BEHAVIOUR OF SHORT-SPAN CONCRETE-FILLED COMPOSITE TUBES WITH ±55◦ FIBER ORIENTATION UNDER BENDING AND SHEAR

Abstract

Concrete-filled fiber-reinforced polymer (FRP) tubes (CFFTs), an alternative to conventional systems, emerged as innovative and sustainable infrastructure systems for various structural applications. This research aimed to investigate the shear and flexural behavior of steel-reinforced CFFTs with ±55◦ fiber orientation. An extensive study was performed by fabricating and testing a total of eighteen, 1219.2 mm long steel-reinforced CFFTs under three-point bending by varying three different test parameters: pressure ratings of the GFRP tube, internal reinforcement ratios, and shear span to depth ratio. The study demonstrates that the increase in the total normalized reinforcement ratio resulted in a significant enhancement in the strength and stiffness of CFFTs. A nonlinear finite element model was developed and analyzed in LS-DYNA using its dynamic solver to predict the complete behavior of CFFTs. Overall, the FE models successfully predicted the failure mode, nonlinear response of CFFTs, and showed a good agreement with the experimental results.