Page 1

Recommendations on Piling (EA-Pf채hle)


Preface of the English Version of the Recommendations of the Piling Committee of the German Geotechnical Society (1) The present English version of the Recommendations of the Piling Committee of the German Geotechnical Society (Empfehlungen des Arbeitskreises „Pfähle“ – EA-Pfähle), is with a few exceptions a direct and complete translation of the 2nd edition 2012 of the German original. Even in case that some issues and, in particular, references might internationally not be known as in Germany, this approach was taken in order not to permit differing provisions between the German and this English version, if the latter is used in German speaking countries. It might also be possible that contractual or legal problems could arise between German and English speaking users if they could refer to a not identical translation. (2) As outlined in Section 1, Germany has published the German language versions of the European design (e.g. Eurocode 7) and execution standards (e.g. EN 1536, EN 12699, etc.). So was EN 1997-1:2004-11: Eurocode 7: Geotechnical design – Part 1: General rules published in Germany as DIN EN 1997-1:2009-09: Eurocode 7: Entwurf, Berechnung und Bemessung in der Geotechnik – Teil 1: Allgemeine Regeln. (3) For application in Germany, the standard DIN EN 1997-1:2009-09 was complemented with additional rules by DIN 1054:2010-12: Baugrund – Sicherheitsnachweise im Erd- und Grundbau – Ergänzende Regelungen zu DIN EN 1997-1 (Ground – Verification of the safety of earthworks and foundations) and by the National Annex EN 1997-1/NA:2010-12: Nationaler Anhang – National festgelegte Parameter – Eurocode 7: Entwurf, Berechnung und Bemessung in der Geotechnik – Teil 1 (National Annex – Nationally determined parameters – Eurocode 7: Geotechnical design – Part 1: General rules). The three documents were implemented together and their application is binding in Germany. (4) Complementing the European execution standards, national specifications were published and implemented in Germany under the heading “DIN SPEC”. (5) DIN 1054:2010-12: Baugrund – Sicherheitsnachweise im Erd- und Grundbau – Ergänzende Regelungen zu DIN EN 1997-1 (Ground – Verification of the safety of earthworks and foundations) frequently refers to the Recommendations of the Piling Committee of the German Geotechnical Society (EAPfähle) e.g. for the application of values based on well established experience for pile resistances, for the static and dynamic load testing, concerning pile resistances under cyclic loads, etc. (6) Where this English version of the Piling Recommendations makes reference to the above mentioned German standards DIN 1054 or the DIN SPEC, VII


the English speaking user should know, that all technical contents of the German complementing standards to Eurocode EC 7 and the European execution standards are also covered in these Recommendations. (7) This means that the user of the Piling Recommendations (EA-Pf채hle), when consequently applying, also fulfils the provisions of the complementing standards implemented in Germany. (8) Technical terms and symbols used in these Recommendations, if in addition to those of DIN EN 1997-1 (Eurocode EC 7-1), are listed in Annex A1 and, as necessary, explained in this English version. (9) In addition, the text can contain notes to supply the user with additional explanations for technical issues which are common in Germany or making reference to international procedures. (10) The Piling Recommendations are technical rules representing good and generally accepted codes of practice. They are the result of technical and scientific co-operation on honorary basis of the members of the Piling Committee of the German Geotechnical Society.

VIII


nd

Preface of the 2 German edition (1) Germany has a long tradition of standardisation with regard to the execution and design of piled foundations and individual pile systems. The German ‘Piles’ standardisation committee (DIN NA 005-05-07 AA) and the German Geotechnical Society’s AK 2.1 ‘Piles’ Working Group (hereafter called as the Piling Committee), have cooperated on these topics for many years, with members sitting in both bodies. In recent decades this joint committee has compiled the piling standards DIN 4026 (driven piles), DIN 4014 (bored piles) and DIN 4128 (grouted piles), and the piling section of DIN 1054 (Section 5), and adapted the individual editions to meet current best practice. (2) Since European standardisation began at the end of the 1980s, the committee has been tasked with accompanying the development of the European execution standards EN 1536 (bored piles), EN 12699 (displacement piles) and EN 14199 (micropiles) as a national mirror committee. It was also tasked to supervise the edition of the German language versions of the execution standards, namely DIN EN 1536, DIN EN 12699 and DIN EN 14199. In terms of pile analysis and design, the committee focused on the piling sections of DIN 1054:2005-01 and DIN 1054:2010-12, paying particular attention to the partial safety factor approach. (3) To supplement this work, the Piling Committee decided to produce summary recommendations for pile analysis and design, of which the first edition was published 2007 as ‘EA-Pfähle’ and which are presented in the second edition. The ‘EA-Pfähle’ sees itself in the tradition of similar DGGT (German Geotechnical Society) recommendations such as EAB (Empfehlungen Arbeitsausschuss Baugruben – Recommendations on Excavations), EBGEO (Empfehlungen für den Entwurf und die Berechnung von Erdkörpern mit Bewehrungen aus Geokunststoffen – Recommendations for Design and Analysis of Earth Structures using Geosynthetic Reinforcements), etc., which are now wellestablished as best practice regulations. (4) With the publication of the Eurocode standards handbooks for structural engineering and the handbook for Eurocode 7, Geotechnical Design – Part 1: General Rules (1st edition 2011), European standardisation in this field has, for the time being, come to a conclusion. The standards were implemented as binding building regulations in Germany with the cut-off date 01.07.2012. The handbook Eurocode 7, Geotechnical Design – Part 1: General Rules, contains as summary DIN EN 1997-1:2009-09 (Eurocode EC 7-1: Geotechnical Design – Part 1: General Rules), DIN 1054:2010-12 (Ground – Verification of the Safety of Earthworks and Foundations – Supplementary Rules to DIN EN 1997-1) and DIN EN 1997-1/NA:2010-12 (National Annex). (5) DIN 1054:2010-12 refers to ‘EA-Pfähle’ at various points dealing with pile analysis and design, e.g. for the tabled values for pile resistances based on IX


well established experience. For formal reasons DIN 1054:2010-12 refers to the first edition of ‘EA-Pfähle’; however, it is only with the this second edition that the technical link to the EC 7-1 Handbook [44] has been properly accomplished thematically. This is especially the case for analysis methods and for terminology with regard to the EC 7-1 Handbook [44], meaning that coherent and coordinated pile foundation analysis and design regulations are now available to the user. (6) In addition, design related issues in terms of the European pile execution standards DIN EN 1536, DIN EN 12699 and DIN 14199 are also dealt with in ‘EA-Pfähle’. A comparative classification of the pile systems used in construction practice (Section 2) simplifies correlation between the standards. Detailed regulations on static and dynamic pile testing (Sections 9 and 10), and quality assurance guidelines and methods (Sections 11 and 12) aim to promote technically high-quality pile construction. (7) A new Section 13, not included in the first edition, deals with load-bearing behaviour and analysis methods for piles subjected to variable actions. Particular attention was paid to the load-bearing behaviour of piles under cyclic loads, such as often occur in foundations for wind turbines (offshore, onshore), but also in highways engineering, etc. (8) Whereas the first edition of ‘EA-Pfähle’ was initially understood to be a draft, and at the time was only recommended for trial use, the draft character is no more applicable on this second edition. In the interim, the piling community has had the opportunity to test the provisions and pass on their comments and proposals to the Piling Committee. This is also the case for the new Section 13, which was previously published in a variety of organs. All statements on the first edition were dealt with by the Committee when compiling the second edition and, if justified, included. Appendices A5, A6 and D contain “informative“ technical guidelines, not yet classified as best practice, but instead representing the current scientific view. (9) In terms of the compulsory nature of the present recommendations ‘EAPfähle’, 2nd edition, the user is referred to the “Notes for the User” published in EAB (2006), 4th edition, Ernst & Sohn, which are applicable in a similar manner here. (10) The German Geotechnical Society’s Piling Committee (AK 2.1 ‘Piles’ Working Group) asks to send any suggestions and correspondence concerning further development of the Recommendations to the Chairman of AK 2.1 (see Imprint for address). Hamburg, 2012

X

Hans-Georg Kempfert


Inhaltsverzeichnis Members of the AK 2.1 Piling Committee of the German Geotechnical Society. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

V

Preface of the English Version of the Recommendations of the Piling Committee of the German Geotechnical Society. . . . . . . . . VII Preface of the 2nd German edition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

IX

1

Introduction to the Recommendations and their Application Principles . . . . . . . . . . . . . . . . . . . . . . . . . . .

