thesis final report ravi printed-libre

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COPYRIGHT

The author has agreed that the library, Department of Civil Engineering, Institute of

Engineering, Pulchowk Campus, may make this thesis freely available for inspection.

Moreover, the author has agreed that permission for extensive copying of this thesis

for scholarly purpose may be granted by the professor who supervised the thesis work

recorded herein or, in his absence, by the Head of the Department or concerning M.

Sc. program coordinator or the Dean of the Institute where the thesis work was done.

It is understood that the recognition will be given to the author of this thesis and to the

Department of Civil Engineering, Institute of Engineering, Pulchowk Campus, in any

use of the material of this thesis. Copying or publication or other use of the thesis for

financial gain without approval of the Department of Civil Engineering, Institute of

Engineering, Pulchowk Campus and the authors written permission is prohibited.

Request for permission to copy or make any use of the material of this thesis in whole

or in part should be addressed to:

Head of Department

Department of Civil Engineering

Institute of Engineering

Pulchowk Campus

Lalitpur, Nepal.


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ABSTRACT

Nepal has large potential of hydropower resources however it is located in one of the

most tectonically active regions of the world. The hydropower resources areenvisaged not only as a supply to satisfy the domestic demand of the country rather an

export commodity. Thus, large scale projects are planned for the export orientated

power generation. These projects involve large dam structures for the impounding of

water. As the risk of failure of dam cannot be ignored due to high seismic activity, the

downstream establishment is always on greater threat.

Several number of earthquake sources are located in Nepal and nearby areas which

may cause devastating effect on large structures such as concrete gravity dam. Near-

field ground motions could cause more damaging effects on structures, as they

observed to differ dramatically from the characteristics of their far field counterparts.

Near field earthquake are characterizes by pulse type velocity time history which

cause large impulsive force on the structures.

In this study we select fifteen near-field earthquake records and five far-field records

for the same earthquake events. Further these selected near-field record are checked

for characteristics of the near field record based on the research papers. From

acceleration time history records, velocity time history records are calculated by

numerical integration using MS-Excel. Further Fourier Amplitude Spectrum is carried

out by using MS- Excels Fast Fourier Transform (FFT) tools. Finite Element

Modeling of the dam (140 m height) of proposed Tanahu hydro-electric project is

prepared on SAP2000 based on the U.S. Army Engineering Manual EM 1110-2-6051.

Linear and Nonlinear time-history analysis are used to assess earthquake performanceof non-overflow gravity dam section. The linear time history analysis is employed to

gain insight into the dynamic behavior of the dam. The nonlinear time history analysis

is employed to identify potential modes of failure. The results of linear time history

analysis are compared with the EM 1110-2-6051 performance acceptance criteria for

gravity dams. This comparison indicated that the dam would suffer significant

cracking along the base for all the fifteen selected near-field earthquake record and

should be assessed on the basis of nonlinear time-history analysis. But comparisonsfor far-field earthquake response indicate that the dam will not suffer profoundly.


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ACKNOWLEDGEMENT

I would like to express my deepest gratitude to my advisor, Dr. Hari Ram Parajuli, for

his outstanding guidance, caring, patience, and providing me with an excellent

atmosphere for doing research. I would like to thanks to Prof. Dr. Prem Nath Maskey,

Prof. Dr. Hikmat Raj Joshi, Dr. Kamal Bahadur Thapa, Dr. Rajan Suwal, Dr. Gokarna

Bahadur Motra, Er. Nabin Chandra Sharma, Er Siddhartha Shankar and all the faulty

members of Department of Civil Engineering, for their excellent course works during

M.Sc. study and valuable suggestion for the improvement of the research during the

long period.

I am indebted to Dr. Roshan Tuladhar, Senior Structural Engineer, for his guidance

and suggestion during this research. Despite being miles away, he was there to guide

me whenever I needed.

I would like to express my sincere gratitude to Dr. Krishna Prasad Dulal, Managing

Director, DK Consult Pvt. Ltd., who helped me in deciding the thesis topic and

inspired me throughout the study period. I also would like to thank Er. MaheshAcharya, Director, Tanahun Hydroelectric Company, who provided me with

necessary data about the project.

I would like to thank my colleague Er. Sandip Uprety, Hydropower Engineer, DK

Consult Pvt. Ltd., for his support and encouragement. Also, I would like to remember

Er. Soyuz Gautam, Senior Structural Engineer at Hydro Consult Pvt. Ltd, and thank

him for his constant motivation in bringing out the thesis. I would like to thanks to all

my friends for their support, knowledge sharing and encouragement throughout the

research.

Last but not the least I would like to thank my parents, relatives, my wife and

daughter for their encouragement and patience during the research.

Ravi Sharma Bhandari

Department of Civil Engineering

Institute of Engineering, Pulchowk Campus

Lalitpur, Nepal


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TABLE OF CONTENTS

COPYRIGHT .................................................................................................................... I

ABSTRACT ..................................................................................................................... III

ACKNOWLEDGEMENT ............................................................................................... V

LIST OF TABLES ....................................................................................................... VIII

LIST OF FIGURES ........................................................................................................ IX

LIST OF SYMBOLS ................................................................................................ XVIII

1. INTRODUCTION ..................................................................................................... 1

1.1.

Seismicity in Nepal .............................................................................................. 2

1.2. Research Objectives ............................................................................................. 3

1.3. Organization of Thesis ......................................................................................... 4

2. LITERATURE REVIEWS ....................................................................................... 5

3. NEAR-FAULT EARTHQUAKE RECORD CHARACTERISTICS ................... 9

3.1. Near-Field Ground Motions ................................................................................. 9

3.2. Criteria for Near-Field Records............................................................................ 9

4. GROUND MOTIONS AND THEIR CHARACTERISTICS .............................. 14

4.1. Seismic Inputs for Structures ............................................................................. 14

4.2. Selection of Ground Motion ............................................................................... 14

4.3. Characteristics of Ground Motions .................................................................... 15

4.4. Near field Ground Motion and Their Fourier Amplitude Spectrum .................. 22

5. FINITE ELEMENT MODELING OF GRAVITY DAM AND MATERIAL

PROPERTIES ................................................................................................................. 37

5.1. Introduction ........................................................................................................ 37

5.2. Analytical Modeling Procedure ......................................................................... 38

5.3. Standard Finite Element Method........................................................................ 38

5.4.

