Upload
others
View
5
Download
0
Embed Size (px)
Citation preview
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -1-
EDCE: Civil and Environmental Engineering CIVIL 706 - Advanced Earthquake Engineering
Risk-based seismic evaluation Technical Note SIA 2018
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -2-
Content
• Problematic
• Compliance factor
• Individual risk
• Live-saving costs
• Commensurability
• Reasonableness
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -3-
Example : EPFL Building GC
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -4-
Example : EPFL Building GC • Parameters
seismic zone : Z1 building class : COII response spectrum : S12 microzonage de Lausanne
• Behavior factor: steel construction, non-ductile ⇒ q = 2.0
• Building: construction : between 1976 and 1982 global occupancy : 49 (180 students + 120 employees)
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -5-
Cross-section GC-D (building A)
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -6-
Plan view GC-D (building A)
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -7-
Braced frames GC-D (building A)
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -8-
GC-C, GC-D (buildings B and A) • 2D modeling: response spectrum method
Direction N-S, 2 CV symmetrical, direction E-W 1 CV centered Accidental eccentricity ⇒ CV cantilever with 60% of the masses
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -9-
GC-C, GC-D (buildings B and A) • 2D modeling: response spectrum method
Direction E-W 1 CV centered
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -10-
GC-C, GC-D (buildings B and A) • Compliance factor min: αeff = 0.44
Critical: bolts (diagonal connections, CV N-S)
• Other elements: Welding joint plate-diagonal (0.55) and anchorage (0.56)
• CV E-W: αeff = 0.64 (diagonal connections)
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -11-
GC-A, GC-B (buildings D and C) • 3D modeling: direction E-W
CV irregular Accidental excentricity according to SIA 261
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -12-
Transversal direction mode : T = 1.43 s
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -13-
Longitudinal direction mode : T = 1.29 s
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -14-
Torsion mode : T = 0.89 s
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -15-
GC-A, GC-B (buildings D and C) • Compliance factor min: αeff = 0.44
Critical: bolts (diagonal connections, CV N-S)
• CV E-W: αeff = 0.58 (diagonal connections)
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -16-
Technical note SIA 2018 • Slides prepared by
Ehrfried Kölz and
Blaise Duvernay, OFEV
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -17-
Risk-based concept
– What can happen? (scenarios)– How likely is it? (probability)– What are the consequences? (losses)
iii CPR ⋅= ∑ ∑ ⋅==i i
iii CPRR
– Definition of Risk
– Individual and collective risk (risk to people)
– Effectiveness of risk mitigation measures– Earthquake safety measures (upgrading)– Cost of measures -> SKM– Risk reduction -> ΔRM
– Life-saving costs [CHF / per life saved]
– Individual risk = probability to be killed in the building which is evaluated– Collective risk = sum of the risks of all the people in the building
M M
M R SK RK Δ =
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -18-
Procedure of SIA 2018
– Force-based method– Displacement-based method– SIA 2018 provides tables of information for the classification of building
materials, which were used in past decades
– Evaluation of the structure (structural analysis)
d
deff E
R=α
d
dReff w
w ,=α
– Compliance factor α– measure of the compliance with the current codes
resistance
action effect
displacement capacity
target displacement
force-based method
displacement-based method
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -19-
Technical note SIA 2018
d
deff E
R=α– Compliance factor from verification :
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2
Erfüllungsfaktor αeff
Ris
ikof
akto
r RF
Ris
k fa
ctor
RF
Compliance factor αeff
– Acceptability of individual risk : P(death/yr) ≤ 1/100‘000
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -20-
Damages EMS 98
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -21-
EMS 98 - Definition of the intensity • Inverted - damages
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -22-
EMS 98 • Vulnerability
classes
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -23-
SIA 2018 - Individual risk • Earthquake return periods
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -24-
SIA 2018 - Individual risk • Ranges of individual risk (1/100�000/yr)
for the vulnerability classes VK
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -25-
Acceptability of individual risk – society choice / not really regulated or normalized – 1/100�000 (10-5) per year based on experience and expert judg.
