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EUROCODES
Background and Applications
“Dissemination of information for training” workshop
18-20 February 2008
Brussels
EN...
Wednesday, February 20 – Palais des Académies
EN 1997 - Eurocode 7: Geotechnical design
Bordet room
9:00-10:00 General pre...
GEOTECHNICAL DESIGN PART 1 GENERAL
RULES
R. Frank
Ecole Nationale des Ponts et Chaussées
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  1. 1. EUROCODES Background and Applications “Dissemination of information for training” workshop 18-20 February 2008 Brussels EN 1997 Eurocode 7: Geotechnical design Organised by European Commission: DG Enterprise and Industry, Joint Research Centre with the support of CEN/TC250, CEN Management Centre and Member States
  2. 2. Wednesday, February 20 – Palais des Académies EN 1997 - Eurocode 7: Geotechnical design Bordet room 9:00-10:00 General presentation of EC 7 Geotechnical design part 1 General rules R. Frank Ecole Nationale des Ponts et Chaussées 10:00-11:00 Section 2: Basis of geotechnical design B. Schuppener Bundesanstalt für Wasserbau 11:00-11:15 Coffee 11:15-12:15 Section 3 Geotechnical data and 6 Spread foundations T. Orr Trinity College Dublin 12:15-14:00 Lunch 14:00-15:00 Section 7 Pile foundations R. Frank Ecole Nationale des Ponts et Chaussées 15:00-16:00 Section 8 Anchorages and Section 9 Retaining structures B. Simpson Arup 16:00-16:15 Coffee 16:15-17:15 Section 10 Hydraulic failure, Section 11 Overall stability and Section 12 Embankments T. Orr Trinity College Dublin 17:15-18:15 Eurocode 7 part 2: Ground investigation and testing B. Schuppener Bundesanstalt für Wasserbau All workshop material will be available at http://eurocodes.jrc.ec.europa.eu
  3. 3. GEOTECHNICAL DESIGN PART 1 GENERAL RULES R. Frank Ecole Nationale des Ponts et Chaussées
  4. 4. Brussels, 18-20 February 2008 – Dissemination of information workshop 1 EUROCODES Background and Applications General presentation of EUROCODE 7 ‘Geotechnical design’ Workshop “Eurocodes: background and applications” Brussels, 18-20 February 2008 Roger FRANK, Professor Ecole nationale des ponts et chaussées, Paris Brussels, 18-20 February 2008 – Dissemination of information workshop 2 EUROCODES Background and Applications 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 Brussels, 18-20 February 2008 – Dissemination of information workshop 3 EUROCODES Background and Applications EN 1990EN 1990 ENEN 19911991 EN 1992EN 1992 EN 1993EN 1993 EN 1994EN 1994 EN 1995EN 1995 EN 1996EN 1996 EN 1999EN 1999 Basis of StructuralBasis of Structural designdesign Actions onActions on structuresstructures ««MaterialMaterial »» resistanceresistance EN 1997EN 1997 EN 1998EN 1998 GeotechnicalGeotechnical andand seismicseismic designdesign STRUCTURAL EUROCODES Brussels, 18-20 February 2008 – Dissemination of information workshop 4 EUROCODES Background and Applications EN 1997EN 1997--1 (2004)1 (2004) :: Part 1Part 1 -- General rulesGeneral rules EN 1997EN 1997--2 (2007)2 (2007) :: Part 2Part 2 -- Ground investigationGround investigation and testingand testing Eurocode 7 – Geotechnical design Brussels, 18-20 February 2008 – Dissemination of information workshop 5 EUROCODES Background and Applications 2. Contents of Eurocode 7 – Parts 1 & 2 Brussels, 18-20 February 2008 – Dissemination of information workshop 6 EUROCODES Background and Applications 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
  5. 5. Brussels, 18-20 February 2008 – Dissemination of information workshop 7 EUROCODES Background and Applications 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 Contents of Part 1 (cntd) Brussels, 18-20 February 2008 – Dissemination of information workshop 8 EUROCODES Background and Applications Informative annexes Annexes D & E : Bearing capacity of foundations R/A' = c' × Nc × bc × sc × ic + q' × Nq × bq × sq × iq + 0,5 × γ' × B '× Nγ × bγ × sγ × iγ R /A' = σv0 + k × p*le Annex C Active earth pressure Annex C – Passive earth pressure Annex F : Settlement of foundations s = p × b × f / Em Brussels, 18-20 February 2008 – Dissemination of information workshop 9 EUROCODES Background and Applications Part 2 (EN 1997-2 ): Geotechnical design - Ground investigation and testing Laboratory and field tests : * essential requirements for the equipment and tests procedures * essential requirements for the reporting and the presentation of results * interpretation of test results and derived values They are NOT test standards see TC 341 Brussels, 18-20 February 2008 – Dissemination of information workshop 10 EUROCODES Background and Applications 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 Brussels, 18-20 February 2008 – Dissemination of information workshop 11 EUROCODES Background and Applications 3. Some aspects of Eurocode 7-1 Characteristic values and design values ULS Design ApproachesULS Design Approaches SLS and deformations of structuresSLS and deformations of structures Brussels, 18-20 February 2008 – Dissemination of information workshop 12 EUROCODES Background and Applications Type of test F= field L= laboratory Correlations Test results and derived values 1 2 3 4 F 1 F 2 L 1 L 2 C1 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 C1 C2 Geotechnical properties
  6. 6. Brussels, 18-20 February 2008 – Dissemination of information workshop 13 EUROCODES Background and Applications Characteristic value of 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%. Brussels, 18-20 February 2008 – Dissemination of information workshop 14 EUROCODES Background and Applications Design value of a parameter : Xd = Xk / γM Design values of actions and resistances fulfilling for STR/GEO ULS : Ed ≤ Rd Ed = E {γF.Fk } and Rd = R { Xk / γM } (= “at the source”, MFA) or Ed = γE.E { Fk } and Rd = R { Xk } / γR (RFA) Design values of geotechnical parameters Brussels, 18-20 February 2008 – Dissemination of information workshop 15 EUROCODES Background and Applications Ultimate limit statesUltimate limit states –– Eurocode 7Eurocode 7--11 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 Brussels, 18-20 February 2008 – Dissemination of information workshop 16 EUROCODES Background and Applications J.A CalgaroJ.A CalgaroEEdd<< RRdd EN1990EN1990 -- Ultimate limit states EQU and STR/GEOUltimate limit states EQU and STR/GEO Brussels, 18-20 February 2008 – Dissemination of information workshop 17 EUROCODES Background and Applications 1,50 0 1,35 1,00 Set A1 γ Q γ Q γ G γ G Symbol Variable Unfavourable Favourable Permanent Unfavourable Favourable Action (γ F) 1,30 0 1,00 1,00 Set A2 1,251,00γc’Effective cohesion 1,00 1,00 1,00 1,00 Set M1 1,25γϕ’ Angle of shearing resistance 1,40γcu Undrained shear strength γγ γqu Symbol 1,00Weight density 1,40Unconfined strength Set M2Soil parameter (γ M ) A2 “+” M2 “+” R1 Or A2 “+” M1 or M2“+” R4 A1 “+” M1 “+” R1 & 1 A1 “+” M1 “+” R22 A1 or A2 “+” M2 “+” R3 Combinations 3 Approach 1,1 1,4 Set R2 1,001,00γRh Sliding 1,00 Set R1 1,00γRv Bearing Portance Symbol Set R3Resistance (γ R ) γR for Spread foundations STR/GEO : persistent and transient situations Brussels, 18-20 February 2008 – Dissemination of information workshop 18 EUROCODES Background and Applications STR/GEOSTR/GEO :: accidental situationsaccidental situations Actions : all values ofActions : all values of γγFF (and(and γγMM) = 1.0) = 1.0 Resistances :Resistances : all values ofall values of γγRR (and(and γγMM) depend) depend on the particular accidenton the particular accident Seismic situations:Seismic situations: see Eurocode 8-5
  7. 7. Brussels, 18-20 February 2008 – Dissemination of information workshop 19 EUROCODES Background and Applications Ultimate limit states (UPL) P T Anchorage W T Anchored structure W u Former ground surface Sand Clay Gravel Clay Sand Clay Gravel b bottom of an excavation Sand Sand Sand Injected sand u Water tight surface slab below water level W TT u Water tight surface b buried hollow structure u σv W atertight surface lightweight embankment during flood Gdst;d + Qdst;d ≤ Gstb;d + RdExamples of situations where uplift might be critical Brussels, 18-20 February 2008 – Dissemination of information workshop 20 EUROCODES Background and Applications Ultimate limit states (HYD) Sand WaterHeave due to seepage of water Permeable subsoil piezometric level in the permeable subsoil low permeability soil Piping udst;d ≤ σstb;d Δudst;d ≤ σ´stb;d Example of situation where heave or piping might be critical Brussels, 18-20 February 2008 – Dissemination of information workshop 21 EUROCODES Background and Applications Ultimate limit states of static equilibriumUltimate limit states of static equilibrium (EQU)(EQU) :: EEd,dstd,dst ≤≤ EEd,stbd,stb Ultimate limit states of resistanceUltimate limit states of resistance (STR/GEO)(STR/GEO) :: EEdd ≤≤ RRdd Ultimate limit state of upliftUltimate limit state of uplift (UPL)(UPL) :: GGdst;ddst;d + Q+ Qdst;ddst;d ≤≤ GGstb;dstb;d + R+ Rdd Ultimate limit state of hydraulic failureUltimate limit state of hydraulic failure (HYD)(HYD) :: uudst;ddst;d ≤≤ σσstb;dstb;d or Sor Sdst;ddst;d ≤≤ GG´´stb;dstb;d Verifications of ULSVerifications of ULS Brussels, 18-20 February 2008 – Dissemination of information workshop 22 EUROCODES Background and Applications EN1990EN1990 -- Serviceability limit states SLSServiceability limit states SLS Verifications :Verifications : CCdd == limiting design value of the relevantlimiting design value of the relevant serviceability criterionserviceability criterion EEdd == design value of the effects of actionsdesign value of the effects of actions specified in the serviceability criterion, determinedspecified in the serviceability criterion, determined on the basis of the relevant combinationon the basis of the relevant combination allall γγFF andand γγMM = 1.0= 1.0 EEdd ≤≤ CCdd Brussels, 18-20 February 2008 – Dissemination of information workshop 23 EUROCODES Background and Applications settlement s, differential settlement δs, rotation θ and angular strain α relative deflection Δ and deflection ratio Δ/L ω and relative rotation (angular distortion) β (after Burland and Wroth, 1975) smax δsmax Movements and deformations of structuresMovements and deformations of structures Brussels, 18-20 February 2008 – Dissemination of information workshop 24 EUROCODES Background and Applications Conclusions - 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 :
  8. 8. Brussels, 18-20 February 2008 – Dissemination of information workshop 25 EUROCODES Background and Applications 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. Brussels, 18-20 February 2008 – Dissemination of information workshop 26 EUROCODES Background and Applications Thank you for your attention !
