长细比对FRP约束混凝土柱承载力的影响

Effect of slenderness ratio on the bearing capacity of FRP-confined concrete columns

随着长细比的增加,FRP约束混凝土柱的承载力和延性有降低的趋势。由于FRP与钢材的性能存在巨大的差异,现有的设计规范不适用于FRP约束混凝土柱承载力的计算。为研究长细比对FRP约束混凝土柱承载力的影响,根据FRP约束混凝土柱的特点,以约束效应系数ξf、FRP管中含纤维复合材料的比率λ和约束效应折减系数kr为主要参数,建立FRP约束混凝土短柱承载力的计算模型。在此基础上,通过对现有试验数据的回归分析,引入FRP约束混凝土柱承载力的稳定系数,提出FRP约束混凝土柱的承载力计算公式,公式计算结果与已有试验数据吻合较好。

The bearing capacity and the ductility of a FRP-confined concrete column decrease with the increase of slenderness ratio. Existing design codes are not applicable to calculation of the bearing capacity of FRP-confined concrete columns because of significant behavior difference between FRP and steel. To study the effect of slenderness ratio on the bearing capacity of FRP-confined concrete columns, the confinement effect coefficient, the gravity ratio of FRP to FRP tube and the reduced coefficient of confinement effect are taken as the main parameters to formulate a model for calculating the bearing capacity of FRP-confined short concrete columns. Based on the proposed model, the stability coefficient of FRP-confined concrete columns is introduced through regression analysis of existing test data, and a calculation formula is proposed for the bearing capacity of FRP-confined concrete columns. The predictions of the formula agree well with the test data.