基于混凝土三轴破坏准则下FRP约束矩形柱的应力—应变模型

A model on stress-strain of rectangular column confined by FRP based on concrete failure rule under three axial compressions

FRP约束矩形截面混凝土柱体在轴心荷载作用下可近似看作为真三轴受压状态,随着侧向应力比的不同,约束效果也不同。根据矩形截面的长宽比、拐角处的圆角半径、外包FRP相关参数来确定侧向约束应力比和大小,基于混凝土的三轴受压试验破坏准则计算极限抗压强度。对FRP约束矩形截面柱峰值应力点处的峰值应变,根据国内外试验数据进行回归分析。给出FRP约束下无下降段曲线的应力—应变计算新模型,与相关试验数据结果进行比较,吻合较好。最后,对FRP约束矩形断面的长宽比、拐角半径的大小以及FRP的包裹层数的影响权重进行比较。

Rectangular section concrete column confined by FRP can be nearly regarded as real three axial state of compressing under axial loading. The confinement effect of FRP to concrete changes with lateral ratio of confining stress. The confining stress and its ratio are defined according to ratio of length and width, radius of corner of section, related parameters about FRP, and the axial compressing capacity of concrete in term of failure tale. The strain model of point of maximum stress is presented by regression on many experimental data. A new model of stress-strain curve on confined concrete column without descending part is put forward and has a good agreement with data, and the above influencing parameters＇ importance is compared.