Featured Project Return to Projects List
Hanover Complex
Project Information
- Project Location:
- King of Prussia, PA
- Approx Contract:
- $400,000
- Status:
- Completed - May 2017
- Structure Type:
- Apartments & Condominiums
Scope Of Work
Scope
The proposed construction consisted of a 6-story residential building and an attached 7-story parking garage (a mirror image of an adjacent property by the same developer). The subsurface testing disclosed evidence of soft soil and/or weathered/voided rock zones within the northern half of the building. This variability in depth and weathering is consistent with the regional geology and is indicative of Karst (sinkhole) activity. To facilitate traditional shallow spread footing construction, a sinkhole mitigation program was designed by the project Geotechnical Engineer.
CGS had worked on an adjacent property in the same vicinity with the same developer and engineer approximately one year prior to this project. Considering the nearly identical design of the structure and very similar subsurface conditions, the same compaction grouting program was implemented for this project. The program was the result of previous value engineering by CGS to adhere to strict project budgets and schedules while still performing as intended by the Geotechnical Engineer. Based on CGS’s past performance, we were awarded first rights to bidding and were awarded the work.
Program
The grouting program consisted of employing a primary and secondary grid pattern below proposed foundations and floor slab areas. The secondary locations were only drilled and grouted if a pre-determined volumetric criterion was triggered by the primary grouting. By using the results of the initial (primary) grouting to modify/amend the grouting program in the field, CGS was able to adequately cover the full treatment area while only acutely treating problematic areas (areas of advanced Karst activity). This methodology satisfied the engineer by covering all areas while also reducing project costs and time schedule for the owner.
Summary
CGS worked with The Hanover Company to mobilize within the project schedule and complete the grouting program ahead of schedule. When completed, the final grouting program consisted of a total of 10,660 linear feet of drilling and a total of 550 cubic yards of grout injected into 266 locations. The project was completed using 2 drilling crews and 3 to 4 grouting crews.
?
