HFRP约束混凝土圆柱应力-应变关系

Stress-strain Relationship of HFRP-confined Concrete Circular Columns

试验研究了碳纤维布、芳纶纤维布、玻璃纤维布和玄武岩纤维布层间混杂约束混凝土圆柱体的应力-应变关系.结果表明,混杂纤维增强聚合物(hybrid fiber reinforced polymer,HFRP)可明显提高圆柱体的强度,尤其能显著改善其延性.对试验结果与国内外大量研究成果进行对比分析,建立了HFRP约束混凝土圆柱体的应力-应变曲线模型.该模型使用轴向、横向和体积应变来衡量约束混凝土的内部损伤,以体现HFRP变约束力对被约束混凝土微观损伤的影响,使模型简化且具有明确的物理含义;该模型采用了更能真实体现约束效应的割线模量,并引入了依赖于混凝土本身特性的割线模量软化系数进行计算.与试验曲线的比较表明,该理论模型与试验曲线吻合良好.

Stress-strain relationships of concrete circular columns confined by interlaminated hybrid fiber sheets of carbon fiber, aramid fiber, glass fiber, and basalt fiber are experimentally researched in this paper. Results show that HFRP can evidently increase the strength of circular columns, and significantly improve the ductility. Based on the experimental data and analysis on the research production, a constitutive confinement model is developed for concrete circular columns confined with HFRP. The feature of the model includes the effects of HFRP confinement on the concrete microstructure by evaluating the internal concrete damage using the axial, lateral, and volumetric strains, which introduces that the confinement model is simple and has a physical and fundamental interpretation with the mechanical behavior of concrete. Meantime, the secant concrete modulus is used in the model and expressed as a function of the secant modulus softening coefficient. The HFRP-confined concrete model accurately predicts the stress-strain relationship of concrete circular columns confined with HFRP as verified in comparison with experiments.