SIST EN ISO 22477-4:2018

Geotechnical investigation and testing - Testing of geotechnical structures - Part 4: Testing of piles dynamic load testing (ISO 22477-4:2018)

ISO 22477-4:2018 establishes the specifications for the execution of dynamic load tests in which a single pile is subject to an axial dynamic load in compression.
ISO 22477-4:2018 outlines the methods of testing required to allow assessment of pile resistance to be determined from the following methods and procedures described in EN1997-1:2004+A1:2013:
a)    dynamic impact testing ? determination of pile compressive resistance by evaluation of measurements of strain and acceleration and or displacement at the pile head with respect to time;
b)    pile driving formulae ? evaluation of pile compressive resistance from blow counts and hammer energy during pile driving;
c)    wave equation analysis ? evaluation of pile compressive resistance from blow counts by modelling of the pile, soil and driving equipment;
d)    multi-blow dynamic testing ? evaluation of pile compressive resistance from a series of blows designed to generate different levels of pile head displacement and velocity.
ISO 22477-4:2018 is applicable to piles loaded axially in compression.
ISO 22477-4:2018 is applicable to all pile types mentioned in EN 1536, EN 12699 and EN 14199.
The tests considered in this document are limited to dynamic load tests on piles only.
NOTE 1    ISO 22477‑4 can be used in conjunction with EN1997-1:2004+A1:2013. Numerical values of partial factors 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 dynamic load tests will be considered equivalent to the measured compressive resistance Rc,m after being subject to appropriate analysis.
NOTE 2    Guidance on analysis procedures for dynamic load testing results is given in Annexes A, B, D, E and F.
ISO 22477-4:2018 provides specifications for:
i)     investigation tests, whereby a sacrificial pile is loaded up to ultimate limit state;
ii)    control tests, whereby the pile is loaded up to a specified load in excess of the serviceability limit state.
NOTE 3    Generally, an investigation test focuses on general knowledge of a pile type; a control test focuses on one specific application of a pile.

Geotechnische Erkundung und Untersuchung - Prüfung von geotechnischen Bauwerken und Bauwerksteilen - Teil 4: Pfahlprüfungen: Dynamische Pfahlprobebelastung (ISO 22477-4:2018)

Das vorliegende Dokument legt die Spezifikationen für die Ausführung von dynamischen Probebelastungen, in denen ein einziger Pfahl einer axialen dynamischen Belastung unterliegt, fest.
Dieses Dokument beschreibt die erforderlichen Prüfmethoden für die Beurteilung des Pfahlwiderstands, der mit den folgenden Methoden und Verfahren, beschrieben in EN 1997-1:2004+A1:2013, bestimmt wird:
a) Stoßprüfung – Bestimmung des Pfahldruckwiderstands durch Auswertung der Messungen von Dehnung und Beschleunigung und/oder Verschiebung am Pfahlkopf in Abhängigkeit von der Zeit;
b) Rammformeln – Bewertung des Pfahldruckwiderstands aus Schlagzahl und Energie des Hammers während der Rammarbeiten;
c) Analyse von Wellengleichungen – Bewertung des Pfahldruckwiderstands aus der Schlagzahl durch die Modellierung des Pfahls, des Bodens und des Rammgeräts;
d) dynamische Multischlag-Prüfung – Bewertung des Pfahldruckwiderstands aus einer Serie von Schlägen, die dazu bemessen sind, unterschiedliche Niveaus von Pfahlkopfverschiebung und -geschwindigkeit zu erzeugen.
Dieses Dokument gilt für axialbelastete, druckbeanspruchte Pfähle.
Dieses Dokument gilt für sämtliche in EN 1536, EN 12699 und EN 14199 genannten Pfahlarten.
Die in diesem Dokument berücksichtigten Prüfungen sind ausschließlich auf dynamische Probebelastungen an Pfählen beschränkt.
ANMERKUNG 1 ISO 22477-4 kann in Verbindung mit EN 1997-1:2004+A1:2013 angewendet werden. Numerische Teilsicherheitsbeiwerte für Grenzzustände aus Pfahlprobebelastungen, die bei der Bemessung berücksichtigt werden müssen, werden in EN 1997-1 zur Verfügung gestellt. Für eine Bemessung nach EN 1997-1 werden die Ergebnisse der dynamischen Probebelastungen als äquivalent zur gemessenen Druckfestigkeit Rc,m angesehen, nachdem diese einer geeigneten Analyse unterzogen wurden.
ANMERKUNG 2 Hinweise zu den Analyseverfahren für die Ergebnisse dynamischer Probebelastungen werden in den Anhängen A, B, D, E und F gegeben.
Dieses Dokument bietet Spezifikationen für:
i) Untersuchungsprüfungen, wobei ein Probepfahl bis zum Grenzzustand der Tragfähigkeit belastet wird;
ii) Kontrollprüfungen, wobei der Pfahl mit einer spezifischen Last oberhalb des Grenzzustands der Gebrauchstauglichkeit belastet wird.
ANMERKUNG 3 Im Allgemeinen konzentriert sich eine Untersuchungsprüfung auf die allgemeinen Kenntnisse zu einem Pfahltyp; eine Kontrollprüfung konzentriert sich auf eine bestimmte Pfahlanwendung.