1.1 1.2

1.3

National and International Regulations for Piling Works. . . . . . . . Types of Analysis and Limit States using the Partial Safety Factor Approach. . . . . . . . . . . . . . . . . . . . . . . . . . . New standards generation and their application to pile foundations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Actions, effects and resistances. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Limit states and national application of the EC 7-1 German Handbook . . . . . . . . . . . . . . . . . . . . . . . . . . . . Transitional regulations for applying of the Recommendations on Piling in conjunction with the EC 7-1 German Handbook . . . . Planning and Testing Pile Foundations . . . . . . . . . . . . . . . . . . . . . . .

2

Pile Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9

2.1 2.2 2.2.1 2.2.1.1 2.2.1.2 2.2.1.3 2.2.1.4 2.2.1.5 2.2.1.6 2.2.1.7 2.2.2 2.2.2.1 2.2.2.2 2.2.2.3 2.2.2.4 2.2.3

Overview and Classification into Pile Systems . . . . . . . . . . . . . . . . Pile Construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bored piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cased bored piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Unsupported excavations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fluid-supported excavations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Soil-supported, continuous flight auger bored piles . . . . . . . . . . . . Soil-supported, partial flight auger bored piles . . . . . . . . . . . . . . . . Bored piles with enlarged bases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Diaphragm wall elements/barettes . . . . . . . . . . . . . . . . . . . . . . . . . . . Prefabricated driven piles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Precast driven concrete piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Prefabricated driven steel and cast-iron piles . . . . . . . . . . . . . . . . . . Prefabricated driven timber piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cast-in-place concrete piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9 12 12 12 14 14 15 16 16 17 17 17 18 18 19 20

1.2.1 1.2.2 1.2.3 1.2.4

1 1 2 2 3 4 7 7

XI


2.2.3.1 Cast-in-place concrete piles with internal driving tube (Franki pile) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.3.2 Cast-in-place top-driven piles (e.g. Simplex piles) . . . . . . . . . . . . . 2.2.4 Screw piles (full displacement bored piles) . . . . . . . . . . . . . . . . . . . 2.2.4.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.4.2 Atlas piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.4.3 Fundex piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.5 Grouted displacement piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.5.1 Pressure-grouted piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.5.2 Vibro-injection piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.6 Micropiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2.7 Tubular grouted piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3 Foundation elements similar to piles . . . . . . . . . . . . . . . . . . . . . . . . .

20 20 21 21 22 22 23 23 23 24 24 25

3

Pile Foundation Design and Analysis Principles. . . . . . . . . . . . .

27

3.1 3.1.1 3.1.2 3.1.3 3.1.4 3.2 3.3 3.4

27 27 28 29 30 32 39

3.4.1 3.4.2 3.4.3 3.4.4 3.4.5 3.4.6 3.4.7 3.5 3.6

Pile Foundation Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Single pile solutions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pile grillages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pile groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Piled raft foundations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Geotechnical Investigations for Pile Foundations . . . . . . . . . . . . . . Classification of Soils for Pile Foundations . . . . . . . . . . . . . . . . . . . Pile Systems for the Execution of Excavations and for Retaining Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pile configurations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pile systems and special execution requirements. . . . . . . . . . . . . . . Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Reinforcement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Concrete . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Impermeability of bored pile walls. . . . . . . . . . . . . . . . . . . . . . . . . . . Piles for the Stabilisation of Slopes . . . . . . . . . . . . . . . . . . . . . . . . . . Use of sacrificial Linings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

40 40 41 41 42 42 42 42 43 44

4

Actions and Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

47

4.1 4.2 4.3 4.4 4.4.1 4.4.2

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pile Foundation Loads Imposed by the Structure . . . . . . . . . . . . . . Installation Effects on Piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Negative Skin Friction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Determination of the characteristic action from negative skin friction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Determination of the design values of actions or effects and method of verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

47 48 48 49 49

4.4.3 XII

50 53


4.4.4 4.5 4.5.1 4.5.2 4.5.3 4.5.4

4.6.1 4.6.2 4.7 4.7.1 4.7.2

Skin friction as a result of heave in the vicinity of the pile . . . . . . Lateral Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Necessity for design of piles for lateral pressure . . . . . . . . . . . . . . . Determination of the characteristic action from flow pressure . . . Determination of the characteristic action from the resulting earth pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Influences of distance and minimum moments . . . . . . . . . . . . . . . . Effects on piles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Additional Effects on Raking Piles Resulting from Ground Deformations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Surcharges resulting from anchoring steel and micropiles . . . . . . . Foundation Piles in Slopes and at Retaining Structures . . . . . . . . . Foundation piles in slopes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Foundation piles at retaining structures . . . . . . . . . . . . . . . . . . . . . . .

62 62 63 65 65 67

5

Bearing Capacity and Resistances of Single Piles. . . . . . . . . . . .

69

5.1 5.2 5.2.1 5.2.2 5.2.3 5.3 5.4 5.4.1 5.4.2 5.4.3 5.4.4 5.4.4.1 5.4.4.2

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Determining Pile Resistances from Static Pile Load Tests. . . . . . . General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Characteristic pile resistances in the ultimate limit state . . . . . . . . Characteristic pile resistances in the serviceability limit state . . . . Determining Pile Resistances from Dynamic Pile Load Tests . . . Axial Pile Resistances Based on Empirical Data . . . . . . . . . . . . . . . General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Guidance for the application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Application principles and limitations of tabled data . . . . . . . . . . . Prefabricated driven piles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Empirical values of base resistance and skin friction of prefabricated driven piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Empirical data on the bearing capacity of open-ended steel tubes and hollow boxes. . . . . . . . . . . . . . . . . . . Experience with prefabricated piles in rock and very dense or cemented soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cast-in-place concrete piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Empirical values of base resistance and skin friction of Simplex piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Empirical values of base resistance and skin friction of Franki piles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bored piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

