This North Carolina compaction grouting project is located at a military facility in eastern North Carolina. To facilitate the renovation of an adjacent office building, the owner installed eight mobile office buildings. Before the mobile offices were put into use, they settled up to three inches. As a result, the owner had to stabilize the structures before moving any equipment and people into the structure.
The site comprises of sand backfill over native loose sands. The eight mobile buildings bear on masonry piers resting on plastic load distribution pads. The piers and pads are on approximately 6′ centers, spread uniformly throughout the structure. The crawlspace is too shallow to safely enter.
CJGeo proposed using CJGrout 35NHV to perform compaction grouting below the piers to stabilize the loose soils. 35NHV is a 3.5lb/cuft rigid polyurethane foam. It performs well for void filling and compaction grouting in wet environments.
Special polyurethane grouting rigs generate CJGrout 35NHV onsite. The rigs have hoses up to 400 feet long, which convey the material from the grouting rigs to the placement area. For this project the 35NHV was injected using sacrificial tubing. The tubing passes through holes in the floor through the crawlspace, to roughly 3′ below the pads.
One of CJGeo’s polyurethane grouting crews was onsite for three days to complete this North Carolina compaction grouting project. CJGeo used rotary lasers to monitor the floor elevation over each pier during grouting. The cutoff criteria was movement of approximately 0.25 inches. Then, a carpentry crew jacked and shimmed the beams after the grouting. Finally, a flooring crew restored the flooring afterwards.
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