INTERNATIONAL STANDARD ISO 22477-10 First edition 2016-09-15 Geotechnical investigation and testing — Testing of geotechnical structures — Part 10: Testing of piles: rapid load testing Reconnaissance et essais géotechniques — Essais de structures géotechniques — Partie 10: Essai des pieux: essai de charge rapide Reference number ISO 22477-10:2016(E) © ISO 2016 ISO 22477-10:2016(E) COPYRIGHT PROTECTED DOCUMENT © ISO 2016, Published in Switzerland All rights reserved Unless otherwise specified, no part o f this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission Permission can be requested from either ISO at the address below or ISO’s member body in the country o f the requester ISO copyright o ffice Ch de Blandonnet • CP 401 CH-1214 Vernier, Geneva, Switzerland Tel +41 22 749 01 11 Fax +41 22 749 09 47 copyright@iso.org www.iso.org ii © ISO 2016 – All rights reserved ISO 22477-10:2016(E) Page Contents Foreword iv Introduction v Scope Normative references Terms, definitions and symbols Testing equipment 4.1 General 4.2 Loading 4.3 Measurements 5 Test procedure 5.1 Preparation for testing f 5.2.1 People and equipment in the surrounding area 5.2.2 Test pile 5.3 Preparation of the pile 5.4 General preparation for testing f Test results Test reporting 10 Annex A (informative) Analysis o f rapid load test results 12 Bibliography 23 Terms and definitio ns Symb o ls S a ety and integrity requirements 5 Wo rking p ile integrity a ter tes ting © ISO 2016 – All rights reserved iii ISO 22477-10:2016(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies) The work o f preparing International Standards is normally carried out through ISO technical committees Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters o f electrotechnical standardization The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part In particular the different approval criteria needed for the di fferent types o f ISO documents should be noted This document was dra fted in accordance with the editorial rules of the ISO/IEC Directives, Part (see www.iso.org/directives) Attention is drawn to the possibility that some o f the elements o f this document may be the subject o f patent rights ISO shall not be held responsible for identi fying any or all such patent rights Details o f any patent rights identified during the development o f the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents) Any trade name used in this document is in formation given for the convenience o f users and does not constitute an endorsement For an explanation on the meaning o f ISO specific terms and expressions related to formity assessment, as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html ISO 22477-10 was prepared by the European Committee for Standardization (CEN) in collaboration with ISO Technical Committee TC 182, Geotechnics, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement) A list of all parts in the ISO 22477 series, published under the general title Geotechnical investigation and testing — Testing of geotechnical structures, can be found on the ISO website iv © ISO 2016 – All rights reserved ISO 22477-10:2016(E) Introduction T h i s p a r t o f I S O 2 47 outl i ne s how a rapid lo ad pi le te s t i s defi ne d and s p e ci fie s the e quipment a nd te s ti ng pro ce du re s re qu i re d I n formative, non-pre s crip tive gu idance i s i nclude d on the ana lys i s o f rapid load pile test results required to determine mobilised or ultimate compressive resistance of a pile © ISO 2016 – All rights reserved v INTERNATIONAL STANDARD ISO 22477-10:2016(E) Geotechnical investigation and testing — Testing of geotechnical structures — Part 10: Testing of piles: rapid load testing Scope This part o f ISO 22477 establishes the specifications for the execution o f rapid load pile tests in which a single pile is subject to an axial load in compression to measure its load-displacement behaviour under rapid loading and to allow an assessment of its measured compressive resistance (Rc, m) and corresponding load-displacement behaviour This part o f ISO 22477 is applicable to piles loaded axially in compression All pile types mentioned in EN 1536, EN 12699 and EN 14199 are covered by this part o f ISO 22477 The tests in this part o f ISO 22477 are limited to rapid load pile tests only NOTE This part o f ISO 22477 can be used in conjunction with EN 1997–1 Numerical values o f partial factors NOTE Guidance on analysis o f the