Mô hình hóa các biện pháp chống chấn động cho các công trình cầu đường sắt có kết cấu khối xây không cốt thép sử dụng phương pháp phần tử ứng dụng tt

AEM SIMULATION OF SEISMIC
RETROFITTING METHODS OF
UNREINFORCED MASONRY RAILWAY
STRUCTURES
రಕͶ͕͜Ζໃ‫۔‬͹ૌ੷ߑଆ෼͹ଳਔึ‫ک‬๏๑
Ͷͯ͏ͱ͹ $(0 ͶΓΖ਼஍εϝϣϪʖεϥϱ

by
PHAN Thanh Ngoc
Student ID number: 17RB903
A Dissertation submitted to
Yokohama National University
In partial fulfillment of the requirements for the degree of
Master of Engineering

Supervisor
Professor Akira HOSODA

Graduate school of Urban Innovation
Yokohama National University
Yokohama, Japan
January 2019


ACKNOWLEDGEMENT

The author would like to express his great appreciation to his research
supervisor, Prof. Dr. Akira Hosoda for his patient guidance, invaluable suggestions,
enthusiastic encouragement and useful critiques at every stage of this research work.
The author is equally grateful to Prof. Dr. Hamed Mohamed Mahmoud Salem,
Structural Engineering Department, Cairo University, Egypt for his consistent guidance

and supports the author in doing numerical analysis using Extreme Loading for
Structures which follows Applied Element Method.
The author’s grateful thanks are also extended to Mss. Sakiko Takahashi,
Assistant Manager, Structural Engineering Center, East Japan railway company for her
kind help in doing data analysis of experimental results.
The author extends his thanks to project 599 of Vietnam International
Education Development of the Ministry of Education and Training of Vietnam which
gave a good scholarship for supporting his study.
Finally, the author wishes to thank his parent and older brother for their
encouragement and support throughout his study.

i|Page


ABSTRACT
AEM SIMULATION OF SEISMIC RETROFITTING METHODS OF
UNREINFORCED MASONRY RAILWAY STRUCTURES

రಕͶ͕͜Ζໃ‫۔‬͹ૌ੷ߑଆ෼͹ଳਔึ‫ک‬๏๑Ͷͯ͏ͱ͹ $(0 Ͷ
ΓΖ਼஍εϝϣϪʖεϥϱ


According to previous surveys on railway structures in the metropolitan area of Japan, it
has been reported that there are some old unreinforced masonry structures made of
bricks or stones or plain concrete while are in service. In order to enhance the
performance of unreinforced masonry piers in very limited spaces under severe seismic
actions, many kinds of strengthening techniques have been planned by JR EAST
company in Japan such as vertical-prestressed steel, grid-steel plate and Concrete Filled
Tubes (CFT) methods. The basic concept of the methods is to prevent the large
horizontal sliding and residual displacement at the mortar joints between bricklayers

which may cause catastrophic failure of structures or difficulty of early resuming
railway service after the earthquake. In this study, an attempt is made to apply the
Applied Element Method (AEM) which is highly developed for simulating the
experimental results in the case of Grid-steel plate retrofitting method. Two separated
low strength concrete column was retrofitted by gird-steel plate method. A Polyvinyl
Chloride (PVC) sheet was inserted between the joint of two column blocks to expect the
reduction of the sliding friction when horizontal displacement was applied to the
specimen. The Grid-steel plates were arranged on the two side surfaces of the column
and joined with the penetrating reinforced bars. The investigated cases include the
alteration of the dimensions, the thickness and the arrangements of the steel plates in the
vertical direction to assess the sensitivity of the related influencing factors on the
performance of the testing specimens. The grid-steel plate retrofitting method showed
good contribution to mitigate the sliding behavior of the retrofitted column at the joint
and caused rocking behavior at the base. The numerical monotonic and cyclic analysis
results showed that the crack occurrences, crack propagation, load-displacement relation
and failure pattern of the experimental specimens are quite comparable and highly
validated. In addition, some possible techniques for the next stage of the research is also
demonstrated.