Reconnaissance et essais géotechniques - Essais de structures géotechniques - Partie 4: Essais de pieux: essai de chargement dynamique (ISO 22477-4:2018)

Le présent document établit les spécifications relatives à l'exécution des essais de chargement dynamique au cours desquels un pieu unique est soumis à une charge de compression axiale dynamique.
Il précise les méthodes d'essai nécessaires pour permettre une évaluation de la résistance d'un pieu, déterminée à partir des méthodes et des procédures décrites dans la norme EN1997-1:2004+A1:2013:
a)    Essai d'impact dynamique: détermination de la résistance à la compression d'un pieu par évaluation des mesures de déformation et d'accélération et/ou de déplacement, prises au niveau de la tête du pieu, en fonction du temps.
b)    Formules de fonçage de pieux: évaluation de la résistance à la compression d'un pieu à partir du nombre de coups de battage et de l'énergie du mouton pendant le fonçage du pieu.
c)    Analyse de l'équation d'onde: évaluation de la résistance à la compression d'un pieu à partir du nombre de coups de battage par modélisation du pieu, du sol et de l'équipement de fonçage.
d)    Essais dynamiques basés sur une série de coups ? évaluation de la résistance à la compression d'un pieu à partir d'une série de coups conçue pour créer des niveaux différents de déplacements et de vitesses de tête de pieu.
Ce document s'applique aux pieux sous chargement axial en compression.
Il s'applique à tous les types de pieux mentionnés par l'EN 1536, l'EN 12699 et l'EN 14199.
Les essais envisagés dans le présent document sont limités aux essais de chargement dynamique des pieux uniquement.
NOTE 1    L'ISO 22477-4 peut être utilisée conjointement à l'EN1997-1:2004+A1:2013. Les valeurs numériques des facteurs partiels des états limites, obtenues à partir des essais de chargement des pieux et devant être prises en compte dans la conception, sont données dans l'EN 1997-1. Dans le cas d'une conception selon l'EN 1997-1, les résultats des essais de chargement dynamique seront considérés comme équivalents à la résistance à la compression mesurée Rc,m après l'analyse appropriée.
NOTE 2    Des consignes relatives aux procédures d'analyse des résultats des essais de chargement dynamique sont données dans les Annexes A, B, D, E et F.
Le présent document fournit des spécifications pour:
i)     les essais préalables, au cours desquels un pieu sacrificiel est chargé jusqu'à l'état limite ultime;
ii)    les essais de contrôle, au cours desquels le pieu est chargé jusqu'à une charge spécifiée au-delà de l'état limite de service.
NOTE 3    En général, un essai préalable se focalise sur la connaissance générale d'un type de pieu; un essai de contrôle se focalise sur une application particulière d'un pieu.

Geotehnično preiskovanje in preskušanje - Preskušanje geotehničnih konstrukcij - 4. del: Preskušanje pilotov: dinamični obremenilni preskus (ISO 22477-4:2018)

Ta standard podaja specifikacije za izvedbo dinamičnih obremenilnih preskusov pilotov, pri katerih je en pilot izpostavljen kratkotrajni osni udarni obremenitvi pri stiskanju, da bi se lahko napovedala njegova končna odpornost na stiskanje in vedenje ob premiku bremena, vključno s porazdelitvijo trenja gredi in nožno odpornostjo.