  9. 9. SECTION 2: BASIS OF GEOTECHNICAL DESIGN B. Schuppener Bundesanstalt für Wasserbau
  10. 10. Brussels, 18-20 February 2008 – Dissemination of information workshop 1 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design EN 1997 Eurocode: Geotechnical design Section 2: Basis of geotechnical design Dr.-Ing. Bernd Schuppener, Federal Waterways Engineering and Research Institute, Karlsruhe, Germany Brussels, 18-20 February 2008 – Dissemination of information workshop 2 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design 2.1 Design requirements 2.2 Design situations 2.3 Durability 2.4 Geotechnical design by calculation 2.5 Design by prescriptive methods 2.6 Load tests 2.7 The Observational Method 2.8 The Geotechnical Design Report Annex A + B 2 Basis of geotechnical design Brussels, 18-20 February 2008 – Dissemination of information workshop 3 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design (1)P For each geotechnical design situation it shall be verified that no relevant limit state, as defined in EN 1990:2002, is exceeded. 2.1 Design requirements limit states (4) Limit states should be verified by one or a combination of the following: • use of calculations as described in 2.4; • adoption of prescriptive measures, as described in 2.5; • experimental models and load tests, as described in 2.6; • an observational method, as described in 2.7. Brussels, 18-20 February 2008 – Dissemination of information workshop 4 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design (8)P In order to establish minimum requirements • for the extent and content of geotechnical investigations, • calculations and • construction control checks, the complexity of each geotechnical design shall be identified together with the associated risks. (10) To establish geotechnical design requirements, three Geotechnical Categories, 1, 2 and 3, may be introduced. 2.1 Design requirements Geotechnical Categories Brussels, 18-20 February 2008 – Dissemination of information workshop 5 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design (14) Geotechnical Category 1 should only include small and relatively simple structures: • for which it is possible to ensure that the fundamental requirements will be satisfied on the basis of experience and qualitative geotechnical investigations; • with negligible risk. 2.1 Design requirements Geotechnical Categories (9) For structures and earthworks of low geotechnical complexity and risk, such as defined above, simplified design procedures may be applied. Brussels, 18-20 February 2008 – Dissemination of information workshop 6 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design (17) Geotechnical Category 2 should include conventional types of structure and foundation with no exceptional risk or difficult soil or loading conditions. (18) Designs for structures in Geotechnical Category 2 should normally include quantitative geotechnical data and analysis to ensure that the fundamental requirements are satisfied. (19) Routine procedures for field and laboratory testing and for design and execution may be used for Geotechnical Category 2 designs. 2.1 Design requirements Geotechnical Categories
  11. 11. Brussels, 18-20 February 2008 – Dissemination of information workshop 7 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design (20) Geotechnical Category 3 should include structures or parts of structures, which fall outside the limits of Geotechnical Categories 1 and 2. (21) Geotechnical Category 3 should normally include alternative provisions and rules to those in this standard. NOTE Geotechnical Category 3 includes the following examples: • very large or unusual structures; • structures involving abnormal risks, or unusual or exceptionally difficult ground or loading conditions; • structures in highly seismic areas; • structures in areas of probable site instability or persistent ground movements that require separate investigation or special measures. 2.1 Design requirements Geotechnical Categories Brussels, 18-20 February 2008 – Dissemination of information workshop 8 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design (1)P Both short-term and long-term design situations shall be considered. 2.2 Design Situations (EN 1997-1) Brussels, 18-20 February 2008 – Dissemination of information workshop 9 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design (1)P At the geotechnical design stage, the significance of environmental conditions shall be assessed in relation to durability and to enable provisions to be made for the protection or adequate resistance of the materials. 2.3 Durability Brussels, 18-20 February 2008 – Dissemination of information workshop 10 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design (1)P The selection of characteristic values for geotech- nical parameters shall be based on results and derived values from laboratory and field tests, complemented by well-established experience. 2.4 Geotechnical design by calculation 2.4.5.2 Characteristic values of geotechnical parameters (2)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. Brussels, 18-20 February 2008 – Dissemination of information workshop 11 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design 4)P The selection of characteristic values for geotechnical parameters shall take account of the following: • ... • the type and number of samples; • the extent of the zone of ground governing the behaviour of the geotechnical structure at the limit state being considered; • the ability of the geotechnical structure to transfer loads from weak to strong zones in the ground. ….. 2.4 Geotechnical design by calculation 2.4.5.2 Characteristic values of geotechnical parameters Brussels, 18-20 February 2008 – Dissemination of information workshop 12 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design (10) If statistical methods are employed in the selection of characteristic values for ground properties, such methods should differentiate between local and regional sampling and should allow the use of a priori knowledge of comparable ground properties. (11) 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%. NOTE In this respect, a cautious estimate of the mean value is a selection of the mean value of the limited set of geotechnical parameter values, with a confidence level of 95%; where local failure is concerned, a cautious estimate of the low value is a 5% fractile. 2.4 Geotechnical design by calculation 2.4.5.2 Characteristic values of geotechnical parameters
  12. 12. Brussels, 18-20 February 2008 – Dissemination of information workshop 13 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design Slope failure in a cut cu = 68 MN/m² cu = 73 MN/m² cu = 65 MN/m² cu = 71 MN/m² cu = 60 MN/m² cu = 55 MN/m² cu = 50 MN/m² cu = 62 MN/m² cu = 76 MN/m² cu = 64 MN/m² cu = 75 MN/m² Selection of characteristic values: Brussels, 18-20 February 2008 – Dissemination of information workshop 14 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design cu = 68 MN/m² cu = 73 MN/m² cu = 65 MN/m² cu = 71 MN/m² cu = 60 MN/m² cu = 55 MN/m² cu = 50 MN/m² cu = 62 MN/m² cu = 76 MN/m² cu = 64 MN/m² cu = 75 MN/m² Selection of characteristic values: Brussels, 18-20 February 2008 – Dissemination of information workshop 15 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design Determination of the characteristic value Xk by statistical methods: Xk = Xmean (1 - kn Vx) where Xmean arithmetical mean value of the parameter values; Vx the coefficient of variation kn statistical coefficient which depends on the number n of test results, the level of confidence and a priori knowledge about the coefficient of variation (case ”Vx unknown” or ”Vx known”). 2.4 Geotechnical design by calculation 2.4.5.2 Characteristic values of geotechnical parameters Brussels, 18-20 February 2008 – Dissemination of information workshop 16 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design Xk(local) Number n of test results * * * * * * * * * * * * Value of parameter Normal distribution through tests results Mean of test results Xmean Xmean kn,mean Vx Xmean Xk(mean) sxsx Xmean kn,fractile Vx 2.4 Geotechnical design by calculation 2.4.5.2 Characteristic values of geotechnical parameters Brussels, 18-20 February 2008 – Dissemination of information workshop 17 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design 2.4 Geotechnical design by calculation 2.4.5.2 Characteristic values of geotechnical parameters Determination of characteristic values proposed by Schneider (1999): Xk = Xmean - 0.5 sx Brussels, 18-20 February 2008 – Dissemination of information workshop 18 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design Example: results of triaxial tests used for the selection of the characteristic values using statistical methods (Vx unknown) Borehole / test Statistical result c’ [kPa] ’ [°] tan ’ [-] BH 1/1 3 31 0,601 BH 1/2 4 30 0,577 BH 2/1 1 35 0,700 BH 2/2 7 28 0,532 Mean value c´mean = 3.75 (tan ´)mean = 0.603 Standard deviation sc = 2.50 s = 0.071 Coefficient of variation Vc = 0.667 Vtan = 0.118 2.4 Geotechnical design by calculation 2.4.5.2 Characteristic values of geotechnical parameters
