overview of eurocodes
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Overview of Eurocodes
9 Introduction to EN 1990
as s o es gn limit state design
combination of actions
9 Introduction to EN 1991
9 Introduction to EN 1993
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Sco e of Eurocodes
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EN 1991 - Actions on structures
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Sco e of Eurocodes
Remaining 8 codes are material-specific:
EN 1992 - Design of concrete structures
EN 1993 - Design of steel structures
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EN 1995 - Design of timber structures EN 1996 - Design of masonry structures
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EN 1998 - Design of structures for earthquakes
EN 1999 - Design of aluminium structures
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s a es a a s ruc ure s a e
designed adequately and you are required to
ruc ura res s ance
Serviceability Durability
Fire resistance
Robustness
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Subscript Definition Example
Ed Design value of an effect MEd Design bending moment
Rd Design resistance MRd Design resistance for bending
El Elastic ro ert W Elastic section modulus
Pl Plastic property Wpl Plastic section modulus
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Actions (F):
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indirect actions - temperature changes, vibrations
both essentially produce same effect
Effects of action(E): on structural members and whole structure
for example bending moments, shear forces,
capacity of a structural element to resist bendingmoment, axial force, shear, etc.
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Permanent actions G : are those that essentiall
do not vary with time such as self-weight of
structure fixed e ui ment
Variable actions Q : leadin and non-leadin
actions, and those that can vary with time such
as imposed loads, wind loads and snow loads
Accidental actions (A): are usually of short
duration, but high magnitude such asexplosions, impacts
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Outlined in EN 1990 Basis of structural Desi n
Based on limit state design
Principal limit states
Ultimate limit state concerned with colla se
yielding; buckling; overturning
Serviceability limit state, concerned with function Deflection; vibration
Other limit states
Fire resistance Durabilit
robustness
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Limit states: s a es eyon w c e s ruc ure can no
longer meets its original design intention
Ultimate limit states:
similar forms of structural failure, for e.g.
,
states correspond to function, beyond which
for e.g. deflection, vibration
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Define relevant limit states
Determine appropriate combined actions {F}, e.g.
temperature changes
e erm ne es gn e ec s
bending moments deflections
Determine desi n resistance R
Ensure no limit state is exceeded {R > E}
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Characteristic values of actions
Representative value of action above which not more than a
small percentage of the action may exceed during the design
working life Design values
es gn va ues use o c ec m s a e con on
Design value of actionshe characteristic value of action multiplied by the
relevant partial factor for action
Design value of strength
The characteristic value of strength divided by the
re evan par a ac or or ma er a
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values for both actions material to account for
variabilit
The value of depends on:
e m s a e un er cons era on
The variable to which it is applied The context e.g. is an action beneficial in relation
to the considered effect
F for actions (loading)
M
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Action Partial factor
Ultimate limit
state
Permanent Action (G)
Unfavourable conditions G = 1.35
= .
Variable Action (Q)
Unfavourable conditions Q = 1.50F
avourable conditions Q = 0.0
Serviceability Permanent Action (G) G
= 0.0
Var a e Act on (Q) Q = 1.00
M
M0 1.00 (1.00) Cross-sectionsM
. .
M2 1.25 (1.10) fracture
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Fundamental combinations of actions may be determined
1.5 combination factor
from EN 1990 using Equation 6.10:
other variable actions
++
,,0,k,11,,, ikiiQQjkjG
QQG (6.10)=
. permanen ac ons .
variable actionscombination factor
Load factors 1.35 and 1.5 are a lied when actions are
unfavorable
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Identif leadin variable action Q ,
The leading variable action is the one that leads to the
most unfavourable effect (i.e. the critical combination)
To generate the various load combinations, eachvariable action should be considered in turn as the
.
