| In this study, the feasibility of utilizing the spin casting technique with structural Fibre-Reinforced Polymer (FRP) tubes and eliminating steel reinforcement is explored for the first time. This would make spun-cast FRP tubes (SCFTs) desirable in pole applications, as they are relatively light-weight, protected from deicing salts and other elements by the tube, and have similar flexural resistance to the completely filled FRP tubes (CFFTs).; This study evaluates the flexural and bond performances of SCFTs through experimental and analytical investigations. The experimental investigation included a total of nine beam specimens, approximately 330 mm in diameter and 2.85 m in length, tested in three and four-point bending. Glass-FRP (GFRP) tubes with different wall thicknesses and proportions of fibres in the longitudinal and hoop directions were used in eight specimens. One control specimen was cut from a conventional prestressed spun-cast pole and tested for comparison. Also, one specimen was essentially a control CFFT. The main parameters studied were tube laminate structure, concrete wall thickness, and the effect of additional steel rebar in SCFTs. The experimental investigation also included six push-off stub specimens tested to examine the bond behaviour of SCFTs. An analytical model predicting the flexural response of SCFT beams was developed, verified, and used in a parametric study to examine a wider range of tube laminate structures, concrete wall thicknesses and FRP tube thicknesses.; The study demonstrated the feasibility of fabrication of SCFTs in conventional precast plants. SCFTs were shown to have similar flexural strength to conventional prestressed spun-cast poles of an equivalent reinforcement index but are less stiff due to the lower modulus of FRP and lack of prestressing. SCFTs with inner-to-outer diameter ratio (Di/Do) up to about 0.6 achieved the same flexural strength as the CFFT specimen. However, the parametric study showed that this optimum (Di/Do) ratio is dependent on tube thickness and laminate structure and is generally smaller in thicker tubes or tubes stiffer in the longitudinal direction. |
