Concrete Filled Carbon FRP Tube (CFRP-CFFT) columns with and without CFRP reinforcing bars: Axial-flexural interactions

Abstract

The axial and flexural behaviors of Concrete Filled Carbon Fiber Reinforced Polymer Tube (CFRP-CFFT) columns have received significant research attention in the last two decades. One of the most attractive advantages of Carbon FRP (CFRP) tube is the high confinement which results in substantial increase in peak axial and flexural loads and deformations. Despite large research efforts, the behavior of CFRP-CFFT with and without CFRP reinforcing bars under different applied axial load eccentricity has not yet been adequately investigated. This study investigates the experimental and analytical axial-flexural (P−M) interactions of CFRP-CFFT columns with and without CFRP reinforcing bars. A total of 12 specimens of 204-205 mm outer diameter and 800-812 mm height were tested under concentric axial load, 25 mm and 50 mm eccentric axial loads and four-point load. The effectiveness of CFRP reinforcement (tube and bar) was observed to be reduced with the increase in the applied axial load eccentricity. Analytical P−M interactions were constructed using available FRP confined concrete design codes which matched well with the experimental P−M interactions. The parametric study showed that the actual confinement ratio, orientation of fibers and CFRP bar reinforcement ratio have significant influences on P−M interactions of CFRP-CFFT specimens.

Compressive Behavior of Composite Concrete Columns with Encased FRP Confined Concrete Cores

“…This investigation indicates that fibers used for FRP-confinement of concrete are most effective when aligned in the hoop direction, with fiber efficiency reducing significantly with an increase in fiber alignment with respect to the hoop direction. Guler et al [16] reviewed design guidelines for CFFT with circular cross-sections, including many parameters, such as concrete strength, FRP tube thickness, fiber orientation, and slenderness ratio [17,18,19].…”

Behavior and Three-Dimensional Finite Element Modeling of Circular Concrete Columns Partially Wrapped with FRP Strips

“…In real application, however, the lateral confinement can be provided by many different approaches, including simple transverse steel reinforcement (e.g., [28,29,30]), steel cage (e.g., [31,32]), steel tube (e.g., [33]), FRP (e.g., [20,34,35]), shape memory alloy (e.g., [36,37]), and active confinement techniques such as post-tensioned metal straps (e.g., [38,39]). In these structures, concrete receives either uniform or non-uniform confinement from its confining mechanism.…”

Behaviour of column constructed with FRP tubes filled with concrete

“…The behaviour of Concrete Filled FRP Tubes (CFFT) have been investigated in the literature for new columns as alternative to CFST and steel RC columns [4], [8][9][10][11][12][13][14]. In this method, FRP tubes are used as formwork to contain the fresh concrete which results in significant cost reduction [5].…”

“…The axial compressive behaviour of CFFT columns have been experimentally investigated over the past two decades [4], [8][9][10][11][12][13][14]. FRP tubes produced by the filament winding method, are reported to deliver strength, ductility and large energy absorption [9,10].…”