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BS EN 1993-1-6:2025 Eurocode 3. Design of steel structures - Strength and stability of shell structures, 2025
- undefined
- European foreword
- 0 Introduction
- 1 Scope [Go to Page]
- 1.1 Scope of EN 1993-1-6
- 1.2 Assumptions
- 2 Normative references
- 3 Terms, definitions and symbols [Go to Page]
- 3.1 Terms and definitions [Go to Page]
- 3.1.1 Structural forms and geometry
- 3.1.2 Limit states
- 3.1.3 Actions
- 3.1.4 Stress resultants and stresses in a shell
- 3.1.5 Types of analysis and their use
- 3.1.6 Stress categories used in stress design
- 3.1.7 Special definitions for buckling calculations
- 3.2 Symbols [Go to Page]
- 3.2.1 Coordinate system
- Figure 3.1 — Coordinate system for a shell of revolution [Go to Page]
- 3.2.2 Shell dimensions
- 3.2.3 Distributed surface loads and pressures
- 3.2.4 Line forces
- 3.2.5 Membrane stress resultants
- 3.2.6 Bending stress resultants
- 3.2.7 Stresses
- 3.2.8 Displacements relative to the shell middle surface
- Figure 3.2 — Symbols in a shell of revolution
- Figure 3.3 — Membrane and bending stress resultants in a cylindrical shell [Go to Page]
- 3.2.9 Tolerances
- 3.2.10 Properties of materials
- 3.2.11 Parameters in resistance assessment
- 3.2.12 Subscripts
- 3.3 Sign conventions
- 4 Basis of design [Go to Page]
- 4.1 General rules [Go to Page]
- 4.1.1 Basic requirements
- 4.1.2 Specific requirements
- 4.2 Types of analysis [Go to Page]
- 4.2.1 General
- 4.2.2 Global analysis
- 4.2.3 Membrane theory analysis
- 4.2.4 Semi-membrane theory analysis
- 4.2.5 Linear elastic shell analysis (LA)
- 4.2.6 Linear elastic bifurcation analysis (LBA)
- 4.2.7 Geometrically nonlinear elastic analysis (GNA)
- 4.2.8 Materially nonlinear analysis (MNA)
- 4.2.9 Geometrically and materially nonlinear analysis (GMNA)
- 4.2.10 Geometrically nonlinear elastic analysis with imperfections explicitly included (GNIA)
- 4.2.11 Geometrically and materially nonlinear analysis with imperfections explicitly included (GMNIA)
- 4.3 Shell boundary conditions
- 4.4 Verification by the partial factor method
- Table 4.1 — Partial factors for resistance
- Table 4.2 (NDP) — Numerical values for partial factors for resistance for shell structures outside the scope of EN 1993-3, EN 1993-4-1 and EN 1993-4-2
- 5 Materials and geometry [Go to Page]
- 5.1 Material properties
- 5.2 Design values of geometrical data
- 5.3 Geometrical tolerances and geometrical imperfections
- 6 Structural analysis [Go to Page]
- 6.1 Types of design [Go to Page]
- 6.1.1 Stress design [Go to Page]
- 6.1.1.1 General
- 6.1.1.2 Primary stresses
- 6.1.1.3 Secondary stresses
- 6.1.1.4 Local stresses
- 6.1.2 Design using standard formulae
- 6.1.3 Design by computational analysis
- 6.2 Stress resultants and stresses in shells [Go to Page]
- 6.2.1 Stress resultants in the shell
- 6.2.2 Modelling of the shell for analysis [Go to Page]
- 6.2.2.1 Geometry
- 6.2.2.2 Boundary conditions
- Table 6.1 — Boundary conditions for shell segments [Go to Page]
- 6.2.2.3 Actions and environmental influences
- 6.2.3 Types of analysis
- Table 6.2 — Types of shell analysis [Go to Page]
- 6.3 Ultimate limit states to be considered [Go to Page]
- 6.3.1 LS1: Plastic failure
- 6.3.2 LS2: Cyclic plasticity
- 6.3.3 LS3: Buckling
- 6.3.4 LS4: Fatigue
- 6.4 Concepts for the limit state verifications [Go to Page]
- 6.4.1 General
- 7 Plastic failure Limit State (LS1) [Go to Page]
- 7.1 Design values of actions
- 7.2 Stress design [Go to Page]
- 7.2.1 Design values of stresses
- 7.2.2 Design values of resistance
- Figure 7.1 — Joint efficiency of lap joints (LS1) [Go to Page]
- 7.2.3 Stress limitation
- 7.3 Design by computational MNA or GMNA analysis
- 7.4 Design using standard formulae
- 8 Cyclic plasticity Limit State (LS2) [Go to Page]
- 8.1 Design values of actions
- 8.2 Stress design [Go to Page]
- 8.2.1 Design values of stress range
- 8.2.2 Design values of resistance
- 8.2.3 Stress range limitation
- 8.3 Design by computational GMNA analysis [Go to Page]