69 70 70 71 72 72 75 75 76 77 79 79

4.5.5 4.5.6 4.6

5.4.4.3 5.4.4.4 5.4.5 5.4.5.1 5.4.5.2 5.4.5.3 5.4.6 5.4.6.1

53 54 54 55 57 58 61 62

82 84 85 86 86 87 88 96 96 XIII


5.4.6.2 Empirical values of base resistance and skin friction of bored piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.6.3 Empirical data for base resistance and skin friction of piles in rock and cemented soils. . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.6.4 Diaphragm wall elements (barettes) . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.6.5 Bored pile walls and diaphragm walls . . . . . . . . . . . . . . . . . . . . . . . . 5.4.7 Partial displacement piles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.8 Screw piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.8.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.8.2 Empirical values of base resistance and skin friction of screw piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.9 Grouted displacement piles and micropiles. . . . . . . . . . . . . . . . . . . . 5.4.9.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.4.9.2 Empirical values of skin friction of pressure-grouted piles . . . . . . 5.4.9.3 Empirical values of skin friction of vibro-injection piles . . . . . . . . 5.4.9.4 Empirical values of skin friction of grouted micropiles . . . . . . . . . 5.4.9.5 Empirical values of skin friction in tubular grouted piles. . . . . . . . 5.4.9.6 Bond stress in grouted displacement piles. . . . . . . . . . . . . . . . . . . . . 5.4.10 Applying the empirical data to tension piles. . . . . . . . . . . . . . . . . . . 5.5 Bored Piles with Enlarged Bases . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.6 Additional Methods Using the EC 7-1 and EC 7-2 Handbooks . . 5.7 Pile Resistances for Grouted Shafts and Bases. . . . . . . . . . . . . . . . . 5.8 Resistances of Piles Under Lateral Loads . . . . . . . . . . . . . . . . . . . . . 5.9 Pile Resistances Under Dynamic Actions . . . . . . . . . . . . . . . . . . . . . 5.10 Internal Pile Capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.10.1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.10.2 Allowable cross-section stresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.10.3 Resistance of piles against buckling failure in soil strata with low lateral support, and buckling analysis . . . . . . . . . . . . . . . . 5.11 Numerical Analyses of the Capacity of Single Piles . . . . . . . . . . . .

98 100 103 104 104 105 105 106 108 108 109 110 110 111 112 112 113 114 114 115 116 116 116 117 118 119

6

Stability Analyses. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

6.1 6.2 6.3 6.3.1 6.3.2 6.3.3 6.4 6.4.1 6.4.2 6.5 6.6

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Limit State Equations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bearing Capacity Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Axially loaded piles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Laterally loaded piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Structural failure in piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Serviceability Analysies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Axially loaded piles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Laterally loaded piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pile Groups and Grillages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Piled Raft Foundations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

XIV

121 121 122 122 123 125 125 125 127 127 127


7

Grillage Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

7.1 7.2

Analysis Models and Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 Non-linear Pile Bearing Behaviour in Grillage Analysis . . . . . . . . 130

8

Analysis and Verification of Pile Groups . . . . . . . . . . . . . . . . . . . 131

8.1 8.1.1 8.1.2 8.1.3 8.2 8.2.1 8.2.1.1 8.2.1.2 8.2.1.3 8.2.1.4 8.2.1.5 8.2.1.6 8.2.2 8.2.3 8.3 8.3.1 8.3.1.1 8.3.1.2 8.3.2 8.3.2.1 8.3.2.2 8.3.2.3 8.3.3 8.4 8.4.1 8.4.2 8.4.3 8.5

Actions and Effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Compression pile groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tension pile groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Laterally loaded pile groups. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bearing Capacity and Resistances of Pile Groups . . . . . . . . . . . . . . Compression pile groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Group effect in terms of the settlements of bored pile groups . . . . Resistances in (bored) group piles . . . . . . . . . . . . . . . . . . . . . . . . . . . Displacement pile groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Micropile groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Layered ground . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tension pile groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Laterally loaded groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bearing Capacity Analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Compression pile groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . External capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Structural analyses of the pile capping slab . . . . . . . . . . . . . . . . . . . Tension pile groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Analysis of the attached soil block in the UPL limit state . . . . . . . Analysis of the capacity of a single tension pile in the GEO-2 limit state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Structural failure of group piles and pile cap structures . . . . . . . . . Serviceability Analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Compression pile groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tension pile groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Laterally loaded pile groups. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Higher Accuracy Pile Group Analyses . . . . . . . . . . . . . . . . . . . . . . .

9

Static Pile Load Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

9.1 9.2 9.2.1 9.2.2 9.2.2.1 9.2.2.2 9.2.2.3

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Static Axial Pile Load Tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Installation of test piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Test planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Number of test piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Test load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

131 131 131 133 133 133 133 134 141 146 147 147 148 148 152 152 152 153 154 154 154 155 155 156 156 157 157 157

159 159 159 160 160 161 162 XV


9.2.2.4 9.2.2.5 9.2.3 9.2.3.1 9.2.3.2 9.2.3.3 9.2.3.4 9.2.3.5 9.2.4 9.2.4.1 9.2.4.2 9.2.4.3 9.2.4.3 9.2.4.5 9.2.4.6 9.2.4.7 9.2.5 9.2.5.1 9.2.5.2 9.2.5.3 9.2.6 9.2.7 9.2.7.1 9.2.7.2 9.2.7.3 9.3 9.3.1 9.3.2 9.3.3 9.3.3.1 9.3.3.2 9.3.3.3 9.3.3.4 9.3.3.5 9.3.3.6 9.3.4 9.3.5 9.3.5.1 9.3.5.2 9.3.5.3 9.3.5.4 9.3.6 9.3.6.1 9.3.6.2 9.3.6.3 XVI

Principles for the instrumentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . Special load situations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Loading systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Reaction systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hydraulic jacks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Embedded hydraulic jacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pile head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Instrumentation and monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Displacement measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Load measurement at the pile head. . . . . . . . . . . . . . . . . . . . . . . . . . . Pile base resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pile shaft resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Special instrumentation for tests with embedded hydraulic jacks . . Pile cross-sectional area and deformation properties . . . . . . . . . . . Protection of monitoring instruments. . . . . . . . . . . . . . . . . . . . . . . . . Testing procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Load steps and loading rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Monitoring intervals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Records . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Documentation and reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Test report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interpretative report. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Static Lateral Load Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Installation of test piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Test planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Number of test piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Test load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ground investigations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Principles for the instrumentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . Load situations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Loading systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Instrumentation and monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Deflection measurement at the pile head. . . . . . . . . . . . . . . . . . . . . . Monitoring of the deflection curve . . . . . . . . . . . . . . . . . . . . . . . . . . . Load measurement at the pile head. . . . . . . . . . . . . . . . . . . . . . . . . . . Protection of monitoring instruments. . . . . . . . . . . . . . . . . . . . . . . . . Testing procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Load steps and loading rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Monitoring intervals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Records . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

164 164 165 165 165 167 168 169 170 170 171 171 172 174 174 174 175 175 177 178 178 181 181 181 182 182 182 183 183 183 184 185 185 185 185 186 187 187 189 189 189 189 189 191 191


9.3.7 9.3.8 9.3.8.1 9.3.8.2 9.3.8.2 9.4 9.4.1 9.4.2 9.4.2.1 9.4.2.2 9.4.2.3 9.4.2.4 9.4.2.5 9.4.3 9.4.3.1 9.4.3.2 9.4.3.3 9.4.4 9.4.4.1 9.4.4.2 9.4.4.3 9.4.4.4 9.4.5 9.4.5.1 9.4.5.2 9.4.5.3 9.4.5.4 9.4.5.5 9.4.6 9.4.7 9.4.7.1 9.4.7.2 9.4.7.3

Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Documentation and reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Test report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interpretative report. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Static Axial Load Tests on Micropiles (Composite Piles) . . . . . . . Installation of test piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Test planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . General notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Number of test piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Test load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Principles for the instrumentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . Special loading situations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Loading systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Reaction systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hydraulic jacks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pile head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Instrumentation and monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Displacement measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Load measurement at the pile head. . . . . . . . . . . . . . . . . . . . . . . . . . . Pile shaft resistance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Protection of monitoring instruments. . . . . . . . . . . . . . . . . . . . . . . . . Testing procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Load steps and loading rates for System A . . . . . . . . . . . . . . . . . . . . Load steps for System B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Monitoring intervals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Records . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Documentation and reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Test report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Interpretative report. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

192 192 192 192 194 194 194 195 195 196 196 197 197 198 198 199 199 200 200 200 200 201 201 201 201 203 204 204 205 207 207 207 208

10

Dynamic pile load tests. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209

10.1 10.2 10.3 10.4 10.4.1 10.4.2 10.4.3 10.4.4 10.4.5

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Range of Application and General Conditions . . . . . . . . . . . . . . . . . Theoretical Principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Description of Testing Methods, Test Planning and Execution. . . Evaluation methods and type of load testing . . . . . . . . . . . . . . . . . . Number of load tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ground investigations and pile installation documentation . . . . . . Time of testing and internal capacity . . . . . . . . . . . . . . . . . . . . . . . . . Dynamic load testing using the high-strain method. . . . . . . . . . . . .