ii | P a g e


CONTENTS
ACKNOWLEDGEMENT ................................................................................................. i
ABSTRACT ..................................................................................................................... ii
TABLES ........................................................................................................................... v
FIGURES ........................................................................................................................ vi
CHAPTER 1 ..................................................................................................................... 1
INTRODUCTION ............................................................................................................ 1
1.1 Background ............................................................................................................. 1

1.2 Objectives and scope .............................................................................................. 2
1.3 Brief outline of the study ........................................................................................ 2
1.3 Methodology and verification process in the study ................................................ 3
1.4 Justification of the research .................................................................................... 3
1.5 Organization of the Thesis ...................................................................................... 4
CHAPTER 2 ..................................................................................................................... 5
LITERATURE REVIEW ................................................................................................. 5
2.1 Previous studies on the seismic failure mode of unreinforced masonry railway
structures ....................................................................................................................... 5
2.2 Previous studies on seismic retrofitting methods of unreinforced masonry railway
structures ....................................................................................................................... 6
2.3 Previous studies on seismic retrofitting methods of unreinforced stone masonry
bridge piers ................................................................................................................... 7
2.4 Numerical simulation of masonry .......................................................................... 8
2.5 Conclusion .............................................................................................................. 9
CHAPTER 3 ................................................................................................................... 10
CONCEPT OF THE RETROFITTING METHOD ....................................................... 10
3.1 Working condition of the existing unreinforced masonry railway bridges .......... 10
3.2 Basic concept of the retrofitting methods ............................................................. 10
3.3 Main seismic retrofitting methods ........................................................................ 11
3.3.1 The Grid-steel plate retrofitting method ........................................................ 11
3.3.2 The Vertical-prestressed steel retrofitting method ........................................ 12
CHAPTER 4 ................................................................................................................... 13
AEM SIMULATION AND METHOD OF VERIFICATION ...................................... 13
4.1 Applied Element Method (AEM) ......................................................................... 13
4.2 AEM and FEM in comparison.............................................................................. 13
4.3 Software used for the Analysis following AEM .................................................. 14
4.4 AEM material models in the study ....................................................................... 14
4.4.1 Concrete model .............................................................................................. 14
4.4.2 Reinforcing bars model ................................................................................. 15

4.4.3 Bearing material model ................................................................................. 16
4.4.4 Elastic material model ................................................................................... 16
4.5 Justification of using AEM as a numerical analysis method for the research ...... 17
4.6. Basic assumptions in AEM simulation................................................................ 18
CHAPTER 5 ................................................................................................................... 19
AEM ANALYSIS OF GRID-STEEL PLATE RETROFITTING METHOD FOR
MASONRY PIERS OF RAILWAY BRIDGES ............................................................ 19
5.1 Experimental program .......................................................................................... 19
5.1.1 General........................................................................................................... 19

iii | P a g e


5.1.2 Specimen’s details ......................................................................................... 19
5.1.3 Materials ........................................................................................................ 22
5.1.4 Testing procedures ......................................................................................... 22
5.1.5 Testing results ................................................................................................ 23
5.2 Verification of AEM simulation Case 1 ............................................................... 26
5.2.1 Interface material between concrete blocks and PVC sheet .......................... 28
5.2.2 Interface material between concrete columns and steel plates ...................... 29
5.2.3 Verification of simulation.............................................................................. 29
5.3 Verification of AEM simulation Case 2 ............................................................... 30
5.3.1 Interface material between concrete blocks and PVC sheet .......................... 32
5.3.2 Verification of simulation.............................................................................. 33
5.4 Verification of AEM simulation Case 3 ............................................................... 33
5.4.1 Interface material between concrete blocks and PVC sheet .......................... 35
5.4.2 Verification of simulation.............................................................................. 35
5.5. Conclusions and future study .............................................................................. 36
5.5.1 Conclusions ................................................................................................... 36
5.5.2 Future study ................................................................................................... 36

