,Contents
Preface to the First Edition .......................................................................................xi
Preface to the Second Edition ..................................................................................xii
Notation...................................................................................................................xiv
Authors................................................................................................................xxviii
Chapter 1 Introduction .......................................................................................... 1
1.1 Applications of FRP in Strengthening Metallic Structures ....... 1
1.2 Improved Performance due to FRP Strengthening .................... 5
1.3 Current Knowledge on FRP Strengthening of Metallic
Structures ................................................................................... 5
1.4 Layout of the Book .................................................................. 12
References .......................................................................................... 13
Chapter 2 FRP Composites and Metals .............................................................. 19
2.1 General .................................................................................... 19
2.2 Fibre-Reinforced Polymer ....................................................... 19
2.2.1 Carbon Fibre-Reinforced Polymers............................ 19
2.2.2 Glass Fibre-Reinforced Polymers .............................. 21
2.3 Adhesives................................................................................. 21
2.4 Cast/Wrought Iron, Steel, and Aluminium .............................. 23
2.4.1 Cast/Wrought Iron ...................................................... 23
2.4.2 Steel ............................................................................ 24
2.4.3 Aluminium ................................................................. 27
2.5 Future Work ............................................................................. 27
References .......................................................................................... 28
Chapter 3 Behaviour of the Bond between FRP and Metal ................................ 31
3.1 General .................................................................................... 31
3.2 Testing Methods ...................................................................... 31
3.2.1 Methods of Bond Test ................................................ 31
3.2.2 Methods of Strain Measurement ................................ 33
3.3 Failure Modes .......................................................................... 35
3.3.1 Typical Failure Modes ................................................ 35
3.3.2 Key Parameters Affecting Failure Modes................... 36
3.4 Bond–Slip Model..................................................................... 38
3.4.1 Strain Distribution ...................................................... 38
3.4.2 Bond–Slip Curves....................................................... 39
3.4.3 Bond–Slip Model ....................................................... 43
3.4.4 Estimation of Bond Strength and Effective Bond
Length......................................................................... 46
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,vi Contents
3.5 Effect of Temperature on Bond Strength ................................. 49
3.5.1 Influence of Subzero Temperature
on Bond Strength ........................................................ 49
3.5.2 Influence of Elevated Temperature
on Bond Strength ........................................................ 50
3.5.3 Theoretical Analysis of Effect of Elevated
Temperature on Bond ................................................. 54
3.5.4 A Temperature-Dependent Bond-Slip Model ............ 55
3.6 Effect of Cyclic Loading on Bond Strength ............................ 57
3.6.1 Effect of Fatigue Loading on the Bond ...................... 57
3.6.2 Effect of Quasi-static Cyclic Loading on the Bond ... 58
3.6.3 Effect of Large Deformation Cyclic Loading
on the Bond ................................................................ 59
3.7 Effect of Impact Loading on Bond Strength ........................... 60
3.7.1 Effect of Impact Loading on Material Properties ....... 60
3.7.2 Effect of Impact Loading on Bond Strength .............. 62
3.8 Durability of Bond between FRP and Metal (Effect of
Environmental Conditions on Bond) ....................................... 64
3.8.1 General ....................................................................... 64
3.8.2 Sea Water Exposure and Humidity............................. 66
3.8.3 Acidic and Humidity Environment ............................ 67
3.8.4 Wet–Dry Cycles ......................................................... 67
3.8.5 Salt Fog Cycles ........................................................... 69
3.8.6 Freeze–Thaw Cycles .................................................. 69
3.8.7 UV Light .................................................................... 72
3.8.8 Strengthening Corroded Steel .................................... 72
3.9 Other Issues and Future Work ................................................. 73
References .......................................................................................... 74
Chapter 4 Flexural Strengthening of Steel and Steel–Concrete Composite
Beams with FRP ................................................................................. 81
4.1 General .................................................................................... 81
4.2 Members in Bending ............................................................... 83
4.2.1 Strengthening Method and Structural Behaviour ....... 83
4.2.2 Failure Modes ............................................................. 87
4.2.3 Flexural Capacity ....................................................... 94
4.3 Debonding Failures for Members in Bending ....................... 104
4.3.1 General ..................................................................... 104
4.3.2 Interfacial Stresses in Elastic FRP-Plated Beams .... 105
4.3.3 Cohesive Zone Modelling of Debonding Failure ..... 108
4.3.4 End Debonding ......................................................... 109
4.3.5 Intermediate Debonding ........................................... 112
4.3.6 Local Buckling ......................................................... 115
4.4 Design for Members in Bending ........................................... 117