  13. 13. Brussels, 18-20 February 2008 – Dissemination of information workshop 19 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design Table: summary of the statistical evaluation of the example Characteristic values of shear parameter Basis and method of statistical evaluation ´k [°] c´k [kPa] ’ and c’ of 4 tests for the case “Vx unknown” 27.5 0.8 ’ and c’ of 4 tests for the case “Vx known” 29.0 2.5 Schneider (1999) 29.5 2.5 2.4 Geotechnical design by calculation 2.4.5.2 Characteristic values of geotechnical parameters Brussels, 18-20 February 2008 – Dissemination of information workshop 20 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design (1)P The definition of actions shall be taken from EN 1990:2002. The values of actions shall be taken from EN 1991, where relevant. Section 1 of EN 1997-1: 1.5.2.1 Geotechnical action Action transmitted to the structure by the ground, fill standing water or groundwater. 2.4 Geotechnical design by calculation 2.4.2 Actions Brussels, 18-20 February 2008 – Dissemination of information workshop 21 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design NOTE (to (9)P) Unfavourable (or destabilising) and favourable (or stabilising) permanent actions may in some situations be considered as coming from a single source. If they are considered so, a single partial factor may be applied to the sum of these actions or to the sum of their effects. 2.4 Geotechnical design by calculation 2.4.2 Actions Brussels, 18-20 February 2008 – Dissemination of information workshop 22 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design 2.4 Geotechnical design by calculation 2.4.2 Actions Wtop Wbottom Wd,dst = (Wbottom - Wtop) dst Wd = Wbottom dst - Wtop stb Brussels, 18-20 February 2008 – Dissemination of information workshop 23 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design • characteristic values • geotechnical parameter • actions • design values • geotechnical ultimate limit states • design approaches DA1, DA2 and DA 3 • serviceability limit states 2.4 Geotechnical design by calculation Brussels, 18-20 February 2008 – Dissemination of information workshop 24 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design 2.4.6.1 Design values of actions (2)P The design value of an action (Fd) shall either be assessed directly or shall be derived from representative values Frep using the following equation: Fd = F Frep (2.1a) with Frep = Fk (2.1b) where F is the partial factor on geotechnical actions or effects of geotechnical actions and is a combination factor. (3)P Appropriate values of shall be taken from EN 1990:2002.
  14. 14. Brussels, 18-20 February 2008 – Dissemination of information workshop 25 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design 2.4.6.1 Design values of actions (2)P The design value of an action (Fd) shall either be assessed directly or shall be derived from representative values Frep using the following equation: Fd = F Frep (2.1a) with Frep = Fk (2.1b) where F is the partial factor on geotechnical actions or effects of geotechnical actions and is a combination factor. (4)P The partial factor F for persistent and transient situations defined in Annex A shall be used in equation (2.1a). Brussels, 18-20 February 2008 – Dissemination of information workshop 26 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design 2.4.6.1 Design values of actions 00Favourable 1,31,5QUnfavourableVariable 1,01,0Favourable 1,01,35GUnfavourablePermanent A2A1 Set SymbolAction Table A.3: Partial factors on actions ( F) or the effects of actions ( E) NOTE The values to be ascribed to G and Q for use in a country may be found in its National annex to EN 1990. The recommended values for buildings in EN 1990:2002 for the two sets A1 and A2 are given in Table A.3. Brussels, 18-20 February 2008 – Dissemination of information workshop 27 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design 2.4.6.2 Design values of geotechnical parameters (1)P Design values of geotechnical parameters (Xd) shall either be derived from characteristic values using the following equation: Xd = Xk / M (2.2) or shall be assessed directly. (2)P The partial factor M for persistent and transient situations defined in Annex A shall be used in equation (2.2). Brussels, 18-20 February 2008 – Dissemination of information workshop 28 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design 2.4.6.2 Design values of geotechnical parameters Table A.4 - Partial factors for soil parameters ( M) Set Soil parameter Symbol M1 M2 Shearing resistance 1 1,0 1,25 Effective cohesion c 1,0 1,25 Undrained strength cu 1,0 1,4 Unconfined strength qu 1,0 1,4 Unit weight density 1,0 1,0 Brussels, 18-20 February 2008 – Dissemination of information workshop 29 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design (1)P Where relevant, it shall be verified that the following limit states are not exceeded: • ………….. • failure or excessive deformation of the ground, in which the strength of soil or rock is significant in providing resistance (GEO); • loss of equilibrium of the structure or the ground due to uplift by water pressure (buoyancy) or other vertical actions (UPL); • hydraulic heave, internal erosion and piping in the ground caused by hydraulic gradients (HYD). 2.4.7 Ultimate limit states 2.4.7.1 General Brussels, 18-20 February 2008 – Dissemination of information workshop 30 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design (1)P When considering a limit state of rupture or excessive deformation of a structural element or section of the ground (STR and GEO), it shall be verified that: Ed Rd (2.5) Ed : the design value of the effects of all the actions; Rd : the design value of the corresponding resistance of the ground and/or structure. 2.4.7.3 Verification of resistance for GEO and STR
  15. 15. Brussels, 18-20 February 2008 – Dissemination of information workshop 31 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design Load and Resistance Factor Approach Rd Ed Rk( ´k, c´k) / R Ek( ´k, c´k) E Rk: characteristic values of ground resistance R: partial factor for the ground resistance Ek: characteristic value of the effect of action E: partial factor for the effect of action or the action ´k,c´k: characteristic values of the shear parameter Brussels, 18-20 February 2008 – Dissemination of information workshop 32 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design Design values of shear parameter ´k, c´k characteristic value of shear parameter ´d, c´d design values of the shear parameter partial factor for the angle of shearing resistance c partial factor for the cohesion intercept tan ´d = (tan ´k) / c´d = c´k / c Brussels, 18-20 February 2008 – Dissemination of information workshop 33 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design Material Factor Approach Rd( ´d, c´d) Ed( ´d, c´d) Rd: design value of the ground resistance Ed design value of the effects of actions of the ground ´d design value of the angle of shearing resistance c´d design value of the cohesion intercept Brussels, 18-20 February 2008 – Dissemination of information workshop 34 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design Gk EQ Qk EG qk Rv = (V, H, M, ´, c´) Example for the three Design Approaches of EN 1997-1 Rv,d Vd V, H, M Brussels, 18-20 February 2008 – Dissemination of information workshop 35 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design Action or effects of actionsDesign Approach structure ground Resistance ground 1 2222 G = 1.35; G,inf = 1.00; Q = 1.50 R;e = R;v = 1.40 R;h = 1.10 332 G = 1.35; G,inf=1.00 Q = 1.50 = c = 1.25 2.4.7.3 Verification of resistance for GEO and STR Brussels, 18-20 February 2008 – Dissemination of information workshop 36 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design Action or effects of actionsDesign Approach Structure Ground Resistance ground Comb. 1 G = 1.35; G,inf = 1.00; Q = 1.50 = c = 1.0 1 Comb. 2 G = 1.00; Q = 1.30 = c = 1.25 2 G = 1.35; G,inf = 1.00; Q = 1.50 R;e = R;v = 1.40 R;h = 1.10 3 G = 1.35; G,inf=1.00 Q = 1.50 = c = 1.25 2.4.7.3 Verification of resistance for GEO and STR Design Approach 1