CHAPTER 6 ................................................................................................................... 37
AEM ANALYSIS OF VERTICAL-PRESTRESSED STEEL RETROFITTING
METHOD ....................................................................................................................... 37
6.1 Experimental program .......................................................................................... 37
6.1.1 General........................................................................................................... 37
6.1.2 Specimen details ............................................................................................ 37
6.1.3 Materials ........................................................................................................ 39
6.1.4 Testing procedures ......................................................................................... 39
6.1.5 Testing results ................................................................................................ 40
6.2 Verification of AEM simulation Case 2 ............................................................... 46
6.2.1 Material properties used in AEM models ...................................................... 46
6.2.2 The use of square section instead of round section when simulating a steel
bar ........................................................................................................................... 48
6.2.3 Modeling prestressed steel bars in AEM model ............................................ 49
6.2.4 Monotonic analysis ........................................................................................ 51
5.5. Conclusions and future study .............................................................................. 52
5.5.1 Conclusions ................................................................................................... 52
5.5.2 Future study ................................................................................................... 52
CHAPTER 7 ................................................................................................................... 53
CONCLUSIONS ............................................................................................................ 53
7.1 General.................................................................................................................. 53
7.2 Conclusions and recommendations regarding Grid-steel plate retrofitting method
.................................................................................................................................... 53
7.2 Conclusions and recommendations regarding verification model of AEM
simulation using in the research ................................................................................. 53
7.4 Future works ......................................................................................................... 54

iv | P a g e

TABLES
Table 5. 1 Details of steel plates, steel anchors, sheath tubes and steel bars..................................20
Table 5. 2 Details of columns and PVC sheet ................................................................................20
Table 5. 3 Characteristics of concrete ............................................................................................22
Table 5. 4 Characteristics of steel ...................................................................................................22
Table 5. 5 Material properties of concrete and steel in ELS models ..............................................27
Table 5. 6 Properties of bearing material in ELS models ...............................................................27
Table 5. 7 Properties of interface material in ELS models .............................................................27
Table 5. 8 Properties of elastic material in ELS models ................................................................27
Table 5. 9 Interface material assignment ........................................................................................28
Table 5. 10 Material properties of concrete and steel in ELS models ............................................31
Table 5. 11 Properties of bearing material in ELS models .............................................................31
Table 5. 12 Properties of interface material in ELS models ...........................................................31
Table 5. 13 Properties of elastic material in ELS models ..............................................................31
Table 5. 14 Interface material assignment ......................................................................................32
Table 5. 15 Material properties of concrete and steel in ELS models ............................................34
Table 5. 16 Properties of bearing material in ELS models .............................................................34
Table 5. 17 Properties of interface material in ELS models ...........................................................34
Table 5. 18 Properties of elastic material in ELS models ..............................................................34
Table 5. 19 Interface material assignment ......................................................................................35
Table 6. 1 Prestressed force used in the test …………………………………………………….38
Table 6. 2 Characteristics of concrete ............................................................................................39
Table 6. 3 Characteristics of steel ...................................................................................................39
Table 6. 4 Material properties of concrete and steel in ELS models ..............................................47
Table 6. 5 Properties of interface material in ELS models .............................................................47
Table 6. 6 Properties of elastic material in ELS models ................................................................47
Table 6. 7 Interface material assignment ........................................................................................48

