EARTHQUAKE PLANNING AND
PROTECTION ORGANIZATION
(E.P.P.O.)
COUNCIL OF EUROPE
EUROPEAN CENTRE ΟΝ
PREVENTION
AND FORΕCASTING
OF EARTHQUAKES
(E.C.P.F.E.)
ATHENS WORKSHOP / EC 8–3 : 2005 and nGCSI : 2012
APRIL 12, 2013
MAIN DIFFERENCES BETWEEN THE TWO CODES
M. CHRONOPOULOS, LRC/NTUA/GR
CODE for STRUCTURAL INTERVENTIONS (2012)
E
Eaarrtthhqquuaakkee P
Pllaannnniinngg aanndd P
Prrootteeccttiioonn O
Orrggaanniizzaattiioonn ooff G
Grreeeeccee ((E
E..P
P..P
P..O
O..))
TEAM FOR DEVELOPMENT OF CODE OF INTERVENTIONS ON REINFORCED CONCRETE BUILDINGS
HARMONIZATION TEAM OF CODE OF INTERVENTIONS TO EUROCODES
ENGLISH TEMPORARY VERSION
CODE OF STRUCTURAL INTERVENTIONS 2012
FINAL HARMONIZED TEXT
AUGUST 2012
• Assessment and Retrofitting of existing structures for non-seismic
actions is not yet covered by the relevant material-dependent EuroCodes (or existing National Codes).
• The “framework” of the EC 8-3 (and the nGCSI) was specifically
developed because :

For many older structures, seismic resistance was not
considered during the original design/construction, whereas
non-seismic actions were catered for, at least by means of
“traditional” construction rules.

Seismic hazard evaluations in accordance with present
knowledge may indicate the need for retrofitting
programmes and campaings (“active” or “passive”).