  16. 16. Brussels, 18-20 February 2008 – Dissemination of information workshop 37 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design 2.4.7.3 Verification of resistance for GEO and STR Design Approach 1 Gd = G Gk = 1.35 Gk Qd = Q Qk = 1.50 Qk EG,d= G EG( ´d,c´d)=1.35 EG( ´k,c´k) EQ,d = EQ( ´k, c´k, qd) qd = Q qk = 1.50 qk Rv,d = Rv(Vd, Hd, Md, ´d, c´d) ´ = c = 1.0 ´d = ´k, c´d = c´k ´ = c = 1.0 ´d = ´k, c´d = c´k Combination 1 Gd = G Gk = 1.00 Gk Qd = Q Qk = 1.30 Qk EG,d = G EG( ´d, c´d) = 1.00 EG( ´d, c´d) qd = Q qk = 1.30 qk tan ´d = tan ´k/ ´ = tan ´k/1.25 c´d = c´k / c = c´k / 1.25 tan ´d = tan ´k/ ´ = tan ´k/1.25 c´d = c´k / c = c´k / 1.25 EQ,d = EQ( ´d, c´d, qd) Rv,d = Rv (Vd, Hd, Md, ´d, c´d) Combination 2 Rv,d Vd Vd, Hd, Md Vd, Hd, Md Vd, Hd, Md Vd, Hd, Md Brussels, 18-20 February 2008 – Dissemination of information workshop 38 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design Action or effects of actionsDesign Approach Structure Ground Resistance ground Comb. 1 G = 1.35; G,inf = 1.00; Q = 1.50 = c = 1.0 1 Comb. 2 G = 1.0; Q = 1.30 = c = 1.25 2 G = 1.35; G,inf = 1.00; Q = 1.50 R;e = R;v = 1.40 R;h = 1.10 3 G = 1.35; G,inf=1.00 Q = 1.50 = c = 1.25 2.4.7.3 Verification of resistance for GEO and STR Design Approach 2 Brussels, 18-20 February 2008 – Dissemination of information workshop 39 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design Gd = G Gk = 1.35 Gk Qd = Q Qk = 1.50 Qk EG,d= G EG( ´d, c´d)=1.35 EG( ´k,c´k) EQ,d = EQ( ´d, c´d, qd) qd = Q qk = 1.50 qk Rv,k = F(Md, Vd, Hd, ´d, c´d) Rv,d Vd ´ = c = 1.00 ´d = ´k, c´d = c´k ´ = c = 1.00 ´d = ´k, c´d = c´k 2.4.7.3 Verification of resistance for GEO and STR Design Approach 2 DA 2 Vd, Hd, Md Vd, Hd, Md Rv,d = Rv,k / Rv = Rv,k /1.40 Gk Qk EQ,k = EQ( ´k, c´k, qk) qk Rv,k= (Mk, Vk, Hk, ´k, c´k) Vd = G VG,k + Q VQ,k Vd = 1.35 VG,k + 1.50 VQ,k EG,k = EG( ´k, c´k) = c = 1.0 ´d = ´k, c´d = c´k = c = 1.0 ´d = ´k, c´d = c´k DA 2* Vk, Hk, Mk Vk, Hk, Mk Rv,d = Rv,k= / Rv = Rv,k/1.40 Brussels, 18-20 February 2008 – Dissemination of information workshop 40 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design Action or effects of actionsDesign Approach Structure Ground Resistance ground Comb. 1 G = 1.35; G,inf = 1.00; Q = 1.50 = c = 1.0 1 Comb. 2 G = 1.0; Q = 1.30 = c = 1.25 2 G = 1.35; G,inf = 1.00; Q = 1.50 R;e = R;v = 1.40 R;h = 1.10 3 G = 1.35; G,inf=1.00 Q = 1.50 = c = 1.25 2.4.7.3 Verification of resistance for GEO and STR Design Approach 3 Brussels, 18-20 February 2008 – Dissemination of information workshop 41 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design Gd = G Gk = 1.35 Gk Qd = Q Qk = 1.50 Qk EQ,d = EQ( ´d, c´d, qd) qd = Q qk = 1.30 qk Rv,d = (Vd, Hd, ´d, c´d) Vd = VG,d + VQ,d EG,d = G EG( ´d,c´d) = 1.00 EG( ´d,c´d) tan ´d = tan ´k/ ´ = tan ´k/1.25 c´d= c´k/ c = c´k / 1.25 tan ´d = tan ´k/ ´ = tan ´k/1.25 c´d= c´k/ c = c´k / 1.25 2.4.7.3 Verification of resistance for GEO and STR Design Approach 3 Rv,d Vd Brussels, 18-20 February 2008 – Dissemination of information workshop 42 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design 2.4.8 Serviceability limit states (1)P Verification for serviceability limit states in the ground or in a structural section, element or connection, shall either require that: Ed Cd, (2.10) or be done through the method given in 2.4.8 (4). Ed: effects of the actions e.g. deformations, differential settlements, vibrations etc. Cd: limiting values (2) Values of partial factors for serviceability limit states should normally be taken equal to 1,0. (5)P …… This limiting value shall be agreed during the design of the supported structure
  17. 17. Brussels, 18-20 February 2008 – Dissemination of information workshop 43 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design (2) The maximum acceptable relative rotations for open framed structures, infilled frames and load bearing or continuous brick walls are unlikely to be the same but are likely to range from about 1/2000 to about 1/300, to prevent the occurrence of a serviceability limit state in the structure. A maximum relative rotation of 1/500 is acceptable for many structures. The relative rotation likely to cause an ultimate limit state is about 1/150. Annex H (informative) Limiting values of structural deformation and foundation movement Brussels, 18-20 February 2008 – Dissemination of information workshop 44 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design 2.7 Observational method (1) When prediction of geotechnical behaviour is difficult, it can be appropriate to apply the approach known as "the observational method", in which the design is reviewed during construction. (2)P The following requirements shall be met before construction is started: • acceptable limits of behaviour shall be established; • the range of possible behaviour shall be assessed and it shall be shown that there is an acceptable probability that the actual behaviour will be within the acceptable limits; Brussels, 18-20 February 2008 – Dissemination of information workshop 45 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design • a plan of monitoring shall be devised, which will reveal whether the actual behaviour lies within the acceptable limits. The monitoring shall make this clear at a sufficiently early stage, and with sufficiently short intervals to allow contingency actions to be undertaken successfully; • the response time of the instruments and the procedures for analysing the results shall be sufficiently rapid in relation to the possible evolution of the system; • a plan of contingency actions shall be devised, which may be adopted if the monitoring reveals behaviour outside acceptable limits. 2.7 Observational method Brussels, 18-20 February 2008 – Dissemination of information workshop 46 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design 2.8 Geotechnical Design Report (1)P The assumptions, data, methods of calculation and results of the verification of safety and serviceability shall be recorded in the Geotechnical Design Report. (2) The level of detail of the Geotechnical Design Reports will vary greatly, depending on the type of design. For simple designs, a single sheet may be sufficient. Brussels, 18-20 February 2008 – Dissemination of information workshop 47 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design Information to be verified during construction. Notes on maintenance and monitoring. Concrete cas on un-softened glacial till with cu 60 kPa (pocket penetrometer) Calculations (or index calculations) Characteristic load 60 kN/m. Local experience plus Local Building Regulations (ref ……..) indicates working bearing pressure of 100 kPa acceptable. Therefore adopt footings 0.6 m wide, minimum depth 0.5 m (Building Regs) but depth varies to reach cu 60 kPa – test on site. Description of site surroundings: Formerly agricultural land. Gently sloping (4°) Assumed stratigraphy used in design with properties: Topsoil and very weathered glacial till up to 1 m thick, overlying firm to stiff glacial till (cu 60 kPa on pocket penetrometer). Codes and standards used (level of acceptable risk) Eurocode 7 Local building regs Section through structure showing actions:Report used: Ground Investigation report (give ref. date) Factual: Bloggs Investigations Ltd report ABC/123 dated 21 Feb 95 Interpretation: Ditto Approved by: Date …………… Checked by: Date …………… Made by: Date …………… Sheet no of ………Job No.Job Title New start housing development Structure Reference: Strip foundations 2.8 Geotechnical Design Report Brussels, 18-20 February 2008 – Dissemination of information workshop 48 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design Summary Section 2: Basis of geotechnical design: • introduces Geotechnical Categories as options, • describes geotechnical design situations • defines characteristic values of • geotechnical actions and • the selection of ground parameter • defines geotechnical ultimate limit states • defines three Design Approaches as options and • introduces the Observational Method as an equivalent geotechnical design method
