SIST EN ISO 22477-1:2019

SLOVENSKI STANDARD
oSIST prEN ISO 22477-1:2017
01-september-2017
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Geotechnical investigation and testing - Testing of geotechnical structures - Part 1: Pile
load test by static axially loaded compression (ISO/DIS 22477-1:2017)
Geotechnische Erkundung und Untersuchung - Prüfung von geotechnischen Bauwerken
und Bauwerksteilen - Teil 1: Pfahlprobebelastungen durch statische axiale
Druckbelastungen (ISO/DIS 22477-1:2017)
Reconnaissance et essais géotechniques - Essais de structures géotechniques - Partie
1: Essai de charge statique axiale en compression (ISO/DIS 22477-1:2017)
Ta slovenski standard je istoveten z: prEN ISO 22477-1
ICS:
93.020 Zemeljska dela. Izkopavanja. Earthworks. Excavations.
Gradnja temeljev. Dela pod Foundation construction.
zemljo Underground works
oSIST prEN ISO 22477-1:2017 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN ISO 22477-1:2017

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oSIST prEN ISO 22477-1:2017
DRAFT INTERNATIONAL STANDARD
ISO/DIS 22477-1
ISO/TC 182 Secretariat: BSI
Voting begins on: Voting terminates on:
2017-07-05 2017-09-26
Geotechnical investigation and testing — Testing of
geotechnical structures —
Part 1:
Pile load test by static axially loaded compression
Reconnaissance et essais géotechniques — Essais de structures géotechniques —
Partie 1: Essai de charge statique axiale en compression
ICS: 93.020
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 22477-1:2017(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
©
PROVIDE SUPPORTING DOCUMENTATION. ISO 2017

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oSIST prEN ISO 22477-1:2017
ISO/DIS 22477-1:2017(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2017, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
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oSIST prEN ISO 22477-1:2017
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Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and symbols . 1
3.1 Terms, definitions . 2
3.2 Symbols . 2
4 Equipment . 3
4.1 General . 3
4.2 Reaction device . 3
4.3 Force input . 5
4.3.1 Practical considerations . 5
4.3.2 Specifications of force input . 5
4.3.3 Measurement of pile head displacements . 5
4.3.4 Measurement of pile load . 6
4.4 Pile instrumentation . 7
5 Test procedure . 7
5.1 Test preparation . 7
5.1.1 Protections . 7
5.1.2 Construction of a test pile . 8
5.1.3 Test date . 8
5.1.4 Preparation of the pile cap . 8
5.2 Loading procedure . 9
5.2.1 General. 9
5.2.2 Load step sequence and duration of load steps for one cycle procedure . 9
5.2.3 Load step sequence and duration of load steps for multiple cycle procedure .10
5.2.4 Maximum test load Q .
max 11
5.2.5 Measuring intervals .11
6 Test report .12
6.1 General information .12
6.2 Data report .13
6.3 Interpretative report .14
Annex A (informative) Critical creep load in compression .20
Annex B (informative) Bidirectionnal load testing.21
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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 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 . i so .org/ iso/ foreword .html.
ISO 22477-1 was prepared by Technical Committee ISO/TC 182, Geotechnics, and by Technical Committee
CEN/TC 341, Geotechnical investigation and testing in collaboration. The committee responsible for this
document is CEN TC341/WG4
ISO 22477 consists of the following parts, under the general title Geotechnical investigation and testing —
Testing of geotechnical structures:
— Part 1: Pile load test by static axial compression
— Part 2: Pile load test by static axially loaded tension
— Part 3: Pile load test by static transversally loaded tension
— Part 4: Pile load test by dynamic axially loaded compression test
— Part 5: Testing of pre-stressed anchors
— Part 6: Testing of nailing
— Part 7: Testing of reinforced fill
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oSIST prEN ISO 22477-1:2017
DRAFT INTERNATIONAL STANDARD ISO/DIS 22477-1:2017(E)
Geotechnical investigation and testing — Testing of
geotechnical structures —
Part 1:
Pile load test by static axially loaded compression
1 Scope
This Standard establishes the specifications for the execution of static pile load tests in which a single
pile is subjected to an axial static load in compression in order to define its load-displacement behaviour.
The provisions of EN 22477-1 apply to vertical piles as well as raking piles.