Fluid-Structure Interaction ................................................................................. 40


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5.4.1. Simplified Added Hydrodynamic Mass Model ........................................ 40

5.5. Foundation-Structure Interaction ....................................................................... 43

5.6. Finite Element Model of Dam ............................................................................ 44

6. STRUCTURAL PERFORMANCE AND DAMAGE CRITERIA ..................... 46

6.1. Introduction ........................................................................................................ 46

6.2. Proposed Criteria ................................................................................................ 46

7. LINEAR TIME HISTORY ANALYSIS TECHNIQUE ...................................... 50

7.1. Introduction ........................................................................................................ 50

7.2. Equation of Motion ............................................................................................ 50

7.3. Direct Integration Method .................................................................................. 50

7.4. Mode Superposition Method .............................................................................. 51

7.5. Dynamic Characteristics .................................................................................... 52

7.6. Evaluation of Linear Response .......................................................................... 55

7.6.1. Near-Fault Response of Dam Section ....................................................... 55

7.6.2. Performance of Dam Section for Near-Fault Earthquakes ....................... 96

7.6.3. Far-Fault Response of Dam Section ......................................................... 98

7.6.4. Performance of Dam Section for Far-Fault Earthquakes ........................ 103

7.7. Result and Conclusion ...................................................................................... 104

8. NONLINEAR TIME HISTORY ANALYSIS TECHNIQUE ........................... 105

8.1. Introduction ...................................................................................................... 105

8.2. Nonlinear Modal Time-History Analysis (FNA) ............................................. 106

8.3. Nonlinear Finite-element Model ...................................................................... 106

8.4. Evaluation of Nonlinear Responses ................................................................. 109

9. CONCLUSION AND RECOMMENDATION ................................................... 111

BIBLIOGRAPHY ......................................................................................................... 113


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LIST OF TABLES

Table 3. 1 Ground motion parameters, measured characteristics and lower-

bound values (Ch.A. Maniatakis 2008) ....................................................................... 11

Table 3. 2 Selected Near-Field Ground Motion Records ............................................ 12 Table 3. 3 Ground motion parameter and measured characteristics for Fault

Normal component....................................................................................................... 13

Table 3. 4 Ground motion parameter and measured characteristics for Fault

Parallel component....................................................................................................... 13

Table 4. 1 Selected Far-Field Ground Motion records ................................................ 15

Table 4. 2 Selected Near-Field Fault Normal Ground Motion Records ...................... 19

Table 4. 3 Selected Near-Field Fault Normal Ground Motion Records ...................... 20 Table 4. 4 Far-Field Ground Motion records ............................................................... 21

Table 6. 1 Load Combination Cases for Combining Static and Dynamic

Stresses for 2-D Analysis ............................................................................................. 49

Table 7. 1 Natural Frequencies for different mode shapes .......................................... 52

Table 7. 2 Maximum Crest Displacement and Stresses due to Near Field

Earthquake Records ..................................................................................................... 97

Table 7. 3 Maximum Crest Displacement and Stresses due to Far Field

Earthquake Records ................................................................................................... 103


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Figure 7. 2 Envelops of maximum stresses (N/mm 2) (a) Horizontal Stress, (b)

Vertical Stress due to Fault-Normal component .......................................................... 56

Figure 7. 3 Envelops of maximum stresses (N/mm 2) (a) Horizontal Stress, (b)

Vertical Stress due to Fault-Parallel component .......................................................... 57

Figure 7. 4 Modified Dam Section .............................................................................. 58

Figure 7. 5 Envelops of maximum stresses (N/mm 2), Left: Horizontal Stress,

Right: Vertical Stress due to Fault-Normal component ............................................... 58

Figure 7. 7 Time history of major principal stress at the heel of dam for

Imperial Valley-06 (Recording station: El Centro Array #6) Earthquake (FN +

V) ................................................................................................................................. 59


Right: Vertical Stress due to Fault-Parallel component ............................................... 59


Imperial Valley-06 (Recording station: El Centro Array #6) Earthquake (FP +

V) ................................................................................................................................. 60

Figure 7. 9 Time History of horizontal displacement at top of the dam due to

Imperial Valley-06 (Recording station: El Centro Array #6) Earthquake, Left:

FN-Component, Right: FP Component ....................................................................... 60







V) ................................................................................................................................. 62



V) ................................................................................................................................. 62


Imperial Valley-06 (Recording station: El Centro Array #7) Earthquake, Left:

FN-Component, Right: FP Component ....................................................................... 63

Figure 7. 15 Envelops of maximum stresses (N/mm2), Left: Horizontal Stress,

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Figure 7. 16 Envelops of maximum stresses (N/mm2), Left: Horizontal Stress,




V) ................................................................................................................................. 64



V) ................................................................................................................................. 65


Loma Prieta (Recording station: LGPC) Earthquake, FN-Component ....................... 65


Loma Prieta (Recording station: LGPC) Earthquake, FN-Component ....................... 65






Erzican- Turkey (Recording station: Erzincan) Earthquake (FN + V) ....................... 67


Erzican- Turkey (Recording station: Erzincan) Earthquake (FP + V) ......................... 67


Erzican- Turkey (Recording station: Erzincan) Earthquake, FN-Component ............. 67


Erzican- Turkey (Recording station: Erzincan) Earthquake, FP-Component ............. 68





Figure 7. 29 Time history of major principal stress at the heel of dam for Cape

Mendocino (Recording station: Cape Mendocino) Earthquake (FN + V) ................... 69


Mendocino (Recording station: Cape Mendocino) Earthquake (FP + V) ................... 69


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Cape Mendocino (Recording station: Cape Mendocino) Earthquake, FN-

Component ................................................................................................................... 70


Cape Mendocino (Recording station: Cape Mendocino) Earthquake, FP-

Component ................................................................................................................... 70






Mendocino (Recording station: Petrolia) Earthquake (FN + V) .................................. 72


Mendocino (Recording station: Petrolia) Earthquake (FP + V) .................................. 72


Cape Mendocino (Recording station: Petrolia) Earthquake, FN-Component ............. 72


Cape Mendocino (Recording station: Petrolia) Earthquake, FP-Component .............. 73






Landers (Recording station: Lucerne) Earthquake (FN + V) ...................................... 74


Landers (Recording station: Lucerne) Earthquake (FP + V) ....................................... 75


Landers (Recording station: Lucerne) Earthquake, FN-Component ........................... 75


Landers (Recording station: Lucerne) Earthquake, FP-Component ............................ 75



Figure 7. 46 Envelops of maximum stresses (N/mm2

), Left: Horizontal Stress,Right: Vertical Stress due to Fault-Parallel component ............................................... 76


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Northridge-01 (Recording station: Newhall - Fire Station) Earthquake (FN +

V) ................................................................................................................................. 77


Northridge-01 (Recording station: Newhall - Fire Station) Earthquake (FP +

V) ................................................................................................................................. 77


Northridge-01 (Recording station: Newhall - Fire Station) Earthquake, FN-

Component ................................................................................................................... 77


Northridge-01 (Recording station: Newhall - Fire Station) Earthquake, FP-

Component ................................................................................................................... 78


Right: Vertical Stress, due to Fault-Normal component .............................................. 78


Right: Vertical Stress, due to Fault-Parallel component .............................................. 79


Northridge-01 (Recording station: Rinaldi Receiving Station) Earthquake (FN

+ V) .............................................................................................................................. 79


Northridge-01 (Recording station: Rinaldi Receiving Station) Earthquake (FP

+ V) .............................................................................................................................. 80


Northridge-01 (Recording station: Rinaldi Receiving Station) Earthquake, FN-

Component ................................................................................................................... 80


Northridge-01 (Recording station: Rinaldi Receiving Station) Earthquake, FP-

Component ................................................................................................................... 80






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Northridge-01 (Recording station: Sylmar Converter Station) Earthquake

(FN + V) ....................................................................................................................... 82


Northridge-01 (Recording station: Sylmar Converter Station) Earthquake

(FP + V) ....................................................................................................................... 82