  18. 18. Brussels, 18-20 February 2008 – Dissemination of information workshop 49 EUROCODES Background and Applications EN 1997-1: Section 2: Basis of geotechnical design Thank you
  19. 19. SECTION 3 GEOTECHNICAL DATA AND 6 SPREAD FOUNDATIONS T. Orr Trinity College Dublin
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  265. 265. SECTION 7 PILE FOUNDATIONS R. Frank Ecole Nationale des Ponts et Chaussées
  266. 266. Brussels, 18-20 February 2008 – Dissemination of information workshop 1 Background and Applications EUROCODES Design of pile foundations following Eurocode 7-Section 7 Workshop “Eurocodes: background and applications” Brussels, 18-20 Februray 2008 Roger FRANK, Professor Ecole nationale des ponts et chaussées, Paris Brussels, 18-20 February 2008 – Dissemination of information workshop 2 EUROCODES Background and Applications 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 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 Brussels, 18-20 February 2008 – Dissemination of information workshop 3 EUROCODES Background and Applications EN 1997-1: E A sample semi-empirical method for bearing resistance estimation H Limiting foundation movements and structural deformation EN 1997-2: D.7 Example of a method to determine the compressive resistance of a single pile (CPT) D.6 Example of a correlation between compressive resistance of a single pile and cone penetration resistance E.3 Example of a method to calculate the compressive resistance of a single pile (PMT) Informative annexesInformative annexes Brussels, 18-20 February 2008 – Dissemination of information workshop 4 EUROCODES Background and Applications Section 7 of EN 1997-1 •• Pile load testsPile load tests •• Axially loaded pilesAxially loaded piles -- ULS compressive or tensile resistanceULS compressive or tensile resistance ((‘‘bearing capacitybearing capacity’’)) -- Vertical displacements of pile foundations:Vertical displacements of pile foundations: serviceability of the supported structureserviceability of the supported structure •• Transversely loaded pilesTransversely loaded piles •• Structural design of pilesStructural design of piles Brussels, 18-20 February 2008 – Dissemination of information workshop 5 EUROCODES Background and Applications Specificity of pile foundations Need to take into account the actions due to ground displacement : - downdrag (negative skin friction) - heave - transverse loading ******************** * the design values of the strength and stiffness of the moving ground should usually be upper values * the ground displacement is treated as an action and an interaction analysis is carried out, or * an upper bound of the force transmited by the ground is introduced as the design action. Brussels, 18-20 February 2008 – Dissemination of information workshop 6 EUROCODES Background and Applications General
  267. 267. Brussels, 18-20 February 2008 – Dissemination of information workshop 7 EUROCODES Background and Applications Pile load tests Brussels, 18-20 February 2008 – Dissemination of information workshop 8 EUROCODES Background and Applications Brussels, 18-20 February 2008 – Dissemination of information workshop 9 EUROCODES Background and Applications Axially loaded piles Brussels, 18-20 February 2008 – Dissemination of information workshop 10 EUROCODES Background and Applications ULS Compressive or tensileULS Compressive or tensile resistance of piles (bearingresistance of piles (bearing capacity)capacity) Brussels, 18-20 February 2008 – Dissemination of information workshop 11 EUROCODES Background and Applications ULS - From static load test results 7.6.2.2 Ultimate compressive resistance from static load tests (8)P For structures, which do not exhibit capacity to transfer loads from weak piles to strong piles, as a minimum, the following equation shall be satisfied: ( ) ( ) ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ = 2 minmc; 1 meanmc; kc; ;Min ξξ RR R (7.2) where ξ1 and ξ2 are correlation factors related to the number of piles tested and are applied to the mean (Rc;m) mean and the lowest (Rc;m )min of Rc;m respectively. NOTE The values of the correlation factors may be set by the National annex. The recommended values are given in Table A.9. Brussels, 18-20 February 2008 – Dissemination of information workshop 12 EUROCODES Background and Applications Characteristic resistance from measured resistances Table A.9 - Correlation factors ξ to derive characteristic values from static pile load tests (n - number of tested piles) ξ for n = 1 2 3 4 ≥ 5 ξ1 1,40 1,30 1,20 1,10 1,00 ξ2 1,40 1,20 1,05 1,00 1,00
  268. 268. Brussels, 18-20 February 2008 – Dissemination of information workshop 13 EUROCODES Background and Applications ULS – From ground test results : ‘Model pile’ method 7.6.2.3 Ultimate compressive resistance from ground test results (5)P The characteristic values Rb;k and Rs;k shall either be determined by: ( ) ( ) ( ) ⎭ ⎬ ⎫ ⎩ ⎨ ⎧ == + =+= 4 mincalc; 3 meancalc;calc;cals;calb; ks;kb;kc; ;Min ξξξξ RRRRR RRR (7.8) where ξ3 and ξ4 are correlation factors that depend on the number of profiles of tests, n, and are applied respectively: to the mean values (Rc;cal )mean = (Rb;cal + Rs;cal)mean = (Rb;cal)mean + (Rs;cal)meanand to the lowest values (Rc;cal )min = (Rb;cal + Rs;cal)min, NOTE The values of the correlation factors may be set by the National annex. The recommended values are given in Table A.10. Brussels, 18-20 February 2008 – Dissemination of information workshop 14 EUROCODES Background and Applications Table A.10 - Correlation factors ξ to derive characteristic values from ground test results (n - the number of profiles of tests) ξ for n = 1 2 3 4 5 7 10 ξ3 1,40 1,35 1,33 1,31 1,29 1,27 1,25 ξ4 1,40 1,27 1,23 1,20 1,15 1,12 1,08 Characteristic resistance from calculated resistances Brussels, 18-20 February 2008 – Dissemination of information workshop 15 EUROCODES Background and Applications ULS – From ground test results : ‘Alternative’ method 7.6.2.3 Ultimate compressive resistance from ground test results (8) The characteristic values may be obtained by calculating: Rb;k = Ab qb;k and ∑ ⋅= i iis qAR k;s;s;;k (7.9) where qb;k and qs;i;k are characteristic values of base resistance and shaft friction in the various strata, obtained from values of ground parameters. NOTE If this alternative procedure is applied, the values of the partial factors γb and γs recommended in Annex A may need to be corrected by a model factor larger than 1,0. The value of the model factor may be set by the National annex. Brussels, 18-20 February 2008 – Dissemination of information workshop 16 EUROCODES Background and Applications ULSULS -- Permanent and transientPermanent and transient design situationsdesign situations -- Load factorsLoad factors Brussels, 18-20 February 2008 – Dissemination of information workshop 17 EUROCODES Background and Applications ULSULS -- Permanent and transientPermanent and transient design situationsdesign situations -- Resistance factorsResistance factors Brussels, 18-20 February 2008 – Dissemination of information workshop 18 EUROCODES Background and Applications CharacteristicCharacteristic value :value : RRkk = R /= R / ξξ where R =where R = γγRdRdRRcalcal or R = Ror R = Rmm (1)(1) DesignDesign value :value : RRdd = R= Rkk//γγtt oror RRdd = R= Rbkbk//γγbb + R+ Rsksk//γγss (2)(2) AppliedApplied compression/tensioncompression/tension loadload :: FFdd == γγFFFFkk (3)(3) General conditionGeneral condition for ULS being :for ULS being : FFdd ≤≤ RRdd (4)(4) equations (1) to (4) lead to :equations (1) to (4) lead to : FFkk ≤≤ R /R / γγFF..γγtt..ξξ = R / FS= R / FS (5)(5) Design resistanceDesign resistance