- 8.3.1 Design values of total accumulated plastic strain
- 8.3.2 Total accumulated plastic strain limitation
- 8.4 Design using standard formulae
- 9 Buckling Limit State (LS3) [Go to Page]
- 9.1 Design values of actions
- 9.2 Special definitions and symbols
- 9.3 Buckling-relevant boundary conditions
- Figure 9.1 — Schematic examples of simple boundary conditions for LS3
- Figure 9.2 — Schematic examples of ring boundary conditions for LS3
- Figure 9.3 — Schematic examples of multi-segment shells [Go to Page]
- 9.4 Buckling-relevant geometrical tolerances [Go to Page]
- 9.4.1 General
- Figure 9.4 — Consistent choice of imperfection amplitude, using as an example
- Table 9.1 — Required tolerance dependent on the shell stress state [Go to Page]
- 9.4.2 Assessment of the dominant membrane stress at any location
- 9.4.3 Out-of-roundness tolerance
- Figure 9.5 — Measurement of diameters for assessment of out-of-roundness
- Table 9.2 — Values for out-of-roundness tolerance parameter Ur,max [Go to Page]
- 9.4.4 Unintended eccentricity tolerance
- Figure 9.6 — Unintended eccentricity and intended offset at a joint
- Table 9.3 — Values for unintended eccentricity tolerances [Go to Page]
- 9.4.5 Dimple tolerances
- Table 9.4 — Values for dimple tolerance parameters U0x,max and U0θ,ref
- Figure 9.7 — Measurement of depths δ0 of initial dimples on the meridian
- Figure 9.8 — Measurement of depths δ0 of initial dimples on the circumference [Go to Page]
- 9.4.6 Interface flatness tolerance
- 9.5 Stress design [Go to Page]
- 9.5.1 Design values of stresses
- 9.5.2 Design resistance (buckling strength)
- 9.5.3 Stress limitation (buckling strength verification)
- 9.6 Design using reference resistances [Go to Page]
- 9.6.1 Principle
- 9.6.2 Design value of actions
- 9.6.3 Design value of resistance
- 9.6.4 Buckling strength verification
- 9.7 Design by computational analysis using LBA and MNA analyses [Go to Page]
- 9.7.1 Design value of actions
- 9.7.2 Design value of resistance [Go to Page]
- 9.7.2.1 General
- 9.7.2.2 Reference elastic critical buckling resistance LBA
- 9.7.2.3 Reference plastic resistance MNA
- Figure 9.9 — Definition of plastic reference plastic resistance Rpl and reference elastic critical buckling resistance Rcr derived from MNA and LBA analyses respectively [Go to Page]
- 9.7.2.4 Elastic-plastic resistance assessment
- 9.7.3 Buckling strength verification
- 9.8 Design by computational analysis using GMNIA analysis [Go to Page]
- 9.8.1 Design values of actions
- 9.8.2 Design value of resistance
- Figure 9.10 — Definition of buckling resistance from a GMNIA analysis
- Table 9.5 — Values for the dimple imperfection amplitude parameter Un [Go to Page]
- 9.8.3 Buckling strength verification
- 10 Fatigue Limit State (LS4) [Go to Page]
- 10.1 Design values of actions
- 10.2 Stress design [Go to Page]
- 10.2.1 General
- 10.2.2 Stress calculation methods
- Table 10.1 — Values for the stress concentration factor kf,imp to compensate for unintended eccentricities not accounted for in the analysis [Go to Page]
- 10.2.3 Multiaxial stress fields
- 10.2.4 Design values of resistance (fatigue strength)
- 10.2.5 Fatigue verification
- Annex A (informative) Membrane theory stresses in unstiffened shells
- A.1 Use of this Annex
- A.2 Scope and field of application
- A.3 General
- A.3.1 Action affects and resistances
- A.3.2 Notation
- A.3.3 Boundary conditions
- A.3.4 Sign convention
- A.4 Cylindrical shells
- Table A.1 — Loads inducing axial (meridional) membrane stresses
- Table A.2 — Loads inducing circumferential membrane stresses
- Table A.3 — Loads inducing membrane shear stresses
- A.5 Conical shells
- Table A.4 — Loads inducing axial (meridional) membrane stresses
- Table A.5 — Loads inducing circumferential membrane stresses
- Table A.6 — Loads inducing membrane shear stresses
- A.6 Spherical shells
- Table A.7 — Loads inducing membrane stresses
- Annex B (informative) Formulae for plastic reference resistances of unstiffened shells and circular plates
