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8/6/2019 (1)Dam Earthquake Engineering
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Yoshikazu YAMAGUCHI
Team Leader, Dam Structures Research TeamHydraulic Engineering Research Group
Public Works Research Institute
Dam Earthquake Engineering
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Seismic Design of Dams
Dam Structures Research TeamHydraulic Engineering Research Group
Public Works Research Institute
Dam Earthquake Engineering
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1. Geological Condition2. Earthquake Observation System
3. Past Earthquakes4. Seismic Design of Dams5. Advanced Seismic Design of Dam
Contents
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Geological Condition
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Location of earthquakes occurred
in the world
JAPAN
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Location of earthquakes occurred
in Japan
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Plate tectonics
EurasiaPlate
PhilippinePlate
Pacific
Plate
trench
Nankai t
rough
Sagamitrough
Japan
trenc
h
Izu-Ogasawaratrench
Chish
ima
trenc
h
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Earthquake types
Ocean PlateLand Plate
Movement of PlateSeveral centimeter per year
Compression force
Inland Type Trench Type
Fault
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Active Faults in Japan
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Earthquake Observation System
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Definition of earthquake size
by Japan Meteorological Agency (JMA)
JMA operates a network made up of about 180 seismographs for continuous
earthquake monitoring and 650 Seismic Intensity Meters, together withSeismic Intensity Meters of about 2000. The observational data are collectedby the Earthquake Phenomena Observation System (EPOS) at theHeadquarters of JMA and the Earthquake and Tsunami Observation System
(ETOS) at the District Meteorological Observatories. As soon as an earthquakeoccurs, EPOS/ETOS processes the observational data to locate the
epicenter
and to determine the magnitude.
After the occurrence of earthquake JMA quickly announces information on
epicenter, magnitude and the distribution of seismic intensity to the publicthrough mass media as well as to the disaster prevention organizations.
It also
provides these observational data for the International Seismological Centre(ISC) in the UK which collects and analyzes seismic observational data over
the world.
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JMA Seismic Intensity ScaleJMA Scale Explanation
7In most buildings, wall tiles and windowpanes are damaged and fall. In
some cases, reinforced concrete-block walls collapse.
6UpperIn many buildings, wall tiles and windowpanes are damaged and fall. Most
unreinforced concrete-block walls collapse.
6lower In some buildings, wall tiles and windowpanes are damaged and fall.
5UpperIn many cases, unreinforced concrete-block walls collapse and tombstonesoverturn. Many automobiles stop due to difficulty to drive. Occasionally,
poorly installed vending machines fall.
5lowerMost people try to escape from a danger. Some people find it difficult to
move
4Many people are frightened. Some peolpe try to escape from a danger.
Most sleeping people awake.
3 Felt by most people in the building. Some people are frightened.
2 Felt by many people in the building. Some sleeping people awake.
1 Felt by only some people in the building .
0 Imperceptible to people.
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Earthquake Observation Systems
Strong Motion Seismograph Network
National Research Institute For Earth
Science and Disaster Prevention
KiK-net (Rockfoundation)
K-net (Surface of ground)
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Online Earthquake Observation
Systems for Dams
NILIM (Tsukuba)
Earthquake Data
Headquaters of MLIT(Tokyo)
Dam Office
Real Time
Database
About 60 dams areconnected on line now.In the future, 410 dams
will be connected.
Seismographs
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Past Earthquakes
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Recent Major Earthquake Disasters
in Japan
Date Earthquake MagnitudeNumberof Lostpersons
Oct. 28, 1891 Nobi Earthquake 8.0 7,273
June 15, 1896 Sanriku Earthquake and Tsunami 8 1/2 22,072
Sept. 1, 1923 Great Kanto Earthquake 7.9 142,807
Mar. 7, 1927 Kitatango Earthquake 7.3 2,925Mar. 3,1933 Sanriku Earthquake and Tsunami 8.1 3,064
Sept. 10, 1943 Tottori Earthquake 7.2 1,083
Dec. 7, 1944 Tonankai Earthquake 7.9 998
Jan. 13, 1945 Mikawa Earthquake 6.8 1,961Dec. 21, 1946 Nankai Earthquake 8.0 1,330
June. 28, 1948 Fukui Earthquake 7.1 3,796
May 26, 1983 Central Japan Sea Earthquake 7.7 104
July 12, 1993 Southwest of Hokkaido Earthquake 7.8 230
Jan. 17, 1995 Southern Hyogo Prefecture Earthquake 7.2 6,427
Oct 6, 2000 Western Tottori Prefecture Earthquake 6.6
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Hyogo-ken Nambe (Kobe) Earthquake
Date : 17 Jan 1995 am 5:46
Epicenter : 3436 North Latitude13502 East Longitude
Focal Depth : 16 km
JMA Magnitude : 7.3
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Distribution of Seismic Intensity
Epicenter
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Location of Nojima Fault
Osaka
Nojima Fault
Kobe
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Photo 1
Collapse of Highway Overpass
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Photo 2
Collapse of Buildings
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Photo 3
Appearance of Nojima Fault
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Location of Dams near the Epicenter
About 50 dams exist within 50 km from the epicenter
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Special Safety Inspections of Dams
Primary Inspection
Visual Inspection immediately after the earthquakeSecondary Inspection
Both a detailed visual inspection andsafety checks of data recorded by instruments
The special safety inspection of 251 dams werecompleted by January 21, 1995
(occurrence of the earthquake was Jan. 17)
No damage requiring emergency protective
countermeasures was reported.
