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Abstract(s)
A presente dissertação resulta de um estudo sobre os diversos aspectos que norteiam as
propostas com critérios de dimensionamento de estruturas de betão armado reforçadas através da
técnica de colagem de sistemas Compósitos Reforçados com Fibras (FRP). O trabalho desenvolvido
procura avaliar e discutir as metodologias de cálculo sugeridas por vários documentos publicados e
propõe um procedimento para a análise e dimensionamento do reforço à flexão através de uma folha
de cálculo simples.
Inicialmente, efectua-se uma revisão bibliográfica sobre o estado do conhecimento no que
concerne ao dimensionamento de reforços com materiais compósitos de FRP. Primeiro, procede-se a
uma breve exposição sobre a importância do conhecimento das características dos materiais, do
comportamento de elementos estruturais reforçados com FRP e à necessidade de se observarem
regras específicas na aplicação destes sistemas de reforço. Em seguida, expõe-se a análise da
verificação de segurança de elementos reforçados à flexão segundo a perspectiva das publicações,
nomeadamente, do American Concrete Institute (ACI) “Committee 440” e da Fédération
Internationale du béton (FIB) “Task Group 9.3 (Bulletin 14)”.
Posteriormente, o trabalho desenvolve-se em três partes principais. Na primeira, estabelece-se
um estudo de análise comparativa entre os resultados experimentais e os previstos pelos referidos
manuais para vários programas experimentais sobre modelos de vigas e de faixas de laje. Os valores
máximos da capacidade resistente (momentos flectores) dos modelos e da extensão no compósito são
confrontados e a importância do conhecimento das características dos materiais discutidos. Com as
informações das etapas anteriores, na segunda parte, sistematiza-se o faseamento e os procedimentos
de cálculo a levar a cabo no projecto de reforço à flexão com sistemas compósitos de FRP,
respeitando as propostas normativas que mais se adequam a Portugal. Paralelamente, estrutura-se
uma folha de cálculo automático, desenvolvida no software Mathcad, na qual se implementam esses
procedimentos. Por último, é apresentado um projecto de reforço de estruturas de betão armado
segundo os critérios organizados nas partes anteriores do trabalho.
Finalmente, salientam-se as principais conclusões e recomendações referentes ao
dimensionamento e verificação de segurança de estruturas reforçadas com sistemas compósitos de
FRP e indicam-se algumas perspectivas de desenvolvimento futuro.
The present dissertation results from a study concerning the main design criteria for reinforcing concrete structures through externally bonding Fibre Reinforced Polymer (FRP) systems. It was developed to evaluate and discuss the design methodologies proposed by present knowledge guidelines publications. Procedures for analysis and design of FRP strengthened RC elements in bending throughout a simple worksheet is also proposed. Initially, a state-of-art concerning design guidelines on the use of FRP strengthening for concrete structures is presented. Emphasis is given on properties of materials, structural behaviour of elements reinforced with composite materials and rules and practical information on strengthening technique. Then, the basis of design and safety concept is exposed, taking into account the present knowledge described in international publications, such as, the American Concrete Institute (ACI) Committee 440 and the Fédération Internationale du béton (FIB) Task Group 9.3 (bulletin 14). After, the work is divided in three main parts. The first part includes the comparative analysis between experimental results and analytic predictions by international guidelines for beams and slabs models. The maximum ultimate capacity of the strengthened element and the maximum FRP strain are compared and discussed. The second part provides a summary of the phasing and design rules for designing FRP strengthened RC elements taking into account the Portuguese design standards. Simultaneously, a simple automatic worksheet is presented for design supported by “Mathcad”, including the design procedure developed in previous research work. The last part concerns one project which was developed for an existing structure to assess the applicability of knowledge acquired in the present work. Finally, conclusions are drawn out and recommendations concerning the design and safety concept for the use of externally bonded FRP reinforcement technique for repair or strengthening existing concrete structures are presented. Work to be developed in the future is also suggested.
The present dissertation results from a study concerning the main design criteria for reinforcing concrete structures through externally bonding Fibre Reinforced Polymer (FRP) systems. It was developed to evaluate and discuss the design methodologies proposed by present knowledge guidelines publications. Procedures for analysis and design of FRP strengthened RC elements in bending throughout a simple worksheet is also proposed. Initially, a state-of-art concerning design guidelines on the use of FRP strengthening for concrete structures is presented. Emphasis is given on properties of materials, structural behaviour of elements reinforced with composite materials and rules and practical information on strengthening technique. Then, the basis of design and safety concept is exposed, taking into account the present knowledge described in international publications, such as, the American Concrete Institute (ACI) Committee 440 and the Fédération Internationale du béton (FIB) Task Group 9.3 (bulletin 14). After, the work is divided in three main parts. The first part includes the comparative analysis between experimental results and analytic predictions by international guidelines for beams and slabs models. The maximum ultimate capacity of the strengthened element and the maximum FRP strain are compared and discussed. The second part provides a summary of the phasing and design rules for designing FRP strengthened RC elements taking into account the Portuguese design standards. Simultaneously, a simple automatic worksheet is presented for design supported by “Mathcad”, including the design procedure developed in previous research work. The last part concerns one project which was developed for an existing structure to assess the applicability of knowledge acquired in the present work. Finally, conclusions are drawn out and recommendations concerning the design and safety concept for the use of externally bonded FRP reinforcement technique for repair or strengthening existing concrete structures are presented. Work to be developed in the future is also suggested.
Description
Keywords
Betão armado Materiais compósitos reforçados com fibras (FRP) Reforço e reabilitação de estruturas Reforço à flexão com sistemas compósitos de FRP Técnica EBR Técnica NSM Dimensionamento Procedimentos para projecto Comportamento experimental Modos de ruína Tensões de corte Mathcad Verificação de segurança
Citation
Azevedo, Diogo (2008). Reforço de estruturas de betão com colagem de sistemas compósitos de CFRP : recomendações para dimensionamento. Porto: FEUP. Tese de Mestrado em Estruturas de Engenharia Civil