rapid load testing results to determine measured compressive resistance for limit states from pile load tests to be taken into account in design are provided in EN 1997–1 For design to EN 1997–1, the results from rapid load pile testing will be considered equivalent to the measured compressive resistance, Rc,m , a fter being subject to appropriate analysis and corresponding load-displacement behaviour is given in Annex A This part o f ISO 22477 provides specifications for the following: a) investigation tests, whereby a sacrificial test pile is loaded up to ultimate limit state; b) control tests, whereby the pile is loaded up to a specified load in excess o f the serviceability limit state NOTE Generally, an investigation test focuses on general knowledge o f a pile type; a control test focuses on one specific application o f a pile Normative references The following documents are re ferred to in the text in such a way that some or all o f their content constitutes requirements o f this document For dated re ferences, only the edition cited applies For undated re ferences, the latest edition o f the re ferenced document (including any amendments) applies There are no normative references in this document © ISO 2016 – All rights reserved ISO 22477-10:2016(E) Terms, definitions and symbols 3.1 Terms and definitions For the purposes o f this document, the terms and definitions given in EN 1997-1 and the following apply ISO and IEC maintain terminological databases for use in standardization at the following addresses: — IEC Electropedia: available at http://www.electropedia.org/ — ISO Online browsing platform: available at http://www.iso.org/obp 3.1.1 trial pile pile installed be fore the commencement o f the main piling works or a specific part o f the works for the purpose o f investigating the suitability o f the chosen type o f pile and for confirming its design, dimensions and bearing resistance Note to entry: The trial pile might be sacrificed to achieve ultimate limit state 3.1.2 working pile pile that will form part of the foundation of the structure 3.1.3 test pile pile to which loads are applied to determine the resistance deformation characteristics of the pile and the surrounding ground Note to entry: A test pile can be a trial pile (3.1.1), or a working pile (3.1.2) 3.1.4 pile load axial compressive load (or force) applied to the head of the pile during the test 3.1.5 rapid load orce applied to the pile in a continuously increasing and then decreasing manner o f a suitable duration (typically less than s) relative to the natural period o f the pile which causes the pile to compress over the full length and translate approximately as a unit during the full loading period f 3.1.6 maximum compressive load maximum axial compressive load (or force) applied to the pile during the test, generally defined prior to the test 3.1.7 rapid load test pile loading test where a pile is subjected to chosen axial analysis o f its capacity rapid load (3.1.5) at the pile head for the 3.1.8 ultimate measured compressive resistance of a pile corresponding state in which the pile foundation displaces significantly with negligible increase o f resistance Note to entry: Where it is di fficult to define an ultimate limit state from a load settlement plot showing a continuous slight increase, a settlement of the pile top equal to 10 % of the pile base diameter should be adopted as the “failure” criterion © ISO 2016 – All rights reserved ISO 22477-10:2016(E) rapid load test (3.1.7 equal to the ultimate measured compressive resistance of a pile The measured resistance obtained from rapid ff f f considered equivalent to the ultimate measured compressive resistance as outlined in Annex A N o te to entr y: T he ma xi mu m compre s s ive re s i s ta nce me a s u re d du r i ng a lo ad te s ti ng mu s t b e a n a l ys e d to remove the e e c ts o ) i s no t ne ce s s a r i l y i ner ti a a nd s o i l dep endent b eh aviou r b e o re it c a n b e 3.1.9 design compressive static resistance of a pile ultimate compressive static resistance of a pile that shall be determined prior to load testing to allow f rapid load test (3.1.7 s p e ci fic ation o appropriate magn itude ) c ycle s 3.1.10 equivalent diameter diameter of an equivalent circle of which the area equals the area of the relevant pile section N o te to entr y: T he e qu i va lent d i a me ter fo r a c i rc u l a r p i le i s the o uter d i a me ter o f