Northridge-01 (Recording station: Sylmar - Converter Station) Earthquake,

FN-Component ............................................................................................................ 82


Northridge-01 (Recording station: Sylmar - Converter Station) Earthquake,

FP-Component ............................................................................................................. 83






Northridge-01 (Recording station: Sylmar - Converter Station East)

Earthquake (FN + V) ................................................................................................... 84



Earthquake (FP + V) .................................................................................................... 85



Earthquake, FN-Component ........................................................................................ 85



Earthquake, FP-Component ......................................................................................... 85






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Northridge-01 (Recording station: Sylmar - Olive View Med FF) Earthquake

(FN + V) ....................................................................................................................... 87


Northridge-01 (Recording station: Sylmar - Olive View Med FF) Earthquake

(FP + V) ....................................................................................................................... 87


Northridge-01 (Recording station: Sylmar - Olive View Med FF) Earthquake,

FN-Component ............................................................................................................ 87


Northridge-01 (Recording station: Sylmar - Olive View Med FF) Earthquake,

FP-Component ............................................................................................................. 88






Kobe-Japan (Recording station: KJMA) Earthquake (FN + V) .................................. 89


Kobe-Japan (Recording station: KJMA) Earthquake (FP + V) ................................... 90


Kobe-Japan (Recording station: KJMA) Earthquake, FN-Component ....................... 90


Kobe-Japan (Recording station: KJMA) Earthquake, FP-Component ........................ 90






Kobe-Japan (Recording station: Takarazuka) Earthquake (FN + V)........................... 92


Kobe-Japan (Recording station: Takarazuka) Earthquake (FN + V)........................... 92

Figure 7. 85 Time History of horizontal displacement at top of the dam due toKobe-Japan (Recording station: Takarazuka) Earthquake, FN-Component ............... 92


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Kobe-Japan (Recording station: Takarazuka) Earthquake, FP-Component ................ 93






Kobe-Japan (Recording station: Takatori) Earthquake (FN + V) ................................ 94


Kobe-Japan (Recording station: Takatori) Earthquake (FP + V) ................................ 95


Kobe-Japan (Recording station: Takatori) Earthquake, FN-Component .................... 95


Kobe-Japan (Recording station: Takatori) Earthquake, FP-Component ..................... 95

Figure 7. 93 Comparison of percentage of overstressed areas with acceptance

limits ............................................................................................................................ 96

Figure 7. 94 Comparison of cumulative duration of stress cycles with

acceptance stresses at the heel of the dam ................................................................... 96


Right: Vertical Stress ................................................................................................... 98


Imperial Valley-06 (Recording station: Coachella Canal #4) Earthquake .................. 99


Right: Vertical Stress ................................................................................................... 99


Mendocino (Recording station: Eureka - Myrtle & West) Earthquake ..................... 100


Right: Vertical Stress ................................................................................................. 100


Landers (Recording station: Eureka - Amboy) Earthquake ....................................... 101

Figure 7. 101 Envelops of maximum stresses (N/mm 2), Left: Horizontal

Stress, Right: Vertical Stress...................................................................................... 101

Figure 7. 102 Time history of major principal stress at the heel of dam forNorthridge-01 (Recording station: Arcadia - Campus Dr) Earthquake ..................... 102


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Figure 7. 103 Envelops of maximum stresses (N/mm 2), Left: Horizontal

Stress, Right: Vertical Stress...................................................................................... 102


Kobe-Japan (Recording station: HIK) Earthquake .................................................... 103

Figure 7. 105 Time history of instantaneous factor of safety for near field

earthquake [NGA#1084] ............................................................................................ 104

Figure 8. 1 Dam finite-element model with gap-friction elements ............................ 107

Figure 8. 2 Constitutive relations of gap-friction element ......................................... 108

Figure 8. 3 Deflected shape at the time of maximum displacement. 31 gap

elements out of 51 experienced opening and sliding (NGA#1120) ........................... 109

Figure 8. 4 Time history of sliding displacements of nodal points (heel and

toe) at the base of the dam (NGA#1120) ................................................................... 110

Figure 8. 5 Time history of horizontal displacement at the top of dam

(NGA#1120) .............................................................................................................. 110


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LIST OF SYMBOLS

PGA : Peak Ground Acceleration

PGV : Peak Ground VelocityPGD : Peak Ground Displacement

CAV : Cumulative absolute velocity

PEER : pacific Earthquake Engineering Research Center

IA : Arias Intensity

FN : Fault normal component of earthquake record

FP : Fault parallel component of earthquake record

I : Damage potential parameter : Root mean square acceleration

g : Acceleration due to gravity

NGA : New generation attenuation

: Time history of ground motion (displacement, velocity

or acceleration)

: Undamped natural frequency

: Damped natural frequency and : The cosines and sine function of amplitudes

corresponding to the nth frequency

: The amplitude corresponding to zero frequency

T : Duration of ground motion

An : Fourier Amplitude

FFT : Fast Fourier Transform

DFT : Discrete Fourier Transform

: Mass matrix of the structure

: Added hydrodynamic mass matrix having nonzero

terms only at the structure-water nodal points

: Velocity and acceleration vectors, respectively

: Overall damping matrix for the entire system

: Combined stiffness matrix for structure and foundation

region


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: Vector of nodal point displacements for the complete

system relative to the rigid base displacement

: Direction cosines to x, y and z- DOFs respectively

: Ground acceleration input in x-, y-, and z-directionrespectively

: Hydrodynamic added mass at point i

H : depth of water

: Height above the base of the dam

: Tributary surface area at point i : The normal direction cosines : Westergaard pressure coefficient : Tensile strength of concrete : Compressive strength of concrete

DCR : Demand Capacity Ratio

: Effective load vector

: Modal coordinate mass

: Modal coordinate damping

: Modal coordinate stiffness : Modal coordinate force

: Shape function for nth mode

: Modal damping ratio

FNA : Fast nonlinear analysis or modal nonlinear time history

analysis

: Stiffness matrix for the linear elastic elements

: Vector of forces from the nonlinear degrees of

freedom in the Link/Support elements

: Normal stress

: yield shear strength

c : Cohesion

: Friction angle


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1

1. INTRODUCTIONNepal has vast potential of hydropower resources but it is located in one of the most

tectonically active regions of the world. The hydropower resources are envisaged not

only as a source to fulfill the domestic demand of the country rather an exportcommodity. Thus, large scale projects are planned for the export orientated power

generation. These projects involve large dam structures for the impounding of water. As

the risk of failure of dam cannot be ignored due to high seismic activity, the downstream

establishment is always on greater threat.

Since the Northridge and Hyogoken-Nanbu (Kobe) earthquakes, there has been abundant

discussion regarding the adequacy of design practice of concrete dams.

The hazard posed by massive dams has been demonstrated since 1928 by the failure of

several dams of all kinds and in many parts of the globe. However, no failure of a

concrete dam has resulted from earthquake excitation; in reality the only complete

collapses of concrete dams have been due to failures in the foundation rock supporting

the dams 1. On the other hand, two important instances of earthquakes damage to concrete

dams occurred in the 1960s: Hsinfengkiang in China and Koyna in India. The damage

was severe enough in each case to need major repairs and strengthening, however the

reservoirs weren t released, thus there was no flooding damage. This wonderful safety

record, however, is not sufficient reason for satisfaction regarding the seismic safety of

concrete dams, as a result of no such dam has yet been subjected to must conceivable

earthquake shaking . For this reason its essential that eve ry one existing concrete dams in

tectonically active regions, also as new dams planned for such regions, be checked to see

that theyre going to perform satisfactorily throughout the great earthquake shaking to

which they might be subjected especially in the near -field regions.

