Petroleum and natural gas industries - Specific requirements for offshore structures - Part 4: Geotechnical and foundation design considerations (ISO 19901-4:2016)

This part of ISO 19901 contains provisions for those aspects of geoscience and foundation engineering
that are applicable to a broad range of offshore structures, rather than to a particular structure type.
Such aspects are:
— site and soil characterization;
— identification of hazards;
— design and installation of shallow foundations supported by the seabed;
— design and installation of pile foundations;
— soil-structure interaction for auxiliary structures, e.g. subsea production systems, risers and
flowlines (guidance given in A.10);
— design of anchors for the stationkeeping systems of floating structures (guidance given in A.11).
Particular requirements for marine soil investigations are detailed in ISO 19901-8.
Aspects of soil mechanics and foundation engineering that apply equally to offshore and onshore
structures are not addressed. The user of this part of ISO 19901 is expected to be familiar with such
aspects.
ISO 19901-4 outlines methods developed primarily for the design of shallow foundations with an
embedded length (L) to diameter (D) ratio L/D < 1 (Clause 7) and relatively long and flexible pile
foundations with L/D > 10 (Clause 8). This part of ISO 19901 does not apply to intermediate foundations
with 1 < L/D < 10. Such intermediate foundations, often known as ‘caisson foundations’, comprise either
shallow foundations with skirts penetrating deeper into the seabed than the width of the foundation,
or shorter, more rigid and larger diameter piles than those traditionally used for founding offshore
structures. The design of such foundations can require specific analysis methods; it is important
that any extrapolation from the design methods described in this part of ISO 19901 to intermediate
foundations be treated with care and assessed by a geotechnical specialist.

Erdöl- und Erdgasindustrie - Besondere Anforderungen an Offshore-Bauwerke - Teil 4: Geotechnische und Fundament-Auslegungsmerkmale (ISO 19901-4:2016)

Industries du pétrole et du gaz naturel - Exigences spécifiques relatives aux structures en mer - Partie 4: Bases conceptuelles des fondations (ISO 19901-4:2016)

La présente partie de l'ISO 19901 contient les dispositions relatives aux aspects géotechniques et de dimensionnement des fondations qui s'appliquent à une vaste gamme de structures en mer, plutôt qu'à un type particulier de structure. Ces aspects sont les suivants:
—          caractérisation du site et des sols;
—          identification des risques;
—          dimensionnement et installation des fondations superficielles supportées par le sol marin;
—          dimensionnement et installation des fondations par pieux;
—          interaction sol-structure pour les structures auxiliaires, par exemple les systèmes de production immergés, les risers (tubes prolongateurs) et les conduites d'écoulement (des indications sont données en A.10);
—          dimensionnement des ancrages des systèmes de maintien en position des structures flottantes (des indications sont données en A.11).
Les exigences particulières relatives aux reconnaissances des sols en mer sont détaillées dans l'ISO 19901‑8.
Les aspects de mécanique des sols et de dimensionnement des fondations qui s'appliquent aussi bien aux structures en mer qu'aux structures terrestres ne sont pas couverts. L'utilisateur de la présente partie de l'ISO 19901 est considéré comme familier de ces aspects.
L'ISO 19901‑4 décrit les méthodes développées principalement pour le dimensionnement des fondations superficielles avec un rapport entre longueur enfouie (L) et diamètre (D) L/D < 1 (Article 7) et des fondations par pieux relativement longs et flexibles avec L/D > 10 (Article 8). La présente partie de l'ISO 19901 ne s'applique pas aux fondations intermédiaires avec 1 < L/D < 10. De telles fondations intermédiaires, souvent appelées «caissons de fondation», comprennent soit des fondations superficielles à jupes pénétrant dans le sol marin sur une profondeur supérieure à la largeur de la fondation, soit des pieux plus courts, plus rigides et de plus grand diamètre que ceux traditionnellement utilisés pour les fondations des structures en mer. Le dimensionnement de telles fondations peut nécessiter des méthodes d'analyse spécifiques; il est important que toute extrapolation des méthodes de dimensionnement décrites dans la présente partie de l'ISO 19901 à des fondations intermédiaires soit traitée avec précaution et évaluée par un spécialiste en géotechnique.

