Biblioteca
Zilch, Konrad

Strengthening of Concrete Structures with Adhesive Bonded Reinforcement : Design and Dimensioning of CFRP Laminates and Steel Plates / Konrad Zilch ; Roland Niedermeier ; Wolfgang Finckh - 1. - Berlin Ernst, Wilhelm & Sohn 2014 - 144 p. : il. ; - BetonKalender .

Incluye Bibliografía e indice

1 Introduction.................................................................................... 1
1.1 The reason behind this book ............................................................... 1
1.2 Strengthening with adhesively bonded reinforcement ........................ 1
2 DAfStb guideline............................................................................ 3
2.1 The reasons for drawing up a guideline .............................................. 3
2.2 Preparatory work................................................................................. 3
2.3 Work on the guideline......................................................................... 4
2.4 The structure and content of the guideline .......................................... 4
2.4.1 General................................................................................................ 4
2.4.2 Design and detailing ........................................................................... 4
2.4.3 Products and systems .......................................................................... 4
2.4.4 Execution ............................................................................................ 5
2.4.5 Planning .............................................................................................. 5
2.5 Safety concept..................................................................................... 5
2.6 Applications........................................................................................ 6
2.6.1 Member to be strengthened................................................................. 6
2.6.2 Strengthening systems ........................................................................ 7
2.6.3 Ambient conditions............................................................................. 7
2.6.4 Fire protection..................................................................................... 8
2.7 Relationship with other regulations..................................................... 9
2.8 Documents and assistance for practical applications........................... 10
3 Design of strengthening measures with externally
bonded CFRP strips...................................................................... 11
3.1 Principles ............................................................................................ 11
3.2 Verification of flexural strength .......................................................... 13
3.3 Bond analysis...................................................................................... 15
3.3.1 Principles ............................................................................................ 15
3.3.2 Simplified method............................................................................... 16
3.3.3 More accurate method......................................................................... 17
3.3.3.1 General................................................................................................ 17
3.3.3.2 Determining the crack spacing............................................................ 19
3.3.3.3 Accurate analysis of concrete element between cracks ....................... 20
3.3.3.4 Simplified analysis of element between cracks ................................... 23
3.3.4 End anchorage analysis....................................................................... 24
3.3.4.1 General................................................................................................ 24
3.3.4.2 End anchorage analysis at flexural crack nearest
to point of contraflexure...................................................................... 24
3.3.4.3 Anchorage analysis at an arbitrary concrete element
between cracks.................................................................................... 26
3.3.4.4 End anchorage analysis with shear wrapping...................................... 27
3.4 Shear force analyses............................................................................ 29
3.4.1 Shear strength...................................................................................... 29
3.4.2 Shear strengthening............................................................................. 30
3.4.2.1 Full wrapping in steel.......................................................................... 31
3.4.2.2 Full wrapping in fibre-reinforced material .......................................... 32
3.4.2.3 U-wrapping ......................................................................................... 32
3.4.3 End strap to prevent concrete cover separation failure........................ 33
3.5 Fatigue analysis................................................................................... 35
3.6 Analyses for the serviceability limit state............................................ 36
3.7 Detailing.............................................................................................. 36
3.7.1 Strip spacing ....................................................................................... 36
3.7.2 Provision of shear straps ..................................................................... 37
3.7.3 Steel shear straps................................................................................. 37
4 Example 1: Strengthening a slab with externally
bonded CFRP strips...................................................................... 39
4.1 System................................................................................................. 39
4.1.1 General................................................................................................ 39
4.1.2 Loading............................................................................................... 39
4.1.3 Construction materials ........................................................................ 40
4.1.3.1 Near-surface tensile strength............................................................... 40
4.1.3.2 Concrete compressive strength ........................................................... 41
4.1.3.3 Type and quantity of existing reinforcement....................................... 41
4.1.3.4 Position of existing reinforcement ...................................................... 41
4.1.3.5 Strengthening system .......................................................................... 41
4.2 Internal forces ..................................................................................... 42
4.3 Determining the prestrain.................................................................... 42
4.4 Simplified analysis .............................................................................. 44
4.5 Accurate analysis ................................................................................ 46
4.5.1 General................................................................................................ 46
4.5.2 Verification of flexural strength .......................................................... 46
4.5.3 Determining the crack spacing............................................................ 48
4.5.4 Accurate analysis of concrete element between cracks ....................... 48
4.5.4.1 Determining the strip forces................................................................ 49
4.5.4.2 Determining the bond strength............................................................ 52
4.5.5 End anchorage analysis....................................................................... 55
4.6 Analysis of shear capacity................................................................... 58
4.7 Serviceability limit state...................................................................... 59
5 Design of strengthening with near-surface-mounted
CFRP strips.................................................................................... 61
5.1 Principles ............................................................................................ 61
5.2 Verification of flexural strength .......................................................... 61
5.3 Bond analysis...................................................................................... 63
5.4 Shear Force Analyses.......................................................................... 65
5.5 Fatigue analysis................................................................................... 66
5.6 Analyses for the serviceability limit state............................................ 67
5.7 Detailing.............................................................................................. 67
6 Example 2: Strengthening a beam with
near-surface-mounted CFRP strips............................................. 69
6.1 System................................................................................................. 69
6.1.1 General................................................................................................ 69
6.1.2 Loading............................................................................................... 69
6.1.3 Construction materials ........................................................................ 71
6.1.3.1 Concrete compressive strength ........................................................... 71
6.1.3.2 Type and quantity of existing reinforcement....................................... 71
6.1.3.3 Position of existing reinforcement ...................................................... 71
6.1.3.4 Strengthening system .......................................................................... 71
6.2 Internal forces ..................................................................................... 72
6.3 Determining the prestrain.................................................................... 72
6.4 Verification of flexural strength .......................................................... 74
6.5 Bond analysis...................................................................................... 76
6.5.1 Analysis point ..................................................................................... 76
6.5.2 Acting strip force ................................................................................ 78
6.5.3 Bond resistance ................................................................................... 79
6.5.4 Bond analysis...................................................................................... 80
6.6 Shear analyses..................................................................................... 80
6.6.1 Shear capacity ..................................................................................... 80
6.6.2 Shear strengthening............................................................................. 81
6.6.3 Check for concrete cover separation failure ........................................ 82
6.7 Analyses for the serviceability limit state............................................ 84
7 Design of column strengthening with CF sheets....................... 87
7.1 Principles ............................................................................................ 87
7.2 Properties of CF sheets relevant to design .......................................... 91
7.3 Load-carrying capacity of cross-section.............................................. 93
7.4 Load-carrying capacity of member ..................................................... 98
7.5 Creep................................................................................................... 102
7.6 Analysis at ultimate limit state ............................................................ 105
7.7 Analysis at serviceability limit state.................................................... 111
8 Example 3: Column strengthening.............................................. 115
8.1 System................................................................................................. 115
8.1.1 General................................................................................................ 115
8.1.2 Loading............................................................................................... 115
8.1.3 Construction materials ........................................................................ 116
8.1.3.1 Concrete.............................................................................................. 116
8.1.3.2 Type and quantity of existing reinforcement....................................... 116
8.1.3.3 Strengthening system .......................................................................... 117
8.2 Internal forces ..................................................................................... 118
8.3 Determining the cross-sectional values............................................... 118
8.4 Boundary conditions ........................................................................... 119
8.5 Verification of column load-carrying capacity.................................... 120
8.5.1 Creep of confined concrete.................................................................. 120
8.5.2 Properties of the CF sheet ................................................................... 121
8.5.3 Distribution of transverse compression............................................... 122
8.5.4 Multi-axial stress state in concrete ...................................................... 122
8.5.5 Calculation of column load-carrying capacity .................................... 123
8.6 Serviceability limit state...................................................................... 127
9 Summary and outlook................................................................... 129
References................................................................................. 131
Index........................................................................................... 145

