R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010 1...

R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 20101

General presentation of Eurocode 7 ‘Geotechnical design’

Roger FRANK

Université Paris-EstEcole nationale des ponts et chaussées

Navier-CERMES

Moscow State Construction UniversityMoscow, 9 & 10 December 2010


1. Introduction

2. Contents of Eurocode 7 - Parts 1 & 2

3. Some aspects of Eurocode 7-1Characteristic values

ULS Design ApproachesSLS –Serviceability limit states

4. Liaisons. Associated standards


EN 1990EN 1990

EN 1991EN 1991

EN 1992EN 1992 EN 1993EN 1993 EN 1994EN 1994

EN 1995EN 1995 EN 1996EN 1996 EN 1999EN 1999

Basis of Basis of Structural designStructural design

Actions onActions onstructuresstructures

«Material » «Material » resistanceresistance

EN 1997EN 1997 EN 1998EN 1998 GeotechnicalGeotechnicaland seismicand seismic

designdesign

STRUCTURAL EUROCODES


EN 1997-1 (2004) :EN 1997-1 (2004) : General rulesGeneral rules

EN 1997-2 (2007) :EN 1997-2 (2007) : Ground investigation Ground investigation and testing and testing

Eurocode 7 – Geotechnical design


2.2. Contents of Eurocode 7 – Contents of Eurocode 7 – Parts 1 & 2Parts 1 & 2


Contents of Part 1 (EN 1997-1)Contents of Part 1 (EN 1997-1)

Section 1 GeneralSection 2 Basis of

geotechnical designSection 3 Geotechnical

dataSection 4 Supervision

of construction, monitoring and maintenance

Section 5 Fill, dewatering, ground improvement and reinforcement


Section 6 Spread foundationsSection 7 Pile foundationsSection 8 Anchorages Section 9 Retaining

structuresSection 10 Hydraulic failureSection 11 Site stability Section 12 Embankments


Informative annexes 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


Contents of Part 2 (EN 1997-2)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 annexesInformative annexes


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

EN 1997- 2EN 1997- 2 Field tests in soils and rocks Field tests in soils and rocks (Section 4)(Section 4)


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

EN 1997- 2EN 1997- 2Laboratory tests on soils and rocks Laboratory tests on soils and rocks (Section 5)(Section 5)


Results of test standardsEN 1997-2 Annex A

Field test Test resultsCPT/CPTU qc , fs , Rf (CPT) / qt , fs , u (CPTU)

Dynamic probing N10 (DPL, DPM, DPH); N10 or N20 (DPSH)

SPT N , Er (SPT), soil description

Pressuremeters (PMT) EM ,,pf , plM (MPM); expansion curve (all)

Flexible dilatometer (FDT) EFDT, deformation curve

Field vane test (FVT) cfv , crv , torque-rotation curve

Weight sounding test (WST) continuous record of penetration depth or Nb

Plate loading test pu

Flta dilatometer test P0 , p1 , EDMT , IDMT , KDMT (DMT)

Laboratory testsSoils: w ; s ; grain size distribution curve ; wP , wL ; emax , emin , ID ; COM ; CCaCO3 ; CSO4

2-, CSO32- ; Ccl ; pH ; compressibility, consolidation, creep curves,

Eoed, ’p or Cs, Cc, ’p, C ; cu (lab vane) ; cu (fall cone) ; qu ; cu (UU) ; - and u curves, paths, Mohr circles ; c’, ’ or cu, cu=f(’c), E’ or Eu ; -u curve, - diagram, c’, ’, residual parameters ; ICBR ; k (direct lab, field or oedometer)

Rocks: w ; and n ; swelling results ; c, E and ; Is50 ; -u curve, Mohr diagram, c’, ’, res par ; T ; - curve, paths, Mohr circles ; c’, ’, E and


Type of testF= field L= laboratory

Correlations

Test results and derived values

1 2 3 4

F 1 F 2 L 1 L 2

C1

C2

Cautious selection

Geotechnical model and characteristic value of geotechnical properties

Design values of geotechnical properties

Application of partial factors

Information from other sources on the site, the

soils and rocks and the project

EN 1997 -1

EN 1997 -2

Geotechnical properties


3. Some aspects of Eurocode 7-13. Some aspects of Eurocode 7-1

Characteristic values

and design values

ULS Design ApproachesULS Design Approaches

SLS and deformations of SLS and deformations of structuresstructures


Characteristic value Characteristic value of geotechnical parametersof geotechnical parameters

P The characteristic valuecharacteristic 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%.