  269. 269. Brussels, 18-20 February 2008 – Dissemination of information workshop 19 EUROCODES Background and Applications Piles in compression :Piles in compression : Piles in tension :Piles in tension : Piles in groupPiles in group Brussels, 18-20 February 2008 – Dissemination of information workshop 20 EUROCODES Background and Applications Brussels, 18-20 February 2008 – Dissemination of information workshop 21 EUROCODES Background and Applications Vertical displacements of pile foundations (serviceability of supported structure) Vertical displacements under SLS conditions must be assessed and checked against limiting value : * Piles in compression - downdrag must be taken into account - settlement due to group action must be taken into account * Piles in tension - check upward displacements in the same manner Brussels, 18-20 February 2008 – Dissemination of information workshop 22 EUROCODES Background and Applications 0 20 40 60 80 100 120 0 1 2 3 4 5 6 7 Pile Load (MN) Settlement(mm) Load Test 2 Pile Load Test Results Load Settlement Settlement (MN) Pile 1(mm) Pile 2 (mm) 0 0 0 0.5 2.1 1.2 1.0 3.6 2.1 1.5 5.0 2.9 2.0 6.2 4.1 3.0 10.0 7.0 4.0 18.0 14.0 5.0 40.0 26.0 5.6 63.0 40.0 6.0 100.0 56.0 6.4 80.0 Load Test 1 Example from pile load test results (Orr, 2005) driven piles B = 0.40 m D = 15.0 m allowable settlement is 10 mm loads : Gloads : Gkk = 20,000 kN and Q= 20,000 kN and Qkk = 5,000 kN= 5,000 kN Brussels, 18-20 February 2008 – Dissemination of information workshop 23 EUROCODES Background and Applications Results From Table, for n = 2 pile load tests : for n = 2 pile load tests : ξ1 = 1.30 and ξ2 = 1.20 Rk = Min{5.3/1.30; 5.0/1.20} = Min{4.08; 4.17} = 4.08 DA 1DA 1--2 : F2 : Fdd = 26.5 MN and R= 26.5 MN and Rdd = 3.14 MN.= 3.14 MN. 9 piles are needed (neglecting group effects)9 piles are needed (neglecting group effects) DA1DA1--1 : F1 : Fdd = 34.5 MN and R= 34.5 MN and Rdd = 4.08= 4.08 9 piles are also needed (neglecting group effects)9 piles are also needed (neglecting group effects) DA 2 : FDA 2 : Fdd = 34.5 MN and R= 34.5 MN and Rdd = 3.71 MN= 3.71 MN 10 piles are needed (neglecting group effects).10 piles are needed (neglecting group effects). Brussels, 18-20 February 2008 – Dissemination of information workshop 24 EUROCODES Background and Applications SLS – Serviceability check * Gk + Qk = 25 MN * load per pile : through analysis of the 2 load curves for s 10 mm * Same analysis as for ULS (ξ1 = 1.30 and ξ2 = 1.20) leads to Rk = Min{3.25/1.30; 3.0/1.20} = 2.5 MN * thus, 10 piles are needed (neglecting group effects)
  270. 270. Brussels, 18-20 February 2008 – Dissemination of information workshop 25 EUROCODES Background and Applications Transversely loaded piles Adequate safety against failure (ULS) Ftr ≤ Rtr One of the following failure mechanisms should be considered : - short piles : rotation or translation as a rigid body - for long slender piles : bending failure of the pile with local yielding and displacement of the soil near the top of the pile Brussels, 18-20 February 2008 – Dissemination of information workshop 26 EUROCODES Background and Applications Transverse resistance Rtr : * from head transverse displacement pile load test * from ground tests results and pile strength parameters The theory of beams with subgrade reaction moduli can be used Brussels, 18-20 February 2008 – Dissemination of information workshop 27 EUROCODES Background and Applications Transverse displacement The following must be taken into account: - non linear soil : E(ε) - flexural stiffness of the piles : EI - fixity conditions (connections) - group effect - load reversals and cyclic loading Brussels, 18-20 February 2008 – Dissemination of information workshop 28 EUROCODES Background and Applications Conclusions * importance of static pile load tests * an innovative approach to pile capacity taking account of number of load tests or number of soil profiles * need of assessing serviceability of structures through displacement calculations Designing pile foundations with Eurocode 7 :Designing pile foundations with Eurocode 7 : Brussels, 18-20 February 2008 – Dissemination of information workshop 29 EUROCODES Background and Applications Thank you for your attention !
  271. 271. SECTION 8 ANCHORAGES SECTION 9 RETAINING STRUCTURES B. Simpson Arup
  272. 272. 1 Brussels, 18-20 February 2008 – Dissemination of information workshop 1 EUROCODES Background and Applications EN1997-1: Anchorages and Retaining structures EN 1997-1 Eurocode 7 Section 8 – Anchorages Section 9 – Retaining structures Brian Simpson Arup Geotechnics 2 © EN 1997-1 Geotechnical design – General Rules BP106.9 BP111.5 BP112.6 BP124-T1.31 1 General 2 Basis of geotechnical design 3 Geotechnical data 4 Supervision of construction, monitoring and maintenance 5 Fill, dewatering, ground improvement and reinforcement 6 Spread foundations 7 Pile foundations 8 Anchorages 9 Retaining structures 10 Hydraulic failure 11 Overall stability 12 Embankments Appendices A to J 3 © 8 AnchoragesBP124-F3.6 8.1 General 8.2 Limit states 8.3 Design situations and actions 8.4 Design and construction considerations 8.5 Ultimate limit state design 8.6 Serviceability limit state design 8.7 Suitability tests 8.8 Acceptance tests 8.9 Supervision and monitoring 4 © 5 © 6 ©
  273. 273. 2 7 © 8 © 9 © 10 © 8 Anchorages • Section depends on EN1537 - Execution of special geotechnical work - Ground anchors • Not fully compatible with EN1537. Further work on this is underway. • BS8081 being retained for the time being. 11 © EN1537:1999 12 © EN1537:1999 Execution of special geotechnical work - Ground anchors
  274. 274. 3 13 © EN1537:1999 Execution of special geotechnical work - Ground anchors - provides details of test procedures (creep load etc) 14 © Partial factors in anchor design 15 © Partial factors in anchor design Brussels, 18-20 February 2008 – Dissemination of information workshop 16 EUROCODES Background and Applications EN1997-1: Anchorages and Retaining structures EN 1997-1 Eurocode 7 Section 8 – Anchorages Section 9 – Retaining structures Brian Simpson Arup Geotechnics Brussels, 18-20 February 2008 – Dissemination of information workshop 17 EUROCODES Background and Applications EN1997-1: Anchorages and Retaining structures EN 1997-1 Eurocode 7 Section 9 – Retaining structures Fundamentals – Design Approaches Main points in the code text Examples: Comparisons with previous (UK) practice Comparison between Design Approaches Lessons from the Dublin Workshop Brussels, 18-20 February 2008 – Dissemination of information workshop 18 EUROCODES Background and Applications EN1997-1: Anchorages and Retaining structures EN 1997-1 Eurocode 7 Section 9 – Retaining structures Fundamentals – Design Approaches Main points in the code text Examples: Comparisons with previous (UK) practice Comparison between Design Approaches Lessons from the Dublin Workshop
  275. 275. 4 19 © Genting Highlands BP87.59 BP106.30 BP111.22 BP112.43 BP119.43 BP124-F3.9 BP130.33 BP145a.8 Genting Highlands BP87.60 BP106.31 BP111.23 BP112.44 BP119.44 BP124-F3.10 BP130.34 BP145a.9 21 © FOS 1 for characteristic soil strengths BP87.61 BP106.32 BP111.24 BP112.45 BP119.45 BP124-F3.11 BP130.35 BP145a.10 - but not big enough 22 © The slope and retaining wall are all part of the same problem. BP87.62 BP106.33 BP111.25 BP112.46 BP119.46 BP124-F3.12 BP130.36 BP145a.11 Structure and soil must be designed together - consistently. 23 © Approaches to ULS design – The merits of Design Approach 1 in Eurocode 7 Brian Simpson Arup Geotechnics BP145a.1 ISGSR2007 - First International Symposium on Geotechnical Safety and Risk Brussels, 18-20 February 2008 – Dissemination of information workshop 24 EUROCODES Background and Applications EN1997-1: Anchorages and Retaining structures EN 1997-1 Eurocode 7 Section 9 – Retaining structures Fundamentals – Design Approaches Main points in the code text Examples: Comparisons with previous (UK) practice Comparison between Design Approaches Lessons from the Dublin Workshop
  276. 276. 5 25 © EN 1997-1 Geotechnical design – General Rules BP106.9 BP111.5 BP112.6 BP124-T1.31 1 General 2 Basis of geotechnical design 3 Geotechnical data 4 Supervision of construction, monitoring and maintenance 5 Fill, dewatering, ground improvement and reinforcement 6 Spread foundations 7 Pile foundations 8 Anchorages 9 Retaining structures 10 Hydraulic failure 11 Overall stability 12 Embankments Appendices A to J 26 © 9 Retaining structures 9.1 General 9.2 Limit states 9.3 Actions, geometrical data and design situations 9.4 Design and construction considerations 9.5 Determination of earth pressures 9.6 Water pressures 9.7 Ultimate limit state design 9.8 Serviceability limit state design 27 © 9.2 Limit states 28 © 9.2 Limit states 29 © 9.3.2 Geometrical data 30 © 9.3.2 Geometrical data 100% 10% 100% 10%
  277. 277. 6 31 © 9.4 Design and construction considerations 32 © 9.4 Design and construction considerations 33 © 9.4.2 Drainage systems 34 © 9.5 Determination of earth pressures 35 © 9.5 Determination of earth pressures 36 © 9.5.3 Limiting values of earth pressure Annex C also provides charts and formulae for the active and passive limit values of earth pressure.
