Jacksonville Bridge Transition Lift

The Challenge

An 8-12 inch void had developed beneath a bridge transition slab.

The Jacksonville Utilities Authority contacted Groundworks regarding a high traffic bridge approach which was experiencing settlement. An 8-12 inch void had developed under the approach slabs due to erosion and poor compaction of soils. During the initial construction, sleeper slabs were installed at the end of the approach to prevent settlement, however, the sleeper slabs added additional weight which further compromised the supporting soils, which in turn accelerated slab settlement and soil consolidation. The condition not only impacted the approach slabs, but also caused the adjoining sidewalk to settle, resulting in both poor driving and walking conditions.

Key Facts

The Solution

Polyurethane injection void filling and slab lifting.

Groundworks performed polyurethane injection void filling and concrete lifting to resolve the problems faced by the bridge. Small holes were drilled to inject expanding polyurethane beneath the slab. The product used is a high-density polyurethane that expands into a rigid foam. Once injected through small 5/8th inch drilled “ports” in the slab, the polyurethane fills voids, stabilizes slabs, and lifts concrete. The product chosen was lightweight so that excess weight was not added and would not further compromise the soils. The injections reestablished connectivity between the soils and bridge slabs, restoring both load bearing capacity and proper grade.

The Impact

1300 pounds of polyurethane filled the void and lifted the bridge transition back to level.

Groundworks installed 1300 pounds of polyurethane over the course of 2 days. They were able to completely fill the void and lift the road and walkways back to their original elevation. The polyurethane’s small footprint allowed Groundworks to keep one lane of traffic open during the entire installation and reopen the road to traffic immediately upon completion.