Resilient Infrastructure Raises the Grade

Following significant flooding in 2019, U.S. Highway 81 required both a temporary grade raise in 2019 and a permanent grade raise in 2022 to improve infrastructure resiliency in the face of future flooding.

BY SARAH REDOHL

UU.S. Highway 81 (US-81) is a major northsouth highway extending 1,220 miles from northern Texas to the Canadian border. Just south of where U.S. Highway 14 crosses US81 is the Twin Lakes region of South Dakota, known for its popular public grounds for hunting waterfowl. However, when South Dakota was inundated with heavy rain throughout 2019, this stretch of highway found itself in the cross hairs.

“We were facing one rain event after another and the water level just kept rising,” said Joe Gilsdorf, project estimator for Bowes Construction, Brookings, South Dakota, which worked on both the temporary and permanent grade raise on US-81 in August 2019 and July 2022, respectively. “US-81 ended up under a foot of water.”

According to Wayne Lloyd, vice president of Prairie State Trucking Inc., Sioux Falls, South Dakota, the prime contractor for both projects, the highway is an important route through the state. “Agriculture is the main industry in South Dakota, and US-81 is a main connector to several [grain] elevators and ethanol plants in the area,” Lloyd said. The area is also home to many dairies and other agriculture facilities.

Located 15 miles west of Interstate 35, US-81 is also a major thoroughfare connecting smaller towns in the region, added Gilsdorf. Bowes Construction also served as the asphalt contractor on the permanent grade raise on US-81.

RAPID EMERGENCY GRADE RAISE

When the highway found itself under water in the summer of 2019, it was no small inconvenience. In order to open the highway to traffic, SDDOT aimed to raise the grade immediately. Shortly after the highway flooded, it tendered a bid for an emergency grade raise.

“The project was bid in July, but it had to be done by the fall,” Lloyd said. “Many contractors didn’t think it could be done in that amount of time, given the volume of material that had to be hauled out there. But, we knew with the amount of trucks we had available and our ability to innovate that we’d be able to get it done in time.”

Construction on the temporary grade raise began in August 2019. “The road was still under a foot of water when we first went in there,”

LEFT: Bowes used its Caterpillar CB36 and CB54XW rollers to compact the mat on the US-81 project. RIGHT: Prairie State trucked in 100,000 tons of riprap from a quarry in Spencer, South Dakota, to go along both sides of the existing road.

By July 2022, Bowes’ crew could begin paving three 2-inch lifts atop the permanent grade raise with its Cat AP1055 paver.

Lloyd said. Over the existing concrete pavement, Prairie State’s crews placed four layers of geogrid and separator fabric, 46 inches of surge rock, pit run, and base course, followed by three 2-inch lifts of asphalt. “The fabric had to be wrapped around the outside of the base course to keep it in place because we built up the aggregate sections vertically.”

“I’ve never done a project like that,” Lloyd said, referencing placing the base course atop the existing pavement. Also unique to the project was beginning work while the road was still underwater. Even after the initial flooding had subsided, an 8-inch rain event during the construction process flooded the road once more. To solve this, Prairie State raised the surge rock section above the new water level. “We were supposed to remove the cable rail but convinced the SDDOT to leave it in place to help contain the aggregate sections,” Lloyd said.

A PERMANENT SOLUTION

When SDDOT looked for a permanent solution, Prairie State once again won the bid. The $8.5 million project would raise the grade on 2.5 miles of US-81 by approximately 2 feet.

First, in four locations along the project, Prairie State removed everything down to the original road’s subbase in order to place four 48-inch equalizer pipes across the road.

Then, they began trucking in 100,000 tons of riprap from a quarry in Spencer, South Dakota, 120 miles from the project. The riprap along both sides of the existing road would be the base for expanding the width of the road by 5 feet on each bound for a total of 12-foot-wide driving lanes and 7-foot-wide shoulders.

