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Designation D8169/D8169M − 18Standard Test Methods forDeep Foundations Under Bi-Directional Static AxialCompressive Load1This standard is issued under the fixed designation D8169/D8169M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon ´ indicates an editorial change since the last revision or reapproval.1. Scope1.1 The test methods described in this standard measure theaxial displacement of a single, deep foundation element whenloaded in bi-directional static axial compression using anembedded bi-directional jack assembly. These methods applyto all deep foundations, referred to herein as “piles,” whichfunction in a manner similar to driven piles, cast in place piles,or barrettes, regardless of their method of installation. The testresults may not represent the long-term performance of a deepfoundation.1.2 This standard provides minimum requirements for test-ing deep foundations under bi-directional static axial compres-sive load. Plans, specifications, and/or provisions prepared bya qualified engineer may provide additional requirements andprocedures as needed to satisfy the objectives of a particulartest program. The engineer in charge of the foundation design,referred to herein as the engineer, shall approve any deviations,deletions, or additions to the requirements of this standard.1.3 This standard provides the following test proceduresProcedure A Quick Test 9.2.1Procedure B Extended Testoptional9.2.21.4 Apparatus and procedures herein designated “optional”may produce different test results and may be used only whenapproved by the engineer. The word “shall” indicates amandatory provision, and the word “should” indicates arecommended or advisory provision. Imperative sentencesindicate mandatory provisions.1.5 The engineer may use the results obtained from the testprocedures in this standard to predict the actual performanceand adequacy of piles used in the constructed foundation. SeeAppendix X1 for comments regarding some of the factorsinfluencing the interpretation of test results.1.6 A qualified engineer specialty engineer, not to beconfused with the foundation engineer as defined above shalldesign and approve the load test configuration and test proce-dures. The text of this standard references notes and footnoteswhich provide explanatory material. These notes and footnotesexcluding those in tables and figures shall not be consideredas requirements of the standard. This standard also includesillustrations and appendixes intended only for explanatory oradvisory use.1.7 UnitsThe values stated in either SI units or inch-pound units presented in brackets are to be regarded sepa-rately as standard. The values stated in each system may not beexact equivalents; therefore, each system shall be used inde-pendently of the other. Combining values from the two systemsmay result in non-conformance with the standard. Reporting oftest results in units other than SI shall not be regarded asnonconformance with this test method.1.8 The gravitational system of inch-pound units is usedwhen dealing with inch-pound units. In this system, the poundlbf represents a unit of force weight, while the unit for massis slugs. The rationalized slug unit is not given, unless dynamicFma calculations are involved.1.9 All observed and calculated values shall conform to theguidelines for significant digits and rounding established inPractice D6026.1.9.1 The procedures used to specify how data are collected,recorded and calculated in this standard are regarded as theindustry standard. In addition, they are representative of thesignificant digits that should generally be retained. The proce-dures used do not consider material variation, purpose forobtaining the data, special purpose studies, or any consider-ations for the user’s objectives; and it is common practice toincrease or reduce significant digits of reported data to becommensurate with these considerations. It is beyond the scopeof this standard to consider significant digits used in analysismethods for engineering design.1.10 This standard offers an organized collection of infor-mation or a series of options and does not recommend aspecific course of action. This document cannot replace edu-cation or experience and should be used in conjunction withprofessional judgment. Not all aspects of this guide may beapplicable in all circumstances. This ASTM standard is notintended to represent or replace the standard of care by whichthe adequacy of a given professional service must be judged,1This test method is under the jurisdiction ofASTM Committee D18 on Soil andRock and is the direct responsibility of Subcommittee D18.11 on Deep Foundations.Current edition approved Jan. 1, 2018. Published February 2018. DOI 10.1520/D8169_D8169M-18.Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade TBT Committee.1nor should this document be applied without consideration ofa project’s many unique aspects. The word “Standard” in thetitle of this document means only that the document has beenapproved through the ASTM consensus process.1.11 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.12 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade TBT Committee.2. Referenced Documents2.1 ASTM Standards2D653 Terminology Relating to Soil, Rock, and ContainedFluidsD1143/D1143M Test Methods for Deep Foundations UnderStatic Axial Compressive LoadD3689/D3689M Test Methods for Deep Foundations UnderStatic Axial Tensile LoadD3740 Practice for Minimum Requirements for AgenciesEngaged in Testing and/or Inspection of Soil and Rock asUsed in Engineering Design and ConstructionD5882 Test Method for Low Strain Impact Integrity Testingof Deep FoundationsD6026 Practice for Using Significant Digits in GeotechnicalDataD6760 Test Method for Integrity Testing of Concrete DeepFoundations by Ultrasonic Crosshole TestingD7949 Test Methods for Thermal Integrity Profiling ofConcrete Deep Foundations2.2 ASME Standards3ASME B30.1 JacksASME B40.100 Pressure Gauges and Gauge Attachments3. Terminology3.1 Definitions3.1.1 For definitions of common technical terms used in thisstandard, refer to Terminology D653.3.2 Definitions of Terms Specific to This Standard3.2.1 axial compressive capacity, nthe maximum axialcompressive load that a deep foundation can transfer to the soiland rock around it at an acceptable axial movement.3.2.2 bi-directional jack, na specialized hydraulic jackthat has a repeatable, linear load-pressure calibration over itsexpansion range.3.2.3 bi-directional axial compressive load test, nan axialcompressive load test performed on a deep foundation elementby pressurizing an embedded jack assembly see definitionbelow, so that the foundation section above the jack assemblymoves upwards and the foundation section below the jackassembly moves downwards, each section providing reactionfrom which to load the other.3.2.4 cast in-place pile, na deep