General Information

• Status: Published
• Public Enquiry End Date: 29-Dec-2016
• Publication Date: 16-May-2018
• ICS: 93.020 - Earthworks. Excavations. Foundation construction. Underground works
• Technical Committee: KON.007 - Geotechnics
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 23-Apr-2018
• Due Date: 28-Jun-2018
• Completion Date: 17-May-2018
• Ref Project: EN ISO 22477-4:2018 - Geotechnical investigation and testing - Testing of geotechnical structures - Part 4: Testing of piles: dynamic load testing (ISO 22477-4:2018)

Standards Content (Sample)

SLOVENSKI STANDARD
01-junij-2018
*HRWHKQLþQRSUHLVNRYDQMHLQSUHVNXãDQMH3UHVNXãDQMHJHRWHKQLþQLKNRQVWUXNFLM
GHO3UHVNXãDQMHSLORWRYGLQDPLþQLREUHPHQLOQLSUHVNXV,62
Geotechnical investigation and testing - Testing of geotechnical structures - Part 4:
Testing of piles dynamic load testing (ISO 22477-4:2018)
Geotechnische Erkundung und Untersuchung - Prüfung von geotechnischen Bauwerken
und Bauwerksteilen - Teil 4: Pfahlprüfungen: Dynamische Pfahlprobebelastung (ISO
22477-4:2018)
Reconnaissance et essais géotechniques - Essais de structures géotechniques - Partie
4: Essais de pieux: essai de chargement dynamique (ISO 22477-4:2018)
Ta slovenski standard je istoveten z: EN ISO 22477-4:2018
ICS:
93.020 Zemeljska dela. Izkopavanja. Earthworks. Excavations.
Gradnja temeljev. Dela pod Foundation construction.
zemljo Underground works
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 22477-4
EUROPEAN STANDARD
NORME EUROPÉENNE
April 2018
EUROPÄISCHE NORM
ICS 93.020
English Version
Geotechnical investigation and testing - Testing of
geotechnical structures - Part 4: Testing of piles: dynamic
load testing (ISO 22477-4:2018)
Reconnaissance et essais géotechniques - Essais de Geotechnische Erkundung und Untersuchung - Prüfung
structures géotechniques - Partie 4: Essais de pieux: von geotechnischen Bauwerken und Bauwerksteilen -
essai de chargement dynamique (ISO 22477-4:2018) Teil 4: Pfahlprüfungen: Dynamische
Pfahlprobebelastung (ISO 22477-4:2018)
This European Standard was approved by CEN on 24 February 2018.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 22477-4:2018 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 22477-4:2018) has been prepared by Technical Committee ISO/TC 182
“Geotechnics" in collaboration with Technical Committee CEN/TC 341 “Geotechnical Investigation and
Testing" the secretariat of which is held by BSI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by October 2018, and conflicting national standards shall
be withdrawn at the latest by October 2018.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 22477-4:2018 has been approved by CEN as EN ISO 22477-4:2018 without any
modification.
INTERNATIONAL ISO
STANDARD 22477-4
First edition
2018-03
Geotechnical investigation and
testing — Testing of geotechnical
structures —
Part 4:
Testing of piles: dynamic load testing
Reconnaissance et essais géotechniques — Essais de structures
géotechniques —
Partie 4: Essais de pieux: essai de chargement dynamique
Reference number
ISO 22477-4:2018(E)
©
ISO 2018
ISO 22477-4:2018(E)
© ISO 2018
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of 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 of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2018 – All rights reserved

ISO 22477-4:2018(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 2
3 Terms, definitions and symbols . 2
3.1 Terms and definitions . 2
3.2 Symbols . 4
4 Testing equipment . 4
4.1 General . 4
4.2 Loading . 5
4.2.1 General. 5
4.2.2 Loading by an impact driving system . 6
4.2.3 Loading by a single or multiple blow drop mass . 6
4.3 Measurements . 6
4.3.1 General. 6
4.3.2 Measurements for dynamic impact tests . 7
4.3.3 Measurements and recordings required for pile driving formula or wave
equation analysis . 8
5 Test procedure . 9
5.1 Preparation for testing . 9
5.2 Safety requirements . 9
5.2.1 People and equipment in the surrounding area . 9
5.2.2 Test pile .10
5.3 Preparation of the pile .10
5.4 Timing of tests .10
5.4.1 General.10
5.4.2 Driving — Continuous monitoring and end of initial driving test .10
5.4.3 Re-driving .10
5.4.4 Bored or cast-in-situ piles .11
6 Test results .11
6.1 Test results for dynamic load test with driving formula .11
6.2 Test results for dynamic load test with wave equation analysis .11
6.3 Test results for dynamic load test with measurements at the pile head .11
7 Test reporting .12
Annex A (informative) Driving formula .14
Annex B (informative) Wave equation analysis .17
Annex C (informative) Examples of transducer attachment and pile extension details .27
Annex D (informative) Evaluation by closed form solutions using empirical damping values .29
Annex E (informative) Evaluation of the measurements by signal matching .36
Annex F (informative) Multi-blow dynamic testing technique .44
Bibliography .51
ISO 22477-4:2018(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of 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 of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of 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 information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity 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.
This document was prepared by the European Committee for Standardization (CEN) Technical
Committee CEN/TC 341, Geotechnical investigation and testing, 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 can be found on the ISO website.
iv © ISO 2018 – All rights reserved