1 Earthquake Engineering for Concrete Dams: Design, Performance, and Research Needs by NationalResearch Council (U.S.) Panel on Earthquake Engineering for Concrete Dams


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2

1.1. Seismicity in Nepal 2

Nepal is located at the boundary between Indian and Tibetan tectonic plates and therefore

lies in a very seismically active region. Historical data proof the occurrence of damaging

great earthquakes in the past.

The great earthquake that occurred in Nepal was Bihar- Nepal earthquake of 1934 A. D.,

Assam great earthquake of 1897, Kangra earthquake 1905, and Assam earthquake 1950.

The earthquake of 1833 also affected the Kathmandu Valley. The record of historical

earthquake is nt complete that poses a problem in assessing the recurrence period of great

damaging earthquakes. From the available data there has been no great damaging

earthquakes of magnitude >8.0 in the gap between the earthquakes of 1905 A. D and

1934 A. D. and there is a genuine threat that a major earthquake may occur in this gap

which will affect Western Nepal.

Figure 1. 1 Geological Map of Nepal

(Source: http://www.geocities.com/geologyofnepal/geology.html )

2 Source: National Seismological Centre, Nepal, http://www.seismonepal.gov.np
http://www.geocities.com/geologyofnepal/geology.htmlhttp://www.geocities.com/geologyofnepal/geology.htmlhttp://www.geocities.com/geologyofnepal/geology.htmlhttp://www.seismonepal.gov.np/http://www.seismonepal.gov.np/http://www.seismonepal.gov.np/http://www.seismonepal.gov.np/http://www.geocities.com/geologyofnepal/geology.html


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3

Figure 1. 2 Seismic Hazard Map of Nepal

(Source: http://earthquake.usgs.gov/earthquakes/world/nepal/gshap.php )

1.2. Research Objectives

i. Performance Study of concrete gravity dams under near field earthquake pulse and

comparison to the far field earthquake effects.

ii. To show the application of linear and nonlinear time history methods to earthquake

response analysis of gravity dams.

iii. To assess stability condition of the dam.

iv. Locations of occurrence of probable cracks on dam during Earthquake.
http://earthquake.usgs.gov/earthquakes/world/nepal/gshap.phphttp://earthquake.usgs.gov/earthquakes/world/nepal/gshap.phphttp://earthquake.usgs.gov/earthquakes/world/nepal/gshap.phphttp://earthquake.usgs.gov/earthquakes/world/nepal/gshap.php


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4

1.3. Organization of Thesis

Thesis work on Non -linear time history analysis of large concrete dam considering near

field earthquake e ffect is totally divided into 9 chapters.

Chapter (1) describe introduction about general background, seismicity in Nepal andresearch objective.

Chapter (2) describes related literature review for the research.

Chapter (3) describes characteristics of near-field earthquake records and criteria to select

near-field records.

Chapter (4) describes ground motion and their characteristics for the selected earthquake.

Ground motion characteristics such as amplitude, Frequency Content, duration are

described in this chapter. Special characteristics of near field record i.e. pulse type

velocity time history are also presented along with acceleration time history and Fourier

Amplitude Spectrum.

Chapter (5) describes the techniques of finite element modeling of gravity dam and

material properties used for this study. Fluid-Structure Interaction, Foundation-Structure

Interaction are also described in this chapter.

Chapter (6) Structural performance and damage criteria are described in this chapter.

Limiting values of cumulative inelastic duration and percentage of overstressed area with

different demand-capacity ratio are described based on U.S. Army Engineering Manual

EM_1110-2-6051.

Chapter (7) describes Linear Time History Numerical solution Techniques for the

evaluation of linear response of the gravity dam for selected earthquake records and

performance of dam is checked for limiting value of performance criteria.

Chapter (8) Describes nonlinear performance of dam by using Nonlinear Time History

Analysis technique.

Chapter (9) describes conclusion of linear and nonlinear response of dam for near field

and far field and recommendation for further research.


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5

2. LITERATURE REVIEWS(Qiumei, et al. October, 2008) analysed the gravity dam subjected to near-field pulse-like

ground motions and this study gave result that near field pulse-like ground motion will

remarkably effect on the concrete gravity dam. Thus cannot be neglected in the design of

RC gravity dam.

(US Army Crops of Engineers 22 December 2003) had developed methodology for Time

history dynamic analysis of concrete hydraulic structures (EM 1110-2-6051). Same

methodology will be used for the analysis of concrete dam and standard in contest of

Nepal will be developed. US Army Corps of Engineers also has developed methodology

for Earthquake Design and Evaluation of Concrete Hydraulic Structures (EM 1110 -2-

6053), (US Army Crops of Engineers 1 May 2007) which also be used for the evaluation

of performance of dam under Earthquake.

(Ohmachi, et al. 2003) had studied effect of near field hidden seismic fault on concrete

dam. The 2000 Western Tottory earthquake (M J 7.3), Japan, was caused by a hidden

seismic fault underlying Kasho Dam, a 46 m-high concrete gravity dam. Strong-motion

accelerometers registered peak accelerations of 2051 and 531 gal at the top of the dam

and in the lower inspection gallery, respectively. Integration of the acceleration records in

the gallery gives a permanent displacement of 28 cm to the north, 7 cm to the west, and

uplift of 5 cm. The dam survived the earthquake without serious damage, but the

reservoir water level dropped suddenly by 6 cm, followed by damped free vibration that

continued for several hours. Based on numerical simulation and field observation, the

water level change is attributed to ground displacement in the near field followed by

seiching of the reservoir. The vibration period in the upstream-downstream direction of

the dam changed noticeably during the main shock, probably due to hydrodynamic

pressure variations.

(Jalali and Ohmachi 2000) had studied aspects of concrete dams response to near fieldground motions and summarized the result as:

Near-field ground motions differ dramatically from their far-field counterparts, and such

kind of ground motions must be treated in different ways, or even may require special

processing to accurately represent their features.


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It is important to select an appropriate suite of time histories not only based on

instrumental parameters such as PA, PV, PD, IV, and ID, or ground motion parameters

based on response spectra, but also the most reliable parameter, input energy of

earthquake ground motion. Maximum incremental velocity (IV) and maximum

incremental displacement (ID) seems to be better parameters for characterizing the

damage potential of earthquakes in near-field region.

The directional frequency contents and amplitude level of near-field ground motions have

fundamental consequences in earthquake response of dam structures. This implies that

the dynamic response of dam structures will be influenced by their orientation relative to

the ground motion and by their proximity to causative faults.

In the case of the arch dam for the most of the ground motions the increase in the

maximum arch and cantilever stresses in the FN direction is about 100 percent. However,

in some cases the maximum arch and cantilever stresses occur in FP direction. It seems

the latter cases are exceptions. It may be concluded that the FN direction is the most

critical direction regarding the stress level in most of near-field ground motions.