foundation element madeof cement grout or concrete and constructed in its finallocation, e.g., drilled shafts, bored piles, caissons, auger castpiles, pressure-injected footings, etc.3.2.5 deep foundation, na relatively slender structuralelement that transmits some or all of the load it supports to soilor rock well below the ground surface also referred to hereinas a “pile”, such as a steel pipe pile or concrete drilled shaft.3.2.6 driven pile, na deep foundation element made ofpreformed material with a predetermined shape and size andtypically installed by impact hammering, vibrating, or pushing.3.2.7 jack assembly, none or more bi-directional jacksarranged together with any plates to act in parallel symmetri-cally around a central axis, which will be embedded within adeep foundation element to apply a bi-directional compressiveload aligned with the central axis of the deep foundationelement.3.2.8 steel reinforcement, nfor the purpose of thisStandard, this may consist of any steel assemblage or steelmember such as a rebar cage, channel frame, box beam,wide-flange beam, etc., used to reinforce the concrete column,or in a non-production pile, to fix the jacks and instrumen-tation in place.3.2.9 telltale rod, nan unstrained metal rod extendedthrough the test pile from a specific point within the pile to beused as a reference from which to measure the change in thelength of the loaded pile section, or the absolute movement atthat specific point.3.2.10 wireline, na steel wire mounted with a constanttension force between two supports and used as a reference lineto read a scale indicating movement of the test pile.4. Significance and Use4.1 The bi-directional axial compressive load test providesseparate, direct measurements of the pile side shear mobilizedabove an embedded jack assembly and the pile end bearingplus any side shear mobilized below the jack assembly. Themaximum mobilized pile resistance equals two times themaximum load applied by the jack assembly. Test results mayalso provide information used to assess the distribution of sideshear resistance along the pile, the amount of end bearingmobilized at the pile bottom, and the long-term load-displacement behavior.4.2 The specified maximum test load should be consistentwith the engineer’s desired test outcome. For permanentworking piles, the engineer may require that the magnitude ofapplied test load be limited in order to measure the pilemovement at a predetermined proof load as part of a qualitycontrol or quality assurance program. Tests that attempt to fully2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standard’s Document Summary page onthe ASTM website.3Available from American Society of Mechanical Engineers ASME, ASMEInternational Headquarters, Two Park Ave., New York, NY 10016-5990, http//www.asme.org.D8169/D8169M − 182mobilize the axial compressive resistance of the test pile mayallow the engineer to improve the efficiency of the pile designby reducing the piling length, quantity, or size.4.3 The engineer and other interested parties may analyzethe results of a bi-directional axial compressive load test toestimate the load versus movement behavior and the pilecapacity that would be measured during axial static compres-sive or tensile loading applied at the pile top see Notes 1-3.Factors that may affect the pile response to axial static loadingduring a static test include, but are not limited to the1 pile installation equipment and procedures,2 elapsed time since initial installation,3 pile material properties and dimensions,4 type, density, strength, stratification, and groundwaterconditions both adjacent to and beneath the pile,5 test procedure,6 prior load cycles.NOTE 1To estimate the load displacement curve for the pile as if itwere loaded in compression at the top as in Test Methods D1143/D1143M, the engineer may use strain and movement compatibility tosum the pile capacity mobilized above and below the embedded jackassembly for a given pile-top movement. This “top-load” curve will belimited by the lesser of the displacement measured above or below theembedded jack assembly. To obtain adequate minimum displacementduring the test, the engineer may wish to specify a maximum test loadgreater than the desired equivalent “top load”.NOTE 2A bi-directional load test applies the test load within the pile,resulting in internal pile stresses and pile displacements that differ fromthose developed during a load test applied at the pile top. Bi-directionaltesting will generally not test the structural suitability of a pile to supporta load as typically placed at the pile top. Structural defects near the piletop may go undetected unless separate integrity tests are performed priorto or after bi-directional testing see Note 8. The analysis of bi-directionalload test results to estimate the pile-top movement that would be measuredby applying a compressive load at the top of the pile should consider straincompatibility and load-displacement behavior. ASTM D1143/D1143Mprovides a standard test method for the direct measurement of pile topmovement during an axial static compressive load applied at the pile top.NOTE 3The analysis of bi-directional load test results to estimate piledisplacements that would be measured by applying a tensile uplift loadat the top of the pile should consider strain and movement compatibility.Users of this standard are cautioned to interpret conservatively the tensilecapacity estimated from the analysis of a compressive load. ASTMD3689/D3689M provides a standard test method for the direct measure-ment of axial static tensile capacity.4.4 For the purpose of fully mobilizing the axial compres-sive capacity, the engineer will usually locate the jack assem-bly at a location within pile where the capacity above theassembly equals the capacity below it. A poorly chosenassembly location may result in excessive movement above orbelow the jack assembly, limiting the applied load and reduc-ing the usefulness of the test result. Determination of theassembly’s location requires suitable site characterization,consideration of construction methods, and the proper applica-tion of engineering principles and judgement see Note 4.More complex test configurations, using multiple levels of jackassemblies, may provide a higher probability that the fullresistance of the pile along its entire length may be determined.Details regarding such complex arrangements are beyond thescope of this standard.NOTE 4The bi-directional load test may not fully mobilize the axialcompressive pile resistance in all sections of the pile. Practical,economical, or code considerations may also result in bi-directional loadtests that are not intended to fully mobilize the axial resistance in some orall sections of the pile. In these cases, interpretation of the bi-directionaltest may under-predict the total axial c
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