SOIL-PILE-STRUCTURE INTERACTION - Geotechnical
SOIL-PILE-STRUCTUREINTERACTION - GeotechnicalRonaldo Luna, Ph.D., P.E.Associate Professor of Civil EngineeringUniversity of MissouriMissouri-Rolla (UMR)Geotechnical and Bridge Seismic Design WorkshopNew Madrid Seismic Zone ExperienceOctober 2828-29, 2004, Cape Girardeau, MissouriSPSI -1SOIL-PILE-STRUCTUREINTERACTION - GeotechnicalInvestigators:Dr. Genda ChenDr. Mostafa El-EngebawyDr. Ronaldo Luna (Lead)Mr. Wanxing LiuDr. Wei ZhengSPSI -21
Presentation Outline Presentation ObjectivesConsiderations of the soil-structureFramework of DevelopmentSoil-structure ModelingValidation of ModelApplication to the NMSZSummary & ConclusionsSPSI -3Objectives Obtain ground motions at ground surfacein time domain modeling Develop soil-pile interface elements andsprings to model soil behavior. Examine the effect of liquefaction onfoundations systems.SPSI -42
Development of SimulationSystem Research Outline1. Deep Ground Response Analysis2. Liquefaction Analysis in the NMSZ3. SPSI Analysis in the NMSZ OpenSees is used as a numericalsimulation tool.SPSI -5Work Chart of ProgrammingNonlinear eesInterfaceElementTCL InterpreterSiteResponseAnalysisSPSI -LiquefactionAnalysisSPSIAnalysis63
Two-Step ApproachNear FieldFar FieldSPSI -7Considerations forSingle Pile Seismic Responsenonlinear responseINERTIALPILE-SOILRADIATIONStatic Axial LoadDynamic Axial LoadHead FixityPile CapEmbeddedResistanceInstall EffectGap/Slap/ScourLateral ResponsestiffnessmaterialdampingAxial cdampingShearWavesSPSI -SurfaceWaves84
Methods for SPSI Analysis Existing methods for SPSI analysis:– Simplified substructure methods that uncouples thesuperstructure and foundation portions of the analysis.– Dynamic beam on Winkler foundation (dynamic pp-ycurve) method.– 2D and 3D modeling of the pile and soil continuum usingfinite element or finite difference method. Dynamic p-y curve methods are considerably lesscomplex than finite element or finite differencemodeling and provide several potential advantagesover the simplified substructure method.SPSI -9What is p-y curve? p – lateral soil resistancey – lateral pile deflectionStiffness derived from field test and normally stiffer with depthNonlinear p-y spring components Elastic component Plastic component Soil-pile gapClay (Matlock,1970)SPSI -Sand(Reese et al.,1984)105
Dynamic nonlinear p-y Curves Boulanger et al. (1999)presented a nonlinear p-yelement. The nonlinear p-ybehavior is conceptualizedas consisting of elastic,plastic, and gapcomponents in series.Characteristics of Dynamicp-y ElementSPSI -Nonlinear11Coupled SPSI ApproachDragp-y mperSoil ColumnττrγrPileγNonlinear SoilModelSPSI -126
Liquefaction Consideration Softening of pp-y relationship with increasing pore waterpressure was found in lots of centrifuge tests. Adegradation parameter Cu is determined and applied tothe ultimate soil resistance Pu.SPSI -13Dobry and Liu (1995)Liquefaction Consideration When considering loading rate, Wilson (1998)found an appropriate multiplier for peak loadsduring an earthquake in a pseudo-staticanalysis in liquefying sand would be 0.25-0.35for Dr 55%, and 0.10 for Dr 35%.Loose sandMedium dense sandCu 1 0.9ruCu 1 0.65ruSPSI -147
Model Calibrationp-y SpringsSP1SuperstructuremassSoil ColumnPilePore pressureDisplacementBending/axial gaugeAccelerometerUMR ModelCentrifuge Tests (UC, Davis)SPSI -15Earthquake EventsEarthquake Events for Centrifuge TestsEventABCDEamax baseinput beSPSI -168
Spectra Comparison - Superstructure4Event Bamax 0.055g3Spectral Acceleration (g)Spectral Acceleration (g)4B-RecordedB-Calculated21C-RecordedC-Caculat ed21000.11Period (s)0.1101Period (s)1044Event Damax 0.2g3Event Eamax 0.58gE-RecordedD-RecordedSpectral Acceleration (g)Spec tal Ac c eleration (g)Event Camax 0.016g3D-Calculat ed21E-Calculated321000.10.11Period (s)1Period (s) 1010Comparison of Spectral Acceleration at Superstructure forSPSI 17Events B-E (5% damping)Acceleration Time HistoriesComparison(a)(b)Comparison of Time Histories during Event B (a)SPSI -(b) 18SuperstructurePile Head9
Displacement and MomentComparison0Peak Moment (MN.M)2Peak Displacement (mm)20040060004800-5-5Superstructure005Depth (m)Depth (m)Pile parison of Calculated and Recorded Peak RelativeDisplacements during Events B-ESPSI -19Application in the NMSZ Presented SPSI analysismethod is applied to ahighway bridge (L472 site). Synthetic ground motionswere used and propagatedup to the bottom of thepile foundations using thesite response analysis.SPSI -L-4722010
Bridge TypeElevation of Bridge L-472This bridge was originally built asa multi-span simply supportedsteel girder bridge in the early1950s, then enlarged and revisedin 1971, and finally revised withdeck repairs in 1984.Elevation ofBridgeSPSI21 L-472Application to L472Axial ForceCap BeamColumnp-y SpringsSoil ColumnPile CapPile2 2 PileGroupFinite Element Model for the Coupled SPSI AnalysisSPSI -2211
Results of Analysis(a)(b)Displacement Histories for Analysis without LiquefactionConsideration in FN Direction (a) Beam Cap (b) Pile CapSPSI -23Results of AnalysisDisplacement Histories at Rock Base and theBottom of Pile Foundation for FN DirectionSPSI -2412
