Fibre Reinforced Polymer (FRP) Reinforcement in Compression Design of short and slender FRP reinforced Concrete Columns considering long-term Material Behaviour

The application of Fibre Reinforced Polymer (FRP) reinforcements in structural concrete, particu-larly for retrofitting purposes, has been steadily increasing. Due to their excellent durability properties, FRP reinforcement is particularly suited for environmentally exposed structures. However, the mechanical properties of FRP reinforcement in compression and the resulting behaviour of concrete members reinforced with FRP in compression, remain unresolved. This thesis develops an experimental method for the determination of the compressive strength and elastic modulus of FRP reinforcement. Using this method, experimental investigations are conducted to characterise the short-term compressive properties of FRP reinforcement bars. Additionally, the long-term interaction between FRP reinforcement and concrete under sustained com-pressive loading is explored experimentally. A comprehensive parameter study, employing a nonlinear method, examines the load-bearing and deformation behaviour of slender concrete members reinforced with FRP in compression. Based on these results, a practical model for the determination of second-order deflections is proposed that accounts for long-term material properties. Finally, reliability analyses of FRP reinforced concrete members in compression are performed, leading to recommendations for partial safety factors regarding FRP compressive strength and elastic modulus.