氏名　ZAIDIR
学位の種類　博士（工学）
学位記番号　博甲第139号
学位授与の日付　平成9年3月25日
学位論文題目　Fatigue Behavior of Concrete in Anchor System　（アンカーシステムにおけるコンクリートの疲労性状）
論文審査委員
　主査　教授　丸山　久一
　副査　教授　鳥居　邦夫
　副査　教授　丸山　暉彦
　副査　教授　長井　正嗣
　副査　助教授　下村　匠

• 論文目次
• 論文要旨

［平成8（1996）年度博士論文題名一覧］ ［博士論文題名一覧］に戻る．

TABLE OF CONTENTS
ABSTRACT　p.i
ACKNOWLEDGMENT　p.iii
TABLE OF CONTENTS　p.iv
LIST OF SYMBOLS　p.vi
CHAPTER 1
GENERAL INTRODUCTION
1.1　GENERAL　p.1
1.2　ANALYSYS OF FATIGUE FRACTURE OF CONCRETE　p.3
1.3　FATIGUE DESIGN CODE OF PRACTICE FOR CONCRETE　p.4
1.4　ANALYSYS OF CRACK MECHANISMIN CONCRETE　p.5
1.5　OBJECTIVES AND SCOPE OF THE STUDY　p.6
1.6　REFERENCES　p.7
CHAPTER 2
BACKGROUND OF CONCRETE FRACTURE MECHANISM
2.1　STATIC FRACTURE MECHANISM OF CONCRETE　p.8
2.2　CONCRETE FATIGUE FRACTURE BEHAVIOR　p.12
2.3　DESIGN CODE FOR FATIGUE STRENGTH OF CONCRETE　p.15
2.4　SIZE EFFECT IN CONCRETE CONE FAILURE　p.17
2.5　CONCLUDING REMARKS　p.22
2.6　REFERENCES　p.24
CHAPTER 3
A TESTING METHOD OF CRACK GROWTH IN CONCRETE
3.1　INTRODUCTION　p.26
3.2　EXPERIMENTAL PROGRAM　p.27
3.2.1　Anchor Bolt and Concrete Block specimens　p.27
3.2.2　Test Configuration and Testing Procedures　p.31
3.3　STATIC TEST RESULTS AND DESCRIPTIONS　p.35
3.3.1　Shape of Concrete Cone Failure　p.35
3.3.2　Load-Displacement curves　p.35
3.3.3　Crack Growth Mechanism　p.35
3.5　CONCLUDING REMARKS　p.46
3.6　REFERENCES　p.47
CHAPTER 4
CRACK GROWTH MECHANISM AND FATIGUE STRENGTH OF CONCRETE CONE FAILURE
4.1　INTRODUCTION　p.49
4.2　EXPERIMENTAL PROGRAM　p.49
4.3　FATIGUE TEST RESULTS AND DESCRIPTIONS　p.50
4.3.1　Shape of Concrete Cone Failure　p.50
4.3.2　Crack Growth Mechanism　p.53
4.3.3　Fatigue Strength of Concrete Cone Failure　p.62
4.5　CONCLUDING REMARKS　p.66
4.6　REFERENCES　p.67
CHAPTER 5
STRESS RESISTANT MECHANISM MODEL AND SIZE EFFECT　p.68
5.1　INTRODUCTION　p.68
5.2　STRESS RESISTANT MECHANISM MODEL IN STATIC　p.68
5.2.1　Stress at a Crack Tip　p.68
5.2.2　Stress Resistant Mechanism Model in Anchor System　p.71
5.3　STRESS RESISTANT MECHANISM MODEL IN FATIGUE　p.76
5.4　CONCLUDING REMARKS　p.83
5.5　REFERENCES　p.84
CHAPTER 6
GENERAL CONCLUSIONS　p.85
PUBLICATIONS　p.88

Many concrete structural members are subjected to repeated fluctuating loads the magnitude of which is well below the maximum load under monotonic or static loading. This type of loading is typically known as fatigue loading. Examples of structures that are subjected to fatigue loading include bridges, offshore structures and machine foundations. The proces of fatigue, which is due to progressive and irreversible deterioration in the material when subjected to repeated loads, may lead to excessive deformations, excessive crack widths, debonding of reinforcement, and rupture of the reinforcement or matrix leading to structural collapse. Unfortunately, the knowledge about fatigue behavior of concrete, however, is still limited especially in terms of the cause and mechanism of failure and crack growth.
Most studies on the fatigue of concrete have so far been directed to interrelate the applied-fatigue stress, and the fatigue life of concrete. This relationship is known a so-called S-N curves or Whohler curves. With the S-N curve enables one to predict the mean fatigue life of concrete under given constant amplitude cyclic stress. Although these investigations were very valuable from a practical point of view, they do not explain the cause and mechanism of crack growth in fatigue fracture. Up to now, no satisfactory theory of the mechanics of fatigue failure has yet been proposed.
Recently, embedded anchor bolts have widespread applications in the engineering design due to increased demand for inserts and fixings in concrete structures. The bearing capacity and failure behavior of anchor bolts are often checked by pull-out testing. The pull-out test is also well known for testing the strength of concrete in nondestructive evaluation. In these respects, many efforts are associated with clarifying the failure process in the pull-out of an anchor bolts.
Embedded anchor bolts in concrete when subjected to tension loading will fail by pulling a cone out of a concrete providing the steel strength of bolt is high enough. The circumferential crack forms this cone and grows in stable manner with increasing of applied load until failure occur. Although from the beginning the failure mechanism is stated very complex, many researchers recognized that the acting stresses in fracture process of concrete cone of an anchor bolt is a combi nation of shear and tension stresses. In static loading, the concrete cone failure process of anchors has much better understood but on the other hand, however, in fatigue loading is still limited.
A major concern of this study is gain more insight in the mechanism of fatigue fracture of this failure mode. For the fatigue of concrete which is associated with initiation and propagation of internal microcracks at the cement paste-aggregate interface and/or within the cement paste itself, it is necessary to conduct more research program with considerations of crack growth mechanism. And since a remarkable progress has been accomplished in the application of fracture mechanics to concrete with the concept of fracture process zone（FPZ）on static crack growth, it is expect that the knowledge, could be extended to fatigue crack growth with proper modification.
In the other hand, during the recent years, size effect problem in concrete structures have become major issues. Concrete strucrutes traditionally have been designed on the basis of strength concept. This implies that geometrically similar structures of different sizes should fail at the same nominal stress defined as the applied load divided by the characteristic structure dimension and the thickness. From experimental evidence, however, this is not quite true in many cases because of the size effect which may be understood as the dependence of the nominal stress at failure on the characteristic dimension of the structures.
In this research work, it is discussed the crack growth and fracture process in concrete under fatigue loading by the pull-out test of an anchor bolt. Firstly, the static pull-out test is conducted to study the applicability of ink-injetion method for tracing the crack growth in concrete. Then, the cyclic pull-out test is performed and a simple model both of static and fatigue fracture mechanism considering the size effect are proposed.