Industrija za predelavo nafte in zemeljskega plina - Posebne zahteve za naftne ploščadi - 4. del: Obravnava geotehničnih in temeljnih značilnosti projektiranja (ISO 19901-4:2016)

Ta del standarda ISO 19901 vsebuje določbe za vidike geoznanosti in temeljenja, ki se uporabljajo za široko paleto naftnih ploščadi, ne zgolj za določeno vrsto konstrukcije.
Takšni vidiki so:
– karakterizacija območja in tal;
– prepoznavanje nevarnosti;
– načrtovanje in postavitev plitkih temeljev s podporo morskega dna;
– načrtovanje in postavitev temeljev na kolih;
– interakcija tla-konstrukcija za pomožne konstrukcije, npr. podmorske proizvodne sisteme, dvižne vode in
cevi, položene na morsko dno (smernice so podane v točki A.10);
– načrtovanje sider za vzdrževalne sisteme plavajočih konstrukcij (smernice so podane v točki A.11).
Posebne zahteve za preiskave morskega dna so opisane v standardu ISO 19901-8.
Vidiki mehanike tal in temeljenja, ki se enakovredno uporabljajo za konstrukcije na morju in na kopnem,
niso obravnavane. Od uporabnika tega dela standarda ISO 19901 se pričakuje, da je seznanjen s takšnimi
vidiki.
Standard ISO 19901-4 opredeljuje metode, ki so bile razvite predvsem za načrtovanje plitkih temeljev z
razmerjem dolžine (L) in premera (D) L/D < 1 (točka 7) ter relativno dolgih in fleksibilnih temeljev
na kolih z razmerjem L/D > 10 (točka 8). Ta del standarda ISO 19901 se ne uporablja za vmesne temelje z razmerjem 1 < L/D < 10. Takšni vmesni temelji, ki se pogosto imenujejo »kesoni«, so sestavljeni iz plitkih temeljev, pri čemer krilo sega globlje v morsko dno, kot je širina temelja, ali krajših, bolj togih kolov z večjim premerom, kot so tisti, ki se običajno uporabljajo za temeljenje naftnih ploščadi. Načrtovanje takšnih temeljev lahko zahteva posebne metode analize; pomembno je, da je vsaka ekstrapolacija iz metod načrtovanja, ki so opisane v tem delu standarda ISO 19901, v vmesne temelje pozorno obravnavana in ocenjena s strani strokovnjaka na področju geotehnologije.

General Information

Status
Published
Public Enquiry End Date
29-Mar-2015
Publication Date
22-Aug-2016
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
19-Aug-2016
Due Date
24-Oct-2016
Completion Date
23-Aug-2016

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Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN ISO 19901-4:2016
01-oktober-2016
1DGRPHãþD
SIST EN ISO 19901-4:2004
,QGXVWULMD]DSUHGHODYRQDIWHLQ]HPHOMVNHJDSOLQD3RVHEQH]DKWHYH]DQDIWQH
SORãþDGLGHO2EUDYQDYDJHRWHKQLþQLKLQWHPHOMQLK]QDþLOQRVWLSURMHNWLUDQMD
,62
Petroleum and natural gas industries - Specific requirements for offshore structures -
Part 4: Geotechnical and foundation design considerations (ISO 19901-4:2016)
Erdöl- und Erdgasindustrie - Besondere Anforderungen an Offshore-Bauwerke - Teil 4:
Geotechnische und Fundament-Auslegungsmerkmale (ISO 19901-4:2016)
Industries du pétrole et du gaz naturel - Exigences spécifiques relatives aux structures
en mer - Partie 4: Bases conceptuelles des fondations (ISO 19901-4:2016)
Ta slovenski standard je istoveten z: EN ISO 19901-4:2016
ICS:
75.180.10 Oprema za raziskovanje, Exploratory, drilling and
vrtanje in odkopavanje extraction equipment
93.020 Zemeljska dela. Izkopavanja. Earthworks. Excavations.
Gradnja temeljev. Dela pod Foundation construction.
zemljo Underground works
SIST EN ISO 19901-4:2016 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------

SIST EN ISO 19901-4:2016

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SIST EN ISO 19901-4:2016


EN ISO 19901-4
EUROPEAN STANDARD

NORME EUROPÉENNE

August 2016
EUROPÄISCHE NORM
ICS 75.180.10 Supersedes EN ISO 19901-4:2003
English Version