Stress level of arch dam is beyond the yield limit of the concrete commonly used in

constructing the dams, and dam will crack under such ground motions, and this will make

non-linear analysis of dams in highly seismic region indispensable.

For gravity dam stress level is very high, and this will lead to severe cracking of the dam

basically in the neck region and interface of the dam and foundation rock, and even

making dam unstable.

Base sliding displacements of gravity dam are dramatically large in FN direction, and

may inflict severe damages to keys, drainage systems, and grout curtains or finally may

lead to loss of reservoir.

In view of many assumptions made in the analyses performed here, the aboveconclusions should be regarded as preliminary, and this is strongly emphasized.

Additional dam heights, configurations, and different suite of strong ground motions need

to be examined. More research should be devoted to effects of large near-field


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earthquakes regarding duration of shaking and frequency contents, in addition to near-

source effects.

(ZHANG and OHMACHI 2000) had studied on seismic cracking and strengthening ofconcrete gravity dam and summarized result as:

1. Concrete gravity dams are likely to experience cracking under intensive

excitations, especially at the heel of dam body and upstream discontinuity.

2. A gentle and smooth upstream face could reduce the tensile stress in the dam

body and avoid the occurrence of cracking.

3. Reinforcing bars cannot prevent the occurrence of cracking under highly tensile

stress, but it can resist the propagation of cracks and reduce the damage of dam

body.

4. Post-tension cables can strengthen the dam body effectively, if it is adequatelydesigned.

(Burman and Reddy October, 2008) had studied on seismic analysis of concrete gravity

dams considering foundation flexibility and nonlinearity and found conclusion as:

1. The displacement and stresses are found to have increased when the flexibility of

the foundation was considered compared to the assumption of rigid foundation.

2. When the material nonlinearity of the foundation was considered, the dam showed

increased amount of displacements and stresses compared to the linear case forEl-Centro excitations. However, the foundation nonlinearity may increase or

decrease the displacement response depending on the characteristics of ground

motion, surrounding foundation properties and the type of structure.

3. The Bouc-Wen hysteretic model is capable of representing strongly nonlinear

behavior under both cyclic and random loading.

(FEMA 65 May 2005) provide a basic framework for the earthquake design and

evaluation of Dams. The general philosophy and principles for each part of the

framework are described in sufficient detail to achieve a reasonable degree of uniformity

in application among the Federal agencies involved in the planning, design, construction,

operation, maintenance, and regulation of dams. The guidelines deal only with the

general concepts and leave the decisions on specific criteria and procedures for


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accomplishing this work up to each agency. Because these guidelines generally reflect

current practices, it will be necessary to make periodic revisions, additions, and deletions

to incorporate state-of-the-practice earthquake engineering.


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3. NEAR-FAULT EARTHQUAKE RECORD CHARACTERISTICS

3.1. Near-Field Ground Motions

A lot of major dam sites is located near to active faults and so could be subjected to near-

field ground motions from massive earthquakes. Information of ground motion in thenear-field region of damaging earthquake is limited by the inadequacy of recorded data.

The near-field of an earthquake is the region within which distinct pulse-like ground

motion are observed due to release and propagation of huge energy from the fault rupture

process. The near-field ground motions are characterized by high peak acceleration

(PGA), high peak velocity (PGV), high peak displacement (PGD), pulse-like time

history and distinct spectral content . The character of near-field ground motions differs

significantly from that of far-field ground motions. The damaging earthquake data clearly

show the presence of systematically larger ground motions in the fault normal direction

than in the fault parallel direction near to faults. The ratio of fault normal to fault parallel

motions increases with increase in magnitude, increase in fault proximity and increase in

period. Further, recent massive earthquakes have shown signs of damage occurring in

chosen directions that correspond to fault normal (north in the 1994 Northridge

earthquake and northwest in the 1995 Kobe earthquake).

3.2. Criteria for Near-Field Records 3

Criteria for Near-Field earthquake record are evaluated based on the paper

Identification of Near-Fault Earthquake record Characteristics by Ch.A.

Maniatakis, I.M. Taflampas and C.C. Spyrakos. The parameters used to select the records

attempt to address the complexity of strong seismic ground motion, such as frequency

content, amplitude and direction, given the fact that it is impossible to characterize strong

motion accurately using any single parameter (Jenning, 1985).

This procedure has been applied in the selected ground motion data from PEER groundmotion database (peer .berkeley.edu/ peer _ ground _ motion _ database) to recognize near-field

records. The following parameters have been selected:

3 The 14 th World Conference on Earthquake Engineering, October 12-17, 2008, Beijing, ChinaIdentification of Near-Fault Earthquake Record CharacteristicsCh.A. Maniatakis, I.M. Taflampas and C.C. Spyrakos


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i) Peak horizontal ground acceleration (PHGA) or (PGA)

ii) Cumulative absolute velocity (CAV), defined as

Where t r is the total duration of the acceleration trace.

iii) Peak horizontal ground velocity (PHGV) or (PGV) which has been found to

be a better indicator of damage potential than PGA (Akkar and Ozen, 2005)

for structures with fundamental frequency in the intermediate range

iv) Arias intensity (I A) (1970), defined as

Where a g(t), is the ground acceleration and I E the integral of the squared ground

acceleration.

v) The damage potential parameter proposed by Fajfar et al. (1990), (I), defined

as

Where t D is the duration of strong motion, according to Trifunac and Brady (1975). The

index incorporates the effects of strong motion duration.

vi) The root mean square acceleration (a rms), defined as

This index accounts for the effects of amplitude and frequency content of strong-motion

record and is directly proportional to the square root of the gradient of the specified

interval of Arias Intensity.

Table 3.1 presents the lower bounds of the parameters listed above that serve as criteria to

identify that correspond to seismic intensities .


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Table 3. 1 Ground motion parameters, measured characteristics and lower-bound values(Ch.A. Maniatakis 2008)

Ground

Motion

parameters

Ground Motion Characteristics

Amplitude Frequency

Content

Duration Energy Lower-

BoundPGA 0.2 gCAV 0.30 g secPGV 20 cm/s

IA 0.4 m/secI 30 cm sec -

arms 0.5 m/sec

Seven earthquake events recorded at fifteen different recording stations are selected for

the evaluation of response of gravity dam. Selected ground motion record (Table 3.2) are

evaluated according to above characteristics and presented in Table 3.3 and Table 4.4.


