In the spring of 2016, the discount sporting goods store chain, Academy Sports + Outdoors began planning the construction of a new store just off Mississippi Hwy 12 in Starkville, Mississippi. The new 60,000 square-foot store would be situated on a previously undeveloped, 11-acre site that would include new parking areas, access drives, related site work and two (2) retaining walls.
Although the required design height of the retaining walls would not be significant, six (6) feet and seven and a one-half (7.5) feet respectively, they would support 5H:1V crest slopes of nearly equal height in marginal soil conditions.
The project geotechnical report described the soils on site as sediments of the Clayton Formation underlain by the Prairie Bluff Chalk. Composed of tan to dark-gray, slightly calcareous clay, silt and sand, the clays of the Clayton Formation can exhibit relatively modest shear strength and be highly unstable and expansive. Both retaining walls would be constructed in the high plasticity clay of the Clayton Formation.
The contractor, Mike Rozier Construction of Hattiesburg, Mississippi, had used the Redi-Rock precast modular block retaining wall system on other projects and contacted MMC Materials in Jackson, Mississippi to inquire if Redi-Rock could once again provide the required retaining wall solution for this project. MMC called on JC Hines and Associates to prepare preliminary designs for cost estimating. Quickly thereafter it was determined that Redi-Rock walls designed as modular gravity retaining wall structures would meet the project requirements.
The final Redi-Rock wall design utilized 41-inch depth blocks on the bottom and transitioned to 28-inch depth blocks at the top of the wall. To overcome the shrink/swell potential of the expansive clay foundation soil, the retaining walls were over excavated an additional two (2) feet below the block leveling pad limits and backfilled with compacted lean clay fill. The typical crushed stone leveling pad was replaced with a 12-inch concrete leveling pad to further mitigate the effects of shrinking and swelling of the foundation soils.
Total face area of the two (2) walls is 1,000 square feet. The natural gray Ledgestone Redi-Rock units were manufactured by MMC Materials in Jackson, Mississippi. Retaining wall construction was completed in 2016.
Academy Sports + Outdoors is headquartered in Katy, Texas and operates approximately 290 retail stores throughout the states of Alabama, Arkansas, Florida, Georgia, Indiana, Kansas, Kentucky, Louisiana, Mississippi, Missouri, North Carolina, Oklahoma, South Carolina, Tennessee and Texas.