v|Page

FIGURES
Fig.1. 1 Unreinforced masonry railway bridges in Kantou area ......................................................1
Fig.1. 2 Damage of Unreinforced masonry railway structures under earthquakes ..........................1
Fig.1. 3 Brief outline of the study.....................................................................................................3
Fig.1. 4 Verification process of AEM simulation ............................................................................4
Fig.2. 1 The Great Kantou Earthquake’s damage to Minatogawa
bridge……………………………………………………………..………………………………5
Fig.2. 2 Loading test on brick masonry wall Fig.2. 3 The degree of seismic resistance .................6
Fig.2. 4Partial steel plate retrofitting method ...................................................................................6
Fig.2. 5Horizontal loading test .........................................................................................................7
Fig.2. 6Typical Elevation Views of Rest Piers with Proposed Mini-piles as
Strengthening Reinforcement ...........................................................................................................8
Fig.2. 7 State of stresses in a masonry prism subjected to vertical compression .............................9
Fig.3. 1 Rocking behavior after retrofitting………………………………………………………10
Fig.3. 2 The use of brackets to prevent falling and overturning .....................................................11
Fig.3. 3 The grid-steel plate retrofitting method ............................................................................11
Fig.3. 4 The Vertical-prestressed retrofitting method ....................................................................12
Fig.4. 1 Connectivity matrix spring ………………………………………………………………13
Fig.4. 2 Analysis domain of AEM compared to FEM....................................................................14
Fig.4. 3 Partial element connectivity ..............................................................................................14
Fig.4. 4 Concrete material model ...................................................................................................15
Fig.4. 5 Reinforcing bars model .....................................................................................................16
Fig.4. 6 Bearing material model .....................................................................................................16
Fig.4. 7 Elastic material model .......................................................................................................17
Fig.4. 8 8-node hexahedron elements .............................................................................................17
Fig.5. 1 The three reinforced concrete specimens ………………………………………………20
Fig.5. 2 The main components of the specimen .............................................................................21
Fig.5. 3 Construction joint between lower block and footing ........................................................21
Fig.5. 4 Spongy pads were inserted to prevent local failure...........................................................21

Fig.5. 5 Compressive strength test and splitting test ......................................................................22
Fig.5. 6 Experimental results Case 1 ..............................................................................................23
Fig.5. 7 Diagonal cracks in Case 1 .................................................................................................24
Fig.5. 8 Experimental results Case 2 ..............................................................................................25
Fig.5. 9 Experimental results Case 3 ..............................................................................................26
Fig.5. 10 The interface material in model case 1............................................................................29
Fig.5. 11 The elastic interface model .............................................................................................29
Fig.5. 12 Monotonic analysis
Fig.5. 13 Cyclic analysis .................................30
Fig.5. 14 Cracks and failure patterns ..............................................................................................30
Fig.5. 15 The interface material in model Case 2 ...........................................................................32
Fig.5. 16Monotonic analysis
Fig.5. 17 Cyclic analysis ..................................33
Fig.5. 18 Cracks and failure patterns ..............................................................................................33
Fig.5. 19 Monotonic analysis
Fig.5. 20 Cyclic analysis ...................................35
Fig.5. 21 The crack patterns ...........................................................................................................36
Fig.6. 1 The main components of the specimen……………………………………….………...37
Fig.6. 3 Experimental results Case 1 ..............................................................................................42
Fig.6. 4 Experimental results Case 2 ..............................................................................................44

vi | P a g e


Fig.6. 5 Experimental results Case 3 ..............................................................................................46
Fig.6. 6 Summation of experimental results ...................................................................................46
Fig.6. 7 Components in ELS model ...............................................................................................48
Fig.6. 8 The corresponding square section of steel bar in AEM model .........................................49
Fig.6. 9 Spring controller setting in ELS ........................................................................................49
Fig.6. 10 Internal force in the PC steel bar .....................................................................................50

Fig.6. 11 Construct scenario option in ELS....................................................................................50
Fig.6. 12 Loading scenario in ELS .................................................................................................51
Fig.6. 13 Applying prestressed force using construct scenario in ELS ..........................................51
Fig.6. 14 Monotonic analysis of Case 2 .........................................................................................52
Fig.6. 15 Failure mode of the ELS model Case 2...........................................................................52

vii | P a g e