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Table 3. 2 Selected Near-Field Ground Motion Records

SN NGA# Event Year Station Mag. MechanismEpc.Dist.(km)

Low.freq (Hz)

1 181 ImperialValley-06 1979 El Centro Array #6 6.53 Strike-Slip 0 0.12

2 182 ImperialValley-06 1979 El Centro Array #7 6.53 Strike-Slip 0.6 0.12

3 779 Loma Prieta 1989 LGPC 6.93 Reverse-Oblique 0 0.12

4 821 Erzican-Turkey 1992 Erzincan 6.69 Strike-Slip 0 0.12

5 825 CapeMendocino 1992 Cape Mendocino 7.01 Reverse 0 0.07

6 828 CapeMendocino 1992 Petrolia 7.01 Reverse 0 0.07

7 879 Landers 1992 Lucerne 7.28 Strike-Slip 2.2 0.1

8 1044 Northridge-01 1994 Newhall - Fire Sta 6.69 Reverse 3.2 0.12

9 1063 Northridge-01 1994 Rinaldi Receiving Sta 6.69 Reverse 0 0.11

10 1084 Northridge-01 1994 Sylmar - Converter Sta 6.69 Reverse 0 0.41

11 1085 Northridge-01 1994 Sylmar - Converter StaEast 6.69 Reverse 0 0.41

12 1086 Northridge-01 1994 Sylmar - Olive ViewMed FF 6.69 Reverse 1.7 0.12

13 1106 Kobe- Japan 1995 KJMA 6.9 Strike-Slip 0.9 0.06

14 1119 Kobe- Japan 1995 Takarazuka 6.9 Strike-Slip 0 0.36

15 1120 Kobe- Japan 1995 Takatori 6.9 Strike-Slip 1.5 0.36


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Table 3. 3 Ground motion parameter and measured characteristics for Fault Normal component

SN Event Mag Station

PGA(g)

CAV(g sec)

PGV(cm/s)

IA(m/s)

I(cm s -0.75)

arms (m/s 2)

1Imperial Valley-

06 6.53 El Centro Array #6 0.44 1.05 111.87 1.77 208.71 0.94

2Imperial Valley-

06 6.53 El Centro Array #7 0.46 0.81 108.97 1.67 195.52 0.99

3 Loma Prieta 6.93 LGPC 0.94 2.16 97.02 8.24 198.70 1.71

4 Erzican- Turkey 6.69 Erzincan 0.49 0.89 95.42 2.03 177.38 1.02

5 Cape Mendocino 7.01 Cape Mendocino 1.27 1.09 59.55 2.90 124.89 0.97

6 Cape Mendocino 7.01 Petrolia 0.61 1.51 82.10 3.67 175.12 1.05

7 Landers 7.28 Lucerne 0.71 2.45 141.02 6.76 338.35 1.13

8 Northridge-01 6.69 Newhall - Fire Sta 0.72 1.74 120.27 6.47 239.47 1.60

9 Northridge-01 6.69 Rinaldi Receiving Sta 0.87 1.87 167.20 8.22 339.31 1.74

10 Northridge-01 6.69 Sylmar - Converter Sta 0.59 1.22 130.27 5.35 301.63 1.17

11 Northridge-01 6.69Sylmar - Converter Sta

East 0.84 1.06 116.56 4.08 236.81 1.25

12 Northridge-01 6.69Sylmar - Olive View

Med FF 0.73 1.35 122.72 3.80 225.21 1.43

13 Kobe- Japan 6.9 KJMA 0.85 2.21 96.27 9.41 197.23 1.82

14 Kobe- Japan 6.9 Takarazuka 0.65 1.03 72.65 2.92 134.81 1.23

15 Kobe- Japan 6.9 Takatori 0.68 2.41 169.58 10.36 355.39 1.84

Table 3. 4 Ground motion parameter and measured characteristics for Fault Parallel component

SN Event Mag Station

PGA(g)

CAV(g sec)

PGV(cm/s)

IA(m/s)

I(cm s -0.75 )

arms (m/s 2)

1 Imperial Valley-06 6.53 El Centro Array #6 0.40 0.98 64.72 1.47 120.03 0.862 Imperial Valley-06 6.53 El Centro Array #7 0.33 0.66 44.53 0.89 74.99 0.81

3 Loma Prieta 6.93 LGPC 0.54 1.44 72.18 3.40 149.51 1.07

4 Erzican- Turkey 6.69 Erzincan 0.42 0.77 45.33 1.27 88.20 0.74

5 Cape Mendocino 7.01 Cape Mendocino 1.43 1.41 119.44 5.44 250.03 1.33

6 Cape Mendocino 7.01 Petrolia 0.63 1.52 60.74 3.57 128.75 1.05

7 Landers 7.28 Lucerne 0.79 2.51 48.12 6.78 115.60 1.138 Northridge-01 6.69 Newhall - Fire Sta 0.65 1.32 50.57 3.56 102.84 1.13

9 Northridge-01 6.69 Rinaldi Receiving Sta 0.42 1.45 62.71 3.52 128.91 1.11

10 Northridge-01 6.69 Sylmar - Converter Sta 0.80 1.03 93.30 4.28 213.24 1.04

11 Northridge-01 6.69Sylmar - Converter Sta

East 0.50 0.91 78.36 2.87 152.16 1.15

12 Northridge-01 6.69Sylmar - Olive View

Med FF 0.60 1.34 54.67 3.82 109.23 1.22

13 Kobe- Japan 6.9 KJMA 0.55 1.60 53.67 4.39 107.16 1.31

14 Kobe- Japan 6.9 Takarazuka 0.70 1.15 83.23 4.06 155.72 1.43

15 Kobe- Japan 6.9 Takatori 0.60 1.94 62.82 6.20 149.10 1.11

Table 3.3 and Table 3.4 shows that all the characteristics of near-fault ground motion

satisfied by the selected ground motion according to Table 3.1.


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4. GROUND MOTIONS AND THEIR CHARACTERISTICS

4.1. Seismic Inputs for Structures

Seismic inputs are the earthquake data that are necessary to perform different types of

seismic analysis. In the context of seismic analysis and design of structures, variousearthquake records may be required depending upon the nature of analysis being carried

out. Seismic inputs for structural analysis are provided either in the time domain or in

frequency domain or in both time and frequency domains. In addition, a number of

earthquake parameters are also used as seismic inputs for completeness of the

information that is required to perform different types of analysis. They include

magnitude, intensity, peak ground acceleration/velocity/displacement, duration,

predominant ground frequency, and so on.

The most general way to describe a ground motion is with a time history record. The

motion parameters may be acceleration, velocity, or displacement, or all the three

combined together. Generally, the directly measured quantity is the acceleration and the

other parameters are the derived quantities.

4.2. Selection of Ground Motion

For this study, we have considered 15 near-field ground motion records (fault-normal and

fault-parallel components) and for the same earthquake events 5 far-field ground motions(recorded one component only) are considered.

The PGAs of 15 near -field fault normal ground motions ranges between 0.44 1.27 and

PGAs of 15 near -field fault parallel ground motions ranges between 0.33 1.43 are

considered. For the same events, PGAs of 5 far -field ground motion records ranges

between 0.09 0.15 are selected. The PGAs and duration of ground motions ra nges

from low to high and frequency content ranges from resonating to non-resonating

frequencies. Near-Field ground motion records are presented in Table 3.1 and Table 3.4.

Far Field records are presented below.