Other variable actions reduced by a combination factor
Accounts for probability of simultaneous occurrence of
multiple variable loads
Imposed load = 0.7
Wind load = 0.6 (SS NA = 0.5)
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the load combinations about EC 3Gk= Dead load (permanent action);
Qk= imposed load;
Wk= wind load
Dead load & imposed load 1.35Gk+ 1.5Qk
. k . k
Dead load, imposed and
wind load1.35Gk+ 1.50Wk+ 1.05Qkor
1.35G + 1.50 + 0.75W
*1.05 = 0.7 1.50Leading variable action 0.75 = 0.5 1.50
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EN 1991-1 contains the following sub-parts: EN 1991-1-1: Densities, self-weight, imposed
loads
EN 1991-1-2: Fire
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EN 1991-1-4: Wind actions
EN 1991-1-5: Thermal actions
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EN 1991-1-7: Accidental actions Im act and
explosions)
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Overview of EN 1993 Eurocode 3
Eurocode 3 EC3 contains 6 arts:
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EN 1993-2: Bridges
EN 1993-3: Towers, masts & chimneys
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EN 1993-5: Piling
EN 1993-6: Crane supporting structures
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Eurocode 3 Part 1 has 12 sub-parts:
EN 1993-1-1: General rules
- - : re EN 1993-1-3: Cold-formed thin gauge
EN 1993-1-4: Stainless steel
EN 1993-1- : P ate e ements
EN 1993-1-6: Shells
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EN 1993-1-7: Plates transversely loaded
EN 1993-1-8: Joints
EN 1993-1-9: Fatigue
EN 1993-1-10: Fracture toughness
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EN 1993-1-12: High strength steels
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Ever Eurocode will contain a National Annex
The National Standard implementing Eurocode
(e.g. SS EN 1993-1-1: 2010) must comprise thefull, unaltered text of that Eurocode, including all
Annexes.
e a ona nnex may on y nc u e n orma on
on those parameters within clauses that have
. .
EN 1993-1-1: 2010)
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Minor axis z-z
Longitudinal axis of element x-x
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Major axis y-yMinor axis z-z
Longitudinal axis of element x-x
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M t i l P ti
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Material Properties Nominal values of yield strengthfyand ultimate tensile
strengthfu for hot-rolled structural steel can be taken froma e 3.1 o EC3-1-1
Table 3.1 of EC3-1-1 (part)
Standardand steel
Nominal thickness of the element (mm)
T40mm 40mm 80mm
fy(N/mm2) fu (N/mm
2) fy(N/mm2) fu (N/mm
2)
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S235 235 360 215 360
S275 275 430 255 410
S335 335 510 335 470
S450 440 550 410 550
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M t i l P ti
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Material Properties
The National Annex may give the choice for the value of
and which could be obtained from either the Product
Standards (EN 10025 for hot-rolled sections) or by using
Table 3.1.
The National Annex of Singapore (NA to SS EN 1993-1-1)choose the earlier. The nominal values of thefyandfu for
structura stee s ou e t ose o ta ne rom t e
product standards.
n ngapore, non- ma er a s are a owe o e use .
Further information on the values offyandfu for steel
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given in BC1: 2012a.a BC1: 2012 Design Guide on Use of Alternative Structural Steel to BS5950 and
Eurocode 3, Building and Construction Authority, Singapore
(ISBN: 978-981-05-9754-2)
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M t i l P ti
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Material Properties
Values of yield strength for the most common grades of- -
S335) form Table 3.1, the product standard EN 10025-2
Thickness EC 32
EN 10025
2
BS 5950
2
EC 3
2
EN 10025
2
BS 5950
2
y y y y y y
S275 S275 S275 S335 S335 S335
40 275 265 265 355 345 345
63 255 255 255 335 335 335
80 255 245 245 335 325 325
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es gn va ues o ma er a coe c en s o e use n
EN 1993-1:
Modulus of elasticityE = 210 000 N/mm2
Shear modulus:
G = E/2(1 +
) = 81 000 N/mm2
Poissons ratio:
= 0.3
Coefficient of thermal expansion:
a= 12 10-6/
(for temperatures below 100 )
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