  278. 278. 7 37 © Annex C Sample procedures to determine limit values of earth pressures on vertical walls • Based on Caquot and Kerisel (and Absi?). • No values for adverse wall friction, which can lead to larger Ka and much smaller Kp. 38 © Wall friction Adverse wall friction may be caused by loads on the wall from structures above, inclined ground anchors, etc. 39 © C.2 Numerical procedure for obtaining passive pressures • Also provides Ka • Programmable formulae (though not simple) • Incorporated in some software (eg Oasys FREW, STAWAL) • Precise source not known (to me), but same values as Lancellotta, R (2002) Analytical solution of passive earth pressure. Géotechnique 52, 8 617-619. • Covers range of adverse wall friction. • Slightly more conservative than Caquot Kerisel when φ and δ/φ large – but more correct? 40 © Ka, Kp charts in Simpson Driscoll 41 © Comparison with Caquot Kerisel Kp(CK) / Kp(EC7) % Ka(CK) / Ka(EC7) % 42 © 9.7 Ultimate limit state design
  279. 279. 8 43 © 9.7.2 Overall stability 44 © 9.7.3 Foundation failure of gravity walls 45 © 9.7.4 Rotational failure of embedded walls 46 © 9.7.5 Vertical failure of embedded walls 47 © 9.7.6 Structural design of retaining structures 48 © 9.7.6 Structural design of retaining structures
  280. 280. 9 49 © 9.7.7 Failure by pull-out of anchorages 50 © 9.8 Serviceability limit state design 51 © 9.8.2 Displacements Brussels, 18-20 February 2008 – Dissemination of information workshop 52 EUROCODES Background and Applications EN1997-1: Anchorages and Retaining structures EN 1997-1 Eurocode 7 Section 9 – Retaining structures Fundamentals – Design Approaches Main points in the code text Examples: Comparisons with previous (UK) practice Comparison between Design Approaches Lessons from the Dublin Workshop 53 © 8m propped wall BP87.71 BP111.33 BP112.49 8m propped wall - data BP78.26 BP111.34 BP112.50 BP119.50 BP124-F3.15 CASE: DA1 -1 DA1 -2 EC7 SLS Unplanned overdig (m) 0.5 0.5 0 Dig level: Stage 1 -8.5 -8.5 -2.5 Stage 2 -8.0 Characteristic φ' ( ) 24 24 24 γ (or M) on tan φ' 1 1.25 1 Design φ' 24 19.6 24 δ'/φ' active 1 1 1 δ'/φ' passive 1 1 1 Ka 0.34 0.42 0.34 Factor on Ka 1 1 1 Design Ka 0.34 0.42 0.34 Kp 4.0 2.9 4.0 Factor on Kp 1 1 1 Design Kp Excd. side Retd. side 4.0 2.9 4.0 1.0 γQ 1 1.3 1
  281. 281. 10 8m propped wall - length and BM BP78.28 BP111.35 BP112.51 BP119.51 BP124-F3.16 CASE: DA1 -1 DA1 -2 EC7 SLS Unplanned overdig (m) 0.5 0.5 0 Design φ' 24 19.6 24 Design Ka 0.34 0.42 0.34 Design Kp Excd. side Retd. side 4.0 2.9 4.0 1.0 γQ 1 1.3 1 Computer program STW STW F Data file PROP11 PROP1 BCAP3A Wall length (m) 15.1 * 17.9 * 17.8 ** Max bending moment (kNm/m) 1097 1519 -236 +682 Factor on bending moment 1.35 1 1 ULS design bending moment (kNm/m) 1481 1519 -236 +682 * Computed ** Assumed Redistribution of earth pressure BP87.75 BP111.36 BP112.52 BP119.52 BP124-F3.17 57 © Compare CIRIA 104 BP87.2 BP111.54 BP112.54 BP119.53 BP124-F3.18 58 © 10kPa (13kPa) 0 -8m (-8.5m) φ′ = 24° (19.6°) 59 © xbcap5-Feb07cEvent3Run3Increment111:2821-02-07:Bendingmoment -20.00-16.00-12.00-8.000-4.000.0 ycoordinate(x=-0.5000m) Scalex1:101y1:13681 -1200. -1000. -800.0 -600.0 -400.0 -200.0 .0 200.0 400.0 Bending moment [kNm/m] 630kN/m 8m propped wall - length and BM BP78.32 BP111.38 BP112.55 BP119.54 BP124-F3.19 CASE: CIRIA Fs CIRIA Fs BS 8002 DA1 -1 DA1 -2 EC7 SLS DA1 -1 DA1 -2 DA1 -2 DA1 -2 Unplanned overdig (m) 0 0 0.5 0.5 0.5 0 0.5 0.5 0.5 0.5 Design φ' 16.5 24 20.4 24 19.6 24 24 19.6 19.6 19.6 Design Ka 0.49 0.36 0.41 0.34 0.42 0.34 0.34 0.42 0.42 Design Kp Excd. side Retd. side 2.1 3.4 2.8 4.0 2.9 4.0 1.0 4.0 2.9 1.0 2.9 1.0 γQ 1 1 1 1 1.3 1 1 1.3 1.3 1.3 Computer program STW STW STW STW STW FREW FREW FREW FREW SAFE Data file PROP4 PROP5 PR1B-03 PROP11 PROP1 BCAP3A BCAPBA BCAP1A BCAP4A XBCAP5 Wall length (m) 20.4 ** 14.1 ** 17.9 * 15.1 * 17.9 * 17.8 ** 17.8 ** 17.8 ** 17.8 ** 17.8 ** Max bending moment (kNm/m) 1870 ## 776 1488 1097 1519 -236 +682 -241 838 1359 -308 1158 -229 1131 Factor on bending moment 1.5 1.0? 1.35 1 1 1.35 1 1 1 ULS design bending moment (kNm/m) 1164 1488? 1481 1519 -236 +682 -325 1131 1359 -308 1158 -229 1131 * Computed ** Assumed ## Not used in design
  282. 282. 11 8m excavation - comparison of methods BP78.34 BP111.39 BP112.56 BP119.55 BP124-F3.20 0 5 10 15 20 25 30 35 CIRIA104 BS8002 EC7-STW EC7- FREW EC7- SAFE Length (m) BM/50 Prop F/50 Redistribution of earth pressure BP87.75 BP111.36 BP112.52 BP119.56 BP124-F3.21 63 © German practice for sheet pile design - EAB (1996) BP87.39 BP111.37 BP112.53 BP119.57 BP124-F3.22 64 © Weissenbach, A, Hettler, A and Simpson, B (2003). Stability of excavations. In Geotechnical Engineering Handbook, Vol 3: Elements and Structures (Ed U Smoltczyk). Ernst Sohn / Wiley. 65 © SAFE Grundbau2 BP116.24 BP119.58 BP124-F3.24 8m φk′=35° γ= 17 kN/m3 δ/φ = 2/3 (active) Ka = 0.224 ? 2m q=80kPa γ = 20 kN/m3 22.4 30.5 15.3 Weissenbach, A, Hettler, A and Simpson, B (2003) Stability of excavations. In Geotechnical Engineering Handbook, Vol 3: Elements and Structures (Ed U Smoltczyk). Ernst Sohn / Wiley. 3.32m 66 © Grundbau in STAWAL BP119.59 BP124-F3.25 [1] .0 [2] [2] -8.000 Toe -10 .59m .0 .0 199.3kN/m Ac tual Pressures Wa ter Pres sure Moment Sh ear -24 0.0 -160.0 -80.00 .0 8 0.00 1 60 .0 240.0 -60 0.0 -400.0 -200.0 .0 2 00.0 4 00 .0 600.0 -24 0.0 -160.0 -80.00 .0 8 0.00 1 60 .0 240.0 Pres s ure [kPa] Bending Mom ent [kNm /m ] Shear Force [kN/m ] Scale x 1:128 y 1:128 -14.00 -12.00 -10.00 -8.000 -6.000 -4.000 -2.000 .0 2.000 ReducedLevel[m]
  283. 283. 12 67 © Grundbau: DA1 and DA2 XBP119.60 BP124-F3.26 C:bxGrundbauPrague[grundbau.xls] 0 50 100 150 200 250 300 350 400 Char DA1-1 DA1-2 DA2 Penetration cm BM kNm/m Strut force kN/m L=10.6 L=10.7 Brussels, 18-20 February 2008 – Dissemination of information workshop 68 EUROCODES Background and Applications EN1997-1: Anchorages and Retaining structures EN 1997-1 Eurocode 7 Section 9 – Retaining structures Fundamentals – Design Approaches Main points in the code text Examples: Comparisons with previous (UK) practice Comparison between Design Approaches Lessons from the Dublin Workshop 69 © Eurocode 7 Workshop Dublin, 31 March to 1 April 2005 BP130.1 Organised by European Technical Committee 10 Technical Committee 23 of ISSMGE GeoTechNet Working Party 2 Retaining Wall Examples 5 to 7 70 © Example 5 – Cantilever Gravity Retaining Wall BP130.2 0.75m B = ? 6m 0.4m Fill Sand 20o Surcharge 15kPa • Design situation - 6m high cantilever gravity retaining wall, - Wall and base thicknesses 0.40m. - Groundwater level is at depth below the base of the wall. - The wall is embedded 0.75m below ground level in front of the wall. - The ground behind the wall slopes upwards at 20 o • Soil conditions - Sand beneath wall: c'k = 0, φ'k = 34 o , γ = 19kN/m3 - Fill behind wall: c'k = 0, φ'k = 38 o , γ = 20kN/m3 • Actions - Characteristic surcharge behind wall 15kPa • Require - Width of wall foundation, B - Design shear force, S and bending moment, M in the wall 71 © Example 5 BP130.3 0.75m B = ? 6m 0.4m Fill Sand 20o Surcharge 15kPa 20o Kaγz 72 © Example 5 BP130.4 0.75m B = ? 6m 0.4m Fill Sand 20o Surcharge 15kPa 20o Kaγz
