Performance of FRCM-Strengthened RC Beams Subject to Fatigue

Fabric-reinforced cementitious matrix (FRCM) is a relatively new material system developed for the repair, retrofit, and rehabilitation of reinforced concrete (RC) and masonry structures. Structures such as bridges experience high traffic volumes and varying vehicle axle weights causing repeated cyclic loading throughout the lifetime of the structure. Cyclic loading may cause progressive damage to the structure, a phenomenon known as fatigue. Due to the novelty of FRCM technology, there is a lack of research regarding the long-term performance of FRCM systems for RC strengthening. This study investigated experimentally the parameters that most influence the flexural fatigue performance of polyparaphenylene benzobisoxazole (PBO) FRCM-strengthened RC beams. Specimens are subjected to both static and cyclic (fatigue) loading. For members subjected to cyclic loading, the following parameters were investigated and discussed: amount of supplemental reinforcement, ultimate strength, applied stress range, fatigue life, failure modes, and residual strength. Results were used to develop a stress ratio versus the number of cycles (S-N) curve with the objective of defining the endurance limit of the FRCM strengthened RC beams. 1 2017 American Society of Civil Engineers.Scopu

Performance of FRCM strengthened RC beams subject to fatigue

Fabric reinforced cementitious matrix (FRCM) is a relatively new material system recently developed for the repair, retrofit, and rehabilitation of reinforced concrete (RC) and masonry structures. Concrete structures such as bridges experience high traffic volumes and varying vehicle axle weights causing repeated cyclic loading throughout their lifetime. Cyclic loading may cause damage to the structure, a phenomenon known as fatigue. Due to the novelty of FRCM technology, there is a lack of research regarding the long-term performance of FRCM systems for RC strengthening. This study aims to investigate experimentally the parameters that most influence the flexural fatigue performance of Polyparaphenylene benzobisoxazole (PBO) FRCM strengthened RC beams. For members subject to cyclic loading, a stress ratio vs. the number of cycles (S-N) curve is developed with the objective of defining the endurance limit of the strengthened beams. Failure mode and fatigue life of the beams during cyclic loading are investigated and discussed. 2016 International Committee of the SCMT conferences. All rights reserved.The project was made possible with the financial support received from the University Transportation Center RE-CAST and the Qatar National Research Fund (a member of Qatar Foundation) under NPRP grant # 7-1720-2-641. The statements made herein are solely the responsibility of the authors.Scopu

Distribuição otimizada do reforço com fibras de carbono em lajes de concreto armado

Neste trabalho é determinada a região de aplicação do reforço com fibras de carbono em lajes de concreto utilizando-se um procedimento de otimização topológica. Embora o procedimento seja aplicado em lajes, a técnica pode ser usada em qualquer estrutura de concreto armado a ser reforçada. As simulações numéricas foram feitas através do Método dos Elementos Finitos, associadas ao procedimento automático de otimização topológica, para indicação da região ótima de posicionamento do reforço. A influência de alguns aspectos do comportamento estrutural da laje no resultado da otimização é apresentada: fissuração do concreto; condições de apoio e de carregamento; e taxa de reforço. Foram verificados os ganhos em termos de rigidez e de resistência das peças reforçadas. A comparação com técnicas convencionais de reforço mostrou que a otimização topológica pode ser uma ferramenta bastante útil para a definição da região do reforço, podendo levar a uma economia de material