the pi le , for a s qu a re p i le the diameter which gives the same area as the square pile (as long as the longest side is smaller than 1,5 times the shortest side) is the equivalent diameter 3.1.11 minimum reference separation distance d i s tance wh ich s ep arate s a s tationar y re ference p oi nt from a p oi nt that wi l l b e s ign i fic antly d i s pl ace d b y the te s ti ng me tho d N o te to entr y: O n l y s tation a r y p oi nts c a n b e u s e d for re ference o f displacement (3.1.12) measurement devices D i s p l acement me a s u r i n g s ys tem s c a n b e p l ace d on the s oi l o uts ide the re ference d i s ta nce without i s ol ati ng (displacement compensating) measures 3.1.12 displacement axial displacement of the pile head measured during testing 3.2 Symbols a pile acceleration cp velo city o f the s tre s s wave i n the te s t pi le cs velo city o f the s he a r wave i n the ground D Fc Fc,max g L Rc,m rref t tf tg w diameter or equivalent diameter of the test pile pile load in compression maximum compressive load acceleration due to gravity total length of the test pile measured ultimate resistance of the ground in the test, or measured geotechnical resistance of the pile minimum reference separation distance time duration of the rapid load application duration of the falling of the mass for a falling mass equipment pile displacement © ISO 2016 – All rights reserved ISO 22477-10:2016(E) Testing equipment 4.1 General T he e qu ipment s hou ld generate a rapid lo ad at the pi le he ad where the du ration o f the lo ad Formula (1): 10 < ( tf × cp L fu l fi l s ) ≤ 000 (1) If information on the ultimate compressive resistance of the pile is one of the aims of the test, the e qu ipment sha l l h ave enough c ap ac ity to re ach the u lti mate compre s s ive re s i s tance u nder rapid lo ad i ng The force applied to the pile head during a rapid load test for measuring the ultimate compressive re s i s ta nce m ight exce e d the de s ign compre s s ive s tatic re s i s tance o f a pi le by a fac tor o f two to th re e due to s oi l s p e c i fic rate e ffe c ts T he ne e d to apply s uch h igh lo ad s s l l b e s idere d when s p e ci fyi ng equipment and pile materials If for a rapid load test one or more of the requirements mentioned in this part of ISO 22477 is not met, f f test, before the results can be interpreted as a rapid load test For long piles where the criteria in Formula (1) is exceeded or where rock sockets result in non-uniform Additional instrumentation should conform to 4.3 it s hou ld b e proven th at thi s s hor tcom i ng s no i n fluence on the ach ievement o s trai n s with i n the pi le, emb e dde d pi le i n s tr u mentation and s p e ci a l i z e d the obj e c tive s o ana lys i s wi l l be the re qu i re d Rapid lo ad te s ti ng s ys tem s rely on a mas s to apply lo ad to a pi le T h i s i s either th rough lau nch i ng a mas s upward s , re ferre d to as a l au nche d ma s s s ys tem, or b y d roppi ng a mas s , re ferre d to as a d rop ma s s s ys tem I n b o th c as e s , the upward or the downward movement o f the mas s i s control le d to pro duce the required load duration in 4.1 f f the movement of the mass should be guided during launched mass testing and drop mass testing To avoid e ccentric lo ad i ng o pi le s and add itiona l s a e ty s ideration s , 4.2 Loading The selection of the loading equipment shall take into account the following: — m o f the te s t; — grou nd cond ition s; — maximum pile load (Fc,max ); — s treng th o f the pi le (materia l) ; — e xe c ution o f the te s t; — s a fe ty s ideration s T he lo ad i ng e qu ipment s l l generate a force apply the re qu i re d ma xi mu m compre s s ive ultimate compressive resistance of a pile force wh ich fu l fi l s the re qu i rements I f a te s t pi le i s te s te d b y s evera l c ycle s b egi n ni ng with a low magn itude force in 4.1 and is able to to mobi l i z e a s p e ci fie d compre s s ive re s i s tance or the o f e ach pro ce e d i ng c ycle shou ld b e la rger than the ma xi mum force force c ycle, the ma xi mu m o f the pre ce d i ng c ycle Where c ycle s o f lo ad i ng are appl ie d, th i s s hou ld b e u nder ta ken i n a man ner that remove s the p o tentia l uncontrolled reloading of the pile This will require the device to have a mass catching mechanism for T he e qu ipment s l l lo ad the pi le acc u rately a long the d i re c tion o f the pi le a xi