Petroleum and natural gas industries - Specific
requirements for offshore structures - Part 4: Geotechnical
and foundation design considerations (ISO 19901-4:2016)
Industries du pétrole et du gaz naturel - Exigences Erdöl- und Erdgasindustrie - Besondere
spécifiques relatives aux structures en mer - Partie 4: Anforderungen an Offshore-Bauwerke - Teil 4:
Bases conceptuelles des fondations (ISO 19901- Geotechnische und Fundament-Auslegungsmerkmale
4:2016) (ISO 19901-4:2016)
This European Standard was approved by CEN on 2 July 2016.

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, 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: Avenue Marnix 17, B-1000 Brussels
© 2016 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 19901-4:2016 E
worldwide for CEN national Members.

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SIST EN ISO 19901-4:2016
EN ISO 19901-4:2016 (E)
Contents Page
European foreword . 3

2

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SIST EN ISO 19901-4:2016
EN ISO 19901-4:2016 (E)
European foreword
This document (EN ISO 19901-4:2016) has been prepared by Technical Committee ISO/TC 67
"Materials, equipment and offshore structures for petroleum, petrochemical and natural gas industries"
in collaboration with Technical Committee CEN/TC 12 “Materials, equipment and offshore structures
for petroleum, petrochemical and natural gas industries” the secretariat of which is held by NEN
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 February 2017, and conflicting national standards
shall be withdrawn at the latest by February 2017.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent
rights.
This document supersedes EN ISO 19901-4:2003.
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, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 19901-4:2016 has been approved by CEN as EN ISO 19901-4:2016 without any
modification.
3

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SIST EN ISO 19901-4:2016

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SIST EN ISO 19901-4:2016
INTERNATIONAL ISO
STANDARD 19901-4
Second edition
2016-07-15
Petroleum and natural gas
industries — Specific requirements
for offshore structures —
Part 4:
Geotechnical and foundation design
considerations
Industries du pétrole et du gaz naturel — Exigences spécifiques
relatives aux structures en mer —
Partie 4: Bases conceptuelles des fondations
Reference number
ISO 19901-4:2016(E)
©
ISO 2016

---------------------- Page: 7 ----------------------

SIST EN ISO 19901-4:2016
ISO 19901-4:2016(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2016, 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
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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved

---------------------- Page: 8 ----------------------

SIST EN ISO 19901-4:2016
ISO 19901-4:2016(E)

Contents Page
Foreword .v
Introduction .vii
1 Scope . 1
2 Normative references . 1
3  Terms and definitions . 2
4 Symbols and abbreviated terms . 4
4.1 General . 4
4.2 Symbols for shallow foundations design . 4
4.3 Symbols for pile foundations design . 7
4.4 Symbols for soil-structure interaction for auxiliary subsea structures, risers
and flowlines .10
4.5 Symbols for design of anchors for stationkeeping systems .11
4.6 Abbreviated terms .12
5  General requirements .13
5.1 General .13
5.2 Design cases and safety factors .14
5.3 Characteristic values of soil properties .14
5.4 Testing and instrumentation .15
6  Geotechnical data acquisition and identification of hazards .16
6.1 General .16
6.2 Shallow geophysical investigation .16
6.3 Geological modelling and identification of hazards .17
6.3.1 General.17
6.3.2 Earthquakes .17
6.3.3 Fault planes .17
6.3.4 Seafloor instability .17
6.3.5 Scour and sediment mobility .18
6.3.6 Shallow gas .18
6.3.7 Seabed subsidence .18
6.4 Carbonate soils .19
7 Design of shallow foundations .19
7.1 General .19
7.2 Principles .20
7.2.1 General principles .20
7.2.2 Sign conventions, nomenclature and action reference point .21
7.2.3 Action transfer .21
7.2.4 Idealization of foundation area and the effective area concept .21
7.3 Acceptance criteria and design considerations .22
7.3.1 Action and material factors .22
7.3.2 Use in design . . .22
7.3.3 Special cases .23
7.3.4 Additional design considerations .24
7.3.5 Alternative method of design based on yield surfaces .26
7.3.6 Selection of soil parameter values for design .27
7.4 Stability of shallow foundations .27
7.4.1 Assessment of bearing capacity .27
7.4.2 Assessment of sliding capacity .29
7.4.3 Assessment of torsional capacity .31
7.5 Serviceability (displacements and rotations) .31
7.5.1 General.31
7.5.2 Displacement under static loading.31
7.5.3 Displacement under dynamic and cyclic actions .34
© ISO 2016 – All rights reserved iii

