October 2, 2003 

Refer to: HSA-10/B-122

Ronald K. Faller, Ph.D., P.E. 

Research Assistant Professor 

Midwest Roadside Safety Facility 

University of Nebraska-Lincoln 

527 Nebraska Hall 

Lincoln, Nebraska 68588-0529 

Dear Dr. Faller: 

In your August 25 letter to Mr. A. George Ostensen, you requested the Federal Highway 

Administration’s formal acceptance of three non-proprietary longitudinal barrier systems for 

use on the National Highway System (NHS). The first design consisted of stacked steel 

H-Sections connected end-to-end and bolted to a simulated bridge deck. It was developed 

specifically for use at locations where typical lateral deflections for temporary concrete barrier 

would be considered excessive. This design was accepted for use on the NHS as a test level 3 

barrier in my September 12 letter, B-117. The second design, an F-shape precast concrete barrier 

bolted to a bridge deck to eliminate most deflection, will be addressed in this letter, and the final 

system, w-beam guardrail posts embedded in solid rock, will be covered in a third letter. 

Each barrier segment used in the test installation of the concrete barrier bolted to a simulated 

bridge deck was a 3.8-m long F-shape barrier, having a minimum 28-day compressive strength 

of 34.5 MPa (5,000 psi). All of the steel reinforcement in the barrier was ASTM A615 Grade 60 

rebar, except for the loop bars, which were ASTM A706 Grade 60 steel. Barrier reinforcement 

consisted of three 16M (No. 5) and two 13M (No. 4) longitudinal bars, twelve 13M (No.4) bars 

for the vertical stirrups, and six 19M (No. 6) bars for the anchor bolt block reinforcement loops. 

The anchor bolt block loops were 889-mm (35-in.) long and were bent into a U-shape to 

reinforce the anchor bolt area. The barriers segments were connected by two sets of three 

separate rebar loops made from ASTM A706 Grade 60 19M (No. 6) bars on each barrier 

interconnection. Each segment end had one or two upper and one or two lower loops (for a total 

of three loops) and the adjacent section had one loop that fit between the two-loop connection of 

the first section, and two loops that fit over and below the adjacent single loop. The vertical pin 

used in the connection consisted of a 32-mm (1.25-in.) diameter x 711-mm (28-in.) long round 

bar composed of ASTM A36 steel. Because of the double shear, triple loop configuration, no 

retaining nut was used on the vertical pin. 

The barriers were fastened to the concrete bridge deck with a 29-mm (1.125-in.) diameter ASTM 

A307 anchor bolts with heavy hex nuts and 76-mm (3-in.) x 76-mm (3-in.) x 13-mm (0.5-in.) 

thick washers at each anchor bolt location. Each anchor bolt was epoxied into the concrete to an 
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embedment depth of approximately 305 mm (12 in). These bolts were installed only on the 

traffic side of the barrier in order to reduce the propensity for barrier tipping and subsequent 

vehicle climbing and vaulting. In separate correspondence, you indicated that alternative 

anchoring designs, including through-bolting, would be acceptable as long as the full tensile 

strength of the anchor bolts can be developed. Overall barrier dimensions and reinforcement 

details are shown in Enclosure 1. 

The National Highway Cooperative Research Program (NCHRP) Report 350 test 3-11 was 

successfully conducted on the final design and is described in the Midwest Roadside Safety 

Facility’s August 22 report entitled, Development and Evaluation of a Tie-Down System for the 

Redesigned F-Shape Concrete Temporary Barrier.” Enclosure 2 is a summary sheet of the test 

results. All NCHRP Report 350 evaluation criteria were met. The maximum vehicle roll angle 

was reported to be 34 degrees. Maximum pitch, although relatively high, was not reported. The 

concrete spalled at all bolt locations on the two barrier segments in the impact zone (segments 8 

and 9) and major structural failure was reported near midspan on segment 9. This failure 

possibly contributed to the relatively high roll and pitch angles noted after impact. Additional 

longitudinal reinforcing would likely improve barrier performance and reduce future 

maintenance/replacement costs. Dynamic deflection, including tipping of the top of the barrier, 

was limited to 287 mm (11.3 inches). Permanent deformation was 89 mm (3.5 inches). 

