Basic Training Course on Earthquake Engineering
Basic Training Course on Earthquake Engineering Lecturers: from the Earthquake Engineering Group & invited speakers Prof Kypros Pilakoutas, Dr Reyes Garcia, Dr Iman Hajirasouliha, Dr Zuhal Ozdemir,, Prof Babak Akhgar (Hallam), Mr Keith Brook (Birkdale), Engr Pramod Neupane (Nepal)
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Basic Training Course on Earthquake Engineering
Course Outline
A series of fairly independent two-hour evening seminars (HEAR Activity Approved– Please sign attendance sheets) It introduces the basic knowledge of the fundamental principles of seismic hazard and risk mitigation. This involves the impact on the economy and society as well as practical strengthening training for use in developing countries. The students will be expected to learn how to organise a field mission.
Thu 15/10/15
Welcome & Introduction to Earthquake Hazard
18:00-20:00 hrs
The 2015 Nepal earthquake
Wed 11/11/15
Introduction to Seismic Resistant Structures and Possible Weaknesses
18:00-20:00 hrs
How to make rapid assessments
Thu 03/12/15
Overview of Social and Economic Impacts of Earthquakes
18:00-20:00 hrs
Special emphasis on Nepal
Mon 18/01/16
Basics of Seismic Risk Mitigation
18:00-20:00 hrs
How to calculate and manage risk
Wed 03/02/16 Seismic Strengthening Techniques 18:00-20:00 hrs
Appropriate technologies
Thu 03/03/16 Practical Seismic Strengthening Laboratory 18:00-20:00 hrs
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Post-Tensioned Metal Straps
Basic Training Course on Earthquake Engineering
How to deal with Risks Risk Assessment! We do it all the time • Identify potential hazards, consequences, location/exposure, cost • Ignore/adapt (knowingly or not!) • Control probability • Prevent controllable/human induced hazards (e.g. fires, driving-accidents) • Avoid/limit exposure (move elsewhere, change time) • Control Consequences (Mitigate/Prepare) • Plan and take measures against them (e.g. laws, codes of practice, town planning, design, emergency plans/provision) • Share Risk (Insure) • Safety in numbers • Opportunity (through better understanding)! http://www.shef.ac.uk/~tmrnet
Basic Training Course on Earthquake Engineering
What is (seismic) Risk? Hazard (probability of harm)
Risk
Vulnerability (to harm)
Exposure (Value)
•Consequence of Hazard •Estimate for future •Economic, personnel, environmental, political… •Why we need it •Decisions, prioritisation, planning, MITIGATION
Earthquake risk is the expectation of loss (economic loss, mortality, loss of function….)
(Risk) = (Earthquake Hazard) x (Vulnerability) x (Exposure) http://www.shef.ac.uk/~tmrnet
Basic Training Course on Earthquake Engineering
Hazard • Can be anything that causes harm • Natural (earthquakes, flooding, storms, meteorites….) • Technological (infrastructure, industrial facilities, equipment..) • Health ( food, disease,, chemicals, medicines…) • Societal (accidents, war, terrorism…) • Earthquake Hazard • Violent ground movement/acceleration, volcanic eruptions, slow ground movements (dams, coast). • Liquefaction, rockfalls, landslides, tsunamis • Plate tectonics • Though most earthquakes are expected to take place near the plate boundaries, numerous faults exist around them, hence seismicity gets to be more distributed and local fault systems need to be understood
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Basic Training Course on Earthquake Engineering
Seismicity • Earthquake Hazard Assessment • Currently, earthquakes cannot be predicted precisely • Monitor movements (slow and violent) to understand stress accumulation • Identify patterns in (historical) seismicity • Historical Records • In some regions records go back to historical times • Not always accurate/consistent • Instrumental Records • Go back to beginning of 20th Century (crude but useful) • Increased exponentially in number and sophistication • Remote sensing technologies can map movement very accurately
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Basic Training Course on Earthquake Engineering
Seismic Sources
Assume geological processes are slow Use historical seismicity Identify major sources Identify regions of similar seismicity For important structures work at the micro-zonation level
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Basic Training Course on Earthquake Engineering
Gutenberg-Richter Recurrence relationship
log10 ( N ) a b M
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Basic Training Course on Earthquake Engineering
1.5
Log (Cumulative Frequency)
Earthquake Recurrence Rates
Kythreoti recurrence relationship Ambraseys data Ambraseys recurrence relationship
1 0.5 0 -0.5 -1 -1.5
0
1
2
3
4
5
6
7
8
logN = 2.25-0.54Ms
Linearity?