4.4.1 General ..................................................................... 117
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4.4.2 Critical Sections and End Anchorage ....................... 117
4.4.3 Strength of the Maximum Moment Section ............. 118
4.4.4 Design Example for Members in Bending ............... 120
4.5 Members in Shear .................................................................. 126
4.5.1 Strengthening Method and Typical Behaviour ......... 126
4.5.2 Failure Mode ............................................................ 129
4.5.3 Calculation and Design Method ............................... 130
4.6 Members Under Torsion ........................................................ 132
4.6.1 Strengthening Method and Typical Behaviour ......... 132
4.6.2 Failure Mode ............................................................ 134
4.6.3 Calculation and Design Method ............................... 136
4.7 Other Issues ........................................................................... 137
4.7.1 Strengthening of Beams without Access to the
Tension Flange Surface ............................................ 137
4.7.2 Rapid Strengthening Methods .................................. 137
4.7.3 Lateral Buckling Strengthening................................ 137
4.7.4 Special Members and Conditions ............................. 138
4.8 Conclusions and Future Research Needs .............................. 140
References ........................................................................................ 140
Chapter 5 Strengthening of Compression Members ......................................... 148
5.1 General .................................................................................. 148
5.2 Methods of Strengthening ..................................................... 150
5.2.1 Method 1: Bonding of FRP Plates/Sheets ................ 150
5.2.2 Method 2: Using Prestressed CFRP Plates .............. 153
5.3 Structural Behaviour .............................................................. 156
5.3.1 Method 1 for Columns ............................................. 156
5.3.2 Method 1 for Shells .................................................. 162
5.3.3 Method 2 for Columns ............................................. 164
5.4 Capacity of FRP-Strengthened Steel Sections ...................... 166
5.4.1 CFRP-Strengthened CHS Sections .......................... 166
5.4.2 GFRP-Strengthened CHS Sections .......................... 172
5.4.3 CFRP-Strengthened SHS Sections ........................... 175
5.4.4 CFRP-Strengthened Lipped Channel Sections ........ 178
5.4.5 CFRP-Strengthened T-Sections ................................ 180
5.5 Capacity of CFRP-Strengthened Steel Members .................. 180
5.5.1 CFRP-Strengthened SHS Columns .......................... 180
5.5.2 CFRP-Strengthened Lipped Channel Columns........ 184
5.6 Capacity of Prestressed CFRP-Strengthened Steel
Members (PCSSM) under Symmetric Buckling ................... 187
5.6.1 Physical Process of PCSSM ..................................... 187
5.6.2 Two Causes of Buckling and Four
Buckling Cases ......................................................... 188
5.6.3 Calculation Method for the Buckling Capacity........ 190
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Preface to the First Edition .......................................................................................xi
Preface to the Second Edition ..................................................................................xii
Notation...................................................................................................................xiv
Authors................................................................................................................xxviii
Chapter 1 Introduction .......................................................................................... 1
1.1 Applications of FRP in Strengthening Metallic Structures ....... 1
1.2 Improved Performance due to FRP Strengthening .................... 5
1.3 Current Knowledge on FRP Strengthening of Metallic
Structures ................................................................................... 5
1.4 Layout of the Book .................................................................. 12
References .......................................................................................... 13
Chapter 2 FRP Composites and Metals .............................................................. 19
2.1 General .................................................................................... 19
2.2 Fibre-Reinforced Polymer ....................................................... 19
2.2.1 Carbon Fibre-Reinforced Polymers............................ 19
2.2.2 Glass Fibre-Reinforced Polymers .............................. 21
2.3 Adhesives................................................................................. 21
2.4 Cast/Wrought Iron, Steel, and Aluminium .............................. 23
2.4.1 Cast/Wrought Iron ...................................................... 23
2.4.2 Steel ............................................................................ 24
2.4.3 Aluminium ................................................................. 27
2.5 Future Work ............................................................................. 27
References .......................................................................................... 28
Chapter 3 Behaviour of the Bond between FRP and Metal ................................ 31
3.1 General .................................................................................... 31
3.2 Testing Methods ...................................................................... 31
3.2.1 Methods of Bond Test ................................................ 31
3.2.2 Methods of Strain Measurement ................................ 33
3.3 Failure Modes .......................................................................... 35
3.3.1 Typical Failure Modes ................................................ 35
3.3.2 Key Parameters Affecting Failure Modes................... 36
3.4 Bond–Slip Model..................................................................... 38
3.4.1 Strain Distribution ...................................................... 38
3.4.2 Bond–Slip Curves....................................................... 39
3.4.3 Bond–Slip Model ....................................................... 43
3.4.4 Estimation of Bond Strength and Effective Bond
Length......................................................................... 46