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Horizontal Accelerations observed at
dam sites
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Acceleration Response Spectrum
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Relationship between the Distance and
the Horizontal Accelerations
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Relationship between the Distance and
the Vertical Accelerations
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Relationship between the Distance and
the Horizontal Accelerations (Soil Sites)
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FEM Analysis (Concrete Gravity Dam)
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Results of FEM Analysis
(Concrete Gravity Dam)
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Results of FEM Analysis
(Concrete Gravity Dam)
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Conclusions of Dam Safety Evaluation
during Hyogo-ken Nambu Earthquake
The special safety inspections by site officers and detailedinvestigations (using dynamic analyses) by PWRI engineersconfirmed that there was no serious damage affecting damsafety or requiring protective countermeasures.The dams were constructed on the rock foundations wherethe earthquake motion were substantially smaller than thoseat soil sites. It is one of major reasons why dams were safe
during the earthquake.Careful geological investigation and site location, adequatesafety factor in designing dams, high-quality construction
were also important to ensure the safety of dams.
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Seismic Design of Dams
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Essentials of a design
The dam shall be of a structure possessingsafety under anticipated loads, the necessary
durability and watertightness, and good operatingproperties. Also, It should be designed withconsideration to its economics.
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Essentials of Design
A Concrete Dam should have such a structure thatwill not slide or overturning under the estimated loads.
An Embankment Dam should have such a structure
that will not show sliding or seepage failure under theestimated loads.
Foundations for dams should be safe from sliding,or seepage failure under the estimated loads.
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Difference in Design Methods
in accordance with Dam Types
Type ofDams
BasicAssumptions
Conditions ofDam Design
ConcreteGravity
Dams
ConcreteArch
DamsEmbankmentDams
2-DimentionalElastic Body
3-DimentionalElastic Body
2-DimentionalNon-Elastic Body
1) Middle third condition2) Hennys formula (Fs4)
3) Allowable stress
1) Allowable stress2) Hennys formula (Fs4)
1) Sliding method(Fs1.2)
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Design Water Levels
Concrete Dam Embankment Dam
SWLNWL
DFL
LWL
SWLNWL
DFL
LWL
MWL
Empty Empty
Drop rapidly
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Design Loads (2)
Reservoir condition Concrete Gravity Dam Concrete Arch Dam Embankment Dam
Middle water level Self weightHydrostatic pressure
Pore pressure
Inertia forceWhen the water level
drops rapidly
Empty reservoir
Self weight
Inertia force
Self weight
Inertia force
Self weight
Pore pressure
Inertia force
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Seismic Loads
Concrete Dam Embankment Dam
Inertia Force Inertia ForceHydrodynamicpressure
Seismic Coefficient Method
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Inertia Force
I = WkWhere,
I inertia force of the dam body duringan earthquakeW weight of dam bodyk design seismic coefficient
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Hydrodynamic Pressure
Where,
Pd hydrodynamic pressurehHkWPd w 875.0=
Ww unit weight of waterk design seismic coefficientH depth of the reservoir
h
depth of the water from the water surface
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Hydrodynamic Pressure
H
h
Pd
2
0)(
12
7HkW
dyPdH
w
H
dynamicw
=
=
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Advanced Seismic Design of Dam
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Advanced Seismic Design
Modified Seismic Coefficient Method
Dynamic Analysis using FEM
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Modified Seismic Coefficient Method
SeismicCoefficient
Method
ModifiedSeismicCoefficientMethod
Distribution of Seismic Coefficient k
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Modified Seismic Coefficient Method
1991.6 SEISMIC DESIGN STANDARD FOR
EMBANKMENT DAMS (DRAFT)
0.0 1.0 2.0 3.0
0.0
0.2
0.4
0.6
0.8
1.02.51.4
k/kf
y/
H
1.76
Hy
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Example of Dynamic AnalysisOct 6, 2000 Western Tottori Prefecture Earthquake
Kasho Dam
Kasho DamEpicenter
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Earthquake Record (Input Data)
20.480
0.010 -503.345 5.930
-500.0
-250.0
0. 0
250.0
500.0
ACCELERATI
ON
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0
20.480
0.010 485.209 6.680
-500.0
-250.0
0. 0
250.0
500.0
ACCELERATION
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0 20.0
Horizontal
Vertical
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Dynamic Analysis using FEM
Principal Stress(Tension)
Principal Stress
(Compression)
X
Y
Z
-7.3479
-183.59
0.
-10.
-20.
-30.
-40.
-50.
-60.-70.
-80.
-90.
-100.
-110.
-120.
-130.
-140.
-150.
-160.
-170.
-180.
-190.
V1L1G1
Output Set: PLAN-S3Contour: PLANE S3
X
Y
Z148.86
5.1191
150.
140.
130.
120.
110.
100.
90.
80.
70.
60.
50.
40.
30.
20.
10.
0.
V1L1G1
Output Set: PLAN-S1Contour: PLANE S1
N Li D i A l i
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Non-Linear Dynamic Analysis
using FEM
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Role of Dynamic Analysis
Design Inspection
Seismic Coefficient Method
Modified SeismicCoefficient Method
Unique solution can beobtained.
Dynamic Analysis usingFEM, BEM, DEM
Results are effected bymethod, model,conditions
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Definition of Earthquake Motions
Level I Earthquake motions is the level in which structuresare not damaged when these motions strike.(OBEOperation Based Earthquake)
Proposal of Earthquake Resistance for Civil Engineering Structures
by Japan Society of Civil Engineering
Level II Earthquake motions is the level in which an ultimatecapacity of earthquake resistance of a structure isassessed in plastic deformation range.(MCEMaximum Credible Earthquake)
A structure is designed so that it may not get damage
A structure is designed so that it may not get fataldamage