Public Sidewalk Trip Hazard Repairs

Trip Hazard Repairs Around Drop Inlets, Richmond, Virginia

Problem:

DOT residency identified 73 drop inlets with trip hazards resulting from settlement of the surrounding concrete sidewalks.  In addition to the sidewalks settled around drop inlets, there were five locations with trip hazards on bridge approaches and at driveway aprons.

The work area was spread out over more than four miles of roadway.  

Constraints:

Due to heavy vehicular traffic on the primary road that the sidewalks ran along, work had to be completed quickly to minimize disruption to traffic.  To avoid cost of redirecting pedestrian traffic, sidewalks had to remain passable during repairs.

There were also very extensive voids around some of the structures.  The repair process had to be able to fill exceptionally large (multiple cubic yard) voids at the same time as correcting sidewalk settlement.  Because the repair area was isolated locations along a four mile stretch of road, the repair process had to be mobile and quick to set up and break down at each location.

Solution:

Sand-based grout slab jacking for the trip hazard repairs by filling voids around the drop inlets and raising existing sidewalk slabs back to position.  Slabjacking was chosen for this project for a few reasons:

  • economical lifting material; sand-based slab jacking grout is relatively inexpensive
  • no lift height limits; there were some areas where extensive voids had to be filled before lifting.  Slab jacking grout can be used for deep void fills & lifting at the same time.
  • good for narrow slabs; some of the slabs which required repair were only 12″ wide.

Results:

CJGeo slab jacking crews filled voids up to four feet deep under the sidewalks and then raised the concrete to establish a safe walkway.  Average time per repair was less than 50 minutes, with no walkway closures.  Rolling lane closures were provided by the DOT.