-2
logN=3.35-0.8Ms
-2.5
9
Examples (Seismicity): Cyprus (Medium) Pakistan (High) Sumatra (Very High)
logN = 2.5-0.64Ms
-3 Magnitude
Time dependency?
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Seismic gaps?
Basic Training Course on Earthquake Engineering
N and Return Period of M>6
log10 ( N ) a b M
1.5 Kythreoti recurrence relationship Ambraseys data Ambraseys recurrence relationship
Log (Cumulative Frequency)
1 0.5
Period (or Return Period) T = 1/N
0 -0.5
0
1
2
3
4
5
6
7
8
logN = 2.25-0.54Ms
-1 -1.5 -2
9
For Cyprus log10 (N) = -1.3 N= 0.05 T= 20 years
logN=3.35-0.8Ms
-2.5
logN = 2.5-0.64Ms
-3 Magnitude
For Pakistan log10 (N) = -0.3 N= 0.5 T= 2 years For Sumatra log10 (N) = 0.5 N= 3.16 T= 0.316 (4 months)
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Basic Training Course on Earthquake Engineering
Earthquake Recurrence Rates
n N t p 1 e
N = frequency of events = number n over period t Period (or Return Period) T = 1/N
n t
q 1 e
1 e N
Nt
Assuming events are unrelated (random)
Probability of exceedance
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Period 10000 1000 500 200 100 50 10 1
N 0.0001 0.001 0.002 0.005 0.01 0.02 0.1 1
q% 4.88 9.52 39.35 63.21 91.79 100.00 100.00 100.00
Period 1000 500 100 50 20 3.333 2 1
p 0.0001 0.0010 0.0020 0.0050 0.0100 0.0198 0.0952 0.6321
For 50 years life and event T
Basic Training Course on Earthquake Engineering
Earthquake Recurrence Rates
n N t
p 1 e
n t
1 e
N
q 1 e
For Cyprus Ms=6 log10 (N) = -1.3 T= 20 years q=92% (too high) q=10% T=500 log10 (N) = -1.69 Ms=6.6 For Pakistan log10 (N) = -0.3 q=10% Ms=8.6 ?? How about nuclear reactors??
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Nt
Period 10000 1000 500 200 100 50 10 1
N 0.0001 0.001 0.002 0.005 0.01 0.02 0.1 1
q% 4.88 9.52 39.35 63.21 91.79 100.00 100.00 100.00
Period 1000 500 100 50 20 3.333 2 1
p 0.0001 0.0010 0.0020 0.0050 0.0100 0.0198 0.0952 0.6321
For 50 years life
Basic Training Course on Earthquake Engineering
Attenuation relationships
Close from epicentre
INTENSITY (Modified Mercalli)
Far from epicentre
IX
M = 7.4 M = 7.0
VIII
M = 6.6 M = 6.0 M = 5.6 M = 5.0 M= 4.4
VI I VI
Attenuation relationships are complex empirical mathematical equations that relate strong-motion effects (e.g. PGA) to seismic source (Magnitude, wave propagation, local soil/moisture conditions)
V
Differ from place to place
IV III 50
100
150
200
250
300
DISTANCE FROM EPICENTRE (km)
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Basic Training Course on Earthquake Engineering
Attenuation relationships They identify how the earthquake will feel at a given location
Ambraseys attenuation relationship compared to observed PGA’s of 2005 Kashmir earthquake, Pakistan
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Basic Training Course on Earthquake Engineering
Attenuation relationships
Theodulidis and Papazachos, 1992 Ln(a) = 0.28+0.67IMM+0.42S
Felt and predicted intensities as a result of the 23rd of February 1995 earthquake (Ms=5.7)
Felt and predicted intensities as a result of the 9th of October 1996 earthquake (Ms=6.5)
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Basic Training Course on Earthquake Engineering
Fault length
•Abbottabad
10
Actual estimated damage distribution after Kashmir 2005 earthquake
k m
PGA calculated from focal point of the Kashmir 2005 earthquake
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PGA calculated from EFL (including the effect of general fault direction of the seismic source zone)
Basic Training Course on Earthquake Engineering
Distribution of Seismic Intensity
