Date:October 2017

Valley Forge II Apartment Structure: Compaction Grouting

King of Prussia, PA – 

For the Valley Forge II project, CGS provided proof drilling for a proposed 6-story residential building that included an attached 7-story parking garage.  The grouting program also considered test boring results from the project on an adjacent property approximately 1 year prior.  Proof drilling for the Valley Forge II project required 28 test borings which revealed soils that may indicate sinkhole activity, a common problem in King of Prussia.

CGS worked with the engineer to develop a pressure grouting program to treat the subsoils beneath the proposed foundations and floor slab areas under the northeast quadrant of the residential structure.  The residential building and garage were to be supported by shallow spread column footings and continuous wall footings with maximum residential column and wall loads of 500 kips and 10 klf, respectively, and maximum garage column and wall loads of 1,500 kips and 30 klf, respectively.  The subject area of the project site seemed fairly level with minor fills, (2 to 3 ft. high) expected. The lump sum proposal included up to 389 total grouting locations and 14,782 lf of drilling. Secondary and tertiary locations were included in the total amount of locations quoted and were considered a possibility in this proposal.

The intent was to perform the work using up to 2 drilling crews and 4 grouting crews full time.  CGS was to complete the project in 4 working weeks.  The project was completed by injecting 266 grout locations and performing 10,660 linear feet of drilling. CGS successfully completed this project in less time and than quoted.