The project
Construction of a new high school in historic Philadelphia required treatment of 20 feet of urban fill. Ground improvement was used to treat the poor subgrade soils.
The School District of Philadelphia planned the construction of a new high school. Although the location was desirable, the subsurface conditions were not.
The challenge
The subsurface profile included 20 feet of uncontrolled urban fill. The miscellaneous urban fill would not support the new school on shallow spread footings.
The solution
Keller and the design engineer developed a rapid impact compaction program to improve the fill to provide an allowable bearing pressure of 4,000 psf. Rapid impact compaction is a dynamic compaction system for improving shallow loose soils. The program specified the compaction of 3,400 points across 150,000 square feet of the building site. It achieved the necessary improvement of the fill to support the design bearing pressure of 4,000 psf within tolerable settlement limits. The rapid impact compaction program successfully improved the urban fill for the Audenried High School site.