HFRP管约束超高性能混凝土的本构模型

Constitutive Model for Ultrahigh-performance Concrete Confined by Hybrid Fiber-reinforced Polymer Tubes

为了研究混杂纤维增强聚合物(hybrid fiber reinforced polymer,HFRP)约束超高性能混凝土(ultra-high performance concrete,UHPC)圆柱体的轴压特性,通过36个圆柱体轴压试验,测定了应力-应变全曲线.试验结果表明:已有的几个有代表性的强度和极限应变预测模型并不适用于HFRP管约束UHPC,因此,考虑了纤维混杂种类对约束效率的影响,提出了新的强度与极限应变的公式,其预测精度较高;已有几个代表性的应力-应变本构模型预测曲线比实测曲线偏低,提出了双线性的本构模型,理论曲线和试验曲线吻合良好,模型表达式简单,便于设计人员使用.

Fiber reinforced polymer(FRP) feature has obvious brittle,while the hybrid fiber reinforced polymer(HFRP) with low brittleness,has multiple fracture characteristics.To research the axial compression behaviors of ultrahigh-performance concrete(UHPC) confined by HFRP,thirty-six HFRPconfined UHPC cylindrical specimens were tested and the stress-strain curves were measured.The experiment shows none of the existing representative models provided a reasonable prediction for strength and strain of HFRP-confined UHPC specimen,therefore a new ultimate strength and strain perdition model considering the confinement effectiveness of different hybrid FRP series was proposed.The new proposed model presented the best fitting results.The stress-strain response predicted by the existing representative models are all below the experimental curves,therefore a new two-stage constitutive model was proposed,which relatively fits the test curves better than that of the existing models.The new proposed model form is simple for engineers to use.