纤维缠绕GFRP管约束混凝土的轴压性能与设计模型

Axial compressive performance and design model of fiber wound GFRP tube confined concrete

设计制作了18组54个纤维缠绕玻璃纤维增强复合材料(GFRP)管约束混凝土圆柱试件,参数包括纤维层数(6、10)、纤维角度(±45°、±60°、±80°)、长细比(2、4)和受压截面(全截面、核心混凝土),基于轴心受压试验结果,提出了依据纤维角度的面向设计的峰值应力预测模型。研究结果表明:GFRP管可有效提高约束试件的强度和延性。试件的峰值强度随着纤维角度和层数的增大而增大,长细比大的试件峰值强度的提升幅度更大,全截面受压会对约束试件的环向性能造成不利的影响。约束模式主要由纤维角度决定,其中±60°和±80°角度的试件为强约束,呈脆性破坏,±45°角度的试件为弱约束,呈延性破坏。通过研究峰值强度与有效约束强度之间的数学关系,所得到的面向设计的简化模型,对于求解不同纤维角度试件的峰值强度具有足够的精度,可为相关的工程实际应用提供参考。

54 fiber-wound glass fiber reinforced polymer(GFRP)tube confined concrete cylindrical specimens classified in eighteen groups were designed and manufactured,and the parameters included the number of fiber layers(6,10),fiber angle(±45°、±60°、±80°)slenderness ratio(2,4)and compression section(full section,core concrete).Based on the axial compression test results,a design-oriented peak stress prediction model in terms of fiber angle was proposed.The results show that GFRP tube can effectively improve the strength and ductility of confined specimens.The peak strength of the specimen increases with the increase of fiber angle and layer number,and the increase of the peak strength of the specimen with large slenderness ratio is larger.The full section compression will adversely affect the circumferential properties of the confined specimen.The confined pattern is mainly determined by the fiber angle.The specimens with±60°and±80°angles are strong confinement,and reveal brittle failure mode.The specimens with±45°angle are weak confinement,and reveal ductile failure mode.By studying the mathematical relationship between the peak strength and the effective confinement strength,the simplified design-oriented model was derived,which has sufficient precision for solving the peak strength of specimens with different fiber angles,and can provide reference for relevant engineering applications.