Static Pile Load Tests on Driven Piles into Intermediate Geo Materials

The Wisconsin Department of Transportation (WisDOT) has concerns with both predicting pile lengths and pile capacities for H-piles driven into Intermediate-Geo Materials (IGM). The goal of the research was to perform 7 static axial load tests at 7 locations to compare results with capacities determined with the WisDOT driving formula, and with PDA and CAPWAP. An additional 208 dynamic load tests were added to the database using the results from production piling. In general, the methods for predicting capacities based on dynamic measurements taken at beginning of restrike predicted static load test capacities of about 85 percent of the static load test value. Dynamic formulas, namely the Federal Highway Administration (FHWA) modified Gates and the Washington State DOT method predicted about 85 and 95 percent of the static capacity as determined by static load tests. A common range of tip resistance in IGM soils was observed to be between 300 and 500 kips. The tip resistance was affected by the Penetration resistance (Nspt) exhibited by the IGM and therefore six test sites were revisited and modified standard penetration tests (MSPT) were conducted to get a more consistent record of IGM strength in the soil profiles. While there was considerable scatter, tip resistance increases as MSPT increase from 30 to 200 bpf. For values greater than 200 bpf, the scatter in the relationship revealed no trend. IGMs that were coarse grained exhibited higher resistance than IGMs that were fined grained. Results of the dynamic load tests were used to develop design recommendations for end bearing and side resistance for piles driven into IGMs. Design equations rely on results of the MSPT.

Language

  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Figures; References; Tables;
  • Pagination: 161p

Subject/Index Terms

Filing Info

  • Accession Number: 01632324
  • Record Type: Publication
  • Report/Paper Numbers: WHRP 0092-12-08, Report No. 08-07
  • Contract Numbers: WisDOT SPR#0092-12-08
  • Files: TRIS, ATRI, USDOT, STATEDOT
  • Created Date: Apr 15 2017 6:46PM