209 209 210 213 213 214 214 214 215 XVII


10.4.5.1 10.4.5.2 10.4.5.3 10.4.5.4 10.4.6 10.4.6.1 10.4.6.2 10.4.6.3 10.4.6.4 10.4.6.5 10.5 10.5.1 10.5.2 10.5.2.1 10.5.2.2 10.5.2.3 10.5.3 10.5.4 10.6 10.7 10.8 10.9

Brief description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Loading system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Instrumentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Performing the test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dynamic load testing using the rapid load method . . . . . . . . . . . . . Brief description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Testing types and timing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Loading system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Instrumentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Testing procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Evaluation and Interpretation of Dynamic Load Tests . . . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Direct methods using empirical damping values . . . . . . . . . . . . . . . Fundamentals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CASE method. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TNO method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Direct method for evaluating a rapid load test using the unloading point method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Extended method with complete modelling . . . . . . . . . . . . . . . . . . . Calibrating Dynamic Pile Load Tests . . . . . . . . . . . . . . . . . . . . . . . . Qualifications of Testing Institutes and Personnel. . . . . . . . . . . . . . Documentation and Reporting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Testing Driving Rig Suitability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

11

Quality Assurance during Pile Execution . . . . . . . . . . . . . . . . . . . 239

11.1 11.2 11.2.1 11.2.2 11.2.2.1 11.2.2.2 11.2.2.3 11.2.3 11.2.3.1 11.2.3.2 11.2.3.3 11.2.3.4 11.2.3.5 11.2.4 11.2.5 11.2.5.1 11.2.5.2 11.2.6 11.2.6.1

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bored Piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Principles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Support to boreholes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cased boreholes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Excavations supported by fluids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Soil-supported boring with continuous flight augers. . . . . . . . . . . . Excavation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Boring below the groundwater table . . . . . . . . . . . . . . . . . . . . . . . . . Drilling tool diameter and speed of operation . . . . . . . . . . . . . . . . . Cleaning the base of the borehole . . . . . . . . . . . . . . . . . . . . . . . . . . . . Enlarged bases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Installation of reinforcement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Concreting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Concrete mix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Concreting procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bored piles constructed with continuous flight augers . . . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

XVIII

215 215 217 219 221 221 221 222 223 224 225 225 225 225 226 227 228 229 231 234 234 236

239 239 239 240 240 241 242 242 242 242 243 244 245 245 247 247 248 250 250


11.2.6.2 11.2.6.3 11.2.6.4 11.2.7 11.3 11.3.1

Soil-supported auger boring. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cased flight auger boring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Concreting and installation of reinforcement . . . . . . . . . . . . . . . . . . Shaft and base grouting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Displacement Piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Prefabricated concrete piles – Guidance for transport, storage and installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3.2 Cast in place concrete displacement piles . . . . . . . . . . . . . . . . . . . . . 11.3.2.1 Water/soil ingress into the drive tube. . . . . . . . . . . . . . . . . . . . . . . . . 11.3.2.2 Concreting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3.3 Displacement effect in cohesive soils . . . . . . . . . . . . . . . . . . . . . . . . 11.4 Grouted Micropiles (Composite Piles). . . . . . . . . . . . . . . . . . . . . . . . 11.4.1 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.4.2 Grouted monobar piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.4.3 Tubular grouted piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.4.4 Testing grouted micropiles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

250 251 251 252 253 253 254 254 254 254 255 255 255 256 257

12

Pile Integrity Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 259

12.1 12.2 12.2.1 12.2.2 12.2.3 12.2.4 12.2.5 12.2.6 12.2.7 12.2.8 12.2.9 12.3 12.3.1 12.3.2 12.3.3 12.3.4 12.3.4.1 12.3.4.2 12.3.5 12.3.5.1 12.3.5.2 12.3.5.3 12.3.6 12.3.7 12.4 12.4.1

Purpose and Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Low Strain Integrity Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Low strain integrity test principles . . . . . . . . . . . . . . . . . . . . . . . . . . . Scope, number of tested piles and limitations. . . . . . . . . . . . . . . . . . Pile preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Testing procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Measurement and instrumentation . . . . . . . . . . . . . . . . . . . . . . . . . . . Evaluation of measurements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Impedance and wave velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Assessment classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Documentation and reporting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ultrasonic Integrity Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Objective and scope. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ultrasonic integrity testing principles . . . . . . . . . . . . . . . . . . . . . . . . Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Test preparation and testing procedure . . . . . . . . . . . . . . . . . . . . . . . Test piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Testing procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Qualitative signal evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Quantitative signal analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pile evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Documentation and report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Special situations: testing secant pile walls and diaphragm walls. Testing Piles by Core Drilling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

259 260 260 261 262 262 263 263 266 268 269 270 270 270 272 274 274 275 275 275 277 278 278 279 279 279 XIX


12.4.2 12.4.3 12.4.3.1 12.4.3.2 12.4.4 12.4.5 12.5 12.5.1 12.5.2 12.5.3 12.5.4 12.5.5 12.5.6

Coring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Visual evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Concrete strength and durability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Downhole tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Other Specific Testing Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Radiometric pile tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Multi-channel low strain testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Parallel seismic method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Induction and mise-a-la-masse methods . . . . . . . . . . . . . . . . . . . . . . Other borehole-based methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

280 280 280 281 281 282 282 282 282 282 283 284 284

13

Bearing Capacity and Analyses of Piles under Cyclic, Dynamic and Impact Actions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 285

13.1 13.2 13.2.1 13.2.2 13.2.3 13.2.4 13.3 13.4 13.4.1 13.4.2 13.4.3 13.5 13.6 13.6.1 13.6.2 13.6.3 13.7 13.7.1 13.7.2 13.8 13.8.1 13.8.2 13.9

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cyclic, Dynamic and Impact Actions. . . . . . . . . . . . . . . . . . . . . . . . . Action and loading types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Actions from cyclic loads. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Actions from dynamic loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Actions from impact loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Supplementary Geotechnical Investigations . . . . . . . . . . . . . . . . . . . Bearing Behaviour and Resistances under Cyclic Loads . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Axial loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lateral loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bearing Behaviour and Resistances under Dynamic Loads . . . . . . Bearing Behaviour and Resistances under Impact Loads . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Axial loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lateral loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stability Analyses of Cyclic, Axially Loaded Piles. . . . . . . . . . . . . Analysis of the bearing capacity of an isolated pile. . . . . . . . . . . . . Analysis of the serviceability of a single pile . . . . . . . . . . . . . . . . . . Stability Analyses of Cyclical, Laterally Loaded Piles . . . . . . . . . . Analysis of the bearing capacity of a single pile . . . . . . . . . . . . . . . Analysis of the serviceability of a single pile . . . . . . . . . . . . . . . . . . Stability Analyses of Dynamic or Impact-loaded Piles. . . . . . . . . .

