ArcelorMittal First to Develop TL-5 Rated Steel Median Safety Barrier

ArcelorMittal First to Develop TL-5 Rated Steel Median Safety Barrier

ArcelorMittal Global Research and Development, working in cooperation with US safety barrier manufacturer Gregory Industries, has developed a new, proprietary high-containment steel center median safety barrier for use in North America.

The new barrier is able to safely contain and redirect a fully loaded 79,000 pound tractor trailer truck, a quad cab pickup truck, and a mid-size car.  It is the first Methods for Assessing Safety Hardware (MASH) Test Level-5 (TL-5) rated steel center median safety barrier developed for the US market.  It is safer for vehicle occupants and a cost effective alternative to concrete cast in-place barriers.

According to the US Department of Transportation, motor vehicle traffic accidents are a leading cause of death, not far behind heart disease, cancer and stroke.  No doubt, some can be attributed to barrier crashes.

“In the early 2000’s, ArcelorMittal worked with European safety barrier manufacturers to design higher performance safety barriers as a result of new regulations that promoted safety performance instead of specifying set barrier configurations,” said Rich Clausius, projects manager, Global R&D, East Chicago.  “This work proved to be quite successful and led to safer roads and increased steel sales in Europe.  In 2008, I was asked to determine if the same approach could be done in the US.”

The answer was yes. It was an opportunity to create additional steel sales in the US and help customers solve a problem.  In addition, development of this product aligns with ArcelorMittal’s commitment to safety.

“It’s a win – win,” said Clausius.  “There are many benefits. This barrier results in lower deceleration rates on impact versus concrete resulting in less damage to the vehicle and injuries to the occupants.  It also has a lower installed cost than a comparable concrete center median barrier.”

In order to contain the vehicle during impact, high strength steel grades were evaluated during the early development phase of the project.  An existing grade 80 HSLA (high strength low alloy) steel provided the best combination of strength, formability, weight savings and cost.

HSLA steels have been used in the auto industry for many years. “But as far as we can tell, this is the first time it’s been used in a US safety barrier application,” added Clausius.

“We reached out to the four largest steel safety barrier manufacturers in the US,” said Clausius. “Of the four, Gregory Industries, proved to be the most interested in our capabilities and in developing a new proprietary barrier for the US market. They were already an ArcelorMittal customer, so that helped too.”

Once a non-disclosure agreement was signed, Clausius, along with representatives from Gregory Industries, focused on market needs expressed during US Transportation Research Board Roadside Safety Design Committee meetings.

These meetings were attended by federal and state highway officials, government contractors and researchers, safety hardware manufacturers and crash test facility experts. It became apparent there was a market for higher performance safety barriers. And at the time, no one was making a TL-5 steel center median barrier.

Successful crash tests

For a TL-5 barrier design to be approved in the US, it has to pass three MASH full scale crash tests. The tests include a mid-size car, quad cab pickup truck, and a fully loaded tractor trailer. In all three tests, the vehicles must be contained (can’t go through or over the barrier), be safely redirected, no rollover, no excessive intrusion into the occupancy department, and must have reasonable deceleration rates.

Before using real vehicles and barriers, computer modeling was done simulating crashes. The barrier design was optimized for performance, based on the results.

Results of the actual crash tests were very good.  The barrier successfully contained and redirected the car, pickup truck and tractor trailer.  No debris or detached elements penetrated the occupancy compartment. The vehicles remained upright with satisfactory vehicle stability and resulted in satisfactory occupancy risk factors.  Overall it was a huge success. And the test performance was very similar to the computer models.

“We applied for patents and expect to receive approval from the US Federal Highway Administration in early 2017,” added Clausius.

As soon as the barrier is approved, Gregory will begin marketing and manufacturing the barrier with ArcelorMittal steel.

When compared to concrete barriers, ArcelorMittal’s new TL-5 steel center median safety barrier has attributes above and beyond its safety benefits. Steel is kind to the environment because it’s 100% recyclable. The barrier has a long service life and it’s easier to repair than concrete making it cost effective. It weighs less than concrete, so transportation costs should be lower.