NUMERICAL SIMULATION OF CONCRETE GRAVITY DAM UNDER SEISMIC LOADING By Mohamed Ashraf Mohamed Abdelazeez Elsayad A Thesis Submitted to the Faculty of Engineering at Cairo University in Partial Fulfillment of the Requirements for the Degree of DOCTOR OF PHILOSOPHY In Structural Engineering FACULTY OF ENGINEERING, CAIRO UNIVERSITY GIZA, EGYPT 2017
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NUMERICAL SIMULATION OF CONCRETE GRAVITY
DAM UNDER SEISMIC LOADING
By
Mohamed Ashraf Mohamed Abdelazeez Elsayad
A Thesis Submitted to the Faculty of Engineering at Cairo University
in Partial Fulfillment of the Requirements for the Degree of
DOCTOR OF PHILOSOPHY
In Structural Engineering
FACULTY OF ENGINEERING, CAIRO UNIVERSITY GIZA, EGYPT
2017
NUMERICAL SIMULATION OF CONCRETE GRAVITY
DAM UNDER SEISMIC LOADING
By
Mohamed Ashraf Mohamed Abdelazeez Elsayad
A Thesis Submitted to the Faculty of Engineering at Cairo University
in Partial Fulfillment of the Requirements for the Degree of
DOCTOR OF PHILOSOPHY In
Structural Engineering
Under the Supervision of
Prof. Dr. Walid A. Attia
…………………………………………..
Prof. Dr. Adel. M. Belal
…………………………………………..
Professor of Structural Analysis &
Mechanics Structures Structural Engineering Department
Department of Civil Engineering Faculty of Engineering, Cairo University
Professor of Structural Analysis
Construction and Building Engineering Department Faculty of Engineering, Arab
Academy for Science, Technology & Maritime Transport, Cairo branch
FACULTY OF ENGINEERING, CAIRO UNIVERSITY
GIZA, EGYPT
2017
NUMERICAL SIMULATION OF CONCRETE GRAVITY
DAM UNDER SEISMIC LOADING
By
Mohamed Ashraf Mohamed Abdelazeez Elsayad
A Thesis Submitted to the
Faculty of Engineering at Cairo University in Partial Fulfillment of the
Requirements for the Degree of DOCTOR OF PHILOSOPHY
In Structural Engineering
Approved by the Examining Committee
Prof. Dr. Walid Abdel Latif Attia, Thesis Main Advisor Professor, Structural Engineering Department, Faculty of Engineering, Cairo University
………………………………………………………………………………
Prof. Dr. Adel Mahmoud Belal, Advisor Professor, Construction and Building Engineering Department, Faculty of Engineering,
Arab Academy for Science, Technology& Maritime Transport
……………………………………………………………………………… Prof. Dr. Mohamed Mohsen El-Attar, Internal Examiner Professor, Structural Engineering Department, Faculty of Engineering, Cairo University
………………………………………………………………………………
Prof. Dr. Eehab Ahmed Badr El-Din Khalil External Examiner Professor, Construction Research Institute (CRI)
Gravity dam is considered one of the most important massive concrete structures which depend on its own weight to resist the external loads. Partial or full failure of this
structure produces proper damages of the society and sometimes death for humans. Nowadays the construction of the concrete dams or rehabilitate work for existing dams
are required the creation for the development of modern tools and methods of the numerical analyses considering the dam-reservoir-foundation interaction. Moreover the transient simulation of the behavior for this structure is considered an important issue in
structural dynamics. In order to achieve the objectives of this thesis, many procedures are executed and explained as follow:
1. Comparisons between 2-D and 3-D F.E. models results are executed. 2. Studying the effect of dam-reservoir- foundation interaction through analyses. 3. Review the influence of the stiffness changes for the longitudinal direction of
the dams through the earthquakes. 4. Produce GUI for executing analyses and structural optimization for the concrete
dams’ cross-sections considering several types of loading.
i
Acknowledgments
First of all, I would like thank Allah (God) for giving me the patience, the knowledge and the strength to finish this work.
I would like to express my deep gratitude to my Ph.D advisor Professor Walid Abdel
Latif Attia for his guidance and mentorship with this dissertation and during my
doctoral studies. He has always been available, and he has provided valuable guidance
throughout my time. His technical guidance and continuous support and encouragement
proved to be invaluable.
