Moscow State Construction University
Moscow, 9 & 10 December 2010
General presentation of Eurocode 7
‘Geotechnical design’
Roger FRANK
Université Paris-Est
Ecole nationale des ponts et chaussées
Navier-CERMES
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
1. Introduction
2. Contents of Eurocode 7 - Parts 1 & 2
3. Some aspects of Eurocode 7-1
Characteristic values
ULS Design Approaches
SLS –Serviceability limit states
4. Liaisons. Associated standards
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
STRUCTURAL EUROCODES
EN 1990
Basis of
Structural design
Actions on
structures
EN 1991
EN 1992 EN 1993 EN 1994
«Material »
resistance
EN 1995 EN 1996 EN 1999
EN 1997
EN 1998
Geotechnical
and seismic
design
R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
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Eurocode 7 – Geotechnical design

EN 1997-1 (2004) : General rules

EN 1997-2 (2007) : Ground investigation
and testing
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
2. Contents of Eurocode 7 –
Parts 1 & 2
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
Contents of Part 1 (EN 1997-1)
Section 1 General
 Section 2 Basis of
geotechnical design
 Section 3 Geotechnical
data
 Section 4 Supervision of
construction, monitoring
and maintenance
 Section 5 Fill, dewatering,
ground improvement and
reinforcement

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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
 Section
6 Spread foundations
 Section 7 Pile foundations
 Section 8 Anchorages
 Section 9 Retaining structures
 Section 10 Hydraulic failure
 Section 11 Site stability
 Section 12 Embankments
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
Informative annexes
Annexes D & E : Bearing capacity of
foundations
R/A' = c'  Nc  bc  sc  ic +
q'  Nq  bq  sq  iq +
0,5  '  B ' N  b  s  i
R /A' = v0 + k  p*le
Annexe F : Settlement of foundations
s = p  b  f / Em
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
Contents of Part 2 (EN 1997-2)
Section 1 General
Section 2 Planning and
reporting of ground
investigations
 Section 3 Drilling, sampling
and gw measurements
 Section 4 Field tests in soils
and rocks
 Section 5 Laboratory tests on
soils and rocks
 Section 6 Ground
investigation report
> Also a number of Informative annexes


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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
EN 1997- 2
Field tests in soils and rocks (Section 4)
Clauses on :
CPT(U), PMT, FDT, SPT, DP, WST, FVT,
DMT, PLT

Objectives, specific requirements, evaluation
of test results, use of test results and derived
values
Annexes with examples on use of results and
derived values for geotechnical design
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
EN 1997- 2
Laboratory tests on soils and rocks (Section 5)











preparation of soil specimens for testing
preparation of rock specimens for testing
tests for classification, identification and
description of soils
chemical testing of soils and groundwater
strength index testing of soils
strength testing of soils
compressibility and deformation testing of
soils
compaction testing of soils
permeability testing of soils
tests for classification of rocks
swelling testing of rock material
strength testing of rock material
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
Results of test standards
EN 1997-2 Annex A
Field test
Test results
CPT/CPTU
Dynamic probing
SPT
Pressuremeters (PMT)
qc , fs , Rf (CPT) / qt , fs , u (CPTU)
N10 (DPL, DPM, DPH); N10 or N20 (DPSH)
N , Er (SPT), soil description
EM ,,pf , plM (MPM); expansion curve (all)
Flexible dilatometer (FDT)
Field vane test (FVT)
Weight sounding test (WST)
Plate loading test
Flta dilatometer test
EFDT, deformation curve
cfv , crv , torque-rotation curve
continuous record of penetration depth or Nb
pu
P0 , p1 , EDMT , IDMT , KDMT (DMT)
Laboratory tests
Soils: w ; r ; rs ; grain size distribution curve ; wP , wL ; emax , emin , ID ; COM ;
CCaCO3 ; CSO42-, CSO32- ; Ccl ; pH ; compressibility, consolidation, creep curves,
Eoed, ’p or Cs, Cc, ’p, Ca ; cu (lab vane) ; cu (fall cone) ; qu ; cu (UU) ; -e and u
curves, -paths, Mohr circles ; c’, ’ or cu, cu=f(’c), E’ or Eu ; -u curve, t-
diagram, c’, ’, residual parameters ; ICBR ; k (direct lab, field or oedometer)
Rocks: w ; r and n ; swelling results ; c, E and n ; Is50 ; -u curve, Mohr
diagram, c’, ’, res par ; T ; -e curve, -paths, Mohr circles ; c’, ’, E and n
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
Geotechnical properties
Type of test
F= field L= laboratory
F1
Correlations
Test results and
derived values
F2
L1
C1
1
2
L2
C2
3
4
EN 1997 -2
EN 1997 -1
Information
from other
sources on
the site, the
soils and
rocks and
the project
Cautious selection
Geotechnical model and characteristic
value of geotechnical properties
Application of
partial factors
Design values of geotechnical
properties
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
3. Some aspects of Eurocode 7-1