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SIST EN ISO 19901-4:2016
ISO 19901-4:2016(E)

7.5.4 Other contributors to foundation settlement .34
7.6 Other design considerations .34
7.6.1 Hydraulic stability .34
7.6.2 Installation, retrieval and removal .34
8 Pile foundation design .35
8.1 Pile capacity for axial compression .35
8.1.1 General.35
8.1.2 Axial pile capacity .36
8.1.3 Skin friction and end bearing in cohesive soils .37
8.1.4 Skin friction and end bearing in cohesionless soils .38
8.1.5 Skin friction and end bearing of grouted piles in rock .40
8.2 Pile capacity for axial tension .41
8.3 Axial pile performance .41
8.3.1 Static axial behaviour of piles .41
8.3.2 Cyclic axial behaviour of piles .41
8.4 Soil reaction for piles under axial compression .41
8.4.1 Axial shear transfer t–z curves .41
8.4.2 End bearing resistance–displacement, Q–z, curve .42
8.5 Soil reaction for piles under lateral actions .44
8.5.1 General.44
8.5.2 Lateral capacity for soft clay .45
8.5.3 Lateral soil resistance–displacement p−y curves for soft clay .45
8.5.4 Lateral capacity for stiff clay .45
8.5.5 Lateral soil resistance–displacement p–y curves for stiff clay .46
8.5.6 Lateral capacity for sand .47
8.5.7 Lateral soil resistance – displacement p–y curves for sand .48
8.6 Pile group behaviour .49
8.6.1 General.49
8.6.2 Axial behaviour .49
8.6.3 Lateral behaviour .50
9 Pile installation assessment .50
9.1 General .50
9.2 Drivability studies .51
9.3 Obtaining required pile penetration .51
9.4 Driven pile refusal .52
9.5 Pile refusal remedial measures .52
9.5.1 Review of hammer performance .52
9.5.2 Re-evaluation of design penetration .52
9.5.3 Modifications to piling procedures .52
9.6 Selection of pile hammer and stresses during driving .53
9.7 Use of hydraulic hammers .53
9.8 Drilled and grouted piles .54
9.9 Belled piles .55
9.10 Grouting pile-to-sleeve connections .55
9.11 Pile installation data .55
9.12 Installation of conductors and shallow well drilling .55
10  Soil-structure interaction for auxiliary subsea structures, risers and flowlines .56
11  Design of anchors for floating structures .56
Annex A (informative) Additional information and guidance .57
Bibliography .175
iv © ISO 2016 – All rights reserved

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SIST EN ISO 19901-4:2016
ISO 19901-4:2016(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 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.
The committee responsible for this document is ISO/TC 67, Materials, equipment and offshore structures
for the petroleum, petrochemical and natural gas industries, Subcommittee SC 7, Offshore structures.
This second edition cancels and replaces the first edition (ISO 19901-4:2003), which has been
technically revised.
ISO 19901 consists of the following parts, under the general title Petroleum and natural gas industries —
Specific requirements for offshore structures:
— Part 1: Metocean design and operating considerations
— Part 2: Seismic design procedures and criteria
— Part 3: Topsides structure
— Part 4: Geotechnical and foundation design considerations
— Part 5: Weight control during engineering and construction
— Part 6: Marine operations
— Part 7: Stationkeeping systems for floating offshore structures and mobile offshore units
— Part 8: Marine soil investigations
The following part is under preparation:
— Part 9: Structural integrity management
ISO 19901 is one of a series of standards for offshore structures. The full series consists of the following
International Standards which are relevant to offshore structures for the petroleum and natural gas
industries:
— ISO 19900, Petroleum and natural gas industries — General requirements for offshore structures
© ISO 2016 – All rights reserved v

---------------------- Page: 11 ----------------------

SIST EN ISO 19901-4:2016
ISO 19901-4:2016(E)

