###### Abstract  
In this study, an experiment on compressive strength of the hybrid concrete-filled fiber-reinforced polymer (FRP) tube (CFFT) confined by filament winding was conducted to improve the longitudinal strength while considering the thickness of filament winding as a variable. A maximum error of 17% was observed when the results of performing the finite element analysis (FEA) by applying the mechanical properties of the fiber-reinforced polymer (FRP) materials suggested in previous studies were compared to those of the compressive strength experiment on the hybrid-CFFT. Moreover, a maximum error of 15% was exhibited when the results derived from the strength equation proposed by analyzing the compressive strength experiment were compared. Furthermore, the compressive strength of the hybrid-CFFT increased by up to 14% when the longitudinal compressive strength of the pre-tensioned spun high strength concrete (PHC) pile and concrete-filled tube (CFT) were compared. compressive strength; hybrid-CFFT; FEA; mechanical properties; FRP +
Footnote †: journal: Applied Sciences  
**Citation**: [PERSON]; [PERSON] Compressive Strength Testing of Hybrid Concrete-Filled Fiber-Reinforced Plastic Tubes Confined by Filament Winding. _Appl. properties in terms of rigidity, strength, fire resistance, and constructability of the entire member because the concrete is confined by the steel pipe. The first application of the CFT in the construction industry was the pier of the Severn Railway Bridge in England, which was completed in 1879. Later in 1901, [PERSON] verified that the rigidity increases if steel pipes are filled with concrete for preventing internal corrosion [3]. [PERSON] et al. developed an equation for predicting the increase in axial compressive strength of concrete confined by a cylinder through an experiment using a concrete test piece [4]. [PERSON] et al. conducted an experiment on the compressive strength of concrete confined by spiral reinforcements per concrete strength, and confirmed that the ratio of longitudinal to axial strain decreases as the confinement effect increases [5]. [PERSON] et al. conducted an experiment on compressive strength by adjusting the distance among spiral reinforcements, which is a concrete reinforcement material, from 30 to 118 mm [6]. The confinement effectiveness coefficient, which signifies the confinement characteristics, was obtained from experimental results. It was confirmed that the increase in compressive strength is due to the confinement of the spiral reinforcements. [PERSON] et al. [7] examined 491 previous studies on the compressive strength of CFT and proposed a hoop stress model of CFT. Moreover, extensive research is being conducted on concrete-filled FRP tubes (CFFTs) in which FRP is used as a material for confining concrete by expanding the CFT structure. In this regard, [PERSON] et al. [8] and [PERSON] [9] verified the increase in the strength of FRP by conducting experiments on the compression of CFTT. [PERSON] et al. [10] conducted an experiment on the compression of short concrete columns confined by CFRP sheets to predict the behavior of concrete under multi-axial loads and verified that the compressive strength varies when the thickness of the CFRP sheet and fiber orientation are adjusted. [PERSON] et al. [11] conducted an experiment on a concrete compression member confined by spiral reinforcements and verified that the axial strength and ultimate strain of the confined concrete member increased by approximately 50% and 70%, respectively, compared to those of unconfined concrete. [PERSON] et al. investigated the effect of column parameters on the axial compression behavior of CFFT [12]. [PERSON] et al. investigated the axial compressive behavior of a glass FRP tube filled with ultra-high performance concrete [13]. [PERSON] et al. [14] presented a new concrete-filled FRP tube (CFFT) with an inner steel wire mesh (WM).