SIST EN 1998-2:2006/A1:2009

SLOVENSKI STANDARD
01-junij-2009
(YURNRG3URMHNWLUDQMHNRQVWUXNFLMQDSRWUHVQLKREPRþMLKGHO0RVWRYL
Eurocode 8: Design of structures for earthquake resistance - Part 2: Bridges
Eurocode 8: Auslegung von Bauwerken gegen Erdbeben - Teil 2: Brücken
Eurocode 8: Calcul des structures pour leur résistance aux séismes - Partie 2: Ponts
Ta slovenski standard je istoveten z: EN 1998-2:2005/A1:2009
ICS:
91.120.25 =DãþLWDSUHGSRWUHVLLQ Seismic and vibration
YLEUDFLMDPL protection
93.040 Gradnja mostov Bridge construction
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 1998-2:2005/A1
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2009
ICS 91.120.25; 93.040
English Version
Eurocode 8: Design of structures for earthquake resistance -
Part 2: Bridges
Eurocode 8: Calcul des structures pour leur résistance aux Eurocode 8: Auslegung von Bauwerken gegen Erdbeben -
séismes - Partie 2: Ponts Teil 2: Brücken
This amendment A1 modifies the European Standard EN 1998-2:2005; it was approved by CEN on 12 February 2009.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for inclusion of this
amendment into the relevant national standard without any alteration. Up-to-date lists and bibliographical references concerning such
national standards may be obtained on application to the CEN Management Centre or to any CEN member.
This amendment exists in three official versions (English, French, German). A version in any other language made by translation under the
responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 1998-2:2005/A1:2009: E
worldwide for CEN national Members.

Foreword
This document (EN 1998-2:2005/A1:2009) has been prepared by Technical Committee CEN/TC 250
"Structural Eurocodes", the secretariat of which is held by BSI.
This Amendment to the European Standard EN 1998-2:2005 shall be given the status of a national
standard, either by publication of an identical text or by endorsement, at the latest by September 2009,
and conflicting national standards shall be withdrawn at the latest by March 2010.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent
rights.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus,
Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia,
Slovenia, Spain, Sweden, Switzerland and United Kingdom.
1) In 1.6.6 Further symbols used in Section 7 and Annexes J, JJ and K of EN 1998-2
Add:
d maximum total displacement of each isolator unit i
m,i
d offset displacement of isolator i
G,i
2) In 7.5.2.4 Variability of properties of the isolator units
Replace (5) and (6) by:
(5) The nominal design properties of simple low-damping elastomeric bearings in accordance
with 7.5.2.3.3(5) and (6), may be assumed as follows:
− Shear modulus  G = α G
b g
NOTE: The value of α typically ranges from 1,1 to 1,4. The appropriate value is best determined by
testing of the device.
− where G is the value of the “apparent conventional shear modulus” in accordance with EN
g
1337-3:2005;
− Equivalent viscous damping ξ = 0,05
eff
(6) The variability of the design properties of simple low-damping elastomeric bearings, due
to ageing and temperature, may be limited to the value of G and assumed as follows:
b
− LBDPs G = G
b,min b
− UBDPs depend on the “minimum bearing temperature for seismic design” T (see J.1(2))
min,b
as follows:
o
- when T ≥ 0 C
min,b
G = 1,2 G
b,max b
o
- when T < 0 C
min,b
the value of G should correspond to T .
b,max min,b
o
NOTE: In the absence of relevant test results, the G value for T < 0 C may be obtained from G
b,max min,b b
adjusted regarding temperature and ageing in accordance with the λ values corresponding to K , specified in
max p
Tables JJ.1 and JJ.2.
3) In 7.5.4 Fundamental mode spectrum analysis
Replace (3) by:
(3) This leads to the results shown in Table 7.1 and Figure 7.4.
Table 7.1: Spectral acceleration S and design displacement d
e cd
T S d
eff e cd
T T
C eff
2,5 a Sη d
g eff C
T ≤ T < T
C eff D
T T
eff C
T T T
C D D
2,5 α Sη d
T ≤ T ≤ 4 s C
g
D eff eff
T T
eff C
where:
a = γ a (7.7)
g I g,R
and
0,625
d = a Sη T (7.8)
C eff C
2 g
π
The value of η should be taken from the expression
eff
0,10
η = ≥ 0,40 (7.9)
eff
0,05+ξ
eff
Maximum shear force
V = M S = K d (7.10)
d d e
eff cd
where:
S, T and T are parameters of the design spectrum depending on the ground type, in
C D
accordance with 7.4.1(1)P and EN 1998-1:2004, 3.2.2.2;
a is the design ground acceleration on type A ground corresponding to the importance
g
category of the bridge;
γ is the importance factor of the bridge; and
I
a is the reference design ground acceleration (corresponding to the reference return period).
g,R
Figure 7.4: Acceleration and displacement spectra
NOTE 1: The elastic response spectrum in EN 1998-1:2004, 3.2.2.2(1)P applies up to periods of 4 s. For
values of T longer than 4 s the elastic displacement response spectrum in EN 1998-1:2004, Annex A may
eff
be used and the elastic acceleration response spectrum may be derived from the elastic displacement
response spectrum by inverting expression (3.7) in EN 1998-1:2004. Nonetheless, isolated bridges with T
eff
> 4 s deserve special attention, due to their inherently low stiffness against any horizontal action.
NOTE 2: For a pier of height H with a displacement stiffness K (kN/m), supported by a foundation with
i si
translation stiffness K (kN/m), rotation stiffness K (kNm/rad), and carrying isolator unit i with effective
ti fi
stiffness K (kN/m), the composite stiffness K is (see Figure 7.5N):
bi eff,i
1 1 1 H
i
= + + + (7.11N)
K
K K K K
eff,i bi si fi
ti
F
i
The flexibility of the isolator and its relative displacement d = typically is much larger than the other
bi
K
bi
components of the superstructure displacement. For this reason the effective damping of the system depends
only on the sum of dissipated energies of the isolators, ΣE , and the relative displacement of the isolator is
Di
practically equal to the displacement of the superstructure at this point (d /d = K /K ≅ 1).
bi id eff,i bi
Key
A – Superstructure
B – Isolator i
C – Pier i
Figure 7.5N: Composite stiffness of pier and isolator i

4) In 7.6.2 Isolating system
Replace (1)P to (5) by:
(1)P The required increased reliability of the isolating system (see 7.3(4)P) shall be
implemented by designing each isolator i for increased design displacements d :
bi,a
d = γ d (7.19)
bi,a IS bi,d
where γ is an amplification factor that is applied only on the design seismic displacement d of
IS bi,d
each isolator i resulting from one of the procedures specified in 7.5.
If the spatial variability of the seismic action is accounted for through the simplified method of
3.3(4), (5), (6) and (7)P, the increased design displacements shall be estimated by application of
the rule of 3.3(7)P, where the displacements d due the inertia response determined in
bi,d
accordance with one of the methods in 7.5 shall be amplified in accordance with expression
(7.19) above, while those corresponding to the spatial variability determined in accordance with
3.3.(5) and (6), need not be amplified.
NOTE The value ascribed to γ for use in a country may be defined in its National Annex. The
IS
recommended value is γ = 1,50.
IS
(2)P The maximum total displacement of each isolator unit in each direction d shall be
m,i
verified from expression (7.19a) by adding to the above increased design seismic displacement,
the offset displacement d potentially induced by:
G,i
a) the permanent actions;
b) the long-term deformat
...