Diseño y construcción de contextos existentes se está convirtiendo cada vez más importante, y con frecuencia las estructuras - a veces de interés histórico - se puede conservar fácilmente ya un costo mínimo mediante el empleo de medidas de fortalecimiento. Elementos de hormigón existentes pueden reforzarse mediante el uso de adhesivos para unir elementos de refuerzo adicionales sobre o dentro de esos miembros. Este libro explica las reglas de diseño, junto con sus antecedentes, y utiliza ejemplos para ilustrar su uso, especialmente para losas, vigas y columnas. Medidas miembros fortalecimiento de hormigón pueden tomar la forma de, por ejemplo, el fortalecimiento de la flexión con tiras unidas CFRP externamente (montaje superficial), hojas CF y placas de acero, flexión fortalecer con bandas de CFRP unidos en ranuras (cerca-montaje en superficie de refuerzo), cizalla fortalecer con láminas unidas externamente CF y placas de acero, y el fortalecimiento de la columna con hojas CF como confinar refuerzo.
El explicaciones y antecedentes información proporcionada se basa principalmente en la nueva directriz alemana "Fortalecimiento de los Miembros de concreto con pegada Estrado" por el Comité Alemán para Hormigón Estructural (DAfStb). Esta es la primera directiva europea para regular este tema en la forma de un suplemento del Eurocódigo. Como está previsto elaborar un documento en un futuro Eurocódigo 2, la directriz DAfStb sirve como punto de partida.
Los autores participan ampliamente en la planificación, el diseño, la operación y la inspección de edificios para la preservación y la reconstrucción, y en la actualización de las Guías Europeas Técnicas aprobación (etags) y reglas de diseño.

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