- B.1 Use of this Annex
- B.2 Scope and field of application
- B.3 General
- B.3.1 Resistances
- B.3.2 Notation
- B.3.3 Boundary conditions
- B.4 Uniform unstiffened cylindrical shells
- B.4.1 Radial ring line load
- Figure B.1 — Radial ring line load on a cylinder
- B.4.2 Radial outward ring line load and axial tension
- Figure B.2 — Radial ring line load with axial tension on a cylinder
- B.4.3 Radial ring line load, internal pressure and axial load
- Figure B.3 — Radial ring line load with internal pressure and axial load on a cylinder
- Table B.1 — Determination of the length measure ℓm
- B.5 Cylindrical shells with local ring stiffeners
- B.5.1 Radial line ring load alone
- Figure B.4 — Radial line ring load on a ring stiffener attached to a cylinder
- B.5.2 Radial line ring load with axial load
- Figure B.5 — Radial line ring load on a ring stiffener attached to a cylinder with axial load
- B.5.3 Radial line ring load, internal pressure and axial load
- Figure B.6 — Radial line ring load on a ring stiffener attached to a cylinder with axial load and internal pressure
- Table B.2 — Parameters in the plastic resistance evaluation
- B.6 Junctions between conical and cylindrical shells
- B.6.1 Meridional forces alone (simplified)
- Figure B.7 — Cone-cylinder junction under only meridional forces
- B.6.2 Internal pressure and meridional forces
- Figure B.8 — Cone-cylinder junction with internal pressure and meridional forces
- Table B.3 — Equivalent thickness evaluation
- Table B.4 — Parameters for plastic resistance evaluation
- B.7 Circular plates with axisymmetric boundary conditions
- B.7.1 Uniform transverse pressure with simply supported boundary
- Figure B.9 — Simply supported circular plate under uniform transverse pressure
- B.7.2 Central circular patch of transverse pressure with simply supported boundary
- Figure B.10 — Simply supported circular plate under central circular patch of transverse pressure
- B.7.3 Uniform transverse pressure with clamped boundary
- Figure B.11 — Clamped supported circular plate under uniform transverse pressure
- B.7.4 Central circular patch of transverse pressure with clamped boundary
- Figure B.12 — Clamped supported circular plate under central circular patch of transverse pressure
- Annex C (informative) Formulae for linear elastic membrane and bending stresses in unstiffened cylindrical shells and circular plates
- C.1 Use of this Annex
- C.2 Scope and field of application
- C.3 General
- C.3.1 Action effects
- C.3.2 Notation
- C.3.3 Boundary conditions
- C.4 Clamped base cylindrical shells
- C.4.1 Uniform internal pressure
- Figure C.1 — Clamped cylinder under uniform internal pressure
- Table C.1 — Maximum stress values
- C.4.2 Axial loading
- Figure C.2 — Clamped cylinder under axial load
- Table C.2 — Maximum stress values
- C.4.3 Uniform internal pressure with axial loading
- Figure C.3 — Clamped cylinder under axial load with internal pressure
- Table C.3 — Maximum stress values
- C.4.4 Hydrostatic internal pressure
- Figure C.4 — Clamped cylinder under hydrostatic internal pressure
- Table C.4 — Maximum stress notation
- Table C.5 — Maximum stress values for different lengths ℓp
- C.4.5 Radial outward base displacement
- Figure C.5 — Clamped cylinder with radial outward base displacement
- Table C.6 — Maximum stress values
- C.4.6 Uniform temperature rise
- Figure C.6 — Clamped cylinder with uniform temperature rise
- Table C.7 — Maximum stress values
- C.5 Pinned base cylindrical shells
- C.5.1 Uniform internal pressure
- Figure C.7 — Pinned cylinder under uniform internal pressure
- Table C.8 — Maximum stress values
- C.5.2 Axial loading
- Figure C.8 — Pinned cylinder under axial load
- Table C.9 — Maximum stress values
- C.5.3 Uniform internal pressure with axial loading
- Figure C.9 — Pinned cylinder under axial load with internal pressure
- Table C.10 — Maximum stress values for different axial to internal pressure ratios
- C.5.4 Hydrostatic internal pressure
- Figure C.10 — Pinned cylinder under hydrostatic internal pressure