Domaine de responsabilité de la collectivité
Individual responsability domain L
imite
val
ues
for
the
mor
tal
indi
vidu
al r
isk
(per
yea
r)
SIA 2018
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -26-
Individual risk (in 1/100�00 per yr)
Additional risks: 400 20 cigarettes/day 300 1 wine bottle/day 150 Motorcycling 100 Delta-plane
20 Car (20-24 years old) 10 Pedestrian 10 Household work 10 10�000 km road
5 Trekking (mountain) 3 10�000 km freeway 1 Plane accidents / flight 1 10�000 km train
0.5 Building fires 0.2 Death - earthq. (CA/US)
0.1 Lightning
Cumulated:
110 25-years old 100 35-years old 300 45-years old 800 55-years old
2000 65-years old 5000 75-years old
Professional risks:
100 Forestry work 90 Forestry industry
50 Construction 15 Chemical industry 10 Mechanical industry
5 Office work
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -27-
Evaluation criteria – Commensurability and reasonableness
0.00
0.50
1.00
10 20 30 40 50 60 70 80 90 100
Restnutzungsdauer [a]
Erf
üllu
ngsf
akto
r αeff
keine Massnahmen empfohlen
Beurteilung der Verhältnismässigkeit
Massnahmen erforderlich
? min
? adm
BWK I und II
BWK I und II
BWK III
BWK III
individual risk not acceptablemeasures required if LSCM reasonable
0.25
Residual life time
no measures recommended
individual risk acceptablemeasures required if
commensurable
Com
plia
nce
fact
or α
eff
αmin
αadm
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -28-
Risk criteria for evaluation
probability to be killed < 1/100�000 per year
– The individual risk must be acceptable
– If the individual risk is not acceptable, the structure must be upgraded, if the life-saving costs are reasonable
– If the individual risk is acceptable, the structure must be upgraded, if the life-saving costs are commensurable
saved life / ) Euro . Mio . ( CHF . Mio RK M 5 6 10 ≤
saved life / ) Euro . Mio ( CHF . Mio RK M 65 100 ≤
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -29-
Life-saving costs – type of activities
Source: Katarisk 2003
SIA 2018: commensurability
SIA 2018: resonableness
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -30-
Safety costs SKM
– Annualized intervention costs
– All the costs for security improvement
Investment costs [francs]MSIK
MM SIKDFSK ⋅= Safety costs [francs/year]
– Reduced if coupled with another intervention (transformation)
1)02,1()02,1(02,0
1)1()1(
−
⋅=
−+
+= n
n
n
n
iiiDF Discount factor [1/year]
Residual life time [years]n
For SIKM = 100�000.- and n = 50 years:
SKM = 0.032 . 100�000 = 3�200 .- / year
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -31-
1.0E-07
1.0E-06
1.0E-05
1.0E-04
1.0E-03
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 compliance factor, α eff
risk
fact
or, R
F
intα
)( intαRF
effα
)( effRF α
ΔRF = 9 . 10-6 / an
Risk reduction ΔRM – Difference of collective risk between initial situation and the
situation after interventionPBRFRFR effM ⋅−=Δ ))()(( intαα [saved lives/yr]
Mean occupancy [pers.]Example office:50 employees8.5 hours / 245 days / 746 weeks / 52
PB = 50*8.5/24*5/7*46/52 = 11
ΔRM = 9.10-6 . 11 = 1.10-4
1 ten thousandth saved lives per year
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -32-
Live-saving costs RKM - calculations
– Ratio between measure costs and the reachable risk reduction
Safety costs [francs/year]MSK
Risk reduction [human saved lives/year]MRΔ
M
MM R
SKRKΔ
= Live-saving costs [francs/human saved live]
/saved live mio. 32 saved lives per year 10 1
year / . 200 ' 3 4 � = .
� = � M RK
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -33-
EPFL Building GC : SIA 2018 assessment • Individual risk
αeff = 0.44 > 0.25 = αmin ⇒ OK, measures required if commensurable
• Commensurability (till αint = 1.0): PB = 49 ΔRF = 4·10-6– 5.8·10-7 = 3.42·10-6
ΔRM = 49·3.42·10-6 = 1.68·10-4
RKm = 10·106 [Fr./life saved] SKm = 10·106·1.68·10-4 = 1680 [Fr./year] n = 40 years DF = 0.037 ⇒ SIKm max. = 1680/0.037 = 45'400 [Fr.]
CIVIL 706 - SIA 2018 risk-based evaluation EDCE-EPFL-ENAC-SGC 2016 -34-
Conclusions
• Compliance with the requirements in the codes for new buildings is desireable but not mandatory
• Risk-based principles for adequate evaluation of existing structures
• Cost-benefit principles
• Prevention of loss to life and limb highest priority