Richmond International Airport
A 270,000 sf, two-story terminal building consisting of six baggage claim carousels, seven rental car counters and 12 ticketing stations as well as renovations of the existing single-story terminal into a baggage make-up area.
The site is underlain by a 4 to 12 ft thick layer of clay to clayey and silty sand fill. The fill is underlain by medium-stiff to stiff clay and medium-dense silty sand, sand, and dense gravel. Schnabel Engineering considered multiple strategies, including over-excavation and replacement and concrete piers. Both approaches were complicated by poor soils, buried obstructions, and a compact worksite.
A preliminary foundation layout with Geopier elements suggested it would remove a substantial amount of cost from the project’s intermediate design stage. Based on those findings, Schnabel recommended converting the foundation from piles with pile caps to a Geopier stabilized subgrade supporting conventional spread footings.
626 Geopier elements were installed with lengths ranging from 8 to 18 ft. Work proceeded at a rapid pace despite on-site congestion and hidden obstacles. Paul E. Diggs, P.E., with Schnabel Engineering stated “The Geopier System takes these issues in stride. I was impressed the first time they found concrete. I learned that they just carry on with augering. If it gets oversized, they would backfill the hole and re-auger it. I thought that was pretty intriguing. Obviously, if we were doing a pile installation, we’d probably have to back away, refigure another pile layout, and reengineer the pile cap—and that would slow the project down.”