Redi-Rock Case History – Mississippi Department of Transportation
Redi-Rock Solves Right of Way Issues in Mississippi DOT Highway Expansion Project
In 2010, the Mississippi Department of Transportation made plans to widen existing bridges and shoulders on I-59 in Laurel, Miss.
The challenge? “We had a limited amount of right of way and we didn’t have time to go buy more. Really what we were trying to do was find a way to limit our footprint so that wherever we corrected our slopes on the shoulders to meet the current standards, they didn’t fall outside of the right of way,” explained Brent Quick, District Area Engineer for the Mississippi DOT at the Laurel project office.
With these parameters in mind, the DOT set out to find a solution that would limit excavation. “That’s where the retaining walls came in,” Quick explained. “The walls allowed us to correct the slopes on the shoulders without going outside of the right of way.”
The DOT had used Redi-Rock on previous projects and Redi-Rock was also on their approved products list. “The DOT recognized the advantage of minimized excavation with Redi-Rock, especially for this project,” explained Jason Sailers of Piedmont Precast, the local Redi-Rock manufacturer and retailer. The massive size of each Redi-Rock block allows tall gravity walls to be built without the need for reinforcement in many applications. Even taller reinforced walls are possible.
The project included a total of 12 separate Redi-Rock walls totaling roughly 60,000 sq. ft. To put that in perspective, that’s over 20,000,000 lbs. of concrete! The walls ranged in height from 10 ft. tall to 25 ft. tall.
The largest wall was 10,000 sq. ft. and was built as a gravity structure (no geogrid required).The base of the gravity wall was built using Redi-Rock 60 In. Base blocks—which weight 3290 lbs., as much as a Chevy Corvette. The rest of the wall was built using Redi-Rock 41 In. blocks—which weigh 2351 lbs. each, as much a one Budweiser Clydesdale. The advantages of gravity walls include minimized excavation as well as minimized installation time—both of which were important for this project.
The rest of the walls were reinforced using geogrid. Even though minimizing excavation was one of the primary objectives of the project, engineers were able to design reinforced walls using Redi-Rock that still fell within the right of way requirements. To learn more about reinforced retaining walls from Redi-Rock, click here.
A great benefit of the Redi-Rock system is that gravity and reinforced walls have the same aesthetic stone face, making it impossible to tell the different between a gravity and reinforced wall once they’re installed.
The project was installed over the course of one year by the General Contractor on the project, Tanner Construction. The walls were backfilled using 57 stone and manufactured sand. On top of the walls, concrete swales direct water to the sides of the walls to prevent erosion.
The DOT chose Redi-Rock’s Cobblestone texture for the project. Although aesthetics wasn’t a primary concern, “I like the way it looks,” Quick said. “The walls do the job that we were looking for.”
Redi-Rock has been used on DOT projects in multiple states, and is approved by 17 state DOTs with several more pending. Spec Redi-Rock on your next project! Visit www.redi-rock.com today for design resources or to get a quote from your local retailer.
I-59 S Curve Project in Laurel, Miss., Case #139
Engineered Earth Solutions
Mississippi DOT Engineering Offices
Tanner Construction Company, Inc.
60,000 sq. ft. of Redi-Rock Retaining Walls
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