Welded High Strength Steel Structures

Jin Jiang, PhD, is Professor in Department of Civil and Environmental Engineering, Shantou University, China, Senior Researcher of Civil Engineering at Nanyang Technological University, Singapore and Associate Director of the Complex Steel Structure Research Center, Guangdong Province, China. He is also a technical assessor with the Singapore Accreditation Council (SAC) and a member of the American Society of Civil Engineers (ASCE), and has previously served as a researcher engineer at the Keppel Offshore and Marine Technology Center.

• List of Figures ixList of Tables xviiPreface xixNotation xxi1 Introduction 11.1 Research Background 11.2 Objectives and Scope 41.3 Contributions and Originality 61.4 Organization 72 Literature Review 92.1 High-Strength Steel 92.1.1 Overview 92.1.2 Delivery Condition of HSS 102.1.3 Fatigue and Fracture of HSS 112.1.4 Codes and Standards of HSS Application 122.2 Welding and Residual Stress 132.2.1 Overview of Arc Welding 132.2.2 Weldability of Steel 152.2.3 Phase Transformation and Other Phenomena in Welding Procedures 162.2.4 The Formation of Residual Stress 202.2.4.1 Origin and Types of Residual Stress 202.2.4.2 Generation of Welding Residual Stress 222.2.5 Residual Stress Investigation Techniques 242.2.5.1 Experimental Investigation 242.2.5.2 Numerical Modeling 262.2.6 Exploration on Residual Stress Effects 282.3 Fatigue Analysis of Tubular Joints 312.3.1 Classification and Parameters of Tubular Joints 312.3.2 Stress Analysis of Intact Tubular Joints 323 Experimental Investigation of Residual Stress for High-Strength Steel Plate-to-Plate Joints 373.1 Introduction 373.2 The Hole-Drilling Method and Specimen Details 383.2.1 The ASTM Hole-Drilling Method 383.2.2 Specimen Specifications 393.2.3 Welding Specifications 413.3 Residual Stress Investigation 433.3.1 Setup and Modification of the Hole-Drilling Guide 433.3.2 Strain Gauge Locations 443.3.3 Calibration Test for Residual Stress Measurement 453.3.4 Residual Stress Measurement Procedure 463.3.5 Cutting of Brace Plate 473.4 Experimental Results 473.4.1 Distribution of Residual Stress Along the Weld Toe 493.4.2 The Effects of Preheating 493.4.3 The Effects of Joint Angle 503.4.4 The Effects of Plate Thickness 513.4.5 The Effects of Brace Plate Cutting 523.5 Static Tensile Testing 543.5.1 Testing Rig 543.5.2 Strain Gauge Locations 543.5.3 Testing Procedure 543.5.4 Testing Results 563.6 The Influence of Residual Stress on SCF Value 573.6.1 Analysis Method 573.6.2 Results and Conclusions 583.7 Conclusion and Summary 604 Numerical Study of Residual Stress for High-Strength Steel Plate-to-Plate Joints 634.1 Introduction 634.2 Modeling Procedure and Results for 2D Models 644.2.1 Overview 644.2.2 Lumped Technique 644.2.3 Weld Filler Addition Technique 674.2.4 Heat Transfer Analysis 684.2.5 Mechanical Analysis 704.2.6 Model Validation and Results 714.2.6.1 Model Validation 714.2.6.2 Numerical Modeling Results 724.3 Modelling Procedure and Results for 3D Models 764.3.1 Overview 764.3.2 Heat Source Model in 3D Analysis 774.3.3 Modeling for the Weld Filler Adding Process 784.3.4 Modeling Validation 804.3.5 Modeling Results 814.3.5.1 Ambient Temperature Joint 814.3.5.2 Preheating Joint 834.3.5.3 Comparison Between Ambient Temperature and Preheated Joints 844.4 Parametric Study 874.4.1 Effect of Boundary Condition 914.4.2 Effect of Preheating Temperature 914.4.3 Effect of Using Different Lumps 934.4.4 Effect of Welding Speed 944.4.5 Effect of Welding Sequence 954.5 Conclusions 965 Experimental Investigation of Residual Stress for Welded Box High-Strength Steel T-Joints 995.1 Introduction 995.2 Experimental Investigation 1005.2.1 Material Properties 1005.2.2 Specimen Fabrication 1015.2.2.1 Overview of the Welding Design 1015.2.2.2 Fabrication of Box Sections 1045.2.2.3 Fabrication of Joint Intersection 1045.2.3 Residual Stress Test Setup and Procedure 1055.2.4 Strain Gauge Schemes for Residual Stress Measurement 1065.2.5 Computation of Residual Stress 1075.3 Testing Results 1095.3.1 Preheated Specimen 1095.3.2 Ambient Temperature Specimen 1145.4 Analyses and Discussion 1185.4.1 Preheating Effect 1185.4.2 Chord Edge Effect 1205.4.3 Corner Effect 1205.4.4 Stress Variation in Depths 1215.5 Conclusions 1236 Numerical Study of Residual Stress for Welded High-Strength Steel Box T/Y-Joints 1256.1 Introduction 1256.2 Modeling Procedure 1266.2.1 Overview 1266.2.2 Heat Source Modeling 1296.2.3 Thermal Interactions 1296.2.4 Arc Touch Movement 1306.2.5 Modeling Summary 1306.3 Modeling of Pure Heat Transfer 1326.4 Fully Coupled Residual Stress Analysis 1366.4.1 Modeling Validation 1366.4.2 Modeling Results 1376.4.2.1 Temperature History 1376.4.2.2 Residual Stress 1386.5 Parametric Study 1416.5.1 Range of the Modeling 1416.5.2 Variation of the Residual Stress with Respect to Joint Angle 1426.5.2.1 Variation of the Residual Stress with Respect to Joint Angle and Welding Starting Location 1426.5.2.2 Variation of the Residual Stress with Respect to Joint Angle and Preheating Temperature 1436.5.3 Variation of the Residual Stress with Respect to b/c (Ratio of Brace Width to Chord Width) 1456.5.3.1 Variation of the Residual Stress with b/c and Preheating Temperature 1456.5.3.2 Variation of the Residual Stress with b/c and Welding Starting Location 1466.5.4 Variation of the Residual Stress with Respect to Welding Speed 1476.5.4.1 Variation of the Residual Stress with Welding Speed and Preheating Temperature 1476.5.4.2 Variation of the Residual Stress with Welding Speed and b/c 1486.6 Conclusions 1497 Stress Concentration Factor of Welded Box High-Strength Steel T-Joint 1537.1 Introduction 1537.2 Test Setup and Specimens 1547.3 Strain Gauge Schemes 1567.4 Test Procedure 1587.5 Test Results 1597.6 Comparision of Test Results with CIDECT Guide 1617.7 Effect of Residual Stress on SCF 1627.8 Conclusion 1638 Conclusion and Recommendation 1658.1 Introduction 1658.2 Conclusions 1668.2.1 Experimental Studies 1668.2.2 Numerical Modeling 1678.3 Recommendations for Future Research Work 168Summary 169Appendix 1 171Appendix 2 175Appendix 3 181References 195Index 201