Characteristic values
and design values

ULS Design Approaches

SLS and deformations of structures
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
Characteristic value
of geotechnical parameters
P The characteristic value of a geotechnical
parameter shall be selected as a cautious
estimate of the value affecting the occurrence of
the limit state.
If statistical methods are used, the characteristic
value should be derived such that the calculated
probability of a worse value governing the
occurrence of the limit state under consideration
is not greater than 5%.
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
Design values of geotechnical parameters
Design value of a parameter : Xd = Xk / M
Design values of actions and resistances
fulfilling for STR/GEO ULS :
Ed = E {F.Fk }
Ed  Rd
and Rd = R { Xk / M }
(= “at the source”)
or
Ed = E.E { Fk }
and Rd = R { Xk } / R
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
Ultimate limit states – Eurocode 7-1
EQU
: loss of equilibrium of the structure
STR : internal failure or excessive deformation
of the structure or structural elements
GEO : failure or excessive deformation of the
ground
UPL : loss of equilibrium due to uplift by water
pressure (buoyancy) or other vertical actions
HYD : hydraulic heave, internal erosion and
piping caused by hydraulic gradients
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
EN1990 - Ultimate limit states
EQU and STR/GEO
Ed< Rd
J.A Calgaro
R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
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STR/GEO : persistent and transient situations
Approaches
1
2
3
Combinations
A1 “+” M1 “+” R1
&
A2 “+” M2 “+” R1
Or A2 “+” M1 or M2“+” R4
A1 “+” M1 “+” R2
A1 or A2 “+” M2 “+” R3
Action ( F)
Symbol
Set A1
Set A2
Permanent
Unfavourable
Favourable
Variable
Unfavourable
Favourable
G
G
1,35
1,00
1,00
1,00
Q
Q
1,50
0
1,30
0
Soil parameter ( M )
Angle of shearing
resistance
Effective cohesion
Resistance ( R )
Bearing capacity
Sliding
Symbol
Rv
Rh
Symbol
Set M1
Set M2
’
1,00
1,25
Undrained shear strength
Unconfined strength
c’
cu
1,00
1,00
1,25
1,40
qu
1,00
1,40
Weight density

1,00
1,00
Set R1
1,00
1,00
Set R2
1,4
1,1
Set R3
1,00
1,00
 R for Spread
foundations
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
Ultimate limit states (UPL)
Examples of situations where uplift
might be critical
Gdst;d + Qdst;d  Gstb;d + Rd
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
Ultimate limit states (HYD)
Heave due
to
seepage
of water
Water
low
permeability
soil
Permeable
subsoil
piezometric level in
the permeable
subsoil
Piping
Sand
udst;d  stb;d
udst;d  ´stb;d
Example of situation where heave or piping might be critical
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
Accidental situations
Actions : all values of F (and M) = 1.0
Resistances :
all values of R (and M) depend
on the particular accident
Seismic situations : see Eurocode 8-5
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
Verifications of ULS
Ultimate limit states of static equilibrium (EQU) :
Ed,dst  Ed,stb
Ultimate limit states of resistance (STR/GEO) :
Ed  Rd
Ultimate limit state of uplift (UPL) :
Gdst;d + Qdst;d  Gstb;d + Rd
Ultimate limit state of hydraulic failure (HYD) :
udst;d  stb;d or Sdst;d  G´stb;d
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
EN1990 - Serviceability limit states
SLS
Verifications :
Ed  Cd
Cd = limiting design value of the relevant
serviceability criterion
Ed = design value of the effects of actions
specified in the serviceability criterion, determined
on the basis of the relevant combination
all F and M = 1.0
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
Movements and deformations of structures