Design value of a parameter : Xd = Xk / M

Design values of actions and resistancesDesign values of actions and resistances

fulfilling for STR/GEO ULS : Ed Rd

Ed = E {F.Fk } and Rd = R { Xk / M }

(= “at the source”)

or Ed = E.E { Fk } and Rd = R { Xk } / R

Design values of geotechnical parameters Design values of geotechnical parameters


Ultimate limit states – Eurocode 7-1Ultimate limit states – Eurocode 7-1

EQU : loss of equilibrium of the structureSTR : internal failure or excessive deformation of the structure or structural elementsGEO : failure or excessive deformation of the groundUPL : loss of equilibrium due to uplift by water pressure (buoyancy) or other vertical actionsHYD : hydraulic heave, internal erosion and piping caused by hydraulic gradients


EN1990 - Ultimate limit statesEN1990 - Ultimate limit statesEQU and STR/GEOEQU and STR/GEO

J.A CalgaroJ.A CalgaroEEdd< R< Rdd


STR/GEO : persistent and transient situationsSTR/GEO : persistent and transient situations

Action ( F) Symbol Set A1 Set A2PermanentUnfavourableFavourable

G

G

1,351,00

1,001,00

VariableUnfavourableFavourable

Q

Q

1,500

1,300

Soil parameter ( M ) Symbol Set M1 Set M2Angle of shearing

resistance ’1,00 1,25

Effective cohesion c’1,00 1,25

Undrained shear

strength cu1,00 1,40

Unconfined strength qu1,00 1,40

Weight density 1,00 1,00

Approaches Combinations

1 A1 “+” M1 “+” R1&

A2 “+” M2 “+” R1 Or A2 “+” M1 or M2“+” R4

2 A1 “+” M1 “+” R2

3 A1 or A2 “+” M2 “+” R3

Resistance ( R ) Symbol Set R1 Set R2 Set R3Bearing capacity Rv

1,00 1,4 1,00Sliding Rh

1,00 1,1 1,00 R for Spread foundations


Ultimate limit states Ultimate limit states (UPL)(UPL)

Gdst;d + Qdst;d Gstb;d + RdExamples of situations where uplift might be critical


Ultimate limit states Ultimate limit states (HYD)(HYD)

Sand

WaterHeave due to

seepage of water

Permeable subsoil

piezometric level in the permeable subsoil

low permeability soil

Piping

udst;d stb;d

udst;d ´stb;d

Example of situation where heave or piping might be critical


Accidental situationsAccidental situations

Actions : all values of Actions : all values of FF (and (and MM) = 1.0) = 1.0

Resistances : Resistances : all values of all values of RR (and (and MM) depend ) depend

on the particular accident on the particular accident

Seismic situations :Seismic situations : see Eurocode 8-5


Ultimate limit states of static equilibrium Ultimate limit states of static equilibrium (EQU)(EQU) : :EEd,dstd,dst E Ed,stbd,stb

Ultimate limit states of resistance Ultimate limit states of resistance (STR/GEO)(STR/GEO) : : EEdd R Rdd

Ultimate limit state of uplift Ultimate limit state of uplift (UPL)(UPL) : :

GGdst;ddst;d + Q + Qdst;ddst;d G Gstb;dstb;d + R + Rdd

Ultimate limit state of hydraulic failure Ultimate limit state of hydraulic failure (HYD)(HYD) : :

uudst;ddst;d stb;d stb;d or S or Sdst;ddst;d GG´́stb;dstb;d

Verifications of ULSVerifications of ULS


EN1990 - Serviceability limit states EN1990 - Serviceability limit states SLSSLS

Verifications :Verifications :

CCdd = = limiting design value of the relevant limiting design value of the relevant

serviceability criterionserviceability criterion

EEdd = = design value of the effects of actions design value of the effects of actions

specified in the serviceability criterion, determined specified in the serviceability criterion, determined on the basis of the relevant combinationon the basis of the relevant combination

all all FF and and MM = 1.0 = 1.0

EEdd C Cdd


settlement s, differential settlement s, rotation and angular strain

relative deflection and deflection ratio /L

and relative rotation (angular distortion)

(after Burland and Wroth, 1975)

Movements and deformations of Movements and deformations of structuresstructures


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 ≈ 1/250SLS : max ≈ 1/1000 à 1/500


4. Liaisons. Associated standards4. 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


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 : Reinforcement of fills (2007), 49 prEN 14490 : 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

Execution of geotechnical works – TC 288 Execution of geotechnical works – TC 288 (April 2010)(April 2010)


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

Investigation and laboratory testing - TC 341TC 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)

DP

DMTWSTSPT

Field (in situ) testing - TC 341TC 341


ConclusionsConclusions

- a tool to help European geotechnical engineers speak the same language

- a necessary tool for the dialogue between geotechnical engineers and structural engineers

Eurocode 7Eurocode 7 helps promoting research

- it stimulates questions on present geotechnical practice from ground investigation to design models

Eurocode 7 Eurocode 7 is :is :


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.


Thank you for your attention !Thank you for your attention !

Acknowledgments :

andMinistry of Regional Development of Russian Federation

Russian Academy of Construction and ArchitectureMoscow State Construction University

Design Buro "Spetsproekt" Ltd

R Frank- General presentation of Eurocode 7, TAIEX & Moscow State Constr U Workshop, 9-10 Dec 2010 1...

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