长期轴压下有初应力的CFRP约束混凝土柱应力-应变关系分析  

Analysis on the stress-strain relationship of CFRP confined concrete with initial stress under long-term sustained load

作　　者：潘毅[1,2] 吴晓飞[1] 曹双寅[3] 万里[1] 

机构地区：[1]西南交通大学,四川成都610031 [2]西南交通大学交通隧道工程教育部重点实验室,四川成都610031 [3]东南大学,江苏南京210096

出　　处：《土木工程学报》2016年第9期9-19,共11页China Civil Engineering Journal

基　　金：国家自然科学基金(51108389);国家留学基金(20123022)

摘　　要：为了研究有初应力的CFRP约束混凝土柱在长期荷载作用下的应力-应变关系,对有不同初应力的12个CFRP约束混凝土柱进行了三种模式的长期荷载试验,观测了初应力和长期荷载对CFRP约束柱的长期变形、峰值点应力、应变及应力-应变曲线特征的影响。试验结果表明,在长期荷载作用下,包裹CFRP后的构件比未包裹的长期变形小,并随初应力水平的提高,构件的长期变形增大;长期荷载对峰值点应力、应变的影响随初应力水平的提高而增大,在初应力水平较高时有减小的趋势;与短期荷载相比,长期荷载作用后的应力-应变曲线特征没有发生明显变化。在此基础上,选取ACI 209-92模型和Findley模型分别作为混凝土和CFRP的徐变模型,提出了CFRP约束混凝土柱长期变形的计算方法,并针对三种加载模式,分别建立了长期荷载下CFRP约束混凝土柱的应力-应变关系计算模型,结果表明模型的计算曲线与试验曲线吻合较好。To study the stress-strain relationship of CFRP confined concrete with initial stress under the sustained load, a total of twelve columns with different initial stress level were tested under three types of the sustained load modes. The influence of initial stress and sustained load on the long-term deformation, the peaks of the strain and the stress of concrete, and the stress-strain relationship of CFPP confined concrete columns were observed. The experimental results show that the axial strain of CFRP confined concrete is smaller than that of unconfined ones, and the axial strain rises with the increase of initial stress level. The peaks of stress and strain of concrete are affected by the sustained load and the initial stress. Meanwhile, the peaks of the stress and strain of concrete decrease with the initial stress level. The characteristic of stress-strain curve under the long-term loading is similar with that under short-term loading. A method to calculate the long-term deformation of the CFPR confined concrete column is proposed. In this method, ACI 209-92 model and Findley model are adopted to simulate the creep of concrete and CFRP, respectively. Moreover, a model for stress-strain curve of CFRP confined concrete column is presented, considering initial stress level and long-term sustained load mode. The results show that the numerical curve agrees well with the experimental curve.

关 键 词：CFRP 约束混凝土柱 长期荷载 初应力 徐变 应力-应变关系 

分 类 号：TU375.3[建筑科学—结构工程]