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Table 4. 1 Selected Far-Field Ground Motion records

Far-Field Ground Motion Records

SN

NGA#

Event Year Station Magnitude

Mechanism

Epicentral

Distance

PGA(g)

1 166 Imperial Valley-06 1979 Coachella Canal #4 6.53 Strike-Slip 50 0.12

2 826 Cape Mendocino 1992 Eureka - Myrtle &West 7.01 Reverse 42 0.15

3 832 Landers 1992 Amboy 7.28Strike-Slip 69 0.12

4 948 Northridge-01 1994 Arcadia - Campus Dr 6.69 Reverse 41 0.09

5 1105 Kobe- Japan 1995 HIK 6.9Strike-Slip 95 0.14

4.3. Characteristics of Ground Motions

It is necessary to describe the characteristics of the ground motion that are of engineering

significance and to identify a number of ground motion parameters that reflect those

characteristics. For engineering purpose, three characteristics of earthquake motions (1)

amplitude, (2) frequency content, and (3) duration of the motion are important to be

studied. Plenty of different ground motion parameter have been proposed, each of which

provides information about one or more of these characteristics. In practice, it is usually

necessary to use more than one of these parameters to characterize a particular ground

motion adequately (Kramer 1996). These (amplitude, frequency, duration) characteristics

differ dramatically between near-field and far-field ground motions.

Current study is on comparison of the response of concrete gravity dam subjected to

effects caused by near-fault ground motions with the effects caused by far-field ground

motions of the same event. Near-fault ground motions are different from ordinary ground

motions in that they often contain strong pulse like velocity time history and permanent

ground displacements. The dynamic motions are dominated by a large long period pulse

of motion that occurs on the horizontal component normal to the strike of the fault,

caused by rupture directivity effects. Forward rupture directivity causes the horizontal

strike-normal component of ground motion to be systematically larger than the strike-

parallel component at periods longer than about 0.5 seconds (Somerville 2002). However,

near fault recordings from recent earthquakes indicated that the pulse is a narrow band


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pulse whose period increases with magnitude, causing the response spectrum to have

peak whose period increases with magnitude, such that the near-fault ground motions

from moderate magnitude earthquakes may exceed those of larger earthquakes at

intermediate period. Parameter like rupture directivity, recording close to the epicenters,

faulting mechanism and duration can cause changes in characteristics of near-fault

ground motions.

Amplitude : Horizontal accelerations have commonly been used to describe the ground

motions. The peak horizontal acceleration for a given component of motion is simply the

largest (absolute) value of horizontal acceleration obtained from the acceleration of that

component. The largest dynamic forces induced in certain types of structures (very stiff)

are closely related to the peak horizontal accelerations (Kramer 1996).

Frequency Content : Only the simplest analyses are required to show that the dynamic

response of structures is very sensitive to frequency at which they are loaded. Earthquake

produce complicated loading with components of motion that span a broad range of

frequencies. The frequency content describes how the amplitude of a ground motion is

distributed among different frequencies. Since the frequency content of an earthquake

motion will strongly influence the effect of that motion, characterization of the motion

cannot be complete without consideration of its frequency content (Kramer 1996).

As the response of any structure depends on the ratio between the natural frequency of

the structure and the frequency of excitation, it is important to know the frequency

contents of the ground motion (Datta 2010). The most common way of providing this

information is by way of Fourier synthesis of the time history of the ground motion.

Assuming that the time history of the ground motion repeats itself with a period equal to

the duration of the ground motion, it can be represented as sum of an infinite number of

harmonic functions by

(4.1)

where

is the time history of ground motion (displacement, velocity or acceleration)


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is the nth frequency

and are the cosines and sine function of amplitudes corresponding to the nth

frequency

is the amplitude corresponding to zero frequency, respectively.

The amplitudes are given by: (4.2)

(4.3)

(4.4)

Where

(4.5)

T is the duration of ground motion.

The Fourier amplitude gives the amplitude of the harmonic at frequency and is given

by:

(4.6)Equation 4.1 can also be represented in the form

(4.7)

In which is the same as

; ; and is given by

(4.8)

The plot of versus frequency is called the Fourier amplitude spectrum and that of

versus is the Fourier phase spectrum.


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To obtain the Fourier amplitude spectrum of a time history of ground motion, integrations

given by Equations 4.2 4.4 need to be performed. As is an irregular function of

time, the integration is carried out by a numerical technique. This operation is performed

very efficiently by discrete Fourier transform (DFT), which is programmed as FFT and

available in most mathematical software. In FFT, the Fourier synthesis of a time history

record is mathematically treated as a pair of Fourier integrals in the complex domain as

given below.

(4.9)

(4.10)

The first integral provides frequency contents of the time history in a complex form,while the second one provides the time history back, given the complex frequency

contents. The second one is performed using IFFT (inverse Fourier transform).

The standard input for FFT is the time history of ground motion sampled at discrete time

interval. IF N is the number of discrete ordinates of the time history at an interval of time

given as the input to FFT, then N numbers of complex quantities are obtained as the

output. The first N/2 complex quantities provide frequency contents of the time history

with amplitude at frequency as:

j = 0, .. , N/2 Where and are the real and imaginary parts of the jth complex quantity,

respectively.

Generally band width is measured at a level of

times of maximum Fourier

amplitude.

Duration : the duration of strong ground motion can have a strong influence on

earthquake damage. It is related to the time required for accumulation of strain energy by

rupture along the fault. There are different procedures for calculating the duration of


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ground motion, out of which we have considered Trifunac and Brady (1975) method for

calculating the duration of ground motion.

Trifunac and Brady Duration (1975) is based on the time interval between the points at

which 5 % and 95 % of the total energy has been recorded.

Details of the ground motions with magnitude, epicentral distance, PGA, duration and

frequency range are given below in table 4.2 to table 4.4. Further the ground motions and

their Fourier Amplitude Spectrums are given in figure 4.1 to figure 4.15.

Table 4. 2 Selected Near-Field Fault Normal Ground Motion Records

Near-Field Fault Normal Ground Motion

SN NGA#

Event Year Station Magnitude

Mechanism

Epicentral

Distance

PGA(g)

Duration

(sec)

Frequency(Hz)

1 181 ImperialValley-06 1979El Centro Array

#6 6.53Strike-Slip 1.35

0.44 12.12 0.24 - 0.39

2 182 ImperialValley-06 1979El Centro Array

#7 6.53Strike-Slip 0.56

0.46 10.37 0.24 - 1.37

3 779 LomaPrieta 1989 LGPC 6.93Reverse-Oblique 3.88

0.94 17.59 1.27 - 1.61

4 821 Erzican-Turkey 1992 Erzincan 6.69Strike-Slip 4.38

0.49 11.95 0.34 - 1.51

5 825 CapeMendocino 1992 Cape Mendocino 7.01 Reverse 6.961.27 19.34 0.37 - 7.35

6 828 Cape

Mendocino1992 Petrolia 7.01 Reverse 8.18 0.61 20.7 1.12 - 2.34

7 879 Landers 1992 Lucerne 7.28 Strike-Slip 2.20.71 33.13 0.20 -12.35

8 1044 Northridge-01

1994 Newhall - FireSta 6.69 Reverse 5.920.72 15.72 0.73 - 1.95


1994 RinaldiReceiving Sta 6.69 Reverse 6.50.87 16.96 0.68 - 1.32


1994 Sylmar -Converter Sta 6.69 Reverse 5.350.59 28.74 0.88 - 0.88


1994Sylmar -

Converter StaEast

6.69 Reverse 5.19 0.84 17.04 0.34 - 1.37


1994 Sylmar - OliveView Med FF 6.69 Reverse 5.30.73 11.34 0.37 - 3.30

13 1106 Kobe-Japan 1995 KJMA 6.9Strike-Slip 0.96

0.85 17.62 0.98 - 1.49

14 1119 Kobe-Japan 1995 Takarazuka 6.9Strike-Slip 0.27

0.65 11.86 0.49 - 4.37

15 1120 Kobe-Japan 1995 Takatori 6.9Strike-Slip 1.47

0.68 19.29 0.46 - 0.90


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Table 4. 3 Selected Near-Field Fault Normal Ground Motion RecordsNear-Field Fault Parallel Ground Motion

