By specifying gravity walls, a specifier can minimize excavation and cut down on installation time and costs.
As part of the Riverside Drive improvement project, the city of Cincinnati was renovating and widening a busy downtown road. The road was located in the historic district of Cincinnati, and a popular riverfront park was located directly below.
“The downtown Cincinnati business district contains structures constructed of natural quarried stone, which engineers try to match as best they can while providing the structural support required in new building projects,” explained Rich Pohana, P.E., with the city of Cincinnati’s Department of Transportation and Engineering.
In searching for a retaining wall solution, aesthetics were obviously a primary concern. In addition, widening the road required raising grades 18 ft without diminishing the parking in the lot directly below the road. The proposed widening began only several feet away from an existing retaining wall that would have been costly and labor-intensive to remove.
Based on these criteria, the city engineers specified Redi-Rock retaining walls in Limestone texture for the project. Redi-Rock blocks are massive, 1-ton blocks that stack like giant Legos to build tall gravity walls and even taller reinforced walls. The city chose Redi-Rock Limestone-texture blocks so the project could blend seamlessly with the natural limestone downtown, as well as the natural limestone wall located in the park.
“Use of other types of segmental units would have required geogrid reinforcement with lengths extending beyond the existing wall—requiring its removal, a costly and time-consuming task,” Pohana said.
By choosing a gravity solution for the project, the city preserved the parking area and also avoided removing the existing wall. Gravity walls are easy to install using an excavator and a small crew of two to four people—saving time and money on installation.
The 400-ft-long gravity portion of the wall stood 11 ft tall at the highest point. This section of wall was installed just 3-6 ft in front of the existing wall using Redi-Rock Zero Batter blocks to maximize parking space. The remainder of the 1,000-ft-long wall was reinforced and stood up to 18 ft high.
Concrete sidewalks and curbs were poured directly atop the gravity-wall blocks, and poured-concrete sidewalks provided access to the street above the parking lot.
The retaining wall is located within the floodplain of the Ohio River, so the wall was engineered to withstand flood events. The city was very pleased with the final look of the project.
“This Riverside Drive project was an exciting and innovative project,” Pohana said, “which expressed Cincinnati's continuing commitment to improving neighborhood vitality through context-sensitive design of our transportation facilities.”