s T he e ccentricity o f the lo ad s l l b e le s s th an 10 % o f the e qu iva lent d i ame ter T he deviation or e ccentric ity o f the a l ignment of the force to the axis of the pile shall be less than 20 mm/m Eccentric loading of the pile is allowed © ISO 2016 – All rights reserved ISO 22477-10:2016(E) diagrams without correction, with the initial displacement for each cycle calculated based upon the elevation o f the pile head prior to application o f the individual load cycle NOTE More information on interpretation is outlined in Annex A Effects such as rate effects (including test and can be different from what is expected from an equivalent static load test creep), excess pore water pressures and inertia e ffects (due to acceleration) can be introduced by the rapid load A copy o f all results shall be recorded in the test report and stored on a back-up medium in an open access format such as ASCII Where required, the velocity o f the pile head shall be calculated by integration o f the measured accelerations with respect to time The velocity and acceleration o f the pile head shall be calculated by di fferentiation o f the measured displacements with respect to time only where accelerometer-based measurements not give satis factory results Derivation o f pile velocity from direct acceleration measurements shall be the pre ferred option Calculation o f the displacement o f the pile head by double integration o f the measured accelerations with respect to time is allowed only i f the final set is checked by a direct optical measurement o f the displacement Test reporting A factual report shall be written for all load tests Where appropriate, this report shall include the following: a) re ference to all relevant standards; b) general information concerning the test site and the test programme: — topographic location o f the test including definition o f the level datum that is used as a re ference for elevation measurements; — general description o f the site; — purpose o f the test; — test date; — the intended and realized testing programme; — name o f the organization which carried out the test; — name o f the organization which supervised the test; c) information concerning the ground conditions: — the ground and groundwater conditions with reference to the relevant site investigation reports; — description o f the ground conditions, in the particular the vicinity o f the test pile; d) specification o f the test pile(s): — the pile type, reason for testing and its re ference number; — the topographic position and level o f the test pile re ferenced to a local datum; — pile data, such as geometry (including as a minimum the total pile length, L , and diameter, D, or equivalent diameter), level o f the pile top and base, pile material (including material density i f known) and rein forcement arrangement; — date o f installation; — description o f the pile installation and o f any problems encountered during the works; 10 © ISO 2016 – All rights reserved I SO 2 47 - : (E) e) — i n s ta l lation re cord s , s uch a s d rivi ng lo gs , concre te s u mp tion, d ri l l i ng pro gre s s; — te s t rep or ts on pi le materia l qua l ity or s p e ci fic ation (where appl ic ab le) ; — rep or t for i ntegrity i nve s tigation i f u nder ta ken prior to te s ti ng; s p e c i fic ation o f the te s t: — the p o s tu late d ma xi mu m te s t lo ad; — the nu mb er o f lo ad c ycle s a nd the — pi le cap de ta i l s; — a de s crip tion o f the lo ad i ng and me a s u ri ng app aratu s and re ac tion or ma s s s ys tem; — i n formation on the p o tenti a l energ y p o tentia l — c a l ibration c uments — the d i s ta nce b e twe en the pi le and the d i s placement me as u rement device; — de ta i l s o f the i n s ta l l ation o f the pi le te s ti ng e quipment b y d rawi ngs and/or to graph s; f) test results: for e ach c ycle (d rop height, ma s s , a mou nt o f fuel) ; , i nclud i ng the d igita l data i n nu meric a l a s defi ne d i n — the rapid lo ad- d i s placement d i agram for lo ad i ng level s; the lo ad cel l s , accelerome ters and d i s placement me as u ri ng device s; — re qui re d g) Clause for fore s e en for e ach c ycle from the d i s placement o f e ach c ycle a s a re s u lt o f rapid lo ad i ng; — the re s u lts o f the h igh pre ci s ion op tic a l level l i ng; — rep or t re as on s for and engi ne eri ng u n its; the me a s ure d s igna l s a nd d i agram s mu lti