Good Vibrations

INFRA RISER adjustment riser installation showing application of polyurethane joint sealer

INFRA-RISER® Multi-purpose Rubber Composite Adjustment Riser


The intersection of Route 13 and Route 40 in New Castle County, Delaware is one of the most heavily trafficked in the state. Hares Corners, as it is known, is Delaware's main north-south transit corridor for the entire state. With a 50 mph speed limit and four lanes of traffic, this intersection suffers a constant flow of tractor-trailers, cement trucks, 18-wheelers and thousands of cars.

Sinking manholes, breakage, cracked pavement, and water infiltration—the problem goes back several decades and existed throughout the county.

As vehicles traveled over the manhole covers, their weight was transferred onto the underground structure and surrounding area, causing tremendous vibration. This stress caused material breakage and structural failure that allowed groundwater to infiltrate the manholes, causing further damage. The freeze-thaw cycles during winter months increased the rate of deterioration exponentially and resulted in "sinking manholes," depressions, and roadway damage.

"It was the most brutal application we could come up with," said Assistant County Engineer Dave Hofer.

The damage at this intersection was so extreme that every two years the county was forced to shut down one lane of traffic in both directions for costly and disruptive repair work. This repair work required a crew of 14 people to dedicate a full day to redo just three manholes at this intersection. Travelers experienced traffic delays and slowdowns as a result. This old remedy was expensive, inconvenient, and inefficient.


A Solution

In a quest to rid the county of this problem, the county installed the INFRA-RISER® multi-purpose rubber composite adjustment risers on a trial basis in 2009. Made from recycled materials, the rings have multiple benefits. They’re a simple, economic, and long-lasting solution that separates the surfaces, preventing water infiltration and traffic vibration damage to concrete and masonry structures, thus extending their lifetime.

Without pavement cracks and holes, the opportunity for water to infiltrate is prevented, further extending the life of the structure and quality of travel. Municipalities that use a combination of a ring and an EJ bolted and gasketed manhole cover can virtually eliminate water infiltration.



"Our crews installed the rings on each manhole at that intersection and we didn't have to rebuild them again," Hofer said. "The problem fell off our radar screen."

Since the project started in 2009, New Castle County required every manhole structure in the county to be installed with the adjustment riser. The cost savings for a system supporting over 40,000 manholes have been substantial.

For repaving projects, the INFRA-RISER® ring offers workers an option to quickly and easily align the structure to the proper grade, saving considerable time and money. Discarded tires make up 92% of the recycled content of this environmentally friendly product.

Learn More

Talk to an expert at EJ to find out how the innovative solutions by EJ can work for your next project. Contact us today or schedule a Lunch and Learn.

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