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FONSECA, T. C. C. S. Strengthening of beam-to-column connections in precast concrete structures by NSM CFRP strips. 2012. In this research, the strengthening of beam-to-column connections in precast concrete structures is evaluated. The strengthening technique used is internationally known as NearSurface-Mounted and involves the bonding of CFRP (Carbon Fiber Reinforced Polymer) strips into slits made in concrete cover. There are no references about the use of this or any else technique in the strengthening of connections in precast structures however it could be an option when the structure presents an unsatisfactory behavior. Because of the innovative characteristic of the purpose, experimental tests are required. A pilot test was performed in a frame with reduced dimensions. The frame had initially pinned connections that were strengthened. The strengthening provided a reduction in the beam deflection and the recovery of the initial stiffness of the frame. Although the promising results, the frame dimensions imposed limitations in relation to the strips bonding length and to the distance to the beam edge that contributed to the premature failure by splitting of strips and concrete. It was also performed a test in a strengthened semi-rigid connection. An increase in the connection stiffness was observed. Experimental static and dynamic tests were performed on three real scaled frame models. The results of these tests demonstrated the effectiveness of the strengthening in the increasing of stiffness, natural frequency and strength of the frame. It was also observed that the strengthening reduced the reinforcement strain. The numerical simulation of the dynamic tests allowed the indirect determination of the connections stiffness and supported the definition of boundary conditions in the simulation of the static tests that allowed a better understanding in relation to cracking and stress distribution. Through this research it was confirmed that the strengthening technique proposed is useful for rehabilitation of structures with disabilities related to ultimate limit state, since the increase in resistance was achieved, and also related to the serviceability limit states, since strengthened structures presented lower vertical displacements and higher natural frequencies. It is highlighted that the dynamic tests were important not only to obtain the modal parameters of the structure, but also to evaluate the real boundary conditions of the static tests. Key-words: Beam-to-column connection. Precast structures. NSM. CFRP. Connection strengthening. DIANA. Dynamic analysis. SUMÁRIO CAPÍTULO 1 Introdução  17 1.1 Objetivos 19 1.2 Metodologia 19 1.3 Apresentação da tese 20 CAPÍTULO 2 Reforço por colagem de barras e laminados de PRF em entalhes  23 CAPÍTULO 3 Estruturas de concreto pré-moldado  35 CAPÍTULO 4 Ensaios de aderência  45 4.1 Modelo de ensaio 46 4.1.1 Confecção do modelo  48 4.2 Propriedades dos materiais 50 4.3 Configuração e instrumentação dos ensaios 51 4.4 Resultados e análises 52 4.4.1 Trabalhabilidade  52 4.4.2 Ruptura  53 4.4.3 Força no laminado  54 4.4.4 Tensão de aderência  56 4.4.5 Variações com o comprimento aderido e comparações  57 4.5 Conclusões 58 CAPÍTULO 5 Ensaio em modelos de ligação semirrígida reforçada  61 5.1 Características dos modelos 61 5.2 Reforço 64 5.3 Propriedades dos materiais  66 5.4 Instrumentação e configuração do ensaio estático  67 5.5 Execução do ensaio  70 5.6 Resultados e análises  71 5.6.1 Ruptura  71 5.6.2 Deformação  73 5.6.3 Rigidez à flexão  73 5.6.4 Força x Deslocamento  82 5.7 Conclusões  84 CAPÍTULO 6 Ensaio-piloto  85 6.1 Propriedades dos materiais  86 6.2 Confecção do modelo  92 6.3 Instrumentação e configuração do ensaio estático  94 6.4 Execução do ensaio  97 6.5 Resultados e análises  98 6.5.1 Ruptura  98 6.5.2 Deformação  99 6.5.3 Rigidez à flexão  104 6.5.4 Deslocamento vertical  107 6.5.5 Conclusões  108 6.6 Simulação numérica com base nos resultados do Ensaio-Piloto  109 6.6.1 Modelo numérico  110 6.6.2 Elementos finitos  111 6.6.3 Modelos constitutivos  112 6.6.4 Resultados  118 6.6.5 Conclusões  128 CAPÍTULO 7 Ensaios principais  129 7.1 Modelo de ensaio  129 7.2 Propriedades dos materiais 133 7.3 Confecção do modelo 138 7.4 Montagem e reforço dos pórticos 140 7.5 Instrumentação e configuração do ensaio estático 142 7.6 Execução dos ensaios estáticos 146 7.6.1 Ensaio da viga  147 7.6.2 Portico1

Reforço de ligações viga-pilar de estruturas de concreto pré-moldado pela colagem de laminados de polímero reforçado com fibra de carbono (PRFC) em entalhes no concreto de cobrimento