FRP加固钢筋混凝土柱经历模拟地震作用后的长期性能试验与分析

Experimental Studies Long-term Behavior of FRP Retrofitted RC Columns with Earthquake Loading Damage

FRP加固钢筋混凝土柱在经历地震荷载作用后的残余性能,对于已建桥梁的加固具有重要意义,而这方面的研究基本上处于空白.此试验制作了8根大比例的钢筋混凝土桥柱模型,采用GFRP和CFRP两种材料对试验柱进行了加固,在轴压比为0.2的恒定轴压力下进行拟静力试验,外包FRP加固层的材料类型和水平延性率是试验的主要参数.5根试验柱在经历有限的地震作用后进行长期轴压试验.受损伤试验柱的长期荷载试验表明:FRP加固柱的徐变变形远小于对比柱的徐变变形;带损伤的加固柱在长期荷载作用下的变形发展与加固柱的损伤程度和FRP的弹性模量密切相关;变形