All types of piles are covered by this standard.
The tests considered in this Standard are limited to maintained load tests. Pile load tests with constant
penetration rate and cyclic load tests are not covered by this standard.
EN ISO 22477-1 shall be used in conjunction with EN 1997-1. Numerical values of partial factors for
limit states and of correlation factors to derive characteristic values from static pile load tests to be
taken into account in design are provided in EN 1997-1.
This Standard provides specifications for:
a) checking that a pile will behave as designed,
b) measuring the resistance of a pile under given geotechnical conditions.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
EN 1990, Eurocode 0: Basis of structural design.
EN 1997-1, Eurocode 7: Geotechnical design — Part 1: General rules.
EN 1997-2, Eurocode 7: Geotechnical design — Part 2: Ground investigation and testing
EN 1536, Execution of special geotechnical work — Bored piles.
EN 10002-2, Metallic materials — Tensile testing — Part 2 : Verification of the force measuring system of
the tensile testing machines.
EN 12699, Execution of special geotechnical work — Displacement piles.
EN 14199, Execution of special geotechnical work — Micropiles.
3 Terms, definitions and symbols
For the purposes of this document, the terms and definitions given in EN 1990, EN 1997 and the
following apply.
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3.1 Terms, definitions
3.1.1
pile load
load applied to the head of the pile during the test
Note 1 to entry: for embedded jack tests, the load may be applied at different levels (see Annex B).
3.1.2
load increment
increment of load added or removed during the course of the test
3.1.3
Equivalent pile base diameter
for noncircular pile sections with A being the area of the relevant pile base, the equivalent diameter
equals ()4./π A
3.1.4
working pile
pile for the foundation of a structure (EN 1536)
3.1.5
test pile
pile to which loads are applied to determine the resistance-displacement characteristics of the pile and
the surrounding ground (EN 1536)
3.1.7
Measured compressive resistance
Measured value of the compressive resistance at the ultimate limit state, in one or several pile load tests
Note 1 to entry: The recommended failure criteria is defined in EN 1997-1.
3.1.6
creep rate
Ratio of the increase in pile head displacement and the logarithm of time during a specified time
interval (usually the last 30 min of a load step)
3.2 Symbols
D equivalent pile base diameter
b
N axial force
Q pile load applied to the head of the pile during the test
ΔQ load increment
Q predefined maximum load to be applied for the test
max
Qb base load
Qs shaft friction
Rb pile base resistance
Rb,m measured value of Rb in one or several pile load tests
R compressive resistance of the ground against a pile, at the ultimate limit state
c
R critical creep load in compression
c,cr
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R measured value of R in one or several pile load tests
c;m c
R pile shaft resistance
s
R measured value of R in on or several pile load tests
s,m s
q unit shaft friction
s
s axial displacement of pile head
h
s axial displacement of pile base
b
t time
z depth
α creep rate
4 Equipment
4.1 General
The selection of the equipment shall take into account the aim of the test, the ground conditions, the
execution of the test and the expected displacement of the pile under the maximum test load.
4.2 Reaction device
The reaction device for pile compressive loads can be:
— dead load (kentledge);
— ground anchorage either by tension piles or ground anchors;
— a structure over the test pile (e.g. for jacked underpinning piles);
Note : The reaction device can be the test pile itself where the load is applied at depth by one or more
hydraulic jacks which are cast into the pile for bi-directional pile loading (see Annex B).
Dead load should not be used for tests of raking piles, unless particular measures are carefully
considered with respect to the stability and displacements of the kentledge system.
The influence of the reaction system on the test pile shall be minimised. Minimum required distances
are shown in Figures 1a to 1e.
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Figure 1 — Reaction system
For static pile load tests on micropiles, this distance may be reduced. However, a minimum clear
distance of 1,5 m is recommended.
The reaction system shall be designed to resist the maximum test load Q in accordance with the
max
relevant European standards.
To avoid excessive uplift or instability of the kentledge, the dead load should be centred and in excess of
the maximum test load Q by at least 10 %.
max
Working piles may be used as reaction piles, provided that their structural resistance is sufficient
and there is no detrimental effect on their ability to perform as part of the structure. The uplift of the
working piles shall be monitored during the test and this data included in the test report
Reaction piles and anchors should be arranged symmetrically around the test pile. In cases of non-
symmetrical reaction systems measures shall be taken to avoid excessive rotation and/or translation of
the reaction system.
