Transfer Station Slab Stabilization
Slab Stabilization and Lifting at Convenience Center, Richmond, Virginia
Concrete slabs installed over abandoned landfill developed voids and settled. 6″ thick parking area slab where customers unloaded trash from their personal vehicles was built on top of 15 feet of compacted fill, which was installed over capped landfill. 18″ thick trailer parking slab installed directly over landfill material settled up to 3 inches in a bowl-fashion.
The underlying landfill material is unstable and would be more likely to settle if excessive weight was placed over it. Additionally, the facility has more than 1 million visits each year by residents dropping off their trash, and there are limited areas available for transfer. Both parking slabs see near-continuous use.
High density polyurethane injection (foam jacking) to fill the voids under the slabs and raise them as possible to complete the slab stabilization. High density polyurethane foam was chosen for its light weight (4 pounds per cubic foot) compared to grout (at least 110 pounds per cubic foot), and minimal downtime.
Single Concrete Jack foam jacking crew installed more than 15 cubic yards of high density polyurethane with minimal disruption to operations. Customers were able to use areas immediately adjacent to work zone due to compact equipment (single box truck) and as soon as areas were addressed, they were opened immediately to customer traffic. This slab stabilization project was completed in one day.