c ycle te s ti ng on a s i ngle pi le i f under ta ken; — for form i ntegrity i nve s tigation i f u nder ta ken a fter te s ti ng; a ny dep ar tu re from th i s p ar t o f I S O 2 47 If the report includes an interpretation of the measured tests results, the following information shall also be added to the test report: for — the me tho d u s e d the i nter pre tation; — the derive d s tatic lo ad- d i s pl acement d iagram; — de ta i l s o f the tre atment o f rate e ffe c ts or s oi l dep endant corre c tion s; — de ta i l s o f the tre atment o f i ner ti a l e ffe c ts; — details of the treatment of effects due to excess pore water pressure (where considered) © ISO 2016 – All rights reserved 11 ISO 22477-10:2016(E) Annex A (informative) A n a l y s i s o f r a p i d l o a d t e s t r e s u l t s A.1 General Annex A gives in formative guidance on one method for analysing rapid load test results (see Reference [5 ]) This in formative guidance is not meant to be prescriptive or limit the type of analysis technique which may be adopted Further guidance on appropriate analysis techniques should be sought from the specialist pile testing contractor undertaking the testing as alternative methods such as signal matching have been applied but experience may be limited (see Re ferences [5],[6] and [7]) Inclusion o f the in formative guidance on the analysis o f rapid load testing should not discourage or inhibit the use, adoption or development o f alternative analysis techniques The measured results obtained from a rapid load pile test should not be considered equivalent to the measured compressive resistance, Rc,m , without appropriate correction for the effects of increased pile acceleration and velocity in excess o f those induced in a static pile test A.2 Unloading Point Method (UPM) for determination of the compressive pile b e h a v i o u r A.2.1 General Rapid load test results can be analysed using the Unloading Point Method (UPM) to derive the measured compressive resistance, Rc,m , and the corresponding load deflection behaviour The approach can be used for either a single load cycle or multiple load cycles (undertaken on a single pile) as required The analysis technique to determine the measured compressive resistance, Rc,m , and the corresponding load deflection behaviour is based upon that outlined in Re ference [5] A A n a l y s i s o f a s i n g l e l o a d c y c l e Rapid load testing may proceed by the application o f a single cycle o f loading or by multiple cycles o f loading This subclause covers the analysis o f a single cycle o f loading The process o f analysis o f a single load cycle is outlined in Figure A.1 to Figure A.3 included to clari fy the steps o f the analysis process The process is as follows a) Obtain the measured signals from the rapid load test b) Calculation of the inertia corrected mobilised pile resistance at the unloading point — Obtain the pile properties required to calculate the mass of the pile, m (pile cross sectional area, pile length, density o f the pile material, records o f the concrete volume used to form the pile) and the mass o f any other components contributing to the inertial resistance o f the pile — Obtain the variation of force (F), velocity (v), displacement (w) and acceleration (a) with time (t) or a single load cycle f — Determine the time (tw-max) during the test where the measured pile velocity becomes m/s or a value close to this Referred to as the unloading point — Determine the magnitude of the force measured at tw-max, Fc, tw-max — Determine the magnitude of the acceleration at tw-max, atw-max 12 © ISO 2016 – All rights reserved I SO 2 47 - : (E) — Solve Formula (A.1) to determine the inertia corrected pile resistance at tw-max R − max = F − max − ( m × a − max ) c , ic , tw c , tw tw (A.1) where atw-max Fc, tw-max m is the acceleration measured during the test at tw-max is the magnitude of the force measured during the test at tw-max ; ; i s the mas s o f the pi le a nd any o ther comp onents contributi ng to i ner tia l re s i s tance o f the pi le; is the inertia corrected pile resistance at tw-max tw-max the time some time after the commencement and before the end of the load applif ff close to this c) Correction of the inertia corrected pile resistance for the soil dependant empirical parameter — Determine the soil dependent empirical parameter based upon Table A.1 recommendations and calculate the corrected derived