 62.3 mph (100.2 km/h) and at an angle of 24.9 degrees. The barrier again successfully redirected the vehicle while meeting all required safety criteria and sustaining a maximum deflection of 28.0 inches (712 millimeters). This deflection was very similar to the 35.9 inches (913 millimeters) deflection measured during testing of the MGS under similar impact conditions.  Crash Test Summary details of this system are provided as enclosures to this correspondence.

Therefore, this system as described is eligible for reimbursement and should be installed under the range of conditions tested, when such use is acceptable to a highway agency.  Please note the following standard provisions that apply to the FHWA eligibility letters:

This letter includes an AASHTO/ARTBA/AGC Task Force 13 designator that should be used to identify any new or updated Task Force 13 drawings.
	This finding of eligibility is limited to the crashworthiness characteristics of the devices and does not cover their structural features, or conformity with the Manual on Uniform Traffic Control Devices.
	Any changes that may adversely influence the crashworthiness of the device will require a new letter.
	Should the FHWA discover that the qualification testing was flawed, that in-service performance reveals unacceptable safety problems, or that the device being marketed is significantly different from the version that was crash tested, we reserve the right to modify or revoke this letter.
	You will be expected to supply potential users with sufficient information on design and installation requirements to ensure proper performance.
	You will be expected to certify to potential users that the hardware furnished has essentially the same chemistry, mechanical properties, and geometry as that submitted for review, and that it will meet the crashworthiness requirements of the FHWA and the AASHTO MASH.
	To prevent misunderstanding by others, this letter is designated as number B-228, and shall not be reproduced except in full.  This letter and the test documentation upon which it is based are public information.  All such letters and documentation may be reviewed at our office upon request.
	This letter shall not be construed as au candidate device, and the FHWA is neither prepared nor required to become involved in issues concerning patent law.  Patent issues, if any, are to be resolved by the applicant.Sincerely yours,

			*/* Signature of Michael S. Griffith */*

			Michael S. Griffith
			Director, Office of Safety Technologies
			Office of Safety U.S. DEPARTMENT OF TRANSPORTATION

**Federal Highway Administration**

1200 NEW JERSEY AVENUE, SE

WASHINGTON, DC 20590

202-366-4000Subscribe to email updates
                    About
  

        
              About FHWA
                Careers
                Org Chart
                Staff Directories
                Work with UsPrograms
  

        
              Acquisition Management
                Civil Rights
                Federal Lands Highway
                Infrastructure
                Innovative Program Delivery
                Operations
                Planning, Environment, and Realty
                Policy
                Research, Development, and Technology
                SafetyPolicies, Rights, Legal
  

        
              About DOT
                Accessibility
                Budget and Performance
                Civil Rights
                FOIA
                Information Quality
                No FEAR Act
                Office of Inspector General
                Privacy Policy
                USA.gov
                Web Policies and Notices
                Web StandardsNews & Events
  

        
              Newsroom
                Press Releases
                Speeches & Testimony
                Media Contacts
                Connect with Us