Damage caused by earthquakes may create the need for
major and costly structural interventions (repair/strengthening),
not to mention other consequences.
DESIGN OF BUILDINGS FOR EARTHQUAKE RESISTANCE
ASSESSMENT AND RETROFITTING or STRUCTURAL (ASSESSMENT AND) INTERVENTIONS
• The EC8-3 : 2005
Main Body/Six (short) Chapters / approx. 30 pages, and
Informative Annex A for RC Structures / approx. 20 pages.
• The nGCSI : 2012, for RC Structures (only),
Final Harmonized Text
Main Body and (Normative) Commentary / Eleven Chapters /
approx. 350 pages.
A new Chapter (no. 12) on Structural Additions or/and
Changes of Use.
Retrofitting = Str. Interventions, Repair or/and Strengthening
THE RATIONALISM OF THE nGCSI : 2012, ITS CONTENTS
1.
2.
3.
4.
SCOPE-FIELD OF APPLICATION-OBLIGATIONS AND RESPONSIBILITIES
BASIC PRINCIPLES, CRITERIA AND PROCEDURES
INVESTIGATION AND DOCUMENTATION OF THE EXISTING BUILDING
BASIC DATA, ASSESSMENT AND REDESIGN
+ Four (4) Appendices (normative)
5. ANALYSIS, BEFORE AND AFTER THE INTERVENTIONS
6. BASIC BEHAVIOUR MODELS
7. THE BEHAVIOUR OF EXISTING OR NEW RC ELEMENTS + INFILLS
+ Four (4) Appendices (normative)
8. DESIGN OF INTERVENTIONS
9. SAFETY VERIFICATIONS
10. REQUIRED CONTENTS OF THE DESIGN FILE, ASSESSMENT AND REDESIGN
11. CONSTRUCTION-QUALITY ASSURANCE-MAINTENANCE
NOTE 1
The definition of the LS of NC given in EC 8-3 is different than that
given in EC 8-1.
Thus, the LS of NC is closer to the actual collapse and corresponds
to the fullest exploitation of the deformation capacity of the
structural elements.
NCEC 8-1  SDEC 8-3
NOTE 2
• Distinction between “ductile” or “brittle” structural elements and
mechanisms, i.e. deformation or strength controlled ones.
See additional details and rules given by the nGCSI
(μ  2 , μφ  3).
• Distinction between “primary” (P) or “secondary” (S) seismic structural
elements, using more or less conservative estimates
of their capacities.
EC’s : S/P+S  15%
nGCSI : S/P+S  25% .
EC8-3 / STATE OF DAMAGE IN THE STRUCTURE
Three (3) LIMIT STATES (LS’s), namely
Near Collapse (NC), Significant Damage (SD) and Damage Limitation (DL).
The National Authorities decide whether all three LS’s shall be
checked, or two of them, or just one of them.
NC : Pe = 2% in Lt = 50 years, Tr = 2.475 years
SD : Pe = 10% in Lt = 50 years, Tr = 475 years
DL : Pe = 20% in Lt = 50 years, Tr = 225 years
_______________________________________________________
nGCSI : DIFFERENCES …
nGCSI / TARGET BEHAVIOUR
PERFORMANCE LEVEL, SEISMIC ACTION
PL
EQ
A/LD
B/SD
C/NC
A1
B1
C1
A2
B2
C2
10% / 50 years
100%
50% / 50 years
60%
IMPORTANCE : I / All, II / All but C2,
III and IV / A1, A2, B1
Since existing structures (old ones, damaged or not) :
(i) reflect the state of knowledge at the time of their construction,
(ii) possibly contain hidden gross errors and problems, and
(iii) may have been submitted to previous actions (accidental or not)
with unknown effects,
structural evaluation/assessment, structural intervention and redesign (if
needed) are typically subjected to a different and a more complex degree
of uncertainly than the design of new structures.
Therefore, different sets of partial safety and structural safety factors
are required, as well as different analysis, dimensioning and verification
procedures, depending (among others) on the completeness and
reliability of the information available.
INVESTIGATION / DOCUMENTATION
EC8-3 / Capacities of ductile or brittle structural elements
•
In general, mean value properties of the existing materials are used, as directly
obtained from in-situ tests and from the additional sources of information,
appropriately divided by the confidence factor (CF), accounting for the knowledge
level (KL) attained.
•
Especially for brittle primary seismic elements, their strengths shall be based on
material strengths divided by appropriate partial safety factors (γm), taking into
account that the γm values of the EC 8-1 are meant for the design of new buildings.
nGCSI : DRL and a full set of mod. γf and γm, as well as of γSd and γRd.
Mat. properties : fm or fm – S.
EC8-3 / KNOWLEDGE LEVEL (KL), CONFIDENCE FACTOR (CF)
Regarding the RC structural system, its components and its elements, for
choosing the allowable type of analysis and the appropriate confidence
factor values ...
Factors determining the appropriate knowledge level :
1) GEOMETRY
From original outline construction drawings with sample visual survey
or from full survey
2) DETAILS
See Table
3) MATERIALS
See Table
____________________________________________________________
KL1 : Limited Knowledge
CF = 1,35
KL2 : Normal Knowledge
CF = 1,20
KL3 : Full (?) Knowledge
CF = 1,00
KL
DETAILS
MATERIALS
ANALYSIS
CF
1
SIMULATED design
+
lim. in-situ inspection
DEFAULT values
+
lim. in-situ testing
LINEAR
1,35
Original design
+
lim. in-situ inspection
Original design
+
lim. in-situ testing
ALL
1,20
ALL
1,00
2
Extended in-situ inspection/testing
3
Original design
+
lim. in-situ inspection
Original design
+
lim. in-situ testing
Comprehensive in situ inspection/testing
… outline or detailed dwgs, visual, full, limited, extended, comprehensive
MIN. REQUIREMENTS FOR INSPECTION (OF DETAILS) AND TESTING (OF MATERIALS)
FOR EACH TYPE OF PRIMARY RC ELEMENT (BEAM, COLUMN, WALL)
LEVEL
DETAILS, PERCENTAGE
OF ELEMENTS
MATERIAL SAMPLES
PER FLOOR
Limited
20
1
Extended
50
2
Comprehensive
80
3
Non-destructive combined with destructive testing …
Cross-checks should be made between the data
collected from different sources to minimize uncertainties.
EC8-3 / THE q – APPROACH
Generally, not suitable for cheching the LS of NC.
For RC structures of any type :
• SD
• NC
q  1,5
q’  4/3 . q  2,0 .
Higher values may be adopted if suitably justified with reference
to the local and global available ductility (and overstrength …).
____________________________________________________________
nGCSI : A lot of provisions, rules, etc.
The m – approach …
Table 4.1 : Values of q*/q΄ ratio depending on the target
Performance level
Immediate use Life protection Collapse prevention
after the
earthquake
(Α)
(Β)
(Γ)
0,6
with
1.0<q*<1.5
1.0
1.4
Table C 4.4 : Values of behaviour factor q΄ for performance level
B (life protection)
Standards applied Favourable presence
for design (and
or absence of infill
construction)
walls (1)
Generally
unfavourable
presence of infill
walls (1)
Substantial damage Substantial damage
in primary elements in primary elements
No
Yes
No
Yes
1995<…
3.0
2.3
2.3
1.7
1985<…<1995(2)
2.3
1.7
1.7
1.3
…<1985
1.7
1.3
1.3
1.1
(1) On the role and effect of infill walls see §5.9 και §7.4.
(2) For buildings of this period, the values of the Table are valid provided
that the check for non-formation of plastic hinges in column ends is
made according to §9.3.3 (by satisfying ΣΜRc ≥1,3ΣΜRb).
For torsionally sensitive structures, or for those with at least 50% of the
mass concentrated in the upper 1/3 of their height (inverted pendula), the
values of the Table are multiplied by 2/3 but can not be lower than 1.0.
THE INFILLED RC FRAMES (OR QUASI-FRAMES)
Existing or even new/added infills …
• EC’s
…
• nGCSI
A lot of provisions, rules, etc.
See a specific presentation.
nGCSI : 2012
•
ASPECTS OF MODELLING AND ANALYSIS
See the presentation by A. Kappos
•
BEHAVIOUR OF EXISTING OR NEW ELEMENTS (RC, infills)
See the presentation by M. Fardis
•
BEHAVIOUR OF REPAIRED/STRENGTHENED ELEMENTS (RC, infills)
See the presentation by S. Dritsos and T. Tassios
•
FINAL CHECKS/SAFETY VERIFICATIONS
See the presentation by M. Fardis