Grocery Store Foundation Repair

Slab Foundation Repair for Grocery Store in Pittsburgh, Pennsylvania

Challenge:

1,925 square feet of floor inside of a grocery store settled up to 4.5 inches in a bowl fashion, causing customers’ carts to roll away, crash into the shelves and knock inventory onto the floor.  Settlement extended under two rows of freezers and three rows of dry goods shelves. 

The store was 30 years old and constructed over an abandoned area of a steel plant in Pittsburgh, Pennsylvania.  Prior to construction of the building, the area had been used as a fly ash disposal pit.  The structural building components were built using a deep foundation system, and showed no signs of failure.

Limits:

All work had to be completed at night without removing inventory or shelving, and area had to be open for use the morning following work, by 9am.  Alloted work time did not allow for repairs to VCT flooring, so work had to minimize disturbances to floor coverings.

The process had to be clean so that it would not soil any of the inventory.

Solution:

Geotechnical polyurethane with a longer reaction profile was chosen for this repair.  This minimized the number of tiles that had to be drilled through for material placement.  One particular advantage of high density polyurethane as the lifting material (as opposed to cement grouts) is the ability for the material to spread significantly from its injection point.  The material still cures relatively quickly, which enables lateral control but also limits the number of injection points needed.  Given that 40% of the work area was covered in stocked shelves, it would have been difficult to complete fine-tune lifting with grout.

Result:

Single CJGeo polyurethane grouting crew raised the entire area and void filled adjacent areas in five hours.  Four VCT tiles had to be replaced.