ISO 22477-4:2018(E)
Introduction
This document establishes the specifications for the execution of dynamic load tests in which a single
pile is subject to an axial load in compression to measure strain, acceleration and displacement under
dynamic loading and to allow an assessment of its compressive resistance. This document outlines
how a dynamic load test is defined and specifies the equipment and testing procedures required.
Informative non-prescriptive guidance is included on the analysis of dynamic load test results required
to determine mobilized or ultimate measured compressive resistance of a pile.
INTERNATIONAL STANDARD ISO 22477-4:2018(E)
Geotechnical investigation and testing — Testing of
geotechnical structures —
Part 4:
Testing of piles: dynamic load testing
1 Scope
This document establishes the specifications for the execution of dynamic load tests in which a single
pile is subject to an axial dynamic load in compression.
This document outlines the methods of testing required to allow assessment of pile resistance to be
determined from the following methods and procedures described in EN1997 -1: 2004+A1: 2013:
a) dynamic impact testing – determination of pile compressive resistance by evaluation of
measurements of strain and acceleration and or displacement at the pile head with respect to time;
b) pile driving formulae – evaluation of pile compressive resistance from blow counts and hammer
energy during pile driving;
c) wave equation analysis – evaluation of pile compressive resistance from blow counts by modelling
of the pile, soil and driving equipment;
d) multi-blow dynamic testing – evaluation of pile compressive resistance from a series of blows
designed to generate different levels of pile head displacement and velocity.
This document is applicable to piles loaded axially in compression.
This document is applicable to all pile types mentioned in EN 1536, EN 12699 and EN 14199.
The tests considered in this document are limited to dynamic load tests on piles only.
NOTE 1 ISO 22477-4 can be used in conjunction with EN1997 -1: 2004+A1: 2013. Numerical values of partial
factors 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 dynamic load tests will be considered equivalent to the measured compressive
resistance R after being subject to appropriate analysis.
c,m
NOTE 2 Guidance on analysis procedures for dynamic load testing results is given in Annexes A, B, D, E and F.
This document provides specifications for:
i) investigation tests, whereby a sacrificial pile is loaded up to ultimate limit state;
ii) control tests, whereby the pile is loaded up to a specified load in excess of the serviceability
limit state.
NOTE 3 Generally, an investigation test focuses on general knowledge of a pile type; a control test focuses on
one specific application of a pile.
ISO 22477-4:2018(E)
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN1997 -1: 2004+A1: 2013, Eurocode 7: Geotechnical design — Part 1: General rules
3 Terms, definitions and symbols
3.1 Terms and definitions
For the purposes of this document, the terms and definitions in EN1997 -1: 2004+A1: 2013 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 before the commencement of the main piling works or a specific part of the works for
the purpose of investigating the suitability of the chosen type of pile and for confirming its design,
dimensions and compressive resistance
Note 1 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 compressive resistance - deformation characteristics
of the pile and the surrounding ground
Note 1 to entry: A test pile can be a trial pile or a working pile.
3.1.4
pile load
axial compressive load (or force) applied to the head of the pile during the test
3.1.5
dynamic load
axial compressive impact load (or force) applied to the head of a pile by a driving hammer or drop mass
3.1.6
maximum pile load
highest axial compressive force applied to the pile during the test
Note 1 to entry: This is generally defined prior to the test.
3.1.7
dynamic load test
test where a pile is subjected to chosen axial dynamic load at the pile head to allow the determination of
its compressive resistance
2 © ISO 2018 – All rights reserved