285 286 286 287 290 291 292 294 294 294 297 299 300 300 300 300 301 301 304 304 304 305 306

Annex A Terms, Partial Safety Factors and Principles for Analysis. . . 307 A1 A2 XX

Definitions and notations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307 Partial safety factors ÎłF and ÎłE for actions and effects from EC 7-1 Handbook [44], Table A 2.1. . . . . . . . . . . . . . . . . . . . . 312


A3 A3.1 A3.2 A4

A4.1 A4.1 A5 A5.1 A5.2 A5.3 A5.4 A5.5 A6 A6.1 A6.2

Partial Safety Factors for Geotechnical Parameters and Resistances from EC 7-1 Handbook [44], Tables A 2.2 and A 2.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Partial safety factors γM for geotechnical parameters . . . . . . . . . . . Partial safety factors γR for resistances . . . . . . . . . . . . . . . . . . . . . . . Correlation Factors Ξi for Determining the Characteristic Pile Resistances for the Ultimate Limit State Acquired from Tested or Measured Data of Static and Dynamic Pile Tests acc. to the EC 7-1 Handbook . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Correlation factors from static pile tests . . . . . . . . . . . . . . . . . . . . . . Correlation factors from dynamic pile tests . . . . . . . . . . . . . . . . . . . Procedure for Determining the Resistance of Piles Against Buckling Failure in Soil Strata with Low Lateral Support (informative) . . . . . . . . . . . . . . . . . . . . . . Guidance notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ground support. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Static system and equilibrium conditions using second-order theory (inclusion of lateral deflections) . . . . . . . . . . . Requirements for the application of the analysis method . . . . . . . . Determining the characteristic resistance against pile buckling . . Bonding Stress in Grouted Displacement Piles (informative) . . . . Guidance notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Characteristic and design values of bonding stresses . . . . . . . . . . .

314 314 315

316 316 317 320 320 320 322 324 325 328 328 328

Annex B Example Calculations for Pile Resistance Analysis and Verifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 331 B1 B1.1 B1.2 B1.3 B1.4 B2 B2.1 B2.2 B3 B3.1 B3.2 B3.2.1 B3.2.2

Determining the Axial Pile Resistances from Static Pile Load Tests, and Ultimate and Serviceability Limit State Analyses . . . . . . . . . . . . . . . . . . . . . . Objectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Deriving the characteristic pile resistances in the ultimate and serviceability limit states. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bearing capacity analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Serviceability analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Characteristic Axial Pile Resistances from Dynamic Load Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Objective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Characteristic pile resistances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Determining the Characteristic Axial Pile Resistances from Empirical Data for a Bored Pile . . . . . . . . . . . . . . . . . . . . . . . . Objective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Analysis for lower and upper table values. . . . . . . . . . . . . . . . . . . . . Determining the pile shaft resistance Rs,k . . . . . . . . . . . . . . . . . . . . . Determining the pile base resistance Rb,k. . . . . . . . . . . . . . . . . . . . . .

331 331 332 334 334 336 336 336 338 338 338 339 339 XXI


B3.2.3 B4 B4.1 B4.2 B4.2.1 B4.2.2 B4.2.3 B5 B5.1 B5.2 B5.2.1 B5.2.2 B5.2.3 B6 B6.1 B6.2 B6.2.1 B6.2.2 B6.2.3 B6.3 B6.4 B7 B7.1 B7.2 B7.2.1 B7.2.2 B7.3 B7.3.1 B7.3.2 B7.3.3 B7.4 XXII

Characteristic resistance-settlement curve. . . . . . . . . . . . . . . . . . . . . Determining the Characteristic Axial Pile Resistances from Empirical Data for a Prefabricated Driven Pile . . . . . . . . . . . Objective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Characteristic axial pile resistance from empirical data for lower and upper table values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Determining the pile shaft resistance Rs,k . . . . . . . . . . . . . . . . . . . . . Determining the pile base resistance Rb,k. . . . . . . . . . . . . . . . . . . . . . Characteristic resistance-settlement curve. . . . . . . . . . . . . . . . . . . . . Determining the Characteristic Axial Pile Resistances from Empirical Data for a Fundex Pile . . . . . . . . . . . . . . . . . . . . . . . Objective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Characteristic axial pile resistance from empirical lower and upper table values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Determining the pile shaft resistance Rs,k . . . . . . . . . . . . . . . . . . . . . Determining the pile base resistance Rb,k. . . . . . . . . . . . . . . . . . . . . . Characteristic resistance-settlement curve. . . . . . . . . . . . . . . . . . . . . Principle of the Evaluation of a Static Pile Load Test Using a Prefabricated Driven Pile shown on an Example and Comparison with Empirical Data after 5.4.4.2 . . . . . . . . . . . . . Objective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Characteristic axial pile resistance from empirical lower and upper table values. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Determining the pile shaft resistance Rs,k . . . . . . . . . . . . . . . . . . . . . Determining the pile base resistance Rb,k. . . . . . . . . . . . . . . . . . . . . . Characteristic resistance-settlement curve for empirical data compared to tested or measured values . . . . . . . Characteristic axial pile resistance from static load tests . . . . . . . . Design values of pile resistances in the ultimate limit state . . . . . . Preliminary Design and Analysis of the Ultimate Limit State of Franki Piles Based on Empirical Data and Comparison to a Pile Load Test Result. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Objective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Determining the base volume from empirical data . . . . . . . . . . . . . Determining the pile shaft resistance Rs,k . . . . . . . . . . . . . . . . . . . . . Determining the pile base volume of a Franki pile . . . . . . . . . . . . . Analysis of the ultimate limit state (ULS, GEO-2) by means of the driving energy expended during pile installation . . . . . . . . . Characteristic pile resistance Rc,k after applying the lower empirical values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Characteristic pile resistance Rc,k after applying the upper empirical values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ultimate limit state analysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Comparison of the axial pile resistance based on empirical data with static load tests. . . . . . . . . . . . . . . . . . . . . . . .

340 341 341 341 342 342 343 345 345 345 345 346 346 348 348 349 349 350 350 351 352 354 354 355 355 356 356 356 357 358 358


B7.4.1 B7.4.2 B8 B8.1 B8.2 B8.3 B8.4 B8.5 B8.6 B9 B9.1 B9.2 B9.3 B9.4 B9.5 B9.6 B9.6.1 B9.6.2 B9.6.3 B9.6.4 B10 B10.1 B10.2 B11 B11.1 B12 B12.1 B12.2 B12.3 B13

