局部损伤GFRP管混凝土柱轴压力学行为与计算模型

Axial Compressive Mechanical Behavior and Computational Model of Concrete-Filled GFRP Tube Columns with Local Damage

摘要:

为探明玻璃纤维增强塑料（GFRP）管局部损伤对GFRP管混凝土（CFFT）柱轴压力学行为的影响及其计算模型，考虑直线型损伤的角度、长度及损伤形状等因素，设计了9种共26根不同损伤形态的CFFT柱。通过轴压试验，观测了试件的破坏形态，测试了其极限承载力及荷载-应变曲线，分析了各因素对CFFT柱轴压力学行为的影响，并建立了相应的承载力计算模型。结果表明：沿纤维缠绕方向的局部损伤对CFFT柱轴压力学行为影响最为显著，轴向损伤次之，环向损伤影响不明显；随着纤维缠绕方向损伤长度的增加，CFFT的轴压刚度和极限承载力显著下降，当损伤长度超过30 mm后，承载力下降速率减缓；在直线型、横向V型和正方形3类损伤形状中，正方形损伤试件的承载力下降幅度最大，接近30%，且损伤形状面积越大，承载力下降越明显。基于现有模型，建立了适用于局部损伤CFFT柱的轴压强度预测模型。

Abstract:

To investigate the influence of local damage in outer tubes on the axial compressive behavior and analytical model of concrete-filled glass fiber reinforced polymer（GFRP） tube（CFFT） columns， nine types of CFFT columns with twenty-six specimens exhibiting various damage patterns were designed. The effects of damage orientation， length， and shape of linear-type defects were considered. Axial compression tests were conducted to observe the failure modes， determine the ultimate bearing capacities， and record the load-strain curves. The effects of each parameter on the axial compressive behavior of CFFT columns were analyzed， and a bearing-capacity prediction model was developed. The results indicate that local damage along the fiber winding direction has a pronounced effect on the axial compressive behavior of CFFT columns， while axial damage exerts a moderate influence and circumferential damage shows little effect. An increase in the damage length along the fiber winding direction causes a significant reduction in both axial stiffness and ultimate bearing capacity； when the damage length exceeds 30 mm， the rate of strength reduction becomes slower. Among the three types of damage shapes—linear， transverse V-shaped， and square-shaped， square-shaped specimens exhibit the greatest loss of capacity， reaching nearly 30%. A larger damaged area results in a more noticeable decrease in bearing capacity. Based on existing models， an axial compressive strength model for locally damaged CFFT column is established.