Reforço ao corte de vigas de betão armado com sistemas compósitos de fibras embebidas em matriz polimérica ou cimentícia

Mafalda De Matos Calapez Sabido Falcão

Key information

Authors:

Mafalda De Matos Calapez Sabido Falcão (Mafalda De Matos Calapez Sabido Falcão)

Supervisors:

João Pedro Lage da Costa Firmo (João Pedro Lage da Costa Firmo); André Filipe Castanheira Alves Furtado (André Filipe Castanheira Alves Furtado)

Published in

June 23, 2025

Abstract

The need for the rehabilitation of reinforced concrete structures has been increasing, particularly in elements with deficiencies in shear resistance. In this context, the development of effective strengthening techniques is essential. CFRP systems (Carbon Fiber Reinforced Polymer) and FRCM systems (Fabric Reinforced Cementitious Matrix) are widely used for this purpose. This dissertation evaluates the effectiveness of both techniques in terms of shear strengthening of reinforced concrete beams with insufficient transverse reinforcement. An experimental study was carried out involving four beams: three were prepared and strengthened within the scope of this dissertation, and one unstrengthened reference beam, previously tested in a study by Azevedo et al. [1], was used as a benchmark for comparison. The three strengthened beams were retrofitted using partial jacketing with externally bonded reinforcement. Two of these beams were reinforced with CFRP sheets, one of which included mechanical anchorages. The third beam was strengthened with an FRCM system.The tests were conducted under three-point bending, with monitoring of displacements, cracking patterns, and failure modes. The results showed that CFRP sheets significantly increased the shear strength, particularly when combined with mechanical anchorage, which prevented premature debonding. The FRCM system also showed promising performance, comparable to the CFRP system without anchorages. It was concluded that both techniques are effective for shear strengthening, with observed increases in resistance of approximately 89% for the CFRP with anchorages, 36% for the CFRP without anchorages, and 52% for the FRCM system, when compared to the unstrengthened reference beam