BRIDGE APPROACH/DEPARTURE SLAB REPAIR
Bridge approach and departure slab settlement is a common problem that many transportation departments are forced to deal with. It has been found that water penetration accompanied with constant impact loading on unstable foundation soils cause this settlement. If ignored, settlement can increase up to several inches, creating unsafe driving conditions. By injecting high-density polyurethane foam beneath the pavement, the approach and/or departure slabs can be lifted back to their proper grade and elevation. The foam injection stabilizes and strengthens the poorly compacted foundation soils, eliminating future settlement and erosion from water intrusion.
BRIDGE APPROACH FAILURE
When bridges are built, the heavy equipment used for compacting foundation soils are not always capable of compacting soils close to the bridge abutment wall. Over time, the unstable soils settle, creating a dip at the approach and/or departure slab of the bridge. This is exactly what happened at the jobsite pictured below. Here, the approach slab had settled 5 inches. By injecting high-density polyurethane foam below the concrete and into the foundation soils, the approach slab was lifted back to its initial elevation, and the soils beneath were compacted to eliminate future settlement. The project was completed in one day, and at least one lane was open for traffic at all times.