Lecture 1 - Eurocode 7 Handout PDF

KB5020 Engineering Geology and Geotechnics Lecture 1 Chuanbin Zhu  Module Overview Site Investigation Lectures (3) Seminars (3) Eurocode 7...

KB5020 Engineering Geology and Geotechnics Lecture 1 Chuanbin Zhu  Module Overview Site Investigation Lectures (3) Seminars (3) Eurocode 7 TW1-3 TW2-4 Lectures (1) Planning investigations TW1 Soil and rock sampling and groundwater measurements Field tests in soil and rock Engineering Geology Shallow Foundations Lectures (4) Seminars (3) Lectures (3) Seminars (3) TW4-5, 7-8 TW5, 7-8 EXAM Revisions TW9-11 TW9-11 Introduction to Earth TW12 Bearing capacity Weathering Settlement Geological mapping Soil improvement Geological structures Activity Week: TW6 (6 March)  Module Assessment ❑ The assessment for this semester module involves a 3hr examination worth 100% of the module mark. ❑ Students MUST conform to the examination specification with respect to any particular instruction relating to wordage and nature of assessment content. ❑ The examination in May, worth 100% of the module mark, will follow the completion of the teaching material and previous examples will be provided in revision sessions. ❑ Mock exam will be provided. Engineering Geology: Why bother? Engineering Geology: Why bother?  Engineering Geology: Why bother? ❑ Why do we need geology in civil construction…? ❑ Civil engineers and construction managers commonly work with geologists to decide on the details about construction and planning: ▪ Where to build the structure (SI) ▪ What to build it out of and where to source materials (Geotechnics) ▪ How to ensure the stability of the structure (Geomorphology; Geotechnics)  Engineering Geology: Why bother? ❑ Civil engineers need to understand and interpret the information provided by specialists and how it influences the siting, design, construction, operation and maintenance of the project. ❑ The success (or failure) of the project will depend on accurate and appropriate information and on its interpretation and incorporation into the works.  Engineering Geology: Why bother? ❑ Site exploration ▪ Most civil engineering works will require the need for site excavation of soils and rock. ▪ Alternatively, the Earth will be required to bear the load from the works. ▪ Excavated material may be used as construction material ▪ Effective planning of site investigation works: o reduces risk; o improves safety; o reduce cost; o increases sustainability; o ensures greater work efficiency.  Module Overview Site Investigation This lecture Lectures (3) Seminars (3) Eurocode 7 TW1-3 TW2-4 Lectures (1) Planning investigations: desk study TW1 Soil and rock sampling and groundwater measurements Field tests in soil and rock Engineering Geology Shallow Foundations Lectures (4) Seminars (3) Lectures (3) Seminars (3) TW4-5, 7-8 TW5, 7-8 EXAM Revisions TW9-11 TW9-11 Introduction to Earth TW12 Bearing capacity Weathering Settlement Geological mapping Soil improvement Geological structures Activity Week: TW6 9  Reading Bond, A. J., and Harris, A. J. (2008). Decoding Eurocode 7, London: Taylor & Francis, 598 pp. BS EN 1997: Eurocode 7: Geotechnical design (EC7) Part 1: General rules (EC7 Part 1) Lecture Outline ❑ Eurocodes ❑ Wider Context ❑ Design Situations ❑ Limit State Design ❑ Design Methods ❑ Basic Variables ❑ Design Approaches ❑ Verification  Eurocodes The Eurocodes published in the UK comprise: Structural safety, serviceability, BS EN 1990: Eurocode Basis of structural design (EC0) durability, and robustness BS EN 1991: Eurocode 1: Actions on structures (EC1) BS EN 1992: Eurocode 2: Design of concrete structures (EC2) BS EN 1993: Eurocode 3: Design of steel structures (EC3) BS EN 1994: Eurocode 4: Design of composite steel and concrete structures (EC4) BS EN 1995: Eurocode 5: Design of timber structures (EC5) BS EN 1996: Eurocode 6: Design of masonry structures (EC6) BS EN 1997: Eurocode 7: Geotechnical design (EC7) – Part 1: General rules (EC7 Part 1) – Part 2: Ground investigation and testing (EC7 Part 2) BS EN 1998: Eurocode 8: Design of structures for earthquake resistance (EC8) BS EN 1999: Eurocode 9: Design of aluminium structures (EC9)  Eurocodes The Eurocodes published in the UK comprise: BS EN 1990: Eurocode Basis of structural design (EC0) BS EN 1991: Eurocode 1: Actions on structures (EC1) Actions on structures BS EN 1992: Eurocode 2: Design of concrete structures (EC2) BS EN 1993: Eurocode 3: Design of steel structures (EC3) BS EN 1994: Eurocode 4: Design of composite steel and concrete structures (EC4) BS EN 1995: Eurocode 5: Design of timber structures (EC5) BS EN 1996: Eurocode 6: Design of masonry structures (EC6) BS EN 1997: Eurocode 7: Geotechnical design (EC7) – Part 1: General rules (EC7 Part 1) – Part 2: Ground investigation and testing (EC7 Part 2) BS EN 1998: Eurocode 8: Design of structures for earthquake resistance (EC8) BS EN 1999: Eurocode 9: Design of aluminium structures (EC9)  Eurocodes The Eurocodes published in the UK comprise: BS EN 1990: Eurocode Basis of structural design (EC0) BS EN 1991: Eurocode 1: Actions on structures (EC1) BS EN 1992: Eurocode 2: Design of concrete structures (EC2) BS EN 1993: Eurocode 3: Design of steel structures (EC3) BS EN 1994: Eurocode 4: Design of composite steel and concrete structures (EC4) Design detailing BS EN 1995: Eurocode 5: Design of timber structures (EC5) BS EN 1996: Eurocode 6: Design of masonry structures (EC6) BS EN 1997: Eurocode 7: Geotechnical design (EC7) – Part 1: General rules (EC7 Part 1) – Part 2: Ground investigation and testing (EC7 Part 2) BS EN 1998: Eurocode 8: Design of structures for earthquake resistance (EC8) BS EN 1999: Eurocode 9: Design of aluminium structures (EC9)  Eurocodes The Eurocodes published in the UK comprise: BS EN 1990: Eurocode Basis of structural design (EC0) BS EN 1991: Eurocode 1: Actions on structures (EC1) BS EN 1992: Eurocode 2: Design of concrete structures (EC2) BS EN 1993: Eurocode 3: Design of steel structures (EC3) BS EN 1994: Eurocode 4: Design of composite steel and concrete structures (EC4) BS EN 1995: Eurocode 5: Design of timber structures (EC5) BS EN 1996: Eurocode 6: Design of masonry structures (EC6) BS EN 1997: Eurocode 7: Geotechnical design (EC7) – Part 1: General rules (EC7 Part 1) Geotechnical and – Part 2: Ground investigation and testing (EC7 Part 2) seismic designs BS EN 1998: Eurocode 8: Design of structures for earthquake resistance (EC8) BS EN 1999: Eurocode 9: Design of aluminium structures (EC9) Eurocodes Eurocode 7 Eurocode 7 Eurocode 7 Eurocode 7 Eurocode 7 ❑ National Annexes contain rules and Nationally Determined Parameters (NDPs) to ensure safety remains a national, and not a European, responsibility. ❑ National Annexes provide: ▪ Nationally Determined Parameters (NDPs) ▪ Country specific data ▪ Procedure to be used, where choice is offered ▪ Guidance on the informative annexes ▪ Reference to non-contradictory, complementary information (NCCI) Eurocode 7 ❑ The main role of national annexes is to take into account the local differences, such as climate, geography and seismicity, between the countries that have adopted Eurocodes. ❑ National Annexes provide the “link” between Eurocode and national standards for each member state.  Eurocode 7 Eurocode 7 Part 1 (BS EN 1997-1:2004) Foreword 8. Anchorages 1. General 9. Retaining structures 2. Basis of Geotechnical design 10. Hydraulic failure 3. Geotechnical data 11. Overall stability 4. Supervision of construction, 12. Embankments monitoring and maintenance Annexes A – J 5. Fill, dewatering, ground improvement and reinforcement Part 1 provides guidance across a 6. Spread foundations range of activities from traditional 7. Pile foundations foundation or retaining wall design to that of slope stability.  Eurocode 7 Eurocode 7 Part 2 (BS EN 1997-2:2007) Foreword 1. General 2. Planning of ground investigation 3. Soil and rock sampling and groundwater Part 2 provides guidance on site measurements investigation and reporting. 4. Field tests in soil and rock 5. Laboratory tests on soil and rock 6. Ground investigation report Annexes A – X  Eurocode 7 Eurocode 7: Geotechnical design Version 1 Version 2 Eurocode 7: Part 1 BS EN 1997-1:2004 BS EN 1997-1:2024 Eurocode 7: Part 2 BS EN 1997-2:2007 BS EN 1997-2:2024 ▪ BS EN 1997-1:2024 was published on 30 Sep 2024. ▪ BS EN 1997-1:2004 will be withdrawn by BSI on 30 March 2028. ▪ For the period of coexistence between 2023 and 2028, both the first and second generation of Eurocodes are applicable. Eurocode 7 Eurocode 7  Eurocode 7 Second generation (published 2023-2026) Access via university library First generation (published 2002-2007) Eurocode 7 Date 11 February 2025 Time 17:30 - 20:00 GMT Location Stephenson's Lecture Theatres Newcastle University Lecture Outline ❑ Eurocodes ❑ Wider Context ❑ Design Situations ❑ Limit State Design ❑ Design Methods ❑ Basic Variables ❑ Design Approaches ❑ Verification  Principles & Application Rules ❑ Eurocode statements are either: ▪ Principles (preceded by the letter P and must be followed): o general statements and definitions for which there is no alternative; o requirements and analytical models for which no alternative is permitted unless specifically stated. ▪ Application Rules (a number in brackets and offering advice) o examples of generally recognised rules, which follow the Principles and satisfy their requirements; o It is permissible to use alternatives to the Application Rules given that it is in accordance with relevant principles. Principles & Application Rules Principles Application Rules  Design working life ❑ The basic requirements of a structure are to sustain all likely actions and influences, to remain fit for purpose, and to have adequate structural safety, serviceability, and durability. These requirements must be met for the structure’s entire design working life, including construction.  Consequence Classes Consequence Classes are used to categorize structures based on the potential consequences of their failure. This classification helps guide the design process by determining the level of safety, robustness, and reliability required for a structure. Geotechnical Complexity Class Geotechnical Category Lecture Outline ❑ Eurocodes ❑ Wider Context ❑ Design Situations ❑ Limit State Design ❑ Design Methods ❑ Basic Variables ❑ Design Approaches ❑ Verification  Design situations ❑ Limit state design involves verifying that relevant limit states are not exceeded in any specified design situation. ❑ Design situations are sets of physical conditions in which the structure finds itself at different moments in its working life: – In normal use, the structure is in a persistent situation; – under temporary conditions, such as when it is being built or repaired, the structure is in a transient situation; – under exceptional conditions, such as during a fire or explosion, the structure is in an accidental situation or (if caused by an earthquake) a seismic situation. Design situations  Design situations The formulation of design situations and their related limit states for geotechnical design should include consideration of the following: ▪ actions and their combinations; ▪ overall stability and ground movements; ▪ characteristics and classification of the various zones of soil, rock and elements of construction; ▪ dipping bedding planes; ▪ mine workings, caves or other underground structures;  Design situations ▪ earthquakes; ▪ the sensitivity of the structure to deformations; ▪ the effect of the new structure on existing ones; ▪ in the case of structures resting on/near rock: - interbedded hard and soft strata; - faults, joints and fissures; - possible instability of rock blocks; - solution cavities and continuing solution processes  Design situations ▪ the environment: - effects of scour, erosion and excavation, leading to changes in the geometry of the ground surface; - effects of chemical corrosion; - effects of weathering; - effects of freezing; - effects of long duration droughts; - variations in ground-water levels; - flooding, failure of drainage systems, water exploitation; - other effects of time and environment;  Design situations ❑What design situations would you consider for a new hospital? – Permanent and transient design situations (self-weight of structure, fixed equipment, staff and patients, wind, snow, etc); – Accidental design situations (fire, explosion, flood, earthquake, helicopter impacts on helipads, etc) – ground instabilities; – weathering/degradation; –... ❑ For each design situation it is necessary to identify the relevant limit state(s) and verify that no relevant limit state is exceeded. Lecture Outline ❑ Eurocodes ❑ Wider Context ❑ Design Situations ❑ Limit State Design ❑ Design Methods ❑ Basic Variables ❑ Design Approaches ❑ Verification  Limit state design ❑ “2.1 (1) P For each geotechnical design situation it shall be verified that no relevant limit state, as defined in EN 1990:2002, is exceeded.” – EC7 ❑ Two categories of limit state: ▪ the serviceability limit state (SLS) ▪ the ultimate limit state (ULS)  Limit state design Serviceability limit states [SLS] They are concerned with the functioning of the structure under normal use, the comfort of people, and the appearance of the construction works. ▪ Examples: – deformation resulting in loss of, or reduction in, function – vibration causing discomfort to occupants – Cracking affecting the appearance or durability of the structure.  