ISO 22477-4:2018(E)
3.1.8
dynamic impact test
pile test with measurement of strain, acceleration and displacement versus time during the impact event
Note 1 to entry: The impact event is normally a hammer blow.
Note 2 to entry: This test is used to assess the compressive resistance of individual piles.
3.1.9
driving formula
formula that relates impact hammer energy and number of blows for a unit distance or permanent set
for a single blow to pile compressive resistance
3.1.10
wave equation analysis
analysis of a dynamically loaded pile by a mathematical model that can represent the dynamic behaviour
of the pile by the progression of stress waves in the pile and the resulting response of the soil
3.1.11
signal matching
operation to evaluate the shaft and base resistance of piles by modelling of the pile and soil with
variation of parameters to match measured signals from pile head strain or displacement and
acceleration measurements
3.1.12
impedance
the dynamic stiffness of a pile determined from the cross-sectional area, material stiffness and density.
Note 1 to entry: For a non-uniform pile the impedance can be different over the length of the pile.
3.1.13
mobilized compressive resistance
the resistance that is mobilized with the available energy of the impact device
3.1.14
ultimate measured compressive resistance
corresponding state in which the pile foundation displaces significantly with negligible increase of
resistance
Note 1 to entry: Where it is difficult 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.
Note 2 to entry: The ultimate compressive resistance is not measured directly during a dynamic load test. The
measured or mobilized compressive resistance obtained from dynamic load testing shall be analysed to remove
the effects of dynamic soil dependent behaviour before it can be considered equivalent to the ultimate measured
compressive resistance as outlined in the appropriate Annex.
3.1.15
design compressive static resistance
ultimate compressive resistance of a pile
Note 1 to entry: This shall be determined prior to load testing to allow specification of the appropriate magnitude
of dynamic load test.
3.1.16
equivalent diameter
diameter of the circle of which the area equals the area of the relevant pile section
Note 1 to entry: The equivalent diameter for a circular pile is the outer diameter of the pile, for a square pile 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.
ISO 22477-4:2018(E)
3.1.17
minimum reference separation distance
distance which separates a stationary reference point from a point that will be significantly displaced
by the testing method
Note 1 to entry: Only stationary points can be used for reference of displacement measurement devices.
Displacement measuring systems can be placed on the soil outside the reference distance without isolating
(displacement compensating) measures.
3.1.18
displacement
axial movement of the pile head measured during testing
3.2 Symbols
a acceleration
A cross-sectional area of the pile at the level being considered
A cross-sectional area of the pile reinforcement at the level being considered
r
c velocity of the stress wave in the test pile
E Young's modulus of the pile material at the measurement level being considered
dyn
E kinetic energy
k
E potential energy
p
F force at the pile head derived from strain measurements
f the characteristic yield strength of the pile reinforcement
yk
g acceleration due to gravity (g = 9,8 m/s )
h drop height (or stroke) the mass or hammer has fallen through
L pile length
m mass
R measured ultimate compressive resistance of the ground in the test, or measured geotechni-
c,m
cal resistance of the pile
t time
v velocity
Z pile impedance
w pile displacement or settlement
ε strain
4 Testing equipment
4.1 General
The loading equipment shall be able to generate sufficient force and energy to be able to mobilize the
compressive resistance to be verified.
4 © ISO 2018 – All rights reserved