- Table C.11 — Maximum stress notation
- Table C.12 — Maximum stress values for different lengths ℓp
- C.5.5 Radial outward base displacement
- Figure C.11 — Pinned cylinder with radial outward base displacement
- Table C.13 — Maximum stress values
- C.5.6 Uniform temperature rise
- Figure C.12 — Pinned cylinder under uniform temperature rise T
- Table C.14 — Maximum stress values
- C.5.7 Boundary rotation
- Figure C.13 — Pinned cylinder with base rotation βϕ
- Table C.15 — Maximum stress values
- C.6 Internal conditions in cylindrical shells
- C.6.1 Step change of internal pressure
- Figure C.14 — Abrupt step change in internal pressure
- Table C.16 — Maximum stress values
- C.6.2 Hydrostatic internal pressure termination
- Figure C.15 — Termination of a hydrostatic internal pressure
- Table C.17 — Maximum stress notation
- Table C.18 — Maximum stress values
- C.6.3 Step change of thickness
- Figure C.16 — Step change of thickness under uniform internal pressure
- Table C.19 — Maximum stress notation
- Table C.20 — Maximum stress values for different changes in thickness
- C.7 Local ring stiffener on a cylindrical shell
- C.7.1 Radial force only on the ring
- Figure C.17 — Ring attached to uniform thickness cylinder with radial load alone
- C.7.2 Axial loading
- Figure C.18 — Ring attached to uniform thickness cylinder under axial load
- C.7.3 Uniform internal pressure
- Figure C.19 — Ring attached to uniform thickness cylinder under uniform internal pressure
- Table C.21 — Maximum stress notation
- Table C.22 — Maximum stress values for different values of κ
- C.8 Circular plates with simply supported boundary conditions
- C.8.1 Uniform transverse load
- Figure C.20 — Circular plate with simply supported edges under uniform transverse pressure
- C.8.2 Local circular distributed load
- Figure C.21 — Circular plate with simply supported edges under local transverse pressure
- C.9 Circular plates with clamped boundary conditions
- C.9.1 Uniform load
- Figure C.22 — Circular plate with clamped edges under uniform transverse pressure
- Table C.23 — Maximum stress values
- C.9.2 Plate with fixed boundary: local distributed load
- Figure C.23 — Circular plate with clamped edges under local transverse pressure
- Table C.24 — Maximum bending and von Mises stress values
- Annex D (normative) Formulae to determine the buckling resistance of unstiffened shells when using stress design
- D.1 Use of this annex
- D.2 Scope and field of application
- D.3 Cylindrical shells of constant wall thickness: basic load cases
- D.3.1 Notation and boundary conditions
- Figure D.1 — Cylinder geometry, membrane stresses and stress resultants
- D.3.2 Dimensionless lengths
- D.3.3 Axial (meridional) compression
- D.3.3.1 Length domains
- D.3.3.2 Critical axial buckling stresses
- D.3.3.3 Axial compression buckling capacity parameters
- Table D.1 — Values of axial compression fabrication quality parameter Qx
- D.3.3.4 Stainless steel cylinders under axial compression
- Table D.2 — Values of the capacity parameters χxh, , μx0 and μxh for cylindrical shells made of austenitic, austenitic-ferritic and ferritic steels
- Table D.3 — Formulae for the capacity parameters βx, ηx0 and ηxp for cylindrical shells made of austenitic, austenitic-ferritic and ferritic steels
- D.3.4 Circumferential (hoop) compression
- D.3.4.1 Length domains
- Table D.4 — External pressure buckling factors for medium-length cylinders Cθ
- Table D.5 — External pressure buckling factors for short cylinders Cθs
- D.3.4.2 Critical circumferential buckling stresses
- D.3.4.3 Circumferential buckling capacity parameters
- Table D.6 — Values of circumferential compression fabrication quality parameter Qθ
- D.3.5 Shear (torsion)
- D.3.5.1 Length domains
- D.3.5.2 Critical shear buckling stresses
- D.3.5.3 Shear buckling capacity parameters
- Table D.7 — Values of shear fabrication quality parameter Qτ
- D.4 Cylindrical shells of constant wall thickness: combined cases
- D.4.1 Axial (meridional) compression with coexistent internal pressure