I would like to express my deep gratitude to my advisor Professor Adel Mahmoud
Belal for the continuous support of my Ph.D study and research, for his patience, motivation, enthusiasm, and immense knowledge. His guidance helped me in all the time of research and writing of this thesis. He helped me find direction in my academic
career, and still provides advice whenever I need it.
I would like to thank my parents for their unfailing and unconditional love, for allowing
me to realize my own potential. All the support they have provided me over the years
was the greatest gift anyone has ever given me. I need to thank my father, who taught
me the value of hard work and an education. My sisters and little brother deserve my
wholehearted thanks as well. I also need to thank my mother because without her, I
may never have gotten to where I am today
I would like to thank my wonderful children for always making me smile and for
understanding on those weekend mornings when I was writing this book instead of
playing with them. I hope that one day they can read this book and understand why I
spent so much time in front of my computer.
Finally, and most importantly, I would like to thank my loving wife for her support
throughout the four years of my doctoral studies. I am indebted to her for her support,
understanding, and love throughout this endeavor. She has been my inspiration and
motivation for continuing to improve my knowledge and move my career forward.
4.4.2. THREE DIFFERENT FINITE ELEMENT SYSTEMS COMPARISON......55 4.4.2.1. STATIC ANALYSES............................................................................................................ 56 4.4.2.2. TRANSIENT ANALYSES.................................................................................................... 60
CHAPTER 5 : TRANSIENT BEHAVIOR OF DAM-RESERVOIR-
FOUNDATION SYSTEM ........................................................................................... 64
Table 4.1: Natural frequencies of the finite element model ........................................... 47 Table 4.2: The comparison between 2-D and 3-D gravity and hydrostatic analysis...... 53 Table 4.3: The full scale natural frequencies comparison .............................................. 55
Table 4.4 Y-Stress results for the gravity and hydrostatic F.E. analyses ....................... 56 Table 5.1: The material properties of the dam, water and foundation rock ................... 66
Table 5.2: Peaks displacement and acceleration values ................................................. 86 Table 6.1 Peak values of different models .................................................................... 97 Table 7.1: Validation of the analyses dam model ........................................................ 120
Table 7.1: Optimization analyses for Pine Flat dam cross section using different ground excitation ..................................................................................................................... 127
Table 7.2: Optimization analyses for Koyna dam cross section using different ground excitation ..................................................................................................................... 130
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List of Figures
Figure 1.1.a: Constructionstage of Austin dam ................................................................ 3 Figure 1.1.b: Sliding failure in 1911of Austin dam ......................................................... 3
Figure 1.2.a: St. Francis dam at downstream ................................................................... 3 Figure 1.2.b: St. Francis dam after the failure .................................................................. 3
Figure 1.3.a: Malpasset dam before failure ..................................................................... 4 Figure 1.3.b: Malpasset Left abutment after failure ......................................................... 4 Figure 1.4.a: Koyna dam downstream view ..................................................................... 4
Figure 1.4.b: Supported buttresses after damage of Koyna dam...................................... 4 Figure 2.1: Typical loads acting on Gravity dam ............................................................. 8
Figure 2.2.a: Sliding stability consideration of Gravity dam ........................................... 9 Figure 2.2.b: Overturning stability consideration of Gravity dam ................................... 9 Figure 2.2.c: Over Stressed stability consideration of Gravity dam ................................ 9
Figure 2.3: Nodal displacement of the dam for O.W.+ full reservoir level + silt pressure condition ......................................................................................................................... 13
Figure 2.4.a: Actual temperature contours for the dam .................................................. 14 Figure 2.4.b: Stresses results at center of dam base ....................................................... 15 Figure 2.5: Observed in-situ cracks for buttress dam in Sweden ................................... 15
Figure 2.6.a: Maximum principal tensile stresses due to summer temperature ............. 16 Figure 2.6.b: Cracks propagation for the fifth year due to summer temperature .......... 16
Figure 2.7: Variation of stresses at the dam base for empty reservoir ........................... 18 Figure 2.8: Variation of stresses at the dam base for full reservoir ................................ 18 Figure 2.9: Maximum principal stresses for Koyna dam due to earthquake in 1967..... 22
