EFFECT OF TRANSVERSE/AXIAL FIBER RATIOS ON THE FLEXURAL CAPACITY OF CONCRETE-FILLED FRP TUBE BEAMS

Abstract

Fiber-reinforced polymer (FRP) composite materials have been used in the field of civil engineering constructions especially in corrosive environment. They can be used as internal reinforcement for beams, slabs, and pavements, or as external reinforcement for rehabilitation and strengthening different structures. One of their innovative applications is the concrete-filled FRP tubes (CFFTs) which are becoming an alternative for different structural members such as piles, columns, bridge girders, and bridge piers due to their high performance, durability and resistance to corrosion. In such integrated systems, the FRP tubes act as stay-in-place forms, protective jackets for the embedded concrete and steel, and as external reinforcement in the primary and secondary direction of the structural member [1,2,3]. This study investigates the flexural behaviour of square filament-wound FRP tubes filled with concrete, without any steel bars. The FRP tubes were fabricated by filament winding process and hand lay-up technique. Several test variables were chosen to investigate the effect of the fiber laminates structure, and the different ratios of axial-andtransverse fiber on the flexural behaviour of such CFFT beams. The beams were tested under four-point loading system. The results of the tested CFFT beams indicate significant gain in strength, stiffness, cracking moment and energy absorption with increasing the axial fiber percentage and by increasing the thickness of the FRP tube.