Characteristic axial pile resistance from empirical data . . . . . . . . . Comparing to the static load test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Negative Skin Friction for a Displacement Pile as a Result of Fill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Objective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Determining the characteristic resistance-settlement curve . . . . . . Determining the characteristic actions Fn,k from negative skin friction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bearing capacity analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Serviceability analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Analysis of internal capacity (structural failure) . . . . . . . . . . . . . . . Determining the Effect on a Laterally Loaded Pile (Perpendicular to the Pile Axis) and Analysis of Structural Failure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Objective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Determining the characteristic action effects and stresses . . . . . . . Design values of the action effects . . . . . . . . . . . . . . . . . . . . . . . . . . . Minimum strength class of concrete and concrete cover . . . . . . . . Design values of materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ultimate limit state design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Design for bending and normal force. . . . . . . . . . . . . . . . . . . . . . . . . Design for shear force to DIN 1045-1 . . . . . . . . . . . . . . . . . . . . . . . . Design for shear force after [5] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Minimum reinforcement for shear force to DIN 1045-1. . . . . . . . . Laterally Loaded Piles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Objective and systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Determining the characteristic actions and effects. . . . . . . . . . . . . . Pillar Foundation on 9 Piles – Ultimate and Serviceability Limit State Analyses Taking the Group Effect into Consideration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Objective and system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tension Pile Group Analyses in the Ultimate Limit State . . . . . . . Objective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Isolated pile analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Analysis of the pile group effect (attached soil monolith) . . . . . . . Laterally Loaded Pile Groups: Determining the Distribution of Horizontal Subgrade Moduli. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

358 359 360 360 361 362 364 364 365 366 366 367 370 371 372 372 372 373 377 378 380 380 381 383 383 389 389 389 390 392

Annex C Examples of Dynamic Pile Load Testing and Integrity Testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395 C1 C 1.1 C 1.2

Dynamic Pile Load Test Evaluation: Example using the Direct Method . . . . . . . . . . . . . . . . . . . . . . . . . . . 395 Objectives and test data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395 Case method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 396 XXIII


C1.3 C2 C2.1 C3 C4 C4.1 C4.2 C4.3 C4.4 C4.5 C5 C5.1 C5.2 C5.3 C5.4 C6

TNO method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dynamic Pile Load Test Evaluation Example Using the Extended Method with Complete Modelling . . . . . . . . . . . . . . . Objectives and test data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rapid Load Tests Evaluation Example Using the Unloading Point Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Low Strain Integrity Test Case Studies . . . . . . . . . . . . . . . . . . . . . . . Example: pile in accordance with specification – Class A1 . . . . . . Example: pile in accordance with specification – Class A2 . . . . . . Example: pile with minor deviations – Class A3 . . . . . . . . . . . . . . . Example: pile with substantial impedance reduction – Class B . . . Example: measurement can not be-evaluated – Class 0 . . . . . . . . . Integrity Tests during Driving and/or High Strain Integrity Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Example: pile in accordance with the specification. . . . . . . . . . . . . Example: defective pile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Example: coupled pile. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Example: Ultrasonic Integrity Testing . . . . . . . . . . . . . . . . . . . . . . . .

396 397 397 401 404 404 404 405 406 407 408 408 409 409 410 411

Annex D Analysis Methods and Examples for Cyclically Loaded Piles (Informative) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 417 D1 D2 D2.1 D2.1.1 D2.1.2 D2.1.3 D2.1.4 D2.2 D2.2.1 D2.2.2 D2.2.3 D2.2.4 D3 D3.1 D3.1.1 XXIV

Guidance notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Piles Subjected to Cyclic Axial Loads . . . . . . . . . . . . . . . . . . . . . . . . Analysis methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pile resistance in the ultimate limit state based on interaction diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Displacement accumulation using an empirical approach . . . . . . . Approximation methods for calculating pile bearing behaviour under cyclic loads after [66] . . . . . . . . . . . . . . . . . . . . . . . Approximation method for analysing pile bearing behaviour under cyclic loads after [142] . . . . . . . . . . . . . . . . . . . . . . Calculation examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ultimate limit state analysis based on interaction diagrams after D2.1.1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Serviceability limit state analysis with an empirical displacement approach after D2.1.2 . . . . . . . . . . . . . . . . . . . . . . . . . . Calculation example for the ultimate and the serviceability limit states using the method after D.2.1.3 . . . . . . . . . . . . . . . . . . . . . . . . . Calculation example for the ultimate and the serviceability limit states using the method after D.2.1.4 . . . . . . . . . . . . . . . . . . . . . . . . . Piles Subjected to Cyclic Lateral Loads . . . . . . . . . . . . . . . . . . . . . . Calculation methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Empirical method for estimating the accumulated deflections . . .

417 418 418 418 420 420 423 428 428 429 430 435 440 440 440


D3.1.2 Calculation approaches for estimating deflection accumulation taking to consideration non-linear soil behaviour . . . . . . . . . . . . . . D3.1.3 Calculation approach with subgrade reaction reduction using the p-y method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D3.2 Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D3.2.1 Estimating deflection accumulation after D3.1.1 . . . . . . . . . . . . . . . D3.2.2 Estimating deflection accumulation after D3.1.2 . . . . . . . . . . . . . . . D3.2.3 Subgrade degradation adopting the p-y method after D3.1.3 . . . . D4 Procedure for determining an equivalent single-stage load spectrum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D4.1 Calculation method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D4.1.1 Method for determining an equivalent load cycle number for piles subjected to cyclic axial loads . . . . . . . . . . . . . . . . . . . . . . . D4.1.2 Method for determining an equivalent load cycle number for piles subjected to cyclic lateral loads . . . . . . . . . . . . . . . . . . . . . . D4.2 Calculation examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D4.2.1 Determining an equivalent load cycle number for piles subjected to cyclic axial loads after D4.1 . . . . . . . . . . . . . D4.2.2 Determining an equivalent load cycle number for piles subjected to cyclic lateral loads after D4.1 . . . . . . . . . . . .

441 441 443 443 445 450 454 454 454 454 456 456 457

Literatur . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 459 List of Advertisers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 469

XXV


(8) If dynamic pile load tests are used where the results acquired from test data Rc,m,i are available as complete resistance-settlement curves (RSC), the guidance in 5.2.3 and 6.4 shall be observed or applied accordingly to derive the characteristic RSC in the serviceability limit state. (9) An example for determining the characteristic pile resistances from the measured dynamic load test data is contained in Annex B2. Annexes C1 and C2 include examples for deriving the static measured pile resistance values Rc,m,i = Rc,stat from the dynamic measurements (10) If both static and dynamic pile load tests are carried out on a site, two cases are differentiated after the EC 7-1 Handbook [44]: − If, after applying the correlation factors, the characteristic pile resistances acquired by evaluating the static pile load tests alone are larger than those acquired by evaluating the dynamic pile load tests, only the results of the static pile load tests may be adopted. − If, after applying the correlation factors, evaluation of the dynamic load tests result in greater bearing capacities, higher characteristic resistances than those from the static pile load tests may only be adopted when if this is comprehensible and justified. The increased resistances must be confirmed for the specific case by the geotechnical expert or the geotechnical designer. 5.4

Axial Pile Resistances Based on Empirical Data

5.4.1 General (1) The EC 7-1 Handbook [44] allows axial pile resistances to be derived from empirical data, in addition to determining pile resistances from both static and dynamic pile load tests, see 5.2 and 5.3. (2) Of the methods described in the EC 7-1 Handbook [44], 7.6.2.3, under the heading ‘Ultimate compressive resistance determined from ground test results’, only the method using Eq. (5.2) below should be adopted in Germany, see EC 7-1 Handbook [44], Nationally Determined Parameters (NDP) to 7.6.2.3 (5)P and NDP to 7.6.3.3 (4). The method is known in Germany as ‘Determining axial pile resistances based on empirical data’ and is dealt with below. The ‘ground tests’ (geotechnical investigations) shall be performed such that it is possible to reliably assign the characteristic empirical data, which have been derived from load tests, for the pile end bearing capacity qb,k and pile skin friction qs,k results. To this end the EC 7-1 Handbook [44] gives the following fundamental equations: R b ,k = A b ◊ q b ,k

(5.2a)

R s ,k = Â As ,i ◊ qs ,i ,k

(5.2b)