ISO 22477-4:2018(E)
If information on the ultimate measured compressive resistance of the pile is one of the aims of the test,
the equipment shall have enough capacity to reach the ultimate measured compressive resistance and
mobilize adequate settlement under dynamic loading with a single or a sequence of single blows.
The maximum pile load during a dynamic load test required to determine the ultimate measured
compressive resistance can exceed the design compressive static resistance. The need to apply such
high loads shall be considered when specifying equipment and pile materials.
If for a dynamic load test, one or more of the requirements in this document is not met; it should be
proven that this shortcoming has no influence on the achievement of the objectives of the test, before
the results can be interpreted as a dynamic load test.
Dynamic load testing systems rely on a mass to apply load to the head of the pile. This is either as
part of a pile driving hammer referred to as an impact driving system or by dropping a mass, referred
to as a drop mass system. Dynamic load testing can be undertaken during pile installation of precast
concrete piles or steel piles (displacement piles) when driving with a hammer. Drop mass systems are
used for the testing of cast-in-situ piles (bored piles, continuous flight auger or other cast-in-situ piles)
or testing associated with re-driving. The type of load application used during testing can depend on
several factors including the availability of pile installation or loading equipment and the phase of the
construction project.
Three types of dynamic pile tests are given in EN1997 -1: 2004+A1: 2013 which relate to the type of
measurements and analysis undertaken and are referred to as dynamic impact tests, pile driving
formula and wave equation analysis. These together with the multi-blow dynamic testing technique
are presented in more detail in the annexes. The measurements taken, equipment and information
required for a dynamic load test will be dependent on the specific dynamic load test being undertaken.
4.2 Loading
4.2.1 General
The selection of the loading equipment shall take into account:
— the aim of the test;
— the type of dynamic test and the analysis to be undertaken;
— the pile type;
— the ground conditions;
— the maximum pile load;
— the strength of the pile (material) and permissible stresses it can carry;
— the execution of the test;
— safety considerations.
The loading equipment shall generate adequate force and energy which fulfils the requirements in
4.1 and is able to apply the required maximum compressive force to mobilize a specified compressive
resistance or the ultimate measured compressive resistance of a pile. The equipment shall load the
pile accurately with appropriate guidance of the drop mass along the direction of the pile axis. The
eccentricity of the load shall be smaller than 10 % of the equivalent diameter. The deviation of the
alignment of the force to the axis of the pile shall be smaller than 20 mm/m.
The stress generated in the pile under the maximum applied load shall not exceed the permissible
stress of the pile material. For concrete piles in compression the maximum stress in the pile, including
any prestress in the pile, shall not exceed 0,8 times the characteristic concrete strength in compression
at the time of driving (as outlined in EN 12699). For concrete piles in tension the tensile force induced
ISO 22477-4:2018(E)
should not exceed 0,9 × f × A minus any compressive prestress force. For steel piles the maximum
yk r
stress in steel piles should not exceed 0,9 times the characteristic yield strength of the steel.
NOTE Where stresses are monitored during impact driving, these can be up to 20 % higher than the values
stated above. The yield strength of materials can increase under dynamic impact loading.
To avoid potential damage to concrete piles, a simulation of the planned loading process can be
undertaken by simulation using wave equation analysis. Based upon wave equation analysis, the loading
scheme can be adjusted and re-simulated for example to avoid high tension stresses in a concrete pile.
4.2.2 Loading by an impact driving system
Impact hammers consist of a mass (ram) and lifting and releasing systems. They are defined by their mass
and maximum stroke (drop height) or the respective potential energy (mass × acceleration × stroke) or
kinetic energy immediately prior to impact.
The frequency of hammer blows should not exceed 120 blows per minute where an evaluation by a
driving formula is to be considered.
4.2.3 Loading by a single or multiple blow drop mass
The mass of the drop mass should be chosen to be greater than 2 % of the design compressive static
resistance of the pile (where the mass of the drop mass is expressed as a weight).
In very hard soils, piles resting on hard bedrock or where a pile is installed with a rock socket drop
mass weights of 1 % of the required design compressive static resistance can be sufficient to mobilize
pile resistance.
The applied energy or the stroke of the drop mass should be adjusted to achieve full mobilization of the
pile skin friction and tip resistance.
4.3 Measurements
4.3.1 General
The measurements taken, equipment and information required for a dynamic load test will be
dependent on the specific dynamic load test being undertaken.
During a dynamic impact test a minimum of three variables shall be directly measured relative to time (t):
— the strain at the pile head (ε);
— the acceleration of the pile head (a);
— the permanent pile displacement per dynamic load application (set per blow).
Where dynamic impact testing is analysed using the multi-blow dynamic load testing technique
(Annex F) this will additionally include:
— the pile head displacement (w).
During a test where pile driving formula or wave equation analysis will be used a minimum of two
variables shall be directly recorded:
— the permanent pile displacement per impact of the hammer referred to as set per blow(s);
— the mass of the piling hammer (or drop mass) and drop height (and/or energy rating).
Where piles are subjected to a single hammer blow or cycles of drop mass loading and are accessible,
the level of the pile head shall be determined relative to a point outside of the minimum reference
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ISO 22477-4:2018(E)
separation distance by optical levelling. The optical levelling measurements shall be controlled by
reference to one or more fixed reference points and should be undertaken to an accuracy of ±1 mm.
4.3.2 Measurements for dynamic impact tests
The transducers and signal processing shall satisfy the requirements from Table 1 to Table 3. Sampling
shall commence a minimum of 10 ms before loading commences and continue for a minimum duration
such that the pile has come to rest. The transducers shall have sufficient measuring range, in order to
avoid re-adjustment or change of position during testing. All instrumentation shall be able to withstand
pile installation and testing procedures. For diesel hammers the duration of pre-event sampling should
be extended to a minimum of 35 ms, and extension of the corresponding duration of measurement to
>125 ms. For longer piles the length of the pile should be considered when determining the duration of
measurement. The particular minimum sampling rate adopted should take into account the type of pile
and test being undertaken.
Table 1 — Dynamic impact test: signal processing general requirements
Parameter Requirement
Sampling rate ≥5 000 samples per second
Duration of pre-event sampling ≥10 ms
Duration of the measurement ≥100 ms
Table 2 — Dynamic impact test: strain transducer requirements
Parameter Requirement
Maximum strain ≥0,015
Resonant frequency ≥2 000 Hz
Table 3 — Dynamic impact test: acceleration transducer requirements
Parameter Requirement
linearity up to 2 000 g
and 2 000 Hz
Table 4 — Dynamic impact test: displacement measurement using
remote theodolite during load application
Parameter Requirement
Sampling rate ≥10 000 samples per second
Accuracy <1 mm
All equipment used for measuring strain, displacement and acceleration in the test shall be calibrated.
The equipment shall be checked on a regular basis. The results of these checks shall be registered
and kept with the most recent calibration. This data shall be made available on request prior to
commencement of the test.
The time between the checks and calibrations is not prescribed, since the duration of validity of a
calibration can depend on the type of measurement device and manufacturers recommendations.
However, checks shall be sufficiently detailed that it can be verified that all measurement devices are
operating correctly during the test. It is preferred that all checks are carried out directly before the
test, to avoid influence of transport and time. In some circumstances, e.g., frequent use or change of
components or presumed damage, additional calibration and checking might be required.
The strain (ε) as a function of time (t) induced in the pile head by the dynamic load, shall be measured
by at least two strain transducers, mounted in an axial direction and diametrically opposed pairs (see
ISO 22477-4:2018(E)
Annex C). The acceleration a as a function of time (t) of the pile head shall be measured by at least one
acceleration transducer, mounted in an axial direction (see Annex C).
4.3.3 Measurements and recordings required for pile driving formula or wave equation
analysis
The permanent pile displacement per impact of the hammer referred to as set per blow(s) is recorded
by manually counting the number of blows for a unit distance of penetration for at least the last 1,0 m of
pile penetration.
Distance markers should be clearly marked on the pile under test prior to testing. In continuous driving,
blows are counted for a unit penetration. As an alternative, a penetration for a defined number of blows
can be determined.
The set per blow is determined either by optical levelling to a reference point which is unaffected by
pile driving operations or by visual observations of marks on the pile passing a stable reference beam
which is unaffected by the pile testing process. The requirements for optical levelling are outlined in
Table 5.
Table 5 — Dynamic load test displacement requirements for set per blow
when determined by optical instrument levelling
Parameter Requirement
Accuracy ≤1 mm
To determine the energy transferred to the pile from the dynamic loading it is necessary to know the
mass of the ram or hammer and the drop height that mass or ram falls through.
The potential energy of the driving system:
E = m × g × h (1)
p
where
E potential energy;
p
m mass of ram or hammer;
g acceleration due to gravity (g = 9,8 m/s );
h drop height (or stroke) the mass or hammer has fallen through.
The drop height or stroke is measured by a visual estimate only if the ram can be seen.
The kinetic energy of the mass or ram directly before impact is given by:
E = m × v/2 (2)
k
where
E kinetic energy;
k
v velocity of mass or ram before impact.
The velocity of the ram before impact can be measured by proximity switches installed as part of the
hammer casing.
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ISO 22477-4:2018(E)
5 Test procedure
5.1 Preparation for testing
It is recommended that in advance of the test, an execution plan should be formulated that is consistent
with the planned final report shown in Clause 7. The plan should include the following where
appropriate:
a) test objectives;
b) the ground and groundwater conditions with reference to the relevant site investigation reports;
c) topographic locations, types and specifications of the test piles;
d) allowable maximum values of the load and stresses on the pile and the pile displacement;
e) required pile displacement and applied load;
f) specification of the loading device;