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Basic Training Course on Earthquake Engineering
Simple Probabilistic Method • • • •
Apply past seismicity using earthquake catalogues Generate synthetic earthquakes using Stochastic method Seismic zones used to determine directivity of fault ruptures Generated events used to determine ground motion values (PGA) in administrative units
Known Fault Focal point of new event
Site of interest
Known Fault
Site of interest
Isoseismals New event location is randomized within this area
Original earthquake event Isoseismals
New EFL Original earthquake event
Focal point of new event
http://www.shef.ac.uk/~tmrnet Epicentral Fault Length (EFL): (a). Kythreoti (2002) ; (b). Khan (2010)
Basic Training Course on Earthquake Engineering
Hazard Maps Αποτίμηση Επικινδυνότητας
(a) Khan (2009)
(b)SOP (2006), (b)
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Basic Training Course on Earthquake Engineering
Hazard Map: Pesharwar-Islamabad
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Basic Training Course on Earthquake Engineering
Hazard Map: Sumatra
(a). Seismic hazard map from USGS. (b). Seismic hazard map from current study.
(a)
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(b)
Basic Training Course on Earthquake Engineering
Exposure Hazard (probability of harm)
Risk
Vulnerability (to harm)
Exposure (Value)
•Single facilities or structures •Treated in more detail •Regions •Normally basic administrative units, as official statistics available •Information on Infrastructure •Location, age, building type/condition, usage/importance, occupancy, soil/water conditions, value (replacement) •Value •Replacement value •People •Location (time), activities
•Value of Human life? Insurance?
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Basic Training Course on Earthquake Engineering
Exposure Remote sensing
Minimal data collection from remote sensing and field surveys
Area of interest
•Good Updated Maps •Satellite images •Machine identification •Of typical constructions/age/changes •Census •Occupancy •Town Planning/Building Control •On buildings •Geological maps •Soil and water?
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Basic Training Course on Earthquake Engineering
Vulnerability Hazard (probability of harm)
Risk
Vulnerability (to harm)
Exposure (Value)
•Consequent of Hazard •Estimate for future •Economic, personnel, environmental, political… •Why we need it •Decisions, prioritisation, planning, MITIGATION
Earthquake risk is the expectation of loss (economic loss, mortality, loss of function….)
(Risk) = (Earthquake Hazard) x (Vulnerability) x (Exposure) http://www.shef.ac.uk/~tmrnet
Basic Training Course on Earthquake Engineering
Vulnerability Vulnerability is the measurement of the proportion of the replacement value an element at risk is expected to lose when actually subjected to a specific severity of earthquake hazard such as ground shaking. Depends on: • adequacy of the lateral force resisting mechanism • quality of design detailing and construction • maintenance • loading
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Basic Training Course on Earthquake Engineering
Vulnerability Assessment Expert Based on expert opinion % damage
EMPIRICAL Based on past evidence/insurance
MMI/PGA
% damage
ANALYTICAL Based on accurate mathematical simulations
PGA
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Basic Training Course on Earthquake Engineering
Vulnerability Curves Vulnerability Curves for Pakistan (GESI Method)
Mean Damage Ratio (MDR, %).