Limit state design Ultimate limit states [ULS] They deal with the safety of people or structures. It defines the conditions under which the structure may fail, leading to catastrophic events such as collapse. ▪ Examples: – Collapsing – Overturning – Excessive deformation  Limit state design Categories of ultimate limit states: ▪ Equilibrium Limit States (EQU) ▪ Uplift Limit States (UPL) ▪ Hydraulic failure limit states (HYD) ▪ Structural Limit States (STR) ▪ Geotechnical Limit State (GEO)  Limit state design ❑ “2.1 (1) P For each geotechnical design situation it shall be verified that no relevant limit state, as defined in EN 1990:2002, is exceeded.” – EC7 How can we verify? Lecture Outline ❑ Eurocodes ❑ Wider Context ❑ Design Situations ❑ Limit State Design ❑ Design Methods ❑ Basic Variables ❑ Design Approaches ❑ Verification  Design methods ❑ Verification that limit states are not being exceeded can be performed in one or more of the following ways: ▪ Design by calculation (DbC) ▪ Design by prescriptive measures ▪ Design by the observational method ▪ Design by experimental models and load tests  Design methods ❑ “Design by calculation (DbC) ▪ Uses an arithmetical approach to the comparison of actions and resistances, mainly using a partial factor method. ▪ It involves actions, properties of materials, geometrical, and limited values of deformations, crack widths, vibrations etc. ▪ The calculation model: o an analytical model; o a semi-empirical model; o a numerical model.  Design methods ❑ Design by prescriptive measures ▪ In design situations where calculation models are not available or not necessary ▪ Relies on past experience of similar structures in similar ground conditions. ▪ The design is typically based on standard pre- defined formulas, charts or guides, or by comparison of working loads and allowable resistances. Design methods  Design methods ❑ Design by experimental models and load tests ▪ For example, load tests on bored piles to determine the actual load-bearing capacity and settlement of a pile under applied loading conditions. ▪ Shaking table test to understand the dynamic behaviour of a structure or complex soil- structure interactions.  Design methods ❑ Design by observational method ▪ “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.” ▪ The design is based on predictions, but these predictions are verified and refined based on real-time data as the project progresses. ▪ Example: settlement monitoring for large structures (e.g., bridges, high-rise buildings).  Design methods ❑ “Design by calculation (DbC) ▪ Uses an arithmetical approach to the comparison of actions and resistances, mainly using a partial factor method. ▪ It involves actions, material properties, geometrical, and limited values of deformations, crack widths, vibrations etc. ▪ The calculation model: o an analytical model; o a semi-empirical model; o a numerical model. Lecture Outline ❑ Eurocodes ❑ Wider Context ❑ Design Situations ❑ Limit State Design ❑ Design Methods ❑ Basic Variables ❑ Design Approaches ❑ Verification  Actions and their effects ❑ An action ‘F’ is a force or imposed deformation applied to a structure. ❑ For example: ▪ the weight of soil, rock and water ▪ earth pressures ▪ dead and imposed loads from structures ▪ movements and accelerations caused by earthquakes, explosions, vibrations and dynamic loads ▪ etc  Actions and their effects ❑ An action can be classified primarily by its variation in time as follows: ▪ Permanent (Persistent) ‘FG’: once applied the action remains unchanged. ▪ Variable (Transient) ‘FQ’: can be applied and removed and reapplied. ▪ Accidental ‘A’: an extreme and unusual, but imaginable, event.  Actions and their effects ❑ The effect of actions refers to the response or internal forces and deformations induced in a structure due to applied actions (loads). ❑ Effects of actions are a function of the actions applied to a structure and that structure’s dimensions, but not of material strength.  Material properties and resistance ❑ The resistance of a structural member is defined as the “capacity of a member or component, or cross- section of a member or component of a structure, to withstand actions without mechanical failure” [EN 1990 §1.5.2.15] ❑ Resistance is a function of the material properties and its dimensions, but not of the magnitude of any actions applied.  