  284. 284. 13 73 © Example 5 – Cantilever Gravity Retaining Wall BP130.5 Example 5 - Gravity wall 1 b 2 N 1 2 3 N 1 N 1 N N N N N 1=3 2 2=N b b 1 2 3 0.0 1.0 2.0 3.0 4.0 5.0 6.0 0 0 1 1 1 2 2 2 2 2 3 3 3 5 5 5 8 8 16 16 17 G C C C C C C C BASEWIDTHm C:BXBX-CEC7Dublin[Dublin-results.xls] 1 , 2 or 3 – EC7 DA1, DA2 or DA3 b – EC7 DA1 Comb 1 only N – national method Contributor 74 © Example 5 – Cantilever Gravity Retaining Wall BP130.2 BP124.A6.11 0.75m B = ? 6m 0.4m Fill Sand 20o Surcharge 15kPa • Design situation - 6m high cantilever gravity retaining wall, - Wall and base thicknesses 0.40m. - Groundwater level is at depth below the base of the wall. - The wall is embedded 0.75m below ground level in front of the wall. - The ground behind the wall slopes upwards at 20 o • Soil conditions - Sand beneath wall: c'k = 0, φ'k = 34 o , γ = 19kN/m3 - Fill behind wall: c'k = 0, φ'k = 38 o , γ = 20kN/m3 • Actions - Characteristic surcharge behind wall 15kPa • Require - Width of wall foundation, B - Design shear force, S and bending moment, M in the wall Additional specifications provided after the workshop: 1 The characteristic value of the angle of sliding resistance on the interface between wall and concrete under the base should be taken as 30º. 2 The weight density of concrete should be taken as 25 kN/m3. 3 The bearing capacity should be evaluated using to the EC7 Annex D approach. 4 The surcharge is a variable load. 5 It should be assumed that the surcharge might extend up to the wall (ie for calculating bending moments in the wall), or might stop behind the heel of the wall, not surcharging the heel (ie for calculating stability). 75 © Example 5 – Cantilever Gravity Retaining Wall BP124.A6.12 C:BXBX-CEC7Dublin[Dublin-results (version 1).xls] 23-Jun-05 00:02 Example 5 - Gravity wall 3 2 1 bb 2=N2 1=3 N N N N N 1 N 1 N3 2 1 N2 b1 0.0 1.0 2.0 3.0 4.0 5.0 6.0 0 0 1 1 1 2 2 2 2 2 3 3 3 5 5 5 8 8 16 16 17 E C C C C C C C BASEWIDTHm 76 © Example 5 – Cantilever Gravity Retaining Wall BP130.5 γE E{γF Frep; Xk/γM; ad} = Ed ≤ Rd = R{γF Frep; Xk/γM; ad}/γR 77 © Example 5 – Cantilever Gravity Retaining Wall BP130.5 Unfavourable (horizontal) force and resistance factored. Favourable (vertical) force not factored in deriving inclination or eccentricity, or for comparison with resistance. Column no. 5 Unfavourable (horizontal) force and resistance factored. Favourable (vertical) force not factored in deriving inclination or eccentricity, but factored for comparison with resistance. Column no. 4 Characteristic eccentricity; unfavourable (horizontal) force and resistance factored. Favourable (vertical) force not factored in deriving inclination or for comparison with resistance. Column no. 3 Characteristic eccentricity and inclination; forces and resistance factored. Column no. 2 Characteristic values of all parameters. Column no. 1 0.680.500.911.042.02Rd/Vd 4714716289811392Rd (kN/m) 1.41.41.41.41γ(R) 65965987913731392R (kN/m) 0.41 See note0.410.300.30Inclination H/V 285285285285207Horizontal force kN/m 690941690941690Vertical force kN/m 2.172.172.612.612.61Effective width B' (m) 0.790.790.570.570.57Eccentricity (m) 3.753.753.753.753.75Base width 54321Column no. 78 © Example 5 – Cantilever Gravity Retaining Wall BP124.A6.12 C:BXBX-CEC7Dublin[Dublin-results.xls] 27-Jun-05 21:43 Example 5 - Gravity wall 321bb 2=N 2 1=3 1 b 2 1 N 1 N N N N 0 200 400 600 800 1000 1200 0 0 1 1 1 2 2 2 2 2 3 3 3 5 5 5 8 8 16 16 17 G C C C C C C C BENDINGMOMENTkNm/m.
  285. 285. 14 79 © Example 5 – Cantilever Gravity Retaining Wall BP124.A6.14 C:BXBX-CEC7Dublin[Dublin-results (version 1).xls] 23-Jun-05 00:02 Example 5 - Gravity wall 321 bb 2=N 2 NN N N 1 N 1b 1 0 50 100 150 200 250 300 0 0 1 1 1 2 2 2 2 2 3 3 3 5 5 5 8 8 16 16 17 E C C C C C C C SHEARFORCEkN/m. 80 © Example 5 – Cantilever Gravity Retaining Wall BP130.8 • Serviceability: – No criteria in the instructions – Mainly ignored – ½(Ka + K0) ? – Middle third ? • Very large range of results • Importance of sequence of calculation and factoring – this is the main difference between the design approaches for this problem • Factors of safety must allow for errors and misunderstanding 81 © Example 6 – Embedded sheet pile retaining wall BP130.9 Sand 10kPa 3.0m D= ? 1.5m • Design situation - Embedded sheet pile retaining wall for a 3m deep excavation with a 10kPa surcharge on the surface behind the wall • Soil conditions - Sand: c'k = 0, φ'k = 37o , γ = 20kN/m3 • Actions - Characteristic surcharge behind wall 10kPa - Groundwater level at depth of 1.5m below ground surface behind wall and at the ground surface in front of wall • Require - Depth of wall embedment, D - Design bending moment in the wall, M 82 © Example 6 – Embedded sheet pile retaining wall BP130.9 Sand 10kPa 3.0m D= ? 1.5m • Design situation - Embedded sheet pile retaining wall for a 3m deep excavation with a 10kPa surcharge on the surface behind the wall • Soil conditions - Sand: c'k = 0, φ'k = 37o , γ = 20kN/m3 • Actions - Characteristic surcharge behind wall 10kPa - Groundwater level at depth of 1.5m below ground surface behind wall and at the ground surface in front of wall • Require - Depth of wall embedment, D - Design bending moment in the wall, M Additional specifications provided after the workshop: 1 The surcharge is a variable load. 2 The wall is a permanent structure. 83 © Example 6 – Embedded sheet pile retaining wall BP130.14 • Huge range of results • Values of Kp ? • CK / EC7 / Coulomb ?? • What about overdig? • 2.4.7.1(5) Less severe values than those recommended in Annex A may be used for temporary structures or transient design situations, where the likely consequences justify it. Kp(CK) / Kp(EC7) % 84 © Example 7 – Anchored sheet pile quay wall BP130.16 10kPa D = ? 1.5m Tie bar anchor 3.0m 3.3m Sand Water GWL 8,0m • Design situation - Anchored sheet pile retaining wall for an 8m high quay using a horizontal tie bar anchor. • Soil conditions - Gravelly sand - φ'k = 35 o , γ = 18kN/m3 (above water table) and 20kN/m3 (below water table) • Actions - Characteristic surcharge behind wall 10kPa - 3m depth of water in front of the wall and a tidal lag of 0.3m between the water in front of the wall and the water in the ground behind the wall. • Require - Depth of wall embedment, D

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