100
80
Reinforced concrete
60
Unreinforced masonry (fired brick, concrete block and shaped stone) 40
Reinforced concrete with unreinforced masonry infill walls Adobe and adobe brick
20
Stone rubble 0 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
PGA (g)
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0.9
1
1.1
Basic Training Course on Earthquake Engineering
Analytical Vulnerability Assessment • Representative Models for Structural Components • Degradation
Capacity Spectrum Method Demand Curve Strength & Stiffness Degrading
C
40
Strength & Stiffness Degrading 40 30
20
20
Capacity Curve 10
-0.2
Force
Force
10
-0.4
0
-0.4 0
-10
0 -0.2 0.2
0.40
-10
-20
-20
-30
-30
-40 Displacem ent
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30
-40 Displacem ent
0.2
D
0.4
Basic Training Course on Earthquake Engineering
MDR
Vulnerability Assessment
Analytical Vulnerability curves for (pre-seismic design) Low-Rise buildings in Cyprus (N Kyriakides) Note the difference in shape- abrupt failure
100 90 80 70 60 50 40 30 20 10 0
Mean
0
1
2
95% POE
3
5% POE
4
5
6 2
PGA (m/s )
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7
8
9
10
Basic Training Course on Earthquake Engineering
Earthquake Risk Assessment RISK = HAZARD × EXPOSURE × VULNERABILITY × VALUE Framework
Vulnerability Module
Hazard Module
Instrumental Seismicity Historical Seismicity
Seismic Hazard Assessment
PSHA
Tsunami Hazard Assessment
PTHA
HAZARD
Faults and Gaps
Building Characteristics
Industrial Components
Building Vulnerability
Building Vulnerability Relationships
Industrial Vulnerability
Vulnerability Relationships for Industrial Components
EXPOSURE
Risk Module
Industrial Inventory Building Inventory
Population Properties
Casualty Model
Risk Assessment
Damage Risk
VULNERABILITY
Injury Risk Casualty Assessment Fatality Risk
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Basic Training Course on Earthquake Engineering
Administrative Units
Study Area in Pakistan, Area = 8314 sq-km
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Basic Training Course on Earthquake Engineering
Vulnerability Assessment
Typology of Building Stock in Study Region URBAN INFORMAL AREAS
URBAN FORMAL AREAS
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RURAL AREAS
Basic Training Course on Earthquake Engineering
Vulnerability Assessment
Satellite Imagery with Minimal Field Sampling
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Basic Training Course on Earthquake Engineering
Case Study: Pakistan
Hazard Map for the Study Area (50 Year Return Period with 10% POE)
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Basic Training Course on Earthquake Engineering
Case Study: Pakistan Risk Map for the Study Area (annual risk per building)
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Basic Training Course on Earthquake Engineering
Case Study: Pakistan Fatalities (per 50 years)
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Basic Training Course on Earthquake Engineering
Case Study: Sumatra 200
8
40
Tsunami Hazard:
2
Average tsunami wave height is ~ 5 m
30
70
35
15
90
!( !(
60
45
Inland Penetration:
5 !(
!( !( 20
Smooth terrain : 2.2 km
!( 10
100
Densely populated buildings: 0.5 km 25
50
Densely treed landscape: 0.1 km
!( !( !(
!( !( !( (! !( !( !( !(
0 20
3.5
7
14
21 Kilometers
80
0
50
!( !( (! (! !( !( !( !( (! !( !( !( (! !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( !( (! !( !( (! 5
Bathymetry and preliminary tsunami hazard analysis for Padang City
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Basic Training Course on Earthquake Engineering
Applications
Mitigation strategies: • Seismic demand on structures (new codes) • Seismic strengthening of existing building stock • Assessing appropriate locations for tsunami vertical evacuation systems • Tsunami evacuation maps • Compare mitigation scenarios Town planning Hospital/emergency response provision Determine premiums for insurance companies
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Basic Training Course on Earthquake Engineering
Course Outline
Wed 03/02/16 Seismic Strengthening Techniques 18:00-20:00 hrs
Appropriate technologies
Thu 03/03/16 Practical Seismic Strengthening Laboratory 18:00-20:00 hrs
Post-Tensioned Metal Straps
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