CONTENTS
1 INTRODUCTION 9
1.1 GENERAL 9
1.2 APPLICATION 9
1.3 NEED OF PRESENT STUDY 10
1.4 OBJECTIVE OF THE DISSERTATION 10
1.5 SCOPE OF THE DISSERTATION 11
1.6 LIMITATIONS OF THE STUDY 11
1.7 ORGANIZATION OF THE DISSERTATION 11
2 LITERATURE REVIEW 13
2.1 GENERAL 13
2.2 TECHNICAL PAPERS 13
2.3 GUIDELINES AND HANDBOOKS 16
2.4 TEXTBOOKS 17
2.5 CODES 17
3 STEEL PIPELINES - A GENERAL INTRODUCTION 18
3.1 UNDERGROUND CONDUITS 18
3.2 SALIENT PROPERTIES OF STEEL PIPE 18
3.2.1 Strength 19
3.2.2 Ease of installation 19
3.2.3 High flow capacity 19
3.2.4 Leak resistance 20
3.2.5 Long service life 20
3.2.6 Reliability and versatility 20
3.2.7 Economy 21
3.3 ADVANTAGES OF STEEL PIPE AS PIPELINE MATERIAL 21
3.4 CRITERIA FOR SELECTING BURIED STEEL PIPE 21
3.5 STRENGTH OF MATERIAL 21
3.6 CLASSIFICATION OF PIPING MATERIAL 22
3.7 PIPELINE ALIGNMENT 22
3.8 SOIL INVESTIGATION 23
3.9 SLIP WELD LAP JOINT 23
3.10 FAILURE OF PIPELINES DUE TO EARTHQUAKE 24
3.10.1 Introduction 24
3.10.2 Failure modes in buried pipelines 24
3.11 FAILURE PATTERN AT THE JOINTS 26
3.11.1 Axial pull out 26
3.11.2 Crushing of bell and spigot joints 26
3.11.3 Flanged joint failure 27
3.11.4 Circumferential flexural failure and joint rotation 27
3.12 FAILURE OF PIPELINES FROM PAST EARTHQUAKES 28
3.12.1 San Fernando Earthquake (1971) 28
3.12.2 Landers and Big Bear Earthquakes (1992): 29
3.12.3 Northridge Earthquake (1994): 29
3.12.4 Kocaeli, Turkey Earthquake (1999) 30
3.12.5 Chi‐Chi Earthquake (1999): 31
4 THEORETICAL FORMULATION 32
4.1 VALIDATION STUDY 32
4.1.1 Introduction 32
4.1.2 Validation model 32
4.1.3 Pipe dimensions 32
4.1.4 Material properties 32
4.2 LOADING 33
4.3 SOIL PIPE INTERACTION 34
4.3.1 Assigning Soil Springs to Model Pipe 34
4.4 RESULTS FROM THE ANALYSIS AND COMPARISON WITH THE
LITERATURE 36
4.5 STEP BY STEP PROCEDURE 37
4.6 SELECTION OF PIPE SAMPLE FOR STUDY 38
4.6.1 Geometric specifications 38
4.6.2 Chemical composition 40
4.6.3 Mechanical properties 40
4.6.4 Operating pressure 41
4.7 RESPONSE SPECTRUM METHOD OF ANALYSIS 41
4.7.1 Introduction 41
4.7.2 Response Spectra 41
4.7.3 Factor Influencing Response Spectra 42
4.7.4 Modal Combination Rules 42
5 LOADING 44
5.1 GENERAL 44
5.2 BEDDING OF PIPE 44
5.2.1 Bedding angle 45
5.3 TYPES OF INSTALLATION CONDITIONS 46
5.3.1 Trench condition: 46
5.3.2 Embankment condition 46
5.4 ASSUMPTIONS FOR CALCULATION OF LOAD ACTING ON THE PIPES ...47
5.5 CALCULATION OF LOADS 47
5.5.1 Vertical earth load 47
5.5.2 Weight of soil calculation 49
5.5.3 Weight of Water (WW) 50
5.5.4 Surface live loads 50
5.5.5 Live load calculation 51
6 SOIL PIPE INTERACTION 52
6.1 GENERAL 52
6.2 MODELING OF SOIL 52
6.3 MODELING OF SEGMENTED PIPELINE 53
6.4 SOIL SPRING REPRESENTATION 54
6.5 DATA ASSUMED FOR SOIL 55
6.6 SOIL SPRING PROPERTIES TO MODEL SOIL-PIPE INTERACTION 55
6.6.1 Axial Soil Spring 55
6.6.2 Lateral Soil Spring 58
6.6.3 Vertical soil spring 60
7 PROBLEM FORMULATION 63
7.1 GENERAL 63
7.2 SELECTION OF THE SOFTWARE 63
7.3 ABOUT THE SOFTWARE 63
7.4 MODEL PREPARATION, LOADING AND ANALYSIS 64
7.4.1 Defining materials 64
7.4.2 Creating pipe geometry 64
7.4.3 Assigning material properties 65
7.4.4 Defining the connections 65
7.4.5 Creating mesh 65
7.4.6 Defining and assigning static loads 67
7.5 ASSIGNING SOIL SPRING PROPERTIES TO THE PIPE 69
7.6 MODAL ANALYSIS 70
7.7 RESPONSE SPECTRUM ANALYSIS 70
8 RESULTS AND DISCUSSION 71
8.1 CHECK FOR BUCKLING CAPACITY IN THE PIPE 71
8.2 AXIAL STRAIN 71
8.2.1 Results from Modal Analysis 72
8.2.2 Response spectrum method 73
8.2.3 Deformation at the joints 74
9 CONCLUSION AND FUTURE SCOPE 76
9.1 CONCLUSION 76
9.2 FUTURE SCOPE 76
10 REFERENCE 77
11 APPENDIX A-CALCULATION OF SLENDERNESS RATIO 79