Report Result

TRP-03-419-19

Cody Stolle, Howie Fang, Miguel Hinojosa, Nathan Dowler

PUBLICATION DATE

2019-11-27

ABSTRACT

The North Carolina Department of Transportation (NCDOT) frequently uses a two-bar metal bridge rail in scenic locations to preserve observational integrity. NCDOT had previously evaluated this system under National Cooperative Highway Research Program (NCHRP) Report No. 350 safety performance criteria, but recent updates to the American Association of State Highway Transportation Officials' Manual for Assessing Safety Hardware (MASH) necessitated further testing to ensure continued compliance with the latest safety standards. A 90-ft long, 30-in. tall vertical concrete parapet was constructed at Midwest Roadside Safety Facility's Outdoor Test Site. The top face of the parapet supported posts attached to two longitudinal elliptical rails offset from the front face of the parapet by 1 in. The bridge rail was evaluated through two full-scale crash tests in accordance with Test Level 3 (TL-3) of MASH 2016. In test no. NCBR-1 (test designation no. 3-10), an 1100C small car impacted the downstream end of the barrier at 63.2 mph and an angle of 25.2 deg. In test no. NCBR-2 (test designation no. 3-11), a 2270P quad cab pickup truck impacted the upstream end of the barrier at 61.9 mph and an angle of 24.9 deg. In both tests, the two-bar metal bridge rail successfully contained and redirected the vehicle and did not penetrate or show potential for debris to penetrate the occupant compartment. All occupant risk measurements were below the maximum threshold. Thus, the NCDOT two-bar metal bridge rail was determined to be crashworthy according to MASH 2016 TL-3 standards.

KEYWORDS

Highway Safety, Crash Test, Compliance Test, MASH 2016, TL-3, Bridge Rail, Concrete Parapet, Combination Rail

REPORT

TRP-03-419-19.pdf