Fig.2.10.a: Frequency at point A of acceleration responses to upstream incident waves ........................................................................................................................................ 23
Fig.2.10.b: Frequency at point B of acceleration responses to upstream incident waves ........................................................................................................................................ 23 Figure 2.11: Fariman dam with the new part ................................................................. 26
Figure 3.3: 3-D failure surface for concrete ................................................................... 33 Figure 3.4: Substructure technique scheme .................................................................... 34 Figure 3.5: Distribution of the hydrodynamic pressure on finite element mesh ............ 35
Figure 3.6: CONTA172 geometry.................................................................................. 40 Figure 4.1: Schematic diagram of the experimental dam model .................................... 43
Figure 4.2: Experimental setup of static test .................................................................. 43 Figure 4.3: Impact hammer test ...................................................................................... 44 Figure 4.4: Finite element model dimensions ................................................................ 45
Figure 4.5: The mesh of the 2-D finite element model ................................................. 46 Figure 4.6: First mode shape .......................................................................................... 47
Figure 4.7: Second mode shape ...................................................................................... 48 Figure 4.8: Third mode shape ........................................................................................ 48 Figure 4.9: Y-component of displacement of 2-D model applied to gravity load (m) .. 49
Figure 4.10: Y-component of stress for 2-D model applied to gravity load (Pa) .......... 49 Figure 4.11: Y-component of displ. for 2-D model applied to hydrostatic load (m) ..... 50
Figure 4.12 Y-component of stress for 2-D model applied to hydrostatic load (Pa) .... 50
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Figure 4.13: The time history of the shaking table acceleration .................................... 51 Figure 4.14: Model acceleration response through harmonic motion at frequency of
17.5 Hz .......................................................................................................................... 52 Figure 4.15: Y-component of stress for 2-D model applied to harmonic load (Pa) ....... 52
Figure 4.16: The mesh of the 3-D finite element model ............................................... 53 Figure 4.17: Experimental, 2-D, and 3-D F.E. modeling response at frequency of 17.5 Hz ................................................................................................................................... 54
Figure 4.18.a: Dam monolith dimensions of the full scaled model................................ 54 Figure 4.18.b: The F.E. model components of the full scaled model ............................ 54
Figure 4.19.a: First mode of full scaled model............................................................... 55 Figure 4.19.b: Second mode of full scaled model ......................................................... 55 Figure 4.19.c: Third mode of full scaled model ............................................................ 55
Figure 4.20.a: Model II for three dimensional modeling ............................................... 56 Figure 4.20.b: Model III for three dimensional modeling .............................................. 56
Figure 4.21: X-component of displacement for model I applied to gravity load (m) .... 57 Figure 4.22: Y-component of stress for model I applied to gravity load (Pa)................ 57 Figure 4.23: X-component of displacement for model II applied to gravity load (m) ... 58
Figure 4.24: Y-component of stress for model II applied to gravity load (Pa) .............. 58 Figure 4.25: X-component of displacement for model III applied to grav. load (m) ..... 59
Figure 4.26: Y-component of stress for model III applied to gravity load (Pa) ............ 59 Figure 4.27.a: Nahanni ground acceleration................................................................... 60 Figure 4.27.b: Nahanni ground velocity ........................................................................ 60
Figure 4.29.a: The horizontal crest acceleration for model I ( ) ........................ 62 Figure 4.29.b: The horizontal crest acceleration for model II ( ) ....................... 62
Figure 4.29.c: The horizontal crest acceleration for model III ( ) ...................... 62
Figure 4.30: Time histories of the base sliding for the three models ............................. 63
Figure 5.1.a: Foundation’s surface topography (in meters) ........................................... 65 Figure 5.1.b: Plan view of the Koyna dam ..................................................................... 65
Figure 5.2.a: Geometry of Koyna dam non-overflow section ........................................ 66 Figure 5.2.b: Geometry of Koyna dam over-flow section.............................................. 66 Figure 5.3.a: Horizontal acceleration component of 1967earthquake............................ 67
Figure 5.3.b: Vertical acceleration component of 1967earthquake................................ 67 Figure 5.4: Reservoir-Dam-Foundation dimensions of Koyna dam model ................... 68
Figure 5.5.a: Case 1 of the Koyna finite element implementation ................................. 69 Figure 5.5.b: Case 2 of the Koyna finite element implementation................................. 69 Figure 5.5.c: Case 3 of the Koyna finite element implementation ................................. 70