static pile resistance, Rc,corrected as per Formula (A.2) — Determine the magnitude of the displacement at tw-max, wtw-max R (A.2) corrected = η × ( R − max ) Rc, ic, tw-max ; c ation ph as e o c, the te s t where the pi le velo city e e c tively b e come s m/s or a va lue c , ic , tw where Rc, corrected wtw-max η is the corrected mobilised resistance at wtw-max magnitude of the pile displacement at tw-max soil dependant empirical parameter ; ; tw-max can be shown to correspond to the ultimate resistance of the pile, then Rc, corrected compressive pile resistance Rc,m The parameters shown in Table A.1 f f conditions as those that were used to determine the parameters as outlined in Reference [5] Where the mobi l i s e d pi le lo ad defle c tion b ehaviour at may b e s idere d e qu iva lent to the me as u re d s hou ld on ly b e adop te d where it c a n b e demon s trate d that rapid lo ad te s ti ng was under ta ken on the s ame typ e o © ISO 2016 – All rights reserved pi le , o s i m i lar leng th and i n comp arable s oi l 13 ISO 22477-10:2016(E) T a S b o l i e l A t y p — S e l e c t i o n o f e s o i C Empirical factor, η Standard deviation Coe fficient o f variation Number of cases Number of sites l l d a e p e n d y 0,66 0,32 0,49 12 a n t e m p i r i c a l p a r a m e t e r η Sand 0,94 0,15 0,15 22 10 NOTE The values shown in this table are based upon data presented in Reference [5] Table C.2 for clay soild and Table C.3 for sand NOTE Only cases with pile head displacements greater than % o f the equivalent pile diameter are considered in this table NOTE The variation o f values in this table is significant for clay soils particularly An alternative suggestion for a selection method for empirical factor for clay based upon measured soil properties can be found in Reference [6 ] The majority o f the values presented in this table are derived from pile tests on driven piles NOTE Guidance on analysis in clays and layered soils is also given in Re ference [8] d) Determination of initial pile stiffness If an approximation of the complete corrected load-displacement behaviour during the test is required, then further analysis steps are necessary to construct a hyperbolic based approximation of the load displacement behaviour (see Figure A.3 ) Firstly, it is necessary to determine the initial pile stiffness at low displacement levels The hyperbola is described by F = w/( p + q × w) where p is the inverse value of the initial pile stiffness kc and q is the inverse value of the hyperbola asymptote In a hyperbola diagram with coordinates w/F and w, a pure hyperbola will be represented by a straight line Background information on this technique can be found in Reference [9] The required steps are as follows — Plot the displacement of the pile (w) divided by the inertia corrected pile resistance (Rc,ic) for the complete test versus the pile displacement up to wFc-max where Fc-max is the maximum measured force — Determine the magnitude of the w/Rc,ic axis intersection with a best fit linear line to determine the value for the hyperbola parameter, p, which represents the inverse of the initial pile stiffness, kc e) Determination of the inertia corrected load displacement curve The procedure for determination of inertia corrected load displacement curve is as follows — Determine the initial stiffness parameter as outlined above — Calculate the remaining the hyperbola formula parameter q as given in Formula (A.3): q =1 R (A.3) − max − p w − max , c , ic , tw tw — Draw the resulting hyperbola load displacement curve using Formula (A.4): R c , ic = w p + ( q × w ) (A.4) f) Determination of the corrected compressive load displacement curve The procedure for determination of the corrected compressive load displacement curve is as follows 14 © ISO 2016 – All rights reserved I SO 2 47 - : (E) — C a lc u late the hyp erb ola p ara me ter Rc, corrected ; qcorrected as per Formula (A.3) with Rc,ic,tw-max replace d b y — Draw the resulting corrected compressed load displacement curve using Formula (A.4) with parameters determined for Rc,corrected F i g u r e A — F l o w c h a © ISO 2016 – All rights reserved r t s h o w i n g t h e a n a l y s i s p r o c e s s f o r a s i n g l e c y c l e o f r a p i d l o a d t e s t i n g 15 I SO 2 47 - : (E ) F 16 i g u r e A — A n a l y s i s p r o c e s s f o r a s i n g l e c y c l e u s i n g e x a m p l e d a t a a n d c a l c u l a t i o n o f Rc, m © ISO 2016 – All rights reserved Displacement/Load [mm/MN] I SO 2 47 - : (E) Figure A.3 — Single cycle load displacement calculation using example data © ISO 2016 – All rights reserved 17 I SO 2 47 - : (E ) A.2.3 Analysis o f multiple load cycles The analysis for multi cycle testing where multiple load cycles are applied consecutively to the same pile follows the principals as outlined above The overall process and differences between the single and multi-cycle analysis are highlighted below The process o f analysis o f multiple load cycles is outlined below with Figure A.4 to Figure A.6 included to clari fy the steps o f the analysis process a) Obtain the measured signals from the rapid load test with multiple load cycles b) Plot the load displacement behaviour for each successive load cycle with each new load cycle starting at the final displacement o f the previous load cycle c) Analyse all o f the load cycles individually and determine Rc,ic,tw-max and corresponding wtw-max for each load cycle and plot these points in a load displacement diagram d) The measured compressive resistance Rc,m corresponds with Rc, corrected from the last cycle e) Trans fer the points into a hyperbola diagram and determine a best fit linear line through these points and determine the p and q parameters for the hyperbola f ) Draw the hyperbola in the load displacement diagram g) Draw the corrected derived load displacement curve with p and qcorrected 18 © ISO 2016 – All rights reserved I SO 2 47 - : (E) co rre s p o n d i n g F i g u r e A — F l o w c h a r © ISO 2016 – All rights reserved t s h o w i n g t h e a n a l y s i s p r o c e s s f o r m u l t i p l e c y c l e s o f r a p i d l o a d t e s t i n g 19 ISO 22477-10:2016(E) F 20 i g u r e A — A n a l y s i s p r o c e s s o f t h e l a s t c y c l e ( ) a n d c a l c u l a t i o n o f Rc,m using example data © ISO 2016 – All rights reserved I SO 2 47 - : (E) F i g u r e A — M © ISO 2016 – All rights reserved u l t i p l e c y c l e l o a d d i s p l a c e m e n t c a l c u l a t i o n u s i n g e x a m p l e d a t a 21 ISO 22477-10:2016(E) A.3 Correlations for pile foundations For the veri fic ation o f Struc tura l (S T R) a nd G e o te ch n ic a l (GE O) l i m it s tate s , correlation and mo del factors should be applied to the Rc, m determined from Rapid Load testing to derive the characteristic re s i s tance o f a xia l ly lo ade d pi le s T he s e shou ld b e de term i ne d b as e d up on appropri ate e xp erience o f comp ari s on o f Rapid L o ad te s ti ng ana lys i s re s u lts with s tatic pi le te s ts ground cond ition s M o del technique used 22 fac tors for s i m i lar pi le typ e s and s hou ld b e u s e d that refle c t the p er formance o f the p ar tic u lar ana lys i s © ISO 2016 – All rights reserved I SO 2 47 - : (E) Bibliography [1] [2] ISO 22476 (all parts), Geotechnical investigation and testing — Field testing ISO 22477-1, Geotechnical investigation and testing — Testing of geotechnical structures — Part 1: Pile load test by static axially loaded compression [3] [4] [5] EN 1997-1, Eurocode 7: Geotechnical design —Part 1: General rules EN 1997-2, Eurocode 7: Geotechnical design —Part 2: Ground investigation and testing Hölscher P., BRASSINGA H., BROWN M.J., MIDDENDORP P., PROFITTLICH M., van TOL F.A 2011) Rapid load testing on piles: Interpretation guideline CUR Building and Infrastructure CUR Guideline 230 The Netherlands, CRC Press/Balkema ISBN: 978-0-415-69520-6 (Hbk), ISBN: 978-0-203-14588-3 (eBook) [6] B rown M.J., & Powell J.J.M Comparison of rapid load test analysis techniques in clay soils J Geotech Geoenviron Eng 2013, (1) pp 152–161 [7] M i yasaka T., Kuwab ara F., Likins G., R ausche F 2008) Rapid load test on high bearing capacity piles Santos, J.A (eds), 8th Int Con f on the Application o f Stress Wave Theory to Piles, Lisbon, Portugal 8-10 September 2008, IOS Press, Netherlands, pp 501-506 [8] We aver T.J., & Rollins K.M Reduction factor for the unloading point method at clay soil sites J Geotech Geoenviron Eng 2010, (4) pp 643–646 [9] C hin F.K 1972) The inverse slope as a prediction of ultimate bearing capacity of piles Lumb, P.L (eds) Proc of the 3rd Southeast Asian Conf on Soil Engineering, Hong Kong [10] Rollberg D Die kraft-setzungslinie von pfahlen Bauingenieur 1978, (5) pp 309–313 139 13 53 © ISO 2016 – All rights reserved 23 I SO 2 47 - : (E ) ICS 93.020 Price based on 23 pages © ISO 2016 – All rights reserved