±60°缠绕的纤维复材管约束混凝土短柱轴压试验研究

EXPERIMENTAL RESEARCH ON CONCRETE-FILLED FRP TUBES SHORT COLUMNS WITH ± 60° FIBER ORIENTATION

目前对于纤维复材(FRP)管约束混凝土的研究主要集中于FRP管纤维缠绕角为±90°或接近±90°的情况,对于其他纤维缠绕角研究较少。通过对18个纤维缠绕角为±60°的FRP管约束混凝土短柱在单调荷载下的轴压试验,对FRP管约束混凝土短柱的破坏形态、应力-应变曲线和承载力进行了研究,分析了FRP管厚度、混凝土强度的影响。同时进行了6个纤维缠绕角为±80°(纤维缠绕方向接近环向即±90°)的FRP管约束混凝土短柱在单调荷载下的轴压试验,以对比研究±80°纤维缠绕角和±60°纤维缠绕角的影响。试验研究结果表明:FRP管约束混凝土短柱的破坏形态与FRP管纤维缠绕角有关;FRP管纤维缠绕角、FRP管厚度和混凝土强度是影响FRP管约束混凝土抗压强度的重要因素;FRP管约束混凝土的极限应变主要与混凝土强度等级有关,且极限应变随着FRP管厚度的增加而增大。

Existing studies of concrete-filled FRP tubes（CFFTs） are mainly focus on FRP tubes with fibers oriented in the hoop direction or close to the hoop direction,the fiber orientation to the longitudinal direction is ± 90° or close to ± 90°.The research on CFFTs with other fiber angles is limited.The paper conducted an axial compression test of 18 CFFTs constructed with FRP tubes which had ± 60° fiber orientation angle,to study their failure mode,stressstrain behavior and bearing capacity,and to investigate the effects of FRP tube thickness and concrete strength.6 CFFTs constructed with FRP tubes which had ± 80° fiber orientation angle were also tested under axial compression to study the effects of fiber orientation angle.Experimental results indicated that,the failure mode of CFFTs was related with the fiber orientation angle.Fiber orientation angle,FRP tube thickness and concrete strength had significant effects on the bearing capaciy of CFFTs; the ultimate strain of CFFTs decreased with the increase of concrete strength and increased with the increase of FRP tube thickness.