“We began hauling that in over the winter and dumping it over the existing guardrail,” Lloyd said, adding that they had placed most of the riprap by spring. They were then able to place a 1- to 3-inch quartzite aggregate to fill the voids in the riprap before placing the base course of 1 foot of class 5 gravel.

Atop the existing lanes paved after Prairie State's emergency grade raise from 2019, the company placed 20 inches of granular aggregate. “I’ve been doing this for 30 years and that’s the first time I’ve ever done that,” Lloyd said.

By July 2022, Bowes’ crew could begin paving. “It certainly felt like new construction paving [rather] than a reconstruction or maintenance project,” Gilsdorf said, adding that it otherwise seemed like a fairly standard paving job. “It went very smoothly.”

In two weeks, the crew paved three 2-inch lifts of standard Q3 state virgin hot-mix asphalt with PG64-34 and 1% hydrated lime as an anti-stripping agent along the 5 lane-miles

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Timeline to Resiliency

Summer 2019 = Multiple rain events lead to flooding, putting a section of U.S. Highway 81 under a foot of water.

August 2019 = Prairie State performs an emergency grade raise while the roadway is under water, placing multiple layers of geogrid, aggregate, and 6 total inches of asphalt. Spring 2022 = Prairie State wins the bid to build a new, permanent, raised grade for 2.5 miles of the roadway.

Summer 2022 = Prairie State removes the structure down to its subbase in some areas to place equalizer pipes across the road, brings in riprap to widen the road, and places 20 inches of granular aggregate atop the existing roadway.

July 2022 = Bowes Construction paves a total of 6 inches of HMA along the 5 lane miles.

Fall 2022 = Prairie State installs new guard rails designed to minimize snow drifting onto the roadway.

Bowes trucked the material with belly dump trucks and used its Barber Green pickup machine to feed the mix into its Cat AP1055 paver.

of the project. The 20,000 tons of mix was produced at Bowes’ Barber Green asphalt plant in Brookings, 25 miles from the project.

They trucked the material with belly dump trucks and used its Barber Green pickup machine to feed the mix into its Cat AP1055 paver, followed by several rollers (Caterpillar CB36, Caterpillar CB54XW).

Then, Prairie State was able to put up the 3-cable guardrail that replaced the existing W-beam guardrail, which SDDOT said should eliminate some of the snow drifting that has been known to occur through this stretch of road.

Bowes Construction is a veteran/ family-owned business. Lyle Bowes served in the Army during Vietnam, his son Jason Bowes served in the Marines on Okinawa in the 1990s, and Jason’s son Logan Bowes is currently serving in the Marines. Bowes’ Head of Marketing and Public Relations Kesmond Willert said the company strives to hire veterans and works closely with the local Veterans Affairs office to recruit them. “Our veteran employees are decisive, dependable and great with thinking on their feet as a result of the training they’ve gone through with the U.S. Military,” he said. “They treat their workplace with the same attention and respect as they did their service.”

OPEN FOR HARVEST SEASON

Ultimately, US-81 opened to traffic Sept. 6, 2022, approximately two weeks ahead of schedule. “By getting the road open [right at] Labor Day, it will be open for the entire harvest season,” Lloyd said, adding that area farmers will have a new road upon which to haul their corn and grain this fall.

“When we were out on 81, I heard our crew talking about how well the road was riding after each and every lift,” Gilsdorf said.

Although the new pavement was the result of a natural disaster, Gilsdorf, who frequently drives this section of US-81 to get to the lake where he camps, said it was only a matter of time before the road needed some repairs. “It wasn’t a terrible drive, but it was getting to the point that it was due for some maintenance,” he said.

One of the next big projects in the area is the repaving of a stretch of US-81 a few miles south of the recently completed project, from the border of Brookings County to Madison.

Lloyd, who grew up in the area and still hunts near the project site, said that flooding has occasionally been a problem in the past. Now, he added, the road is above a 100-year flood event. “The road is high enough that the water won’t come across it,” he said. “Instead, it’ll drain to the southeast toward Big Sioux River.”