settlement s,
differential settlement
s, rotation  and
angular strain a
relative deflection 
and deflection ratio /L
 and relative rotation
(angular distortion) 
(after Burland and Wroth,
1975)
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
Foundations of buildings (Eurocode 7, 1994)
*
*
•
Serviceability limit states (SLS) : max ≈ 1/500
Ultimate limit states (ULS)
:
max ≈ 1/150
smax ≈ 50 mm
smax ≈ 20 mm
Foundations of bridges
Moulton (1986) for 314 bridges in the US and Canada :
*
max ≈ 1/250
(continuous deck bridges)
and max ≈ 1/200
(simply supported spans)
* sHmax ≈ 40 mm
In France, in practice :
ULS : max ≈ 1/250
SLS : max ≈ 1/1000 à 1/500
R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
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4. Liaisons. Associated standards





EN 1990: Eurocode : Basis of structural
design
EC 8 - 5 : Earthquake resistance design:
foundations, retaining structures
and geotechnical aspects
TC 288 : Execution of geotechnical works
TC 341 : Geotechnical investigation and
testing
ISO/TC 182 Geotechnics :
SC1 Soil and rock classification
SC3 Foundations, retaining structures &
earthworks
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
Execution of geotechnical works – TC 288
(April 2010)
Published standards
EN 1536
: Bored piles (1999), 79 p
EN 1538
: Diaphragm walls (2000), 46 p
EN 1537
: Ground anchors (2000), 56 p
EN 12063
: Sheet piling (1999), 76 p
EN 12699
: Displacement piles (2001), 45 p
EN 12715
: Grouting (2000), 49 p
EN 12716
: Jet-grouting (2001), 36 p
EN 14199
: Micropiling (2005), 45 p
EN 14475
prEN 14490
: Reinforcement of fills (2007), 49
: Soil Nailing (2010)
EN 14679
: Deep mixing (2005), 49 p
EN 14731
: Deep vibration (2006), 22 p
EN 15237
: Deep vertical drainage(2007), 52 p
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
Investigation and laboratory testing - TC 341
Standards (4) – Short title (date of publication)
EN ISO 14688-1
: Identification of soils (2002-08)
EN ISO 14688-2
: Classification of soils (2004-07)
EN ISO 14689-1
: Identification of rock (2003-12)
EN ISO 22475-1
: Sampling - principles (2006-9)
Technical specifications (12)
TS 22475-2 : Sampling - qualification criteria (2006-9)
TS 22475-3 : Sampling – conformity assessment (2007-12)
TS 17892-1 to 12 (2004-11) to be replaced by ENs:
Water content, Density of fine grained soils,
Density of solid particles, Particle size distribution,
Oedometer test, Fall cone test,
Unconfined compression test,
Unconsolidated triaxial test,
Consolidated triaxial test,
Direct shear test,
Permeability test,
Atterberg Limits
R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
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Field (in situ) testing - TC 341
Published standards (4) – Short title (date of publication)
EN ISO 22476-2 : Dynamic probing (2005-01)
EN ISO 22476-3 : Standard penetration test (2005-01)
Published technical specifications (2)
TS 22476-10 : Weight sounding test (2005-05)
TS 22476-11 : Flat dilatometer test (2005-05)
SPT
WST
DMT
DP
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
Conclusions
Eurocode 7 is :
- a tool to help European geotechnical
engineers speak the same language
- a necessary tool for the dialogue
between geotechnical engineers and
structural engineers
Eurocode 7 helps promoting research
- it stimulates questions on present
geotechnical practice from ground
investigation to design models
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
and to really conclude :

It should be considered that knowledge
of the ground conditions depends on
the extent and quality of the
geotechnical investigations. Such
knowledge and the control of
workmanship are usually more
significant to fulfilling the fundamental
requirements than is precision in the
calculation models and partial factors.
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010
Thank you for your attention !
Acknowledgments :
Ministry of Regional Development of Russian Federation
Russian Academy of Construction and Architecture
Moscow State Construction University
Design Buro "Spetsproekt" Ltd
and
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R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010