D.C. Parking Deck Lateral Load Reduction
The Job
On this parking deck lateral load reduction project, we provided a load reducing backfill solution at the historic St. Elizabeth’s Hospital campus in Washington, D.C. Our goal was to bring the excavated area around the new structure up to the final grade without compromising its structural integrity.
Placing CJFill-Ultra Lightweight cellular concrete around the structure.
The Challenge
The project’s design set the parking deck directly into an existing slope. This meant that traditional backfill would impose significant lateral earth pressures against the structure’s walls. However, the parking deck’s engineering had a zero-tolerance for passive earth pressure. This situation required an innovative backfill solution that would not exert any significant lateral force.
The Solution
CJGeo’s solution used CJFill-Ultra Lightweight cellular concrete to create a stable, self-supporting mass that eliminates lateral pressure. First, the general contractor cut a permanently stable slope behind the structure. They then constructed a thin, 6-inch thick concrete wall parallel to the main parking deck wall, which was designed to handle a minimal liquid head pressure of 50 PSF.
Our crew then placed 25 lb/cuft CJFill-Ultra Lightweight Load Reducing Fill into the void in carefully managed 2-foot lifts. Because the lightweight fill becomes a solid, self-supporting mass, it exerts negligible lateral force. This method successfully protected the new deck’s structural integrity while bringing the area to grade.
Speak With An Expert
Have a project with unique geotechnical or structural challenges? Facing issues with lateral earth pressure, poor soils, or hard-to-access voids?
