In 2010, BG Consultants’ bridge expert, Moni El-Aasar, was honored with the ACEC of Kansas Engineering Excellence Award for his innovative research in bridge railings. Building upon the work of another researcher, El-Aasar was tasked to design crash-worth rail systems for an innovative new deck material.

In 1996, a bridge was built on a rural road near Russell, Kansas, using a material known as Fiber Reinforced Polymer (FRP) deck panels. Designed by another researcher, the material itself is more expensive than traditional concrete or steel, making it impractical for most new constructions or total bridge replacements. However, for bridges with sound superstructures and substructures but deteriorated decks, the economic advantages of FRP decks are incredible. Previously, the best option for bridges in this condition was often to replace the entire bridge, a more expensive and lengthy process.

An FRP deck replacement, in comparison, is overall less costly. Because it is so light, more weight can be carried on the existing girders and substructure. In addition, the roadway can be made wider without adding significant weight to the structure. Both of these advantages are important for accommodating heavy trucks and growing farm equipment. 

And the best news for travelers: the FRP deck can be implemented in a single day.

BG Consultants has implemented several FRP decks across the country. However, the technology could only be used on trussed bridges, which severely limited the applicability of this innovative technology.

The problem was that in order to be used on highways according to AASHTO standards, the deck needed a crashworthy guardrail to go with it. That’s where El-Aasar came in. Around 10 years ago, KDOT approached him to design, build, and test a guardrail suitable for FRP bridges.

El-Aasar accepted the challenge—after all, he thinks challenges make his job more fun. 

Armed with a federal grant, El-Aasar designed mathematically sound steel post and concrete guardrail systems. Both designs passed the initial static tests, conducted at K-State. But in order for the rails to be deemed safe for highways, they had to withstand a live crash test.

For that, El-Aasar took his design to Lincoln, Nebraska, to one of only three crash test facilities in the nation. The Federal Highway Administration enforces strict guidelines for crash testing guardrails. A vehicle with a standardized weight must hit the rail at specific angles going 62.1 mph. The railing must not only keep the vehicle on the bridge, but also keep it upright without rolling or flipping to its side.

The steel post guardrail system passed all tests with flying colors. However, when the vehicle crashed into the concrete barrier—a system adapted from the commonly used Jersey traffic barriers—the vehicle flipped. El-Aasar’s design failed the test.

“As a structural engineer,” El-Aasar said, “you don’t think about the vehicle flipping. You think about the rail staying in place.”

But El-Aasar wasn’t ready to give up. He studied tapes of the crash test and reviewed his designs. The problem, he found, was with the shape of the Jersey barriers, which taper upward from the roadway. Vehicles hitting the barrier would ride up this slope and often flip to their sides. He made adjustments, got another federal grant, and tried again.

“For the first time ever,” El-Aasar explains, “we put the taper on the back of the barrier, making the front like a wall.”

This time, the vehicle didn’t flip. The test passed, and the design successfully expanded the uses of a highly advantageous technology. Yet one of the biggest advantages of this research is safety—El-Aasar proved that the Jersey barriers, often used to separate lanes of traffic, could be made much safer for drivers.

Although BG Consultants has yet to utilize his bridge railings, El-Aasar hopes to see it more widely-used in the future as the FRP panels become less expensive.