A section of roadway in Huntington, N.Y., was prone to flooding. Officials with the New York State Department of Transportation (NYSDOT) had a plan to eliminate the significant ponding, but they had difficulty finding a partner to supply the grates and frames for their “extreme” trench-system solution.
In Suffolk County, N.Y., a project to improve the drainage of Rte. 110 was calling for box culverts with transverse drainage grates. While the average grate’s span is typically 12-24 in., these extreme grates would need to cover a span of 102 in. Add to that several more challenges: a higher H25-wheel load requirement and concerns about traction on these extreme grates.
“NYSDOT designed a grating with very challenging requirements. They couldn’t find a supplier to take on this extreme trench grate span until they found us,” said Tim McKernan, technical sales manager with EJ, which is headquartered in East Jordan, Mich. “I’ve done this for 36 years, and I’ve never seen a project like this. The state specified something that no one else was willing to try, but we went to work on a solution.”
The project would consist of 42 large and six smaller heavy-duty, galvanized-steel, bolted trench grates and frames.
EJ engineers did the structural analysis and developed a grate height designed to handle the H25 loads and to fit the DOT-specified frames, which would be installed in the concrete. However, because of the size of these grates, there was concern that vehicles might lose traction if they needed to stop quickly on them.
“They specified a skid-resistance number based on a standard bridge coefficient-of-friction test, but for this type of grating product, there weren’t existing tests,” said McKernan. “Because we do slip-resistant testing for our products to meet Americans with Disabilities Act [ADA] requirements for pedestrian walkways, we decided to ask an independent testing facility to develop methods for testing the resistance of several grate designs and surface treatments for this highway application.”
Using ADA slip testing as a starting point, the lab tested four variations:
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Regular, flat grate;
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Serrated grate (with cuts and points);
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Serrated grate with special slip-resistant materials (Safety Sure Grip from EJ); and
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Regular, flat grate with Safety Sure Grip.
After reviewing the test results, NYSDOT approved the regular, flat grate with Safety Sure Grip on the top surface, which offered the best resistance. Safety Sure Grip is used on the top of hatches and grating in sidewalks for ADA standards. These NYSDOT grates exceed those ADA requirements.
Even though the slip-resistant materials were designed for pedestrians, it also can improve vehicular stopping performance. “It’s also very durable and wear-resistant,” said McKernan.
The grates were manufactured by EJ at their Syracuse fabrication facility in New York, using American steel and materials to meet Buy America requirements.