Results of AnalysisÅ Cap Beam(a)Å Pile Cap(b)Displacement Histories for Analysis withLiquefaction Consideration in FN Direction(a) Beam Cap (b) Pile CapSPSI -0Peak Moment (MN.M)120Depth (m)Results ofAnalysisPeak MomentComparison in FNDirection255Without Liquef act ionWith Liquef action10SPSI -2613
Other Considerations Dynamic Group Pile Effects– from scaled testing (Lok(Lok (1999) Effect of liquefaction was only considered in thesaturated foundation soils. However, the impacton the embankment was considered. These different geotechnical components wereassembled around the structure to simulatedynamic behavior.SPSI -27Modeling Geotechnical Conditions tothe placement Time Histories wereapplied to the nonlinear springs,which include liquefaction effectsSPSI -2814
Summary & ConclusionsSPSI -29Summary of Findings A coupled SPSI analysis method was developedand verified with an instrumented centrifuge testresults. This method has been applied to evaluate theseismic response of the highway bridges in theNMSZ. Dynamic nonlinear p-y method was adopted tosimulate the interaction between pile and soil.SPSI -3015
Summary of Findings A degradation multiplier at the pile soil-interfaceis introduced to the p-y curve to considersoftening due to pore water pressure generationwhich induces liquefaction. The results indicate that the degradation of soilspring due to the pore water pressure greatlyinfluence the foundation and superstructureresponse. Larger displacements and momentswere found due to the softening of the soilsprings.SPSI -31Summary of Findings Near field energy pulse could be transmitted tothe piles and other bridge components afterpropagating through the inelastic behavior ofpile-soil interaction. However, near-field properties in thesuperstructure are not as significant as when thedegradation of soil springs due to the pore waterpressure is considered.SPSI -3216
Final Comments The nonlinear effects near the surface tend todecrease the acceleration response spectra.However, there is a trade-off for these reducedspectra, that is, the larger deformations(straining) that the soil-structure undergoes todissipate that energy. In saturated depositsthese large nonlinear deformations may be aresult of liquefaction which dramatically reducesthe soil’s ability to bear load.SPSI -33Thank You!Questions/CommentsSPSI -3417
Dynamic nonlinear p-yCurves Boulanger et al. (1999) presented a nonlinear p-y element. The nonlinear p-y behavior is conceptualized as consisting of elastic, plastic, and gap components in series. Characteristics of Dynamic Nonlinear p-yElement SPSI - 12 Coupled SPSI Approach Soi
different soil-pile parameters would affect the soil-pile response. The parametric study has indicated that the E-modulus of the soil and pile spacing have larger impact on the soil-pile response than the hysteretic damping property. Finally, velocity from field measurement is comp
To observe the design capacity, a test pile is constructed and estimated load is given upon the designed pile. There are three kinds of static pile load testing. 1. Compression pile load test. 2. Tension pile load test. 3. Lateral pile load test. A lobal Journal of Researches in Engineering V olume XVI Issue IV Ve rsion I 41 Year 201 E
Pile designers therefore looked at calculation based on theoretical soil mechanics. 16 Geotechnical Design to EC7 13 January 2017 Layer 1 Layer 2 Layer 3 L 1 L 2 L 3 Q s1 Q s2 Q s3 Q b Ultimate pile resistance Q u Q s Q b Traditional Pile Design to BS 8004. 17 Geotechnical Design to EC7 13 January 2017 Traditional Pile Design to BS 8004 The usual approach is to divide the ground into .
pile shaft under fully coupled inelastic soil-pile-structure interaction, and (ii) compute the equivalent-linear (EL) pile head impedance functions under the controlled dynamic and earthquake loading modes. Hence, a three-dimensional finite element (FE) model of the soil-pile system,
sheet pile and ground vibrations during sheet pile vibratory driving. And second, to analyze a selected portion of the collected data with focus on the sheet pile - soil vibration transfer. Both aspects of the thesis work aim, more generally, to contribute to the understanding of ground vibration generation under vibratory sheet pile driving.
PHC pile, with a diameter of 1000mm and a wall thickness of 130mm , is adopted for the wall pile frame structure of this project. The pipe pile prefabrication is carried out by dalian prefabrication factory. The parameters of the PHC prestressed concrete pipe pile are as follows: Table 1 parameters of PHC pile of wall pile frame structure .
to pile cap resistance to lateral loads. The focus of the literature review was directed towards experimental and analytical studies pertaining to the lateral resistance of pile caps, and the interaction of the pile cap with the pile group. There is a scarcity of published information available in the subject area of pile cap lateral resistance.
Keywords: Soil-pile-structure interaction, nonlinear soil, soil dynamics, structural dynamics, seismic response 1. INTRODUCTION Great advances have been developed on the study of dynamic behaviour of pile foundations. However, there are some problems remaining, and some parameters are uncertain