R c,k = R b,k + R s,k

(5.2c)

i

75


(3) However, in principle, the EC 7-1 Handbook [44] allows all data derived from experience to be used, in addition to the empirical data dealt with below, assuming their utility for the proposed case can be appropriately demonstrated. (4) The applicability of the empirical data given in the subsequent paragraphs, as well as other, general data derived from experience must be confirmed by a geotechnical expert or a geotechnical designer for the proposed application. (5) The standard procedure for determining the characteristic resistances of tension piles is the static pile load test. A deviation from this rule should be made in exceptional circumstances only and if expressly confirmed by a geotechnical expert for the particular case. 5.4.2

Guidance for the application

(1) The national empirical axial pile resistance data forming the basis for applying the EC 7-1 Handbook [44] are summarised below. (2) Analogous to 5.4.1 (3) and (4), other empirical data may also be adopted if their validity can be appropriately demonstrated. (3) After the EC 7-1 Handbook [44], the characteristic values of the pile resistances shall be specified, in principle, on the basis of the results of geotechnical investigations in accordance with the EC 7-2 Handbook [45] and other information. For the construction of pile foundations normally a geotechnical expert shall be involved. (4) The empirical data are summarised below as ranges of axial pile resistances for the various pile systems (see Section 2). Characteristic values of the pile resistances Rc,k for the proposed application may be derived from these empirical data if a geotechnical expert or a geotechnical designer is involved and the provisions of the EC 7-1 Handbook [44] are met. The given empirical data should normally only be used to derive characteristic compression pile resistances, see 5.4.1 (5) and 5.4.10. (5) The given empirical data refer to both non-cohesive and cohesive soils. See 3.3 for classifications. The EC 7-1 Handbook [44] and 3.3 also include guidance on classifying coarse-grained, fine-grained and mixed-grained soils under the headings of non cohesive and cohesive soils to DIN 18196. In the context of determining the characteristic pile resistances, consulting a geotechnical expert is recommend, in particular where mixed-grained soils are present. (6) The following recommendations should be understood by the client, the geotechnical expert or designer, and the structural engineer such that more favourable pile capacities and resistances may be adopted as a benefit for increased extend of project-related geotechnical investigations for classifying and describing the respective ground, also see 5.4.3. (7) Classification of the prevalent soils for the respective case as necessary to apply the empirical pile resistance data summarised in the following 76


tables shall be based on the EC 7-2 Handbook [45] and, in particular, should address: − − − −

Stratification; Grain size distribution; Density, strength and consistency conditions; Shear parameters and stiffness.

In addition to direct site investigations, e.g. through boreholes and laboratory testing, the results of indirect investigations should be available, e.g. static or dynamic probing (CPT or DPH), borehole dynamic probing (BDP), vane tests, etc., also see 3.2. 5.4.3

Application principles and limitations of tabled data

(1) Empirical pile end bearing capacity and pile skin friction data for the various pile systems are summarised in tables below as a function of the respective ground conditions. The numerical values listed in the tables refer to the CPT cone resistances qc in non-cohesive soils and the undrained shear strength cu of cohesive soils. (2) The EC 7-1 [44] and EC 7-2 [45] Handbooks state that soil parameters scatter considerably as a result of the geological formation conditions and history. This applies especially to pile capacity and pile resistances in the ultimate and serviceability limit states, see Figure 5.2, because in addition to the ground-related scatter, considerable influences can result from the execution. When specifying characteristic soil properties, normally ‘conservative mean values’ are adopted. See EC 7-1 Handbook [44], and 5.2 and 5.3 for details of the procedure for specifying pile resistances from the results of pile load tests. (3) The empirical pile base resistance qb and pile skin friction qs data ranges summarised in the tables below are based on numerous and predominantly static pile load test results, which were analysed for this purpose. The evaluation strategies and principles are described in [29], [57], [85] and [158]. As outlined in [57], empirical pile load test evaluations were made and related to statistical values, differentiated into 10%, 20% and 50% quantiles as input for

Figure 5.2 Qualitative distribution of pile resistances in the serviceability (a) and ultimate limit states (b)

77


the tables. This allows the user to also assess the probability and the risk of pile resistance deviations below of the tabled values for a specific project application. (4) The following tables contain a range of empirical values for quantiles from 10 % to 50 % as shown in Figure 5.3. This means that, as a result of scatter, around 10 % of the in-situ pile resistances can be below the lower value in the tables, and around 50 % below the upper value (mean value). (5) Concerning the magnitude of the range of table values it is expressly pointed out that the quantile range in Figure 5.3 represents an orientation only. The stated boundaries of around 10 % to 50 % can vary depending on the adopted load test results and the resulting distribution and scatter, because they are based on the adopted load test result population and the boundary conditions of the ground.

Figure 5.3 Fractiles for the ranges of pile resistance table data from empirical data, compared to load test results

(6) Normally and under condition that the site investigation has been carried out in line with the EC 7-2 Handbook [45] and 3.2, and that the provisions of 5.4.2 are observed, the lower table values (minimal values) should be adopted. (7) The lower table values can also be adopted for the preliminary design if the final, project-related site investigation results as mentioned in (6) are not yet available. (8) Pile resistances above the lower (minimal) values, interpolated between the lower and the upper table values, may only be selected for the specific application by the designer if they are expressly confirmed by a geotechnical expert. Local conditions and experience, and the actual situation on the ground must be taken into consideration. The local conditions and experience, and the proposed application, must also be taken into consideration. (9) If, in terms of pile type and ground conditions, comparable load test results are available, they can be adopted to determine pile resistances as outlined in the EC 7-1 Handbook [44]. Comparability must be confirmed by a geotechnical expert or geotechnical designer, also see 5.2.1 (4) and (5). 78


(10) The soil strength range given in the table data includes mean CPT cone resistances qc = 7,5 to 25 MN/m² for non-cohesive soils and undrained shear strengths cu,k = 100 to 250 kN/m² for cohesive soils related to the end bearing capacity, and cu,k = 60 to 250 kN/m² related to skin friction. (11) Skin friction and support from soil layers where qc < 7,5 MN/m² or cu,k < 60 kN/m² may only be taken into consideration if confirmed by the geotechnical expert or geotechnical designer and the different deformations of the layers for the mobilisation of the skin friction are considered. (12) In layered ground with soil layers exceeding or falling short of the requirements stipulated in (11), the same rule applies. In addition, the provisions of 4.4 must be observed. (13) For the serviceability limit state analysis acc. to 6.4, the measured and derived characteristic resistance-settlement curves should be modified for the serviceability state, if necessary, and applying 5.2.3 as appropriate. (14) Guidance on comparing the empirical table data to measured data from static and dynamic pile load tests: the tabled characteristic values of pile base resistance and skin friction were derived from pile load test results by statistical application of the quantiles mentioned above to the measured data. Correlation factors ξ, see Annexes 4.1 and 4.2, were not applied. They are instead already incorporated in the partial factors for empirical values as stipulated in the EC 7-1 Handbook [44], Table A2.3 and Annex A3.2. This is done by a model factor ηE in accordance with the EC 7-1 Handbook [44], NDP to 7.6.2.3 (8) and NDP to 7.6.3.3 (6). A fact to be realised when comparing the characteristic table data to characteristic values derived from data measured during pile load tests. Also see 5.3 (6). 5.4.4