g) specifications of the measurement devices and calibration certificates if applicable;
h) specifications of additional measurement-devices;
i) plan of the test site;
j) testing programme;
k) list of key personnel, showing who is responsible for supervision, safety, test execution, data
recording and other tasks;
l) logistical requirements on site (for example flat ground, vehicle requirements and limitations,
lifting plan, working space around the pile, etc.);
m) accessibility of the pile for sensor attachment;
n) procedures for preventing pile damage and detecting pile damage in the case of cast-in-situ piles;
o) assessment of feasibility of testing by wave equation analysis;
p) safety requirements.
It is recommended that the execution plan is made available at least seven days prior to commencement
of testing.
5.2 Safety requirements
5.2.1 People and equipment in the surrounding area
Safety of personnel and equipment in the surrounding area shall be given due consideration during
execution of the test and should be undertaken in accordance with EN 16228 where applicable.
People in neighbouring buildings that are likely to be affected by testing shall be informed of the nature
of testing and the programme of tests to be undertaken. Separate notification of dynamic load testing
is not required where the testing forms part of a larger programme of displacement pile installation
where notification has already occurred.
Disturbance to vibration sensitive processes in neighbouring buildings should be prevented where
possible. Where testing is undertaken close to existing buildings consideration should be given to the
age, integrity and sensitivity of the structure.
ISO 22477-4:2018(E)
5.2.2 Test pile
The test pile should be designed, manufactured and installed such that the test pile should not be
damaged by the maximum compressive load that will be applied during the test. As cast-in-situ piles
(bored piles, continuous flight auger or other injection piles) are not normally designed for dynamic
loading, pile heads should be reinforced by a steel casing. Prior to the test the allowable compression
and tension stresses for the pile should be defined and compared to wave equation analysis for the pile.
For cast-in-situ piles integrity testing should be undertaken before and after dynamic load testing.
NOTE During a dynamic load test, the test pile is loaded with a force which can exceed the static equivalent
test loads. Test piles are to be designed to withstand the resulting higher stresses. For concrete piles a pile
cushion is usually used to reduce and evenly distribute stresses.
For working piles the maximum accumulated final displacement of the pile head shall be agreed before
commencement of the test. The displacement of the pile head shall not exceed 10 % of the (equivalent)
diameter under normal circumstances without prior approval from all parties concerned.
5.3 Preparation of the pile
The pile head shall be flat, plane, perpendicular to the pile axis and undamaged. The heads of concrete
piles shall be protected by a pile cushion. The test pile shall have enough length above the ground
surface to attach the measurement devices. Proposed positioning of transducers and pile extension
details are given in Annex C.
5.4 Timing of tests
5.4.1 General
The compressive resistance of a pile has the tendency to vary significantly depending on the time after
installation at which it is tested. This should be given due consideration for dynamic load testing as
testing can be carried out during pile installation or at some time later.
5.4.2 Driving — Continuous monitoring and end of initial driving test
In continuous pile driving for installation each individual impact can be considered as a separate
dynamic load test. Usually a compressive resistance calculation is undertaken when the pile is
penetrating what is considered a competent ground layer or when it achieves final penetration.
As the ground resistance can be reduced in continuous driving the pile compressive resistances
determined during initial driving or at end of initial driving can be lower than that determined from
static pile load tests. In certain soil conditions the compressive resistance at end of driving can also
be larger than the compressive resistance in re-driving. The potential for difference in the measured
characteristic compressive pile resistance due to the timing of testing should be given appropriate
consideration.
5.4.3 Re-driving
Re-driving is a dynamic load test carried out some time after the installation of the pile and is a separate
operation to testing during pile installation. It can be considered that a dynamic load test undertaken
during re-driving is less influenced by the pile installation process if adequate time after installation
is allowed to elapse. The optimum timing for re-drive dynamic load testing should be assessed for the
specific ground conditions at the site.
Where re-driving gives lower pile resistance than that measured during driving for installation this
shall be used as the basis for ultimate compressive resistance assessment (EN1997 -1: 2004+A1: 2013,
Clause 7). If re-driving gives higher results, these can be considered.
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ISO 22477-4:2018(E)
For certain ground conditions re-driving should be carried out. Re-driving should usually be carried
out in silty soils, unless local comparable experience has shown it to be unnecessary.
NOTE Re-driving of friction piles in clayey soils normally results in reduced compressive resistance.
5.4.4 Bored or cast-in-situ piles
Between the installation of a bored or cast-in-situ test pile and the beginning of the test, adequate time
shall be allowed to ensure that the required strength of the pile material is achieved and the soil has
sufficient time to recover from the process of pile installation a
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