Geometrical data ❑ Geometrical data include: ▪ the dimensions of the geotechnical structure ▪ the level and slope of the ground surface, ▪ water levels, ▪ levels of interfaces between strata, excavation levels  Design values & partial factors The design value of an action (Fd) shall either be assessed directly or shall be derived from representative values using Fd = Frep. γF Partial factor for actions  Design values & partial factors The design value of material properties (Xd) shall either be assessed directly or shall be derived from representative values using Xd = XK/γM  Design values & partial factors The design value of geometrical data (ad): The partial action and material factors include an allowance for minor variations in geometrical data and, in such cases, no further safety margin on the geometrical data should be required. In cases where deviations in the geometrical data have a significant effect on the reliability of a structure, design values of geometrical data (ad) shall either be assessed directly or be derived from nominal values using the following equation: ad = anom ± Δa  Design values & partial factors ❑ In Eurocode 7: partial factors are applied to ▪ actions or their effects (i.e. loads or load effects), ▪ material properties (i.e. shear strength), and/or ▪ resistances (i.e. bearing capacity). ❑ The logic behind it lies in balancing safety, reliability, and economy while accounting for uncertainties/variabilities in actions, material properties, and analysis methods. Partial factors provide a margin of safety by systematically addressing these uncertainties. Design values & partial factors Before the creation of Eurocodes, some EU countries only applied Actions partial factors to actions alone, material properties alone, while some to actions + material Material properties, and others to actions + properties resistance. Resistance Design values & partial factors To accommodate these differing Actions wishes, a compromise was reached whereby each country could choose – through its National Material Annex – one (or more) of three properties Design Approaches that should be used within its jurisdiction. Resistance Lecture Outline ❑ Eurocodes ❑ Wider Context ❑ Design Situations ❑ Limit State Design ❑ Design Methods ❑ Basic Variables ❑ Design Approaches ❑ Verification  Design approaches (STR & GEO) Design approaches determine the manner how partial factors are applied: Design Approach 1 factors are applied to actions alone (in Combination 1) and mainly to material factors (in Combination 2). Design Approach 2 factors are applied to actions (or effects of actions) and to resistances simultaneously. Design Approach 3: factors are applied to structural actions (but not to geotechnical actions) and to material properties National choice of Design Approach for simultaneously. shallow foundations (after Bond, 2013) Factors are applied to?  Design approaches (STR & GEO) The manner how partial factors are applied is determined via Design Approaches. National choice of Design Approach for shallow foundations (after Bond, 2013) Lecture Outline ❑ Eurocodes ❑ Wider Context ❑ Design Situations ❑ Limit State Design ❑ Design Methods ❑ Basic Variables ❑ Design Approaches ❑ Verification  Verticaition ❑ “2.1 (1) P For each geotechnical design situation it shall be verified that no relevant limit state, as defined in EN 1990:2002, is exceeded.” – EC7 ❑ serviceability (2.4.8) limit state (SLS) ▪ Equilibrium Limit States (EQU) (2.4.7.2) ▪ Structural Limit States (STR) (2.4.7.3) ❑ ultimate limit state (ULS) ▪ Geotechnical Limit State (GEO) ▪ Uplift Limit States (UPL) (2.4.7.4) ▪ Hydraulic failure limit states (HYD) (2.4.7.5) Partial factor & Design Approaches o Analytical o Semi-empirical o Numerical  Module Overview Site Investigation Lectures (3) Seminars (3) Eurocode 7 TW1-3 TW2-4 Lectures (1) Planning investigations: desk study TW1 Soil and rock sampling and Next lecture groundwater measurements Field tests in soil and rock Engineering Geology Shallow Foundations Lectures (4) Seminars (3) Lectures (3) Seminars (3) TW4-5, 7-8 TW5, 7-8 EXAM Revisions TW9-11 TW9-11 Introduction to Earth TW12 Bearing capacity Weathering Settlement Geological mapping Soil improvement Geological structures Activity Week: TW6 83