Figure 5.5.d: Case 4 of the Koyna finite element implementation................................. 70 Figure 5.6: The first five modes shapes comparison for the dam cases ......................... 71
Figure 5.7.a: Mode 1 of Case 1 ...................................................................................... 71 Figure 5.7.b: Mode 1 of Case 2 ...................................................................................... 72 Figure 5.7.c: Mode 1 of Case 3 ...................................................................................... 72
Figure 5.7.d: Mode 1 of Case 4 ...................................................................................... 72 Figure 5.8.a: Horizontal displacement of Case 1 ........................................................... 73
Figure 5.8.b: Horizontal displacement of Case 2 ........................................................... 74 Figure 5.8.c: Horizontal displacement of Case 3 ........................................................... 74 Figure 5.8.d: Horizontal displacement of Case 4 ........................................................... 74
Figure 5.9.a: Horizontal acceleration of Case 1 ............................................................. 75 Figure 5.9.b: Horizontal acceleration of Case 2 ............................................................. 75
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Figure 5.9.c: Horizontal acceleration of Case 3 ............................................................. 76 Figure 5.9.d: Horizontal acceleration of Case 4 ............................................................. 76
Figure 5.10.a: Upstream variation of stresses in Y-direction for four cases (the dam movement in the upstream direction) ............................................................................. 77
Figure 5.10.b: Downstream variation of stresses in Y-direction for four cases (the dam movement in the upstream direction) ............................................................................. 77 Figure 5.11.a: Upstream variation of stresses in Y-direction for the four cases (the dam
movement in the downstream direction) ........................................................................ 78 Figure 5.11.b: Downstream variation of stresses in Y-direction for the four cases (the
dam movement in the downstream direction) ................................................................ 78 Figure 5.12.a: Upstream variation of stresses in X-direction for the four cases (the dam movement in the upstream direction) ............................................................................. 79
Figure 5.12.b: Downstream variation of stresses in X-direction for the four cases (the dam movement in the upstream direction) ..................................................................... 79
Figure 5.13.a: Upstream variation of stresses in X-direction four cases (the dam movement in the downstream direction) ........................................................................ 80 Figure 5.13.b: Downstream variation of stresses in X-direction four cases (the dam
movement in the downstream direction) ........................................................................ 80 Figure 5.14.a: Upstream variation of stresses in XY-direction for the four cases (the
dam movement in the upstream direction) ..................................................................... 80 Figure 5.14.b: Downstream variation of stresses in XY-direction for the four cases (the dam movement in the upstream direction) ..................................................................... 81
Figure 5.15.a: Upstream variation of stresses in XY-direction for the four cases (the dam movement in the downstream direction) ................................................................ 81
Figure 5.15.b: Downstream variation of stresses in XY-direction for the four cases (the dam movement in the downstream direction) ................................................................ 81 Figure 5.16: Peak dam horizontal displacement for case 1 (m) ..................................... 82
Figure 5.17: Peak Von-Misses stresses contours for case 1 (Pa) ................................... 82 Figure 5.18: Peak dam horizontal displacement for case 2 (m) ..................................... 83
Figure 5.19: Peak Von-Misses stresses contours for case 2 (Pa) ................................... 83 Figure 5.20: Peak dam horizontal displacement for case 3 (m) ..................................... 84 Figure 5.21: Peak Von-Misses stresses contours for case 3 (Pa) ................................... 84
Figure 5.22: Peak dam horizontal displacement for case 4 (m) ..................................... 85 Figure 5.23: Peak Von-Misses stresses contours for case 4 (Pa) ................................... 85
Figure 5.24.a: The peak Y-stresses distribution along the dam base when the peak displacement in downstream direction ........................................................................... 87 Figure 5.24.b: The peak Y-stresses distribution along the dam base when the peak
displacement in upstream direction ................................................................................ 87 Figure 5.25.a: The peak X-stresses distribution along the dam base when the peak
displacement in downstream direction ........................................................................... 88 Figure 5.25.b: The peak X-stresses distribution along the dam base when the peak displacement in upstream direction ................................................................................ 88