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3.5 Effect of Temperature on Bond Strength ................................. 49
3.5.1 Influence of Subzero Temperature
on Bond Strength ........................................................ 49
3.5.2 Influence of Elevated Temperature
on Bond Strength ........................................................ 50
3.5.3 Theoretical Analysis of Effect of Elevated
Temperature on Bond ................................................. 54
3.5.4 A Temperature-Dependent Bond-Slip Model ............ 55
3.6 Effect of Cyclic Loading on Bond Strength ............................ 57
3.6.1 Effect of Fatigue Loading on the Bond ...................... 57
3.6.2 Effect of Quasi-static Cyclic Loading on the Bond ... 58
3.6.3 Effect of Large Deformation Cyclic Loading
on the Bond ................................................................ 59
3.7 Effect of Impact Loading on Bond Strength ........................... 60
3.7.1 Effect of Impact Loading on Material Properties ....... 60
3.7.2 Effect of Impact Loading on Bond Strength .............. 62
3.8 Durability of Bond between FRP and Metal (Effect of
Environmental Conditions on Bond) ....................................... 64
3.8.1 General ....................................................................... 64
3.8.2 Sea Water Exposure and Humidity............................. 66
3.8.3 Acidic and Humidity Environment ............................ 67
3.8.4 Wet–Dry Cycles ......................................................... 67
3.8.5 Salt Fog Cycles ........................................................... 69
3.8.6 Freeze–Thaw Cycles .................................................. 69
3.8.7 UV Light .................................................................... 72
3.8.8 Strengthening Corroded Steel .................................... 72
3.9 Other Issues and Future Work ................................................. 73
References .......................................................................................... 74
Chapter 4 Flexural Strengthening of Steel and Steel–Concrete Composite
Beams with FRP ................................................................................. 81
4.1 General .................................................................................... 81
4.2 Members in Bending ............................................................... 83
4.2.1 Strengthening Method and Structural Behaviour ....... 83
4.2.2 Failure Modes ............................................................. 87
4.2.3 Flexural Capacity ....................................................... 94
4.3 Debonding Failures for Members in Bending ....................... 104
4.3.1 General ..................................................................... 104
4.3.2 Interfacial Stresses in Elastic FRP-Plated Beams .... 105
4.3.3 Cohesive Zone Modelling of Debonding Failure ..... 108
4.3.4 End Debonding ......................................................... 109
4.3.5 Intermediate Debonding ........................................... 112
4.3.6 Local Buckling ......................................................... 115
4.4 Design for Members in Bending ........................................... 117
4.4.1 General ..................................................................... 117
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4.4.2 Critical Sections and End Anchorage ....................... 117
4.4.3 Strength of the Maximum Moment Section ............. 118
4.4.4 Design Example for Members in Bending ............... 120
4.5 Members in Shear .................................................................. 126
4.5.1 Strengthening Method and Typical Behaviour ......... 126
4.5.2 Failure Mode ............................................................ 129
4.5.3 Calculation and Design Method ............................... 130
4.6 Members Under Torsion ........................................................ 132
4.6.1 Strengthening Method and Typical Behaviour ......... 132
4.6.2 Failure Mode ............................................................ 134
4.6.3 Calculation and Design Method ............................... 136
4.7 Other Issues ........................................................................... 137
4.7.1 Strengthening of Beams without Access to the
Tension Flange Surface ............................................ 137
4.7.2 Rapid Strengthening Methods .................................. 137
4.7.3 Lateral Buckling Strengthening................................ 137
4.7.4 Special Members and Conditions ............................. 138
4.8 Conclusions and Future Research Needs .............................. 140
References ........................................................................................ 140
Chapter 5 Strengthening of Compression Members ......................................... 148
5.1 General .................................................................................. 148
5.2 Methods of Strengthening ..................................................... 150
5.2.1 Method 1: Bonding of FRP Plates/Sheets ................ 150
5.2.2 Method 2: Using Prestressed CFRP Plates .............. 153
5.3 Structural Behaviour .............................................................. 156
5.3.1 Method 1 for Columns ............................................. 156
5.3.2 Method 1 for Shells .................................................. 162
5.3.3 Method 2 for Columns ............................................. 164
5.4 Capacity of FRP-Strengthened Steel Sections ...................... 166
5.4.1 CFRP-Strengthened CHS Sections .......................... 166
5.4.2 GFRP-Strengthened CHS Sections .......................... 172
5.4.3 CFRP-Strengthened SHS Sections ........................... 175
5.4.4 CFRP-Strengthened Lipped Channel Sections ........ 178
5.4.5 CFRP-Strengthened T-Sections ................................ 180
5.5 Capacity of CFRP-Strengthened Steel Members .................. 180
5.5.1 CFRP-Strengthened SHS Columns .......................... 180
5.5.2 CFRP-Strengthened Lipped Channel Columns........ 184
5.6 Capacity of Prestressed CFRP-Strengthened Steel
Members (PCSSM) under Symmetric Buckling ................... 187
5.6.1 Physical Process of PCSSM ..................................... 187
5.6.2 Two Causes of Buckling and Four
Buckling Cases ......................................................... 188
5.6.3 Calculation Method for the Buckling Capacity........ 190
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