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4.3 Force input
One or more hydraulic jacks should be used to apply the load on the test pile.
If several hydraulic jacks are used to apply the test load, they shall be arranged symetrically, the same
make and model and be supplied by a common supply from one hydraulic unit. Each hydraulic jack shall
be provided with a shut-off valve and an additional pressure gauge.
4.3.1 Practical considerations
A spherical seating shall be incorporated above the hydraulic jack.
If a single jack is used, it shall be arranged centrally on the pile cap in order to ensure the pile is loaded
axially without eccentricity of loading.
A rigid plate shall be placed on the pile head or cap to distribute the load.
4.3.2 Specifications of force input
The jacking force and stroke of the jack shall exceed Q and the expected deformations (pile head
max
displacement and those of the reaction system under load).
It shall be possible to decrease or increase the load fluently without any shocks or vibrations and to
maintain the load at any required value.
NOTE To satisfy the required accuracies, an automatic and continuous electric or hydraulic control and
regulation of the jack force may be used. Alternatively, a hand pump with accurate measurement of pressure or
load and permanent regulation may be considered.
The accuracy of the force regulation shall be in accordance to the test purpose.
The accuracy of the force regulator shall be better than 0,5 % of Q or 5 kN, whichever the greatest.
max
4.3.3 Measurement of pile head displacements
The displacements of the pile head shall be measured either by dial gauges or transducers, supported
from reference beams.
Reference beams should be supported independently from the test pile.
The clear distance between the supporting ends of the reference beams and the test pile and reaction
piles or the nearest edge of the kentledge support should be at least 2,5 m or 2.5D, whichever is the
greatest.
One end of each reference beam should be free to slide.
The position of the reference beams shall be checked by a secondary control measuring system, such as
levelling methods or other measurement methods. The position of the pile head should be also checked
by this secondary control system.
The axial pile head displacement shall be measured with at least three displacement transducers or
dial gauges. They shall be arranged symmetrically (see Figure 1) and parallel to the axis of the pile. The
friction between the pile head and the sensors should be minimized by using suitable devices such as
glass plates fixed beneath the sensors.
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Key
1) Displacement transducers
Figure 2 — Location of displacement transducers
The overall accuracy of the measured pile head displacement shall be better than 0,1 mm or 0,2 % of
the measured value, whichever the greatest. Therefore dial gauges or transducers shall enable readings
to be made to a resolution of at least 0,01 mm and any optical system of 0,1 mm.
The dial gauges or transducers should also have a sufficient measuring range, in order to avoid
readjustment during testing.
The secondary control measuring system shall enable readings to an accuracy of at least 0,1 mm.
The optical levelling measurements shall be controlled by reference to one or more fixed reference points.
The potential transversal displacement of the test pile under axial load should be checked by two dial
gauges or transducers with the same accuracy as above, positioned in orthogonal directions and fixed
on reference beams. Alternatively, transversal pile head displacements can be obtained from horizontal
survey. These measurements shall be made during load tests on raking or slender (flexible) piles.
To safeguard against failure of the supports, the corner points of a kentledge, or the anchor heads
should be included in the levelling checks.
4.3.4 Measurement of pile load
Load measurement should be obtained from a load cell (load cells) or from the pressure of the jack or
jack system, by means of suitable calibrated pressure gauges.
NOTE additional guidance may be found in national foreword.
The load measurement devices shall be calibrated against a suitable master device giving full
traceability to National Standard or EN 10002–2.
The accuracy of the load measurement should be 1 % or less.
When the load is measured using both a load cell and pressure gauges, the calibration shall be done
within a period of 12 months before the test.
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When the load is measured using only the jack pressure, the calibration shall be done within a period of
6 months before the test.
NOTE 1 In some circumstances, e.g. shock or eccentric loading or deviations of electronic load cells, additional
calibration is recommended.
NOTE 2 In some circumstances, e.g. frequent use or change of components or presumed damage, additional
calibration is recommended.
4.4 Pile instrumentation
The pile instrumentation depends on the aim of the static pile load test :
— determine the overall resistance,
— determine the pile base resistance and the shaft resistance,
— determine the pile base resistance and the distribution of the shaft friction along the length of the pile.
The load distribution along the pile shaft can be determined by means of direct or indirect measurement
of the force at cross sections of the pile at various depths.
The load distribution along the pile shaft can be measured for example by
— built-in or removable extensometer;
— strain-measuring devices such as vibrating wires strain gauges, optical fibre sensors, etc.;
The pile base resistance can be measured with a load cell at the pile base.
The depth, the number of measuring levels, the number of devices at each level, shall take into account
the ground conditions, the type and the size of the test pile and the aim of the test.
Removable extensometers shall be installed in the centre of smaller diameter piles (shaft diameter
≤ 0,6 m), or in diametrically opposed pairs for larger diameter piles (shaft diameter > 0,6 m), and this
for each depth to be measured.
Strain gauges or strain gauge devices should be fixed to the reinforcement or embedded in the concrete
of concrete piles or attached to the walls of steel piles at least three symmetrically arranged pieces for
each depth to be measured.
Strain measurements using continuous fiber optics shall be arranged within at least in two loops
symmetrically arranged.
NOTE 1 To determine load from strain, the cross section A and the pile material modulus of elasticity have to
be assessed. All the materials present in the pile shall be considered.
5 Test procedure
5.1 Test preparation
5.1.1 Protections
Throughout the test period all necessary precautions shall be taken to prevent external conditions
(such as weather, vibrations, etc.) to interfere with the test results.
Techniques to fulfil this requirement may include:
— covering the entire testing set-up by a tent or similar;
— protective covers,
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— adequate choice of materials for reference beams and conception of these beams,
— use of temperature compensated measuring devices.
— reference beams painted white
All components, cables and measuring devices embedded in or arranged outside the pile shall be
protected against damage during all stages of construction and testing. This includes in particular
adequate insulation of electric gauges and cables against water as well as mechanical protection against
damage during the concreting and trimming of the pile, the preparation of the pile head and the setting
up of the test installation and devices of the test.
Any other site activities that may influence the measurements, for example vibrations caused by
ongoing construction activities, should be suspended for the duration of the test.
The air temperature shall be recorded regularly during the course of the test to identify any temperature
effects on the test results.
5.1.2 Construction of a test pile
Test piles should be constructed in a similar manner as working piles (same installation method,
machinery and materials).
Test piles should be of the same diameter as the working piles. Load tests on smaller diameter test piles
may be considered following the specifications and restrictions specified in 7.6.2.2 (4) of EN 1997-1.
Test piles shall be designed to resist the maximum test load, so extra reinforcement and concrete of
increased strength are permitted. However, their possible influence on the pile’s behaviour shall be
assessed.
The influence of pile instrumentation on the pile construction and integrity shall be minimised.
Particular care should be given to the supervision and the monitoring of the installation of the test piles
and the elaboration of piling records. Guidance on the various items to be monitored and recorded is
given-in the respective European piling execution codes.
5.1.3 Test date
The following time periods between installation and testing of a pile are recommended:
Table 1 — Time periods between installation and testing of a pile
Soil type Pile type Minimum time (days)
Coarse soils All 7
Fine soils Bored 21
Displacement 28
NOTE 1: Alternative time periods can be specified with appropriate justification.
NOTE 2: In sensitive soils sometimes longer times periods are necessary.
NOTE 3: In rock, specific time intervals may be necessary.
Load testing on cast-in-place concrete piles and grouted micropiles shall only begin when the material
has reached the strength to accept the test load.
5.1.4 Preparation of the pile cap
The pile cap shall be designed and constructed such that the load can be applied uniformly and centrally
without damage to the head of the pile. The top surface shall be flat, smooth and normal to the pile axis.
There shall be no load transfer between the pile cap and the soil.
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5.2 Loading procedure
The load test should be executed following one single loading/unloading cycle. Alternatively multiple
loading/unloading cycles may be used.
NOTE additional guidance may be found in national foreword.
During the pile load test, the load-displacement graph should be manually or automatically plotted. The
creep rate α should be calculated during the test.
5.2.1 General
The loading procedure should start by a first load of maximum 0,05 Q , in order to check the loading
max
and measurement equipment. If necessary the pile is unloaded and the equipment adjusted.
The loading should be increased or decreased
...