Prefabricated driven piles

5.4.4.1 General (1) Information on the characteristic base resistance and skin friction of prefabricated driven piles derived from empirical data acquired in recent investigations based on [57], and guidance on their application, are provided below. After DIN EN 12699:2001-05 prefabricated driven piles comprise prefabricated concrete, steel, timber and cast-iron piles, see 2.2.2. (2) The following table data do not apply to timber and cast-iron piles. The capacity of timber piles may be assessed on the basis of DIN 4026:1975-08. (3) The elements of the characteristic resistance-settlement curve for prefabricated displacement piles (prefabricated driven piles) corresponding to the proposals in [57] are shown in Figure 5.4 for a settlement up to sult = sg. See 5.2.2 (3) for details of sult and sg. (4) Differentiation is made between the settlement-dependent pile base resistance Rb (s) and the pile shaft resistance Rs (s). 79


Figure 5.4 Elements of the characteristic resistance-settlement curve for prefabricated driven piles

(5) The limit settlement for Rb,k (sult = sg) applies in analogy to Eq. (5.1): sult = sg = 0,10 · Deq

(5.3)

where: Deq equivalent diameter of the pile base [m]. For square and rectangular, prefabricated piles and steel sections, the equivalent pile base diameter is calculated using Eq. (5.4): Deq = 1,13 · as

(5.4a)

for square piles and Deq = 1,13 ◊ a s ◊ a L a s

(5.4b)

for rectangular piles and steel sections. where: as aL

side length of a pile with square cross-section or length of the smaller side of a rectangular, prefabricated pile or steel section; length of the longer side of the cross-section of a rectangular, prefabricated pile or steel section. For steel sections the respective dimensions of the profile shall be taken.

(6) When mobilising the ultimate limit state, the characteristic settlement for Rs,k (ssg*) is calculated using Eq. (5:5); use MN as dimension of Rs,k (ssg*):

ssg* [cm] = 0,5 ◊ R s ,k (ssg* ) [ MN] £ 1 [cm] 80

(5.5)


(7) The characteristic axial pile resistance is determined from: R c ,k (s) = R b,k (s) + R s,k (s) = hb ◊ q b,k ◊ A b + Â hs ◊ q s,k,i ◊ As,i

(5.6)

i

where: Ab As,i qb,k qs,k,i ηb ηs Rc,k(s) Rb,k(s) Rs,k(s) ssg* ssg

nominal pile base area, for steel section piles as shown in Figure 5.5; nominal pile shaft area in stratum i; for steel section piles as shown in Figure 5.5 with the effective circumference U; characteristic value of the base resistance, derived from Tables 5.1 and 5.3; characteristic value of the skin friction in stratum i, derived from Tables 5.2 and 5.4; base resistance model factor from Table 5.5; skin friction model factor from Table 5.5; settlement-dependent, characteristic compression pile resistance; settlement-dependent, characteristic pile base resistance; settlement-dependent, characteristic shaft resistance; characteristic settlement at which mobilisation of the ultimate skin friction for the settlement-dependent, characteristic pile shaft resistance begins; limit settlement for the settlement-dependent, characteristic pile shaft resistance (ssg = sg).

Figure 5.5 Nominal values of pile base areas and pile shaft areas of steel sections

81


5.4.4.2 Empirical values of base resistance and skin friction of prefabricated driven piles (1) The empirical base resistance and skin friction data given in Table 5.1 to Table 5.4 apply to the following piles, provided they are embedded at least 2,50 m into a load-bearing layer and the model factors listed in Table 5.5 are taken into account: − prefabricated, reinforced concrete and prestressed concrete driven piles where Deq = 0,25 to 0,50 m; − closed-ended steel tube piles with diameters up to 800 mm; − open-ended steel tube and hollow box piles with diameters between 300 mm and 1 600 mm; − steel sections with flange widths between 300 mm and 500 mm, and section heights between 290 mm and 500 mm, and − steel box piles. The table data apply to prefabricated driven piles. The table values must be reduced when piles are installed through vibration, because substantial capacity reductions have been reported for isolated cases of vibrated piles, e.g. in [92]. The amount of the reduction must be confirmed by the geotechnical expert. For the base resistances the reduction is dispensed with if the pile is driven into the load-bearing stratum for the final 8 · Deq (in m). (2) The validity of the table values depends on: − the mean cone resistance qc of the CPT in non-cohesive soil and − the shear strength of the undrained soil cu,k for cohesive soils. (3) When specifying the governing mean cone resistance qc of the CPT or the characteristic undrained shear strength cu,k differentiation shall be made between: − the zone governing the pile base resistance (from 1 · Deq above to 4 · Deq below the pile base) and − the zone governing the skin friction (mean value for the affected stratum). If the ground stratification has a greater impact on the CPT cone resistance or the undrained shear strength, two or more mean skin friction zones must be specified separately. (4) When applying the values given in Table 5.1 and Table 5.3 it is assumed that: − the thickness of the load-bearing stratum below the pile base is not less than five times the equivalent pile base diameter, but at least 1,50 m and; − qc ≥ 7,5 MN/m² or cu,k ≥ 100 kN/m² are confirmed for this zone. Regardless of this, it is recommended that in non-cohesive soils the pile bases are founded in zones where qc ≥ 10 MN/m². 82


(5) If the above geometrical values given are not met, analysis of safety against a punching failure is required. In addition, it must then be verified that the underlying ground does not substantially impair the settlement behaviour. (6) If Tables 5.1 to 5.5 are applied in approximation to mixed-grained soils, the definitions for cohesive and non-cohesive soils in accordance with the EC 7-1 Handbook [44] or 3.3 may be adopted. If the table values are applied to mixed-grained soils, particular attention should be paid to 5.4.2 (5). (7) Also see 5.4.3 for the conditions for applying the table values. Table 5.1 Empirical data ranges for the characteristic base resistance qb,k for prefabricated, reinforced concrete and prestressed concrete driven piles in non-cohesive soils Relative pile head settlement s/Deq

Pile base resistance qb,k [kN/m²] mean CPT cone resistance qc [MN/m²] 7,5

15

25

0,035

2 200 – 5 000

4 000 – 6 500

4 500 – 7 500

0,100

4 200 – 6 000

7 600 – 10 200

8 750 – 11 500

Intermediate values may be linearly interpolated. Table 5.2 Empirical data ranges for the characteristic skin friction qs,k for prefabricated, reinforced concrete and prestressed concrete driven piles in non-cohesive soils Settlement

Pile skin friction qs,k [kN/m²] mean CPT cone resistance qc [MN/m²] 7,5

15

25

ssg*

30 – 40

65 – 90

85 – 120

ssg = sg = 0,1 Deq

40 – 60

95 – 125

125 – 160

Intermediate values may be linearly interpolated. Table 5.3 Empirical data ranges for the characteristic base resistance qb,k for prefabricated, reinforced concrete and prestressed concrete driven piles in cohesive soils Relative pile head settlement s/Deq

Pile base resistance qb,k [kN/m²] shear strength cu,k of the undrained soil [kN/m²] 100

150

250

0,035

350 – 450

550 – 700

800 – 950

0,100

600 – 750

850 – 1 100

1 150 – 1 500

Intermediate values may be linearly interpolated.

83


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Deutsche Gesellschaft für Geotechnik e.V.: Recommendations on Piling (EA Pfähle)

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*In EU countries the local VAT is effective for books and journals. Postage will be charged. Whilst every effort is made to ensure that the contents of this leaflet are accurate, all information is subject to change without notice. Our standard terms and delivery conditions apply. Prices are subject to change without notice. Date of information: August 2013 homepage_sample_chapter

Recommendations on Piling (EA-Pfähle) - Deutsche Gesellschaft für Geotechnik e.V.  

This handbook provides a complete overview of pile systems and their application and production. It shows their analysis based on the new sa...

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