- D.4.1.1 Pressurised critical axial buckling stress
- D.4.1.2 Pressurised axial buckling capacity parameters
- D.4.2 External pressure under a wind pressure distribution
- D.4.2.1 Critical circumferential buckling pressure under wind
- Figure D.2 — Wind pressure distribution
- D.4.3 Combinations of axial (meridional) compression, circumferential (hoop) compression and shear
- Figure D.3 — Examples of interaction-relevant groups of membrane stress components
- D.5 Cylindrical shells of stepwise variable wall thickness
- D.5.1 General
- D.5.1.1 Notation and boundary conditions
- D.5.1.2 Geometry and joint offsets
- Figure D.4 — Intended offset e0 in a butt-jointed shell
- D.5.2 Axial (meridional) compression
- D.5.3 Circumferential (hoop) compression
- D.5.3.1 Critical circumferential buckling pressure and stresses
- Figure D.5 — Stepped cylinder notation
- D.5.3.2 Critical circumferential buckling pressure under wind
- D.5.3.3 Buckling strength verification for circumferential compression in a stepped wall
- D.5.3.4 Stiffening rings to resist buckling under external pressure and wind
- D.5.3.4.1 General
- D.5.3.4.2 Stiffness requirement for the top ring
- Table D.8 — Simple values of the minimum flexural stiffness of a top ring
- D.5.3.4.3 Bending moments in the top ring
- D.5.4 Shear
- D.5.4.1 Critical shear buckling stresses
- D.5.4.2 Buckling strength verification for shear
- D.6 Lap jointed cylindrical shells
- D.6.1 General
- D.6.1.1 Definitions
- D.6.1.1.1 Circumferential lap joint
- D.6.1.1.2 Meridional lap joint
- D.6.1.2 Geometry and stress resultants
- Figure D.6 — Lap jointed shell
- D.6.2 Axial (meridional) compression
- D.6.3 Circumferential (hoop) compression
- D.6.4 Shear
- D.7 Complete and truncated conical shells
- D.7.1 General
- D.7.1.1 Notation
- Figure D.7 — Cone geometry, membrane stresses and stress resultants
- D.7.1.2 Boundary conditions
- D.7.1.3 Geometry
- D.7.2 Design buckling stresses
- D.7.2.1 Equivalent cylinder
- D.7.2.2 Meridional compression
- D.7.2.3 Circumferential (hoop) compression
- D.7.2.4 Uniform external pressure
- D.7.2.5 Shear
- D.7.2.6 Uniform torsion
- D.7.3 Buckling strength verification
- D.7.3.1 Meridional compression
- D.7.3.2 Circumferential (hoop) compression and uniform external pressure
- D.7.3.3 Shear and uniform torsion
- Annex E (normative) Formulae to determine the buckling resistance of unstiffened shells when using reference resistance design
- E.1 Use of this annex
- E.2 Scope and field of application
- E.3 Cylindrical shells under uniform global bending
- E.3.1 General
- E.3.1.1 Notation
- Figure E.1 — Cylinder under uniform global bending
- E.3.1.2 Boundary conditions
- E.3.1.3 Loading conditions
- E.3.1.4 Length characterisation
- E.3.2 Buckling resistance under uniform global bending
- E.3.2.1 Reference plastic resistance
- E.3.2.2 Reference elastic critical buckling resistance
- E.3.2.3 Length domains
- E.3.2.4 Buckling capacity parameters
- Table E.1 — Values of fabrication quality parameter Qb
- E.3.2.5 Characteristic buckling resistance
- E.3.3 Buckling resistance under uniform global bending with axial compression
- E.3.3.1 General
- E.3.3.2 Interaction verification
- E.4 Spherical dome shells
- E.4.1 General
- E.4.1.1 Scope
- E.4.1.2 Notation
- Figure E.2 — Spherical shell geometry
- E.4.1.3 Support and boundary conditions
- Figure E.3 — Illustrations of different support conditions
- E.4.1.4 Loading conditions
- Figure E.4 — Spherical dome subjected to uniform external pressure
- E.4.2 Tolerances for spherical shells
- E.4.3 Buckling design for uniform external pressure
- E.4.3.1 Limitation on buckling calculations
- E.4.3.2 Reference elastic critical buckling resistance
- E.4.3.3 Reference plastic resistance
- E.4.3.4 Buckling capacity parameters for simple conditions
- Table E.2 — Values of dome fabrication quality parameter Qs
- E.4.3.5 Characteristic buckling resistance
- E.4.4 Buckling strength verification for uniform external pressure
- Bibliography [Go to Page]