Investigation of the Resistance of Pile Caps and Integral Abutments to Lateral Loading

00795254436371692000Final contract report.July 1998 - June 1999PDFTech ReportFHWA/VTRC 00-CR400050918Backfill soilsBridge abutmentsField testsLaboratory testsLiterature reviewsLoad testsMathematical modelsPile capsPile groupsSoil testsSoilsSpreadsheetsTest facilitiesBridgesDesignHighwaysGeotechnologyI24: Design of Bridges and Retaining WallsIntegral abutmentsLateral loadsP-Y curvesVirginiaUnited StatesVirginia Transportation Research CouncilMokwa, Robert LDuncan, J. MVirginia. Dept. of TransportationVirginia Transportation Research CouncilVirginia Polytechnic Institute and State University. Charles E. Via Dept. of Civil and Environmental EngineeringUnited States. Federal Highway AdministrationUS Transportation CollectionThis research provides a means of assessing and quantifying many important aspects of pile group and pile cap behavior under lateral loads. The program of work performed in this study includes developing a full-scale field test facility, conducting approximately 30 lateral load tests on pile groups and pile caps, performing laboratory geotechnical tests on natural soils obtained from the site and on imported backfill materials, and performing analytical studies. A detailed literature review was also conducted to assess the current state of practice in the area of laterally loaded pile groups. A method called the "group-equivalent pile" approach (abbreviated GEP) was developed for creating analytical models of pile groups and pile caps that are compatible with established approaches for analyzing single laterally loaded piles. A method for calculating pile cap resistance-deflection curves (p-y curves) was developed during this study, and has been programmed in the spreadsheet called PYCAP. A practical, rational, and systematic procedure was developed for assessing and quantifying the lateral resistance that pile caps provide to pile groups. Comparisons between measured and calculated load-deflection responses indicate that the analytical approach developed in this study is conservative, reasonably accurate, and suitable for use in the design of pile caps and integral abutments. The results of this research are expected to improve the current state of knowledge and practice regarding pile group and pile cap behavior