Experimental Study of FRP Tube-encased Concrete Columns GUOQIANG LI,1, * SADI ́ TORRES,2

ABSTRACT: Fiber-reinforced plastic (FRP) tube-encased concrete columns (FRP/ ECCs) represent a formwork-free, steel-free, and corrosion-resistant alternative for construction of new infrastructure. In this study, twenty-seven 101.6 304.8mm2 FRP/ECCs are prepared. The composite columns are divided into three equal groups. Each group is prepared using concrete with different 28-d compressive strength. The first group is prepared using 35MPa concrete, the second group using 50MPa concrete, and the third one using 80MPa concrete. FRP tubes with 5-mm wall thickness are used, which are filament-wound E-glass fiber-reinforced vinyl ester tubes with fibers orientated at 54 from the axial direction. Coaxial compression, four-point bending, and push-out tests are conducted. Strain gages are used to monitor the local strain distributions of the FRP tubes. It has been found that the structural behavior of FRP/ECCs depends on the concrete strength. The confinement efficiency and the interfacial bonding strength are low for very high strength concrete. KEY WORDS: FRP, concrete, column, encasement, confinement