SN NGA#

Event Year Station Magnitude Mechanism

Epicentral

Distance

PGA(g)

Duration(sec)

Frequency(Hz)

1 181 ImperialValley-06 1979 El Centro Array#6 6.53 Strike-Slip 1.35 0.40 11.84 0.39 - 1.22

2 182Imperial

Valley-06 1979El Centro Array

#7 6.53 Strike-Slip 0.56 0.33 8.04 0.34 - 1.42

3 779Loma

Prieta 1989 LGPC 6.93Reverse-

Oblique 3.88 0.54 18.4 1.56 - 1.76

4 821Erzican-

Turkey 1992 Erzincan 6.69 Strike-Slip 4.38 0.4214.3

3 0.39 - 3.52

5 825Cape

Mendocino 1992Cape

Mendocino 7.01 Reverse 6.96 1.43 19.2 2.12 - 7.47

6 828Cape

Mendocino 1992 Petrolia 7.01 Reverse 8.18 0.6320.1

8 1.32 - 1.98

7 879 Landers 1992 Lucerne 7.28 Strike-Slip 2.2 0.7933.3

111.43 -11.43

8 1044Northridge-01 1994

Newhall - FireSta 6.69 Reverse 5.92 0.65 17.1 1.39 - 4.03


RinaldiReceiving Sta 6.69 Reverse 6.5 0.42

17.86 2.64 - 3.27


Sylmar -Converter Sta 6.69 Reverse 5.35 0.80

27.28 0.54 - 1.81


Sylmar -Converter StaEast 6.69 Reverse 5.19 0.50

14.22 0.63 - 1.27


Sylmar - OliveView Med FF 6.69 Reverse 5.3 0.60

15.94 1.25 - 2.25

13 1106 Kobe-Japan 1995 KJMA 6.9 Strike-Slip 0.96 0.55 15.9 1.86 - 3.0

14 1119Kobe-

Japan 1995 Takarazuka 6.9 Strike-Slip 0.27 0.7012.2

5 0.61 - 2.20

15 1120Kobe-

Japan 1995 Takatori 6.9 Strike-Slip 1.47 0.6031.7

2 0.56 - 0.93


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Table 4. 4 Far-Field Ground Motion records

SN NGA# Event Year Station

Magnitude Mechanism

EpicentralDistance

PGA(g)

1

166 Imperial

Valley-

1979 Coachella

Canal #4

6.53 Strike-Slip 50 0.12

2826 Cape

Mendoc

1992 Eureka -

Myrtle & West7.01 Reverse 42 0.15

3832 Landers 1992 Amboy 7.28 Strike-Slip 69 0.12

4948 Northrid

ge-011994 Arcadia -

Campus Dr6.69 Reverse 41 0.09

51105

Kobe-

Japan1995 HIK 6.9 Strike-Slip 95 0.14


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4.4. Near field Ground Motion and Their Fourier Amplitude Spectrum

(a) (d)

(b) (e)

(c) (f)

Figure 4. 1 Imperial Valley -06 (Recording Station: El Centro Array #6) near-field

(a) Fault Normal acceleration time history, (b) Fault normal velocity time history, (c)

Fault Normal Fourier amplitude Spectrum, (d) Fault parallel acceleration time history, (e)

Fault parallel velocity time history, (e) Fault parallel Fourier amplitude spectrum


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-0.4

-0.2

0

0.2

0.4

0 10 20 30 40 A c c e l e r a t i o n

( g )

Time (Sec.)

-150

-100

-50

0

50

100

0 20 40

V e

l o c i t y

( c m / s )

Time (Sec.)

-60

-40

-20

0

20

40

60

0 10 20 30 40 V e

l o c i t y

( c m

/ s )

Time (Sec.)

-0.005

0.000

0.005

0.010

0.015

0.020

0.025

0.030

-5 5 15 25

F o u r i e r A m p

l i t u

d e

Frequency (Hz)-0.005

0.000

0.005

0.010

0.015

0.020

-5 5 15 25 F o u r i e r A m p

l i t u

d e

Frequency (Hz)

-0.6

-0.4-0.2

0

0.2

0.4

0.6

0 10 20 30 40

A c c e

l e r a t i o n

( g )

Time (Sec.)

(a) (d)

(b) (e)

(c) (f)

Figure 4. 2 Imperial Valley -06 (Recording Station: El Centro Array #7) near-field(a) Fault Normal acceleration time history, (b) Fault normal velocity time history, (c) Fault

Normal Fourier amplitude Spectrum, (d) Fault parallel acceleration time history, (e) Fault

parallel velocity time history, (e) Fault parallel Fourier amplitude spectrum


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Figure 4. 3 Loma Prieta (Recording Station: LGPC) near-field





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Figure 4. 4 Erzican- Turkey (Recording Station: Erzincan) near-field





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Figure 4. 5 Cape Mendocino (Recording Station: Cape Mendocino) near-field





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Figure 4. 6 Cape Mendocino (Recording Station: Petrolia) near-field





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Figure 4. 7 Landers (Recording Station: Lucerne) near-field(a) Fault Normal acceleration time history, (b) Fault normal velocity time history, (c)




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Figure 4. 8 Northridge-01 (Recording Station: Newhall - Fire Station) near-field





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Figure 4. 9 Northridge-01 (Recording Station: Rinaldi Receiving Station) near-field





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Figure 4. 10 Northridge-01 (Recording Station: Sylmar - Converter Station) near-field





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Figure 4. 11 Northridge-01 (Recording Station: Sylmar - Converter Station East) near-field





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Figure 4. 12 Northridge-01 (Recording Station: Sylmar - Olive View Med FF) near-field





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Figure 4. 13 Kobe-Japan (Recording Station: KJMA) near-field





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Figure 4. 14 Kobe-Japan (Recording Station: Takarazuka) near-field





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Figure 4. 15 Kobe-Japan (Recording Station: Takatori) near-field





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5. FINITE ELEMENT MODELING 4 OF GRAVITY DAM ANDMATERIAL PROPERTIES

5.1. Introduction

Concrete gravity dam are massive concrete structures that

retain the impounded water by resisting the forces imposed

on them mainly by their own weight (Figure 5.1). They are

designed so that every unit of length is stable independent

of the adjacent units.

Traditionally, analysis of gravity dam considered a very simple

mathematical model of the structure. Such a method was based on the concept that the

resistance to external forces was 2-D in nature, so only a unit slice of the dam taken in the

upstream-downstream direction was analyzed. The earthquake forces were expressed as

the product of a seismic coefficient and were treated simply as static forces. Only the

effects of horizontal ground motion applied in the upstream-downstream direction were

considered. However, to represent the resistance mechanism realistically, it now has

become standard practice to use some form of finite element model in th

thesis final report ravi printed-libre

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