Figure 5.26.a: The peak XY-stresses distribution along the dam base when the peak displacement in downstream direction ........................................................................... 88
Figure 5.26.b: The peak XY-stresses distribution along the dam base when the peak displacement in upstream direction ................................................................................ 89 Fig.6.1.a: The meshed element of model I for seismic analysis..................................... 92
Fig.6.1.b: The meshed finite elements of model II for seismic analysis ........................ 93 Fig.6.1.c: The meshed finite elements of model III for seismic analysis ....................... 93
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Figure 6.2: The time history of horizontal crest displacement for model I analysis compared by Chopra displacement during Koyna earthquake ....................................... 95
Figure 6.3: The time history of horizontal crest displacement for model I analysis compared by model II linear analysis during Koyna earthquake ................................... 96
Figure 6.4: The time history of horizontal crest displacement for model I analysis compared by model II non- linear analysis during Koyna earthquake............................ 96 Figure 6.5: The time history of horizontal crest displacement for model I compared by
model III during Koyna earthquake ............................................................................... 97 Figure 6.6: Formation failure criteria damage for model I........................................... 101
Figure 6.7: Red cross section that was used for the results extraction for model II..... 102 Figure 6.8: Frist crack propagation for model II at peaks times during Koyna earthquake..................................................................................................................... 103
Figure 6.9: Red cross section that was used for the results extraction for model III ... 104 Figure 6.10: Frist crack propagation for model III at peaks times during Koyna
earthquake..................................................................................................................... 105 Figure 7.1: General flowchart that describing the F.E. implementation model ........... 108 Fig.7.2.a: One part dam type that available in the developed program ........................ 109
Fig.7.2.b: Two parts dam type that available in the developed program ..................... 109 Figure 7.3: The designed GUI using MATLAB .......................................................... 110
Figure 7.4: The geometry of the selected model (m) ................................................... 112 Figure 7.5: The meshed finite element model .............................................................. 113 Figure7.6: X-displacement through gravity simulation................................................ 114
Figure7.7: Y-Stress through gravity simulation ........................................................... 114 Figure 7.8: X-displacement through hydrostatic simulation ........................................ 115
Figure 7.9: Y-Stress through hydrostatic simulation.................................................... 115 Fig.7.10.a: Mode shape number 1 of the F.E. model ................................................... 116 Fig.7.10.b: Mode shape number 2 of the F.E. model ................................................... 117
Fig.7.10.c: Mode shape number 3 of the F.E. model ................................................... 117 Fig.7.11.a: Horizontal acceleration records of Taft ground motion ............................. 118
Fig.7.11.b: Vertical acceleration records of Taft ground motion ................................. 118 Figure 7.12: Displacement time history of the model crest.......................................... 119 Figure 7.13: Displacement contours of the model at peak value time ........................ 119
Fig.7.14.a: Principal stresses of the model (Pa) ........................................................... 120 Fig.7.14.b: Principal stresses of Løkkeꞌs model (Pa) ................................................... 121
Figure 7.15: Geometrical model of the concrete dam .................................................. 122 Figure 7.16: Dimensions of the tallest monolith of Pine Flat dam............................... 124 Figure 7.17: The optimization trails of Pine Flat dam.................................................. 125
Figure 7.18: The horizontal displacement of the optimized section at peak time ........ 126 Figure 7.19: The vertical stresses of the optimized section at peak time ..................... 126
Figure 7.20: El-Centro horizontal acceleration records ............................................... 127 Figure 7.21: The optimization trails of Koyna dam ..................................................... 128 Figure 7.22: The horizontal displacement of the optimized section at peak time ........ 129
Figure 7.23: The vertical stresses of the optimized section at peak time .................... 129
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Nomenclature
Symbols
: Hydrostatic force
: Hydrodynamic force
: Silt load
: Own weight of the dam
: Vertical water force
U: Uplift force
: Horizontal earthquake component
: Vertical earthquake component
: Sliding factor of safety
: Overturning factor of safety
: Overstressing factor of safety
[M]: Structural mass matrix
[C]: Structural damping matrix
[K]: Structural stiffness matrix
: Nodal acceleration vector
: Nodal velocity vector
: Nodal displacement vector
: Applied load vector
{ (t)}: Internal load vector.
: The magnitude of the load
Ω: The model circular frequency measured in radians/time