— ISO 19901 (all parts), Petroleum and natural gas industries — Specific requirements for offshore
structures
— ISO 19902, Petroleum and natural gas industries — Fixed steel offshore structures
— ISO 19903, Petroleum and natural gas industries — Fixed concrete offshore structures
— ISO 19904, Petroleum and natural gas industries — Floating offshore structures
— ISO 19905-1, Petroleum and natural gas industries — Site-specific assessment of mobile offshore
units — Part 1: Jack-ups
— ISO/TR 19905-2, Petroleum and natural gas industries — Site-specific assessment of mobile offshore
units — Part 2: Jack-ups commentary and detailed sample calculation
— ISO 19905-3, Petroleum and natural gas industries — Site specific assessment of mobile offshore
units — Part 3: Floating units (under preparation)
— ISO 19906, Petroleum and natural gas industries — Arctic offshore structures
Other ISO standards can have implications for the geotechnical design of foundations for offshore
structures, in particular:
— ISO 13623 (all parts), Petroleum and natural gas industries — Pipeline transportation systems
— ISO 13628 (all parts), Petroleum and natural gas industries — Design and operation of subsea
production systems
vi © ISO 2016 – All rights reserved

---------------------- Page: 12 ----------------------

SIST EN ISO 19901-4:2016
ISO 19901-4:2016(E)

Introduction
The International Standards for offshore structures, ISO 19900 to ISO 19906, constitute a common basis
covering those aspects that address design requirements and assessments of all offshore structures
used by the petroleum and natural gas industries worldwide. Through their application, the intention
is to achieve reliability levels appro
...

SLOVENSKI STANDARD
oSIST prEN ISO 19901-4:2015
01-marec-2015
,QGXVWULMD]DSUHGHODYRQDIWHLQ]HPHOMVNHJDSOLQD3RVHEQH]DKWHYH]DQDIWQH
SORãþDGLGHO2EUDYQDYDJHRWHKQLþQLKLQWHPHOMQLK]QDþLOQRVWLSURMHNWLUDQMD
,62',6
Petroleum and natural gas industries - Specific requirements for offshore structures -
Part 4: Geotechnical and foundation design considerations (ISO/DIS 19901-4:2015)
Erdöl- und Erdgasindustrie - Besondere Anforderungen an Offshore-Bauwerke - Teil 4:
Geotechnische und Fundament-Auslegungsmerkmale (ISO/DIS 19901-4:2015)
Industries du pétrole et du gaz naturel - Exigences spécifiques relatives aux structures
en mer - Partie 4: Bases conceptuelles des fondations (ISO/DIS 19901-4:2015)
Ta slovenski standard je istoveten z: prEN ISO 19901-4
ICS:
75.180.10 Oprema za raziskovanje in Exploratory and extraction
odkopavanje equipment
93.020 Zemeljska dela. Izkopavanja. Earthworks. Excavations.
Gradnja temeljev. Dela pod Foundation construction.
zemljo Underground works
oSIST prEN ISO 19901-4:2015 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN ISO 19901-4:2015

---------------------- Page: 2 ----------------------
oSIST prEN ISO 19901-4:2015
DRAFT INTERNATIONAL STANDARD
ISO/DIS 19901-4
ISO/TC 67/SC 7 Secretariat: BSI
Voting begins on: Voting terminates on:
2015-01-22 2015-04-22
Petroleum and natural gas industries — Specific
requirements for offshore structures —
Part 4:
Geotechnical and foundation design considerations
Industries du pétrole et du gaz naturel — Exigences spécifiques relatives aux structures en mer —
Partie 4: Bases conceptuelles des fondations
ICS: 75.180.10
ISO/CEN PARALLEL PROCESSING
This draft has been developed within the International Organization for
Standardization (ISO), and processed under the ISO lead mode of collaboration
as defined in the Vienna Agreement.
This draft is hereby submitted to the ISO member bodies and to the CEN member
bodies for a parallel five month enquiry.
Should this draft be accepted, a final draft, established on the basis of comments
received, will be submitted to a parallel two-month approval vote in ISO and
THIS DOCUMENT IS A DRAFT CIRCULATED
formal vote in CEN.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
To expedite distribution, this document is circulated as received from the
IN ADDITION TO THEIR EVALUATION AS
committee secretariat. ISO Central Secretariat work of editing and text
BEING ACCEPTABLE FOR INDUSTRIAL,
composition will be undertaken at publication stage.
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 19901-4:2014(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 2014