I agree with your conclusion that this design met all NCHRP Report 350 evaluation criteria for a 

test level 3 barrier and conclude that it can be used as a temporary barrier on concrete bridge 

decks on the NHS when its use is acceptable to the contracting agency. 

Sincerely yours, 

 (original signed by John R. Baxter) 

John R. Baxter, P.E. 

 Director, Office of Safety Design 

2 Enclosures 


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0.044 sec 0.084 sec 0.231 sec 0.469 sec 0.000 sec

! Test Number . . . . . . . . . . . . . . . . . . . . . KTB-1! Date . . . . . . . . . . . . . . . . . . . . . . . . . . . 7/31/02! Appurtenance . . . . . . . . . . . . . . . . . . . . Kansas Temporary Barrier

Tie Down System

! Total Length . . . . . . . . . . . . . . . . . . . . . 62.23 m! Placement . . . . . . . . . . . . . . . . . . . . . . 25 mm from concrete bridge deck edge! Key Elements . . . . . . . . . . . . . . . . . . . . Nine 3,810-mm long Kansas 

Temporary BarriersSeven 3,810-mm long Iowa F-ShapeTemporary Barriers

! Barrier Joint Pin Connections . . . . . . . 32-mm diameter by 712-mm long A36

steel rod with 64x102x132-mm plate

! Tie-Down Anchors . . . . . . . . . . . . . . . . 28.575 mm ASTM A307 Threaded Dowels

Number per Barrier . . . . . . . . . . . . 3Embedment into Concrete . . . . . . . 305 mm

Placement . . . . . . . . . . . . . . . . . . . Traffic side only

! Vehicle Model . . . . . . . . . . . . . . . . . . . 1997 Chevrolet 2500 3⁄4-ton pickup

Curb . . . . . . . . . . . . . . . . . . . . . . . 1,991 kgTest Inertial . . . . . . . . . . . . . . . . . . 2,018 kgGross Static . . . . . . . . . . . . . . . . . . 2,018 kg

! Vehicle Speed

Impact . . . . . . . . . . . . . . . . . . . . 99.8 km/hrExit (resultant) . . . . . . . . . . . . . . 81.5 km/hr

! Vehicle Angle

Impact (orientation) . . . . . . . . . . . . . . . 25.3 degExit (trajectory) . . . . . . . . . . . . . . . . . . 14.4 deg

! Vehicle Snagging . . . . . . . . . . . . . . . . . . . . . None ! Vehicle Pocketing . . . . . . . . . . . . . . . . . . . . . None! Vehicle Stability . . . . . . . . . . . . . . . . . . . . . . Satisfactory! Occupant Ridedown Deceleration (10 msec avg.)

Longitudinal . . . . . . . . . . . . . . . . . . . . . 10.98 G’s< 20 G’sLateral (not required) . . . . . . . . . . . . . . 10.60 G’s

! Occupant Impact Velocity

Longitudinal . . . . . . . . . . . . . . . . . . . . . 5.68 m/s < 12 m/sLateral (not required) . . . . . . . . . . . . . . 7.01 m/s

! Vehicle Damage . . . . . . . . . . . . . . . . . . . . . . Moderate

TAD14 . . . . . . . . . . . . . . . . . . . . . . . . . . 1-RFQ-3

SAE15 . . . . . . . . . . . . . . . . . . . . . . . . . . 1-RFAW3

! Vehicle Stopping Distance . . . . . . . . . . . . . . 56.25 m downstream

12.80 m laterally behind

! Barrier Damage . . . . . . . . . . . . . . . . . . . . . . . Moderate! Maximum Rail Deflections

Permanent Set . . . . . . . . . . . . . . . . . . . 89 mmDynamic . . . . . . . . . . . . . . . . . . . . . . . . 287 mm

! Working Width . . . . . . . . . . . . . . . . . . . . . . . 534 mm

Figure 16. Summary of Test Results and Sequential Photographs, Test KTB-1