BASIS OF STRUCTURAL DESIGN (EN1990:2002) Ultimate limit state verification (EN1990,cl.6.4.1(1)P) The following ultimate limit states shall be verified as relevant: EQU: Loss of equilibrium of the structure, (considering for sliding, overturning or uplift) STR: Internal failure or excessive deformation of the structure of structural member (Design of structural for strength of members and frames), GEO: Failure due to excessive deformation of the ground (Design of structural members such as footing, piles, basement walls, etc.), FAT: Fatigue failure of the structure or structural member. Design working life (CYS NA EN1990,Table 2.1) Design working life category Indicative design working life (years) Examples 1 10 Temporary structures (1) 2 10 – 25 Replaceable structural parts, e.g. gantry girders, bearings 3 15 – 30 Agricultural and similar structures 4 50 Building structures and other common structures 5 100 Monumental building structures, bridges, and other civil engineering structures (1) Structures or parts of structures that can be dismantled with a view to being re-used should not be considered as temporary. In the case of replaceable structural parts the design life for the structural determination of loads should be the design life of the structure. Design Working life Ultimate Limit State (ULS) Ultimate Limit State Concern (EN1990,cl.3.3(1)P) Safety of people, Safety of the structure Protection of the contents Design situations (EN1990,cl.3.2(2)P) Persistent design situation: Normal use condition Transient design situation: Temporary condition, e.g. during execution or repair Accidental design situation: Exceptional condition, e.g. fire, explosion, impact. Seismic design situation: Structure subject to seismic events.
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BASIS OF STRUCTURAL DESIGN
(EN1990:2002)
Ultimate limit state verification
(EN1990,cl.6.4.1(1)P)
The following ultimate limit states shall be verified as relevant:
EQU: Loss of equilibrium of the structure, (considering for sliding, overturning or uplift)
STR: Internal failure or excessive deformation of the structure of structural member (Design of structural for
strength of members and frames),
GEO: Failure due to excessive deformation of the ground (Design of structural members such as footing,
piles, basement walls, etc.),
FAT: Fatigue failure of the structure or structural member.
Design working life
(CYS NA EN1990,Table 2.1)
Design working life
category
Indicative design
working life (years)
Examples
1 10 Temporary structures (1)
2 10 – 25 Replaceable structural parts, e.g. gantry girders,
bearings
3 15 – 30 Agricultural and similar structures
4 50 Building structures and other common structures
5 100 Monumental building structures, bridges, and other
civil engineering structures
(1) Structures or parts of structures that can be dismantled with a view to being re-used should
not be considered as temporary.
In the case of replaceable structural parts the design life for the structural determination of loads should be
the design life of the structure.
Design Working life
Ultimate Limit State (ULS)
Ultimate Limit State Concern
(EN1990,cl.3.3(1)P)
Safety of people,
Safety of the structure
Protection of the contents
Design situations
(EN1990,cl.3.2(2)P)
Persistent design situation: Normal use condition
Transient design situation: Temporary condition, e.g. during execution or repair
Accidental design situation: Exceptional condition, e.g. fire, explosion, impact.
Seismic design situation: Structure subject to seismic events.
Ultimate Limit State (ULS)
COMBINATION OF ACTIONS FOR PERSISTENT/TRANSIENT DESIGN SITUATION
(EN1990,cl.6.4.3.2)
Persistent and transient design situation – EQU Equation 6.10 (Set A)
6.10 Ed=ΣγG Gk +γQ Qk1 + γQ ψ0,2 Qk2
Action Favourable
γ
Unfavourable
γ
Permanent (dead,
earth), γG 0.9 1.1
Variable (imposed,
wind), γQ 0 1.5
Note: Single source is not applicable for EQU design situation. Different γ factors can be used in favourable and unfavourable
areas.
Persistent and transient design situation – STR/GEO Equation 6.10, 6.10a & 6.10b (Set B)
6.10
6.10a
6.10b
Ed=ΣγG Gk +γQ Qk1 + γQ ψ0,2 Qk2
Ed=ΣξγG Gk +γQ ψ0,1 Qk1 + γQ ψ0,2 Qk2
Ed=ΣγG Gk +γQ Qk1 + γQ ψ0,2 Qk2
Action Favourable
γ
Unfavourable
γ
Permanent (dead,
earth), γG 1.0 1.35
Variable (imposed,
wind), γQ 0 1.5
Note: Single source is applicable for STR/GEO design situation.
Persistent and transient design situation – GEO Equation 6.10 (Set C)
6.10 Ed=ΣγG Gk +γQ Qk1 + γQ ψ0,2 Qk2
Action Favourable
γ
Unfavourable
γ
Permanent (dead,
earth), γG 1.0 1.0
Variable (imposed,
wind), γQ 0 1.3
Note: Single source is applicable for STR/GEO design situation.
Important notes
(EN1990,cl.3.2(2)P)
Approach 2 (CYS NA EN1990,Table.A1.2(B)) should be used for the
design of the structural members of substructure (i.e. footings, piles,
basement walls, etc.) (CYS NA EN1990,cl. 2.2.3.4).
Actions that cannot exist simultaneously due to physical of functional
reasons should not be considered together in combination.
The use of expression 6.10a and 6.10b lead to a more economic
design in most circumstances.
Summary table of partial, combination and reduction factors for the STR and GEO ultimate limit states for