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Old suspended timber floors flexurally-strengthened with different structural materials, Biscaia, Hugo, Franco Noel, Nunes Ricardo, and Chastre Carlos , Key Engineering Materials, Volume 713, p.78-81, (2016) Abstract

The design of timber beams has strict limits when it comes to the Serviceability Limit States (SLS) either in short-term or in long-term deflections. In order to face this aspect efficiently, the increase of the cross section of the beams might be considered as a solution. However, the prohibitive increase of the costs associated to this solution or the change of the initial architecturedesign of the building, opens the opportunity to find new and more efficient solutions. In that way, the use of additional reinforcements to the timber beams may be seen as a promising solution because either new or old structures would keep always their original aesthetical aspect with no significant self-weight increase and improving their behaviour to short and long-term actions.Therefore, the current study is dedicated to the analysis of composite timber beams where Fiber Reinforcement Polymers (FRP), steel or stainless steel are used to improve the stiffness, strength and deflection behaviour of old suspended timber floors. An experimental program was conducted where old suspended timber floors reinforced with CFRP strips were subjected to 4-point bending tests. A simplify nonlinear numerical model was developed to simulate the bending behaviour of the specimens and several other cases with other reinforcement configurations and different structural materials were assumed. The numerical analysis herein presented also takes into account both Ultimate and Serviceability Limit States of the reinforced specimens.

Lateral cyclic behaviour of RC columns confined with carbon fibres, Faustino, Pedro, Frade Pedro, and Chastre Carlos , Structures, February 2016, Volume 5, p.196-206, (2016) AbstractWebsite

Reinforced concrete (RC) columns with various strengthening systems and different conditions were tested to cyclic lateral and axial loading for the purpose of performance assessment. Tests included confinement strengthening with carbon-fiber-reinforced polymer (CFRP) sheets, longitudinal strengthening with CFRP laminates and confining CFRP jacket, longitudinal strengthening with stainless steel bars and confining CFRP jacket, tested column until reinforcing steel failure, repair and CFRP confining jacket, and longitudinal strengthening with stainless steel bars. The analysis of the tests results as to load-displacement relationship and energy dissipation led to the conclusion that the use of external longitudinal strengthening with CFRP confinement is effective for performance retrofitting and upgrading, and viable in terms of execution. The load capacity increase due to strengthening reached 36–46% with good ductile behaviour. Nonlinear numerical modelling was carried out using two approaches which represent reasonably well the global performance of the studied columns for the prediction of the ascending load-displacement relationship and the peak load values in each cycle.