---------------------- Page: 3 ----------------------
oSIST prEN ISO 19901-4:2015
ISO/DIS 19901-4:2014(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2014
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
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
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2014 – All rights reserved

---------------------- Page: 4 ----------------------
oSIST prEN ISO 19901-4:2015
ISO/DIS 19901-4
Contents
Foreword . vii
Introduction . ix
1 Scope .1
2 Normative references .1
3 Terms and definitions .2
4 Symbols and abbreviated terms .4
4.1 General .4
4.2 Symbols for shallow foundations design .4
4.3 Symbols for pile foundations design.7
4.4 Symbols for soil–structure interaction for auxiliary subsea structures, risers and
flowlines . 10
4.5 Symbols for design of anchors for mooring systems . 11
4.6 Abbreviated terms . 12
5 General requirements . 13
5.1 General . 13
5.2 Design situations and safety factors . 14
5.2.1 Design cases for fixed steel structures . 14
5.2.2 Design cases for anchors for stationkeeping systems for floating structures . 14
5.3 Characteristic values of soil properties . 14
5.4 Testing and instrumentation . 15
6 Geotechnical data acquisition and identification of hazards . 15
6.1 General . 15
6.2 Shallow geophysical investigation . 16
6.3 Geological modelling and identification of hazards . 17
6.3.1 General . 17
6.3.2 Earthquakes . 17
6.3.3 Fault planes . 17
6.3.4 Seafloor instability . 17
6.3.5 Scour and sediment mobility . 18
6.3.6 Shallow gas . 18
6.3.7 Seabed subsidence . 18
6.4 Geotechnical investigation . 19
6.5 Carbonate soils . 19
7 Design of shallow foundations . 19
7.1 General . 19
7.2 Principles . 20
7.2.1 General principles. 20
7.2.2 Sign conventions, nomenclature and action reference point . 20
7.2.3 Action transfer . 21
7.2.4 Idealization of foundation area and the effective width concept . 21
7.3 Acceptance criteria and design considerations . 21
7.3.1 Action and material factors . 21
7.3.2 Use in design . 22
7.3.3 Special cases . 24
7.3.4 Additional design considerations . 24
7.3.5 Alternative method of design based on yield surfaces . 26
7.3.6 Selection of soil parameter values for design . 27
7.4 Stability of shallow foundations . 27
7.4.1 Assessment of bearing capacity . 27
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7.4.2 Assessment of sliding capacity . 29
7.4.3 Assessment of torsional capacity . 30
7.5 Serviceability (displacements and rotations) . 31
7.5.1 General . 31
7.5.2 Displacement under static loading . 31
7.5.3 Displacement under cyclic (dynamic) loading . 33
7.5.4 Other contributors to foundation settlement. 34
7.6 Other design considerations . 34
7.6.1 Hydraulic stability . 34
7.6.2 Installation, retrieval and removal . 34
8 Pile foundation design . 35
8.1 Pile capacity for axial compression . 35
8.1.1 General . 35
8.1.2 Axial pile capacity . 36
8.1.3 Skin friction and end bearing in cohesive soils . 36
8.1.4 Skin friction and end bearing in cohesionless soils . 38
8.1.5 Skin friction and end bearing of grouted piles in rock . 40
8.2 Pile capacity for axial tension . 41
8.3 Axial pile performance . 41
8.3.1 Static axial behaviour of piles . 41
8.3.2 Cyclic axial behaviour of piles . 41
8.4 Soil reaction for piles under axial compression . 41
8.4.1 Axial shear transfer t–z curves . 41
8.4.2 End bearing resistance–displacement, Q–z, curve . 42
8.5 Soil reaction for piles under lateral actions . 44
8.5.1 General . 44
8.5.2 Lateral capacity for soft clay . 45
8.5.3 Lateral soil resistance–displacement p−y curves for soft clay . 45
8.5.4 Representative lateral capacity for stiff clay . 45
8.5.5 Lateral soil resistance–displacement p–y curves for stiff clay . 45
8.5.6 Representative lateral capacity for sand . 46
8.5.7 Lateral soil resistance – displacement p–y curves for sand . 47
8.6 Pile group behaviour . 48
8.6.1 General . 48
8.6.2 Axial behaviour . 48
8.6.3 Lateral behaviour . 48
8.6.4 Resistance factors . 49
9 Pile installation assessment . 49
9.1 General . 49
9.2 Drivability studies . 49
9.3 Obtaining required pile penetration . 50
9.4 Driven pile refusal . 50
9.5 Pile refusal remedial measures . 51
9.5.1 Review of hammer performance . 51
9.5.2 Re-evaluation of design penetration . 51
9.5.3 Modifications to piling procedures . 51
9.6 Selection of pile hammer and stresses during driving . 52
9.7 Use of hydraulic hammers. 52
9.8 Drilled and grouted piles . 53
9.9 Belled piles . 53
9.10 Grouting pile-to-sleeve connections . 54
9.11 Pile installation data . 54
9.12 Installation of conductors and shallow well drilling . 55
10 Soil–structure interaction for auxiliary subsea structures, risers and flowlines . 55
11 Design of anchors for floating structures . 56
Annex A (informative) Additional information and guidance . 57
A.1 Scope . 57
A.2 Normative references . 57
A.3 Terms and definitions . 57
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A.4 Symbols and abbreviated terms . 57
A.5 General requirements . 57
A.5.1 General . 57
A.5.2 Design situations and safety factors . 57
A.5.3 Characteristic values of soil properties . 59
A.5.4 Testing and instrumentation . 59
A.6 Geotechnical data acquisition and identification of hazards . 59
A.6.1 General . 59
A.6.2 Shallow geophysical investigation . 59
A.6.3 Geological modelling and identification of hazards . 60
A.6.4 Geotechnical investigation . 62
A.6.5 Carbonate soils . 62
A.7 Design of shallow foundations . 64
A.7.1 General . 64
A.7.2 Principles . 64
A.7.3 Acceptance criteria and design considerations . 69
A.7.4 Stability of shallow foundations . 75
A.7.5 Serviceability (displacements and rotations) . 82
A.7.6 Other design considerations . 83
A.8 Pile foundation design . 85
A.8.1 Pile capacity for axial compression . 85
A.8.2 Pile capacity for axial tension . 99
A.8.3 Axial pile performance . 99
A.8.4 Soil reaction for piles under axial compression . 102
A.8.5 Soil reaction for piles under lateral actions . 103
A.8.6 Pile group behaviour . 104
A.9 Pile installation assessment . 105
A.9.1 General . 105
A.9.2 Drivability studies . 105
A.9.3 Obtaining required pile penetration . 105
A.9.4 Driven pile refusal . 105
A.9.5 Driven pile refusal measures . 106
A.9.6 Selection of pile hammer and stresses during driving . 106
A.9.7 Use of hydraulic hammers . 106
A.9.8 Drilled and grouted piles . 106
A.9.9 Belled piles . 106
A.9.10 Grouting pile-to-sleeve connections . 106
A.9.11 Pile installation data . 106
A.9.12 Installation of conductors and shallow well drilling . 107
A.10 Soil–structure interaction for auxiliary subsea structures, risers and flowlines . 107
A.10.1 General . 107
A.10.2 Geotechnical investigation . 107
A.10.3 Foundations for manifolds and subsea production structures . 108
A.10.4 Geotechnical design for steel catenary risers . 108
A.10.5 Geotechnical design for top tension risers . 115
A.10.6 Foundation design for riser towers . 119
A.10.7 Geotechnical design for flowlines and pipelines . 121
A.11 Design of anchors for floating structures . 125
A.11.1 General . 125
A.11.2 Geotechnical investigation . 125
A.11.3 Anchor types . 126
A.11.4 Geotechnical design of drag anchors . 133
A.11.5 Geotechnical design of anchor piles . 143
A.11.6 Geotechnical design of plate anchors . 157
A.11.7 Geotechnical design of other types of anchors . 162
A.11.8 Test loading of anchors . 167
Bibliography . 170

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oSIST prEN ISO 19901-4:2015
ISO/DIS 19901-4
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 identifie
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