August 17, 2001

Mr. Daniel J. MacDonald Refer to: HSA-10/B-86

Standards Engineer

Oregon Department of Transportation

222 Transportation Building

Salem, Oregon 97310

Dear Mr. MacDonald:

The information on the Oregon precast barrier that you sent with your May 25 letter was 

forwarded to my staff for review. Although the tested barrier, an 810-mm tall, 3.84-m long Fshape barrier with a pin and loop connection, appeared to meet all evaluation criteria contained 

in the National Cooperative Highway Research Program (NCHRP) Report 350 at test level 3 

(TL-3), the test report, prepared by KARKO Engineering Automotive Research Center, did not 

contain all of the information recommended in Chapter 6 of NCHRP Report 350. The most 

obvious omission was the lack of a detailed description of the test article, including internal 

reinforcing and connection details, and there were questions concerning the accuracy of some of 

the data. 

On July 26, you sent Mr. Richard Powers copies of revised reports, both for the original 810-mm 

barrier (Test Report No. KAR21007-01) and for a subsequent test of a 1065-mm tall precast 

concrete barrier (Test Report No. KAR21007-02). Descriptions of each of these designs and their 

crash performance are as follows: 

Standard barrier: test installation consisted of 16 precast concrete F-shape segments, each 810-

mm high, 3.8-m long, 610-mm wide at the base, and 240-mm wide at the top. The pin and loop 

connection consisted of two 19-mm A36 steel loops near the top of one segment end, above a 

single 19-mm steel loop near the bottom on the same end. The corresponding loops on the 

adjacent barrier segment consisted of a single loop near the top and double loops on the bottom. 

When placed together, the single loops fit between the double loops, forming two connection 

points, each consisting of three loops. A 25-mm diameter , 735-mm long ASTM A449 steel pin, 

with no nut or retention device, was dropped through the loops to complete the connection. This 

system was impacted near its midpoint with a 2000-kg pickup truck at 100.7 km/h and a 25 

degree angle. Occupant impact velocity was reported to be 5.8 m/sec and maximum 10-

millisecond ridedown acceleration was 18.2 g’s. The maximum roll angle of the vehicle was less 

than 15 degrees and the barrier dynamic deflection was only 762 mm. This design is shown in 

Enclosure 1.

Tall barrier: test installation consisted of 20 precast concrete F-shape segments, each 1065-mm 

high, 3.02-m long, 660-mm wide at the base, and 230-mm wide at the top. The connection 

between segments consisted of two sets of two perforated C-shape steel channels with the open 

sides alternately positioned such that one leg of each channel fits between the legs of the mating 

channel on the adjacent barrier segment. A 25-mm diameter ASTM A449 end bolt, 760-mm 

long, was inserted through holes in each C-channel leg and into a nut welded to the bottom of the 

lower C-channel, effectively forming eight points of connection. This system was impacted near 

its midpoint with a 2000-kg pickup truck at 102.4 km/h and a 25 degree angle. Occupant impact 

velocity was reported to be 6.2 m/sec and maximum 10-millisecond ridedown acceleration was 

19.4 g’s. Maximum vehicle roll was approximately 16 degrees and the barrier dynamic deflection 

was 813 mm. This design is shown in Enclosure 2.
Based on the reported results of the tests run on these barriers, both the 810-mm tall and the 

1065-mm tall designs are considered to meet the evaluation criteria of the National Cooperative 

Highway Research Program (NCHRP) Report 350 at test level 3 (TL-3) and may be used on the 

National Highway System when such use is acceptable to the contracting authority. Both 

barriers exhibited the least amount of deflection and resulted in the most stable, post-impact 

vehicle trajectories of any free-standing, precast barrier tested to date. I understand that the 

drawings for these non-proprietary barriers can be obtained by contacting you at (503) 986-3779 

or from your web site at ftp://ftp.odot.state.or.us/techserv/roadway/standards under drawing nos. 

odot_apwa500.pdf and odot_apwa545.pdf.Sincerely yours,

(original signed by Frederick G. Wright, Jr.)

Frederick G. Wright, Jr.

 Program Manager, Safety

2 Enclosures