This volume addresses the specific subject of fatigue, a subject not familiar to many engineers, but still relevant for proper and good design of numerous steel structures.
This volume addresses the specific subject of fatigue, a subject not familiar to many engineers, but still relevant for proper and good design of numerous steel structures. It explains all issues related to the subject: Basis of fatigue design, reliability and various verification formats, determination of stresses and stress ranges, fatigue strength, application range and limitations. It contains detailed examples of applications of the concepts, computation methods and verifications.
TABLE OF CONTENTS
FOREWORD
PREFACE
ACKNOWLEDGMENTS
SYMBOLOGY
TERMINOLOGY
Chapter 1 INTRODUCTION
1.1 Basis of fatigue design in steel structures
1.1.1 General
1.1.2 Main parameters influencing fatigue life
1.1.3 Expression of fatigue strength
1.1.4 Variable amplitude and cycle counting
1.1.5 Damage accumulation
1.2 Damage equivalent factor concept
1.3 Codes of Practice
1.3.1 Introduction
1.3.2 Eurocodes 3 and 4
1.3.3 Eurocode 9
1.3.4 Execution (EN 1090-2)
1.3.5 Other execution standards
1.4 Description of the structures used in the worked examples
1.4.1 Introduction
1.4.2 Steel and concrete composite road bridge (worked example 1)
1.4.3 Chimney (worked example 2)
1.4.4 Crane supporting structures (worked example 3)
Chapter 2 APPLICATION RANGE AND LIMITATIONS
2.1 Introduction
2.2 Materials
2.3 Corrosion
2.4 Temperature
2.5 Loading rate
2.6 Limiting stress ranges
Chapter 3 DETERMINATION OF STRESSES AND STRESS RANGES
3.1 Fatigue loads
3.1.1 Introduction
3.1.2 Road bridges
3.1.3 Railway bridges
3.1.4 Crane supporting structures
3.1.5 Masts, towers, and chimneys
3.1.6 Silos and tanks
3.1.7 Tensile cable structures, tension components
3.1.8 Other structures
3.2 Damage equivalent factors
3.2.1 Concept
3.2.2 Critical influence line length
3.2.3 Road bridges
3.2.4 Railway bridges
3.2.5 Crane supporting structures
3.2.6 Towers, masts and chimneys
3.3 Calculation of stresses
3.3.1 Introduction
3.3.2 Relevant nominal stresses
3.3.3 Stresses in bolted joints
3.3.4 Stresses in welds
3.3.5 Nominal stresses in steel and concrete composite bridges
3.3.6 Nominal stresses in tubular structures (frames and trusses)
3.4 Modified nominal stresses and concentration factors
3.4.1 Generalities
3.4.2 Misalignments
3.5 Geometric stresses (Structural stress at the hot spot)
3.5.1 Introduction
3.5.2 Determination using FEM modelling
3.5.3 Determination using formulas
3.6 Stresses in orthotropic decks
3.7 Calculation of stress ranges
3.7.1 Introduction
3.7.2 Stress range in non-welded details
3.7.3 Stress ranges in bolted joints
3.7.4 Stress range in welds
3.7.5 Multiaxial stress range cases
3.7.6 Stress ranges in steel and concrete composite structures
3.7.7 Stress ranges in connection devices from steel and concrete composite structures
3.8 Modified Nominal stress ranges
3.9 Geometric stress ranges
Chapter 4 FATIGUE STRENGTH
4.1 Introduction
4.1.1 Set of fatigue strength curves
4.1.2 Modified fatigue strength curves
4.1.3 Size effects on fatigue strength
4.1.4 Mean stress influence
4.1.5 Post-weld improvements
4.2 Fatigue detail tables
4.2.1 Introduction
4.2.2 Non-welded details classification (EN 1993-1-9, Table 8.1)
4.2.3 Welded plated details classification (general comments)
4.2.4 Longitudinal welds, (built-up sections, EN1993-1-9 Table 8.2), including longitudinal butt welds
4.2.5 Transverse butt welds (EN1993-1-9 Table 8.3)
4.2.6 Welded attachments and stiffeners(EN 1993-1-9 Table 8.4),andload-carrying welded joints (EN 1993-1-9 Table 8.5)
4.2.7 Welded tubular details classification (EN 1993-1-9 Tables 8.6
and 8.7)
4.2.8 Orthotropic deck details classification (EN 1993-1-9 Tables 8.8
and 8.9)
4.2.9 Crane girder details (EN 1993-1-9 Table 8.10)
4.2.10 Tension components details (EN 1993-1-11)
4.2.11 Geometric stress categories (EN 1993-1-9, Annex B, Table B.1)
4.2.12 Particular case of web breathing, plate slenderness limitations
4.3 Determination of fatigue strength or life by testing
Chapter 5 RELIABILITY AND VERIFICATION
5.1 Generalities
5.2 Strategies
5.2.1 Safe life
5.2.2 Damage tolerant
5.3 Partial factors
5.3.1 Introduction
5.3.2 Action effects partial factor
5.3.3 Strength partial factor
5.4 Verification
5.4.1 Introduction
5.4.2 Verification using the fatigue limit
5.4.3 Verification using damage equivalent factors
5.4.4 Verification using damage accumulation method
5.4.5 Verification of tension components
5.4.6 Verification using damage accumulation in case of two or more cranes
5.4.7 Verification under multiaxial stress ranges
Chapter 6 BRITTLE FRACTURE
6.1 Introduction
6.2 Steel quality
6.3 Relationship between different fracture toughness test results
6.4 Fracture concept in EN 1993-1-10
6.4.1 Method for toughness verification
6.4.2 Method for safety verification
6.4.3 Flaw size design value
6.4.4 Design value of the action effect stresses
6.5 Standardisation of choice of material: maximum allowable thicknesses
REFERENCES
ANNEX A STANDARDS FOR STEEL CONSTRUCTION
ANNEX B FATIGUE DETAIL TABLES WITH COMMENTARY
B.1 Plain members and mechanically fastened joints (EN 1993-1-9, Table 8.1)
B.2 Welded built-up sections (EN 1993-1-9, Table 8.2)
B.3 Transverse butt welds (EN 1993-1-9, Table 8.3)
B.4 Attachments and stiffeners (EN 1993-1-9, Table 8.4)
B.5 Load carrying welded joints (EN 1993-1-9, Table 8.5)
B.6 Hollow sections (T ≤ 12.5 mm) (EN 1993-1-9, Table 8.6)
B.7 Lattice girder node joints (EN 1993-1-9, Table 8.7)
B.8 Orthotropic decks - closed stringers (EN 1993-1-9, Table 8.8)
B.9 Orthotropic decks - open stringers (EN 1993-1-9, Table 8.9)
B.10 Top flange to web junction of runway beams (EN 1993-1-9, Table 8.10)
B.11 Detail categories for use with geometric (hot spot) stress method (EN 1993-1-9, Table B1)
B.12 Tension components
B.13 Review of orthotropic decks details and structural analysis
ANNEX C MAXIMUM PERMISSIBLE THICKNESSES TABLES
C.1 Maximum permissible values of element thickness t in mm
C.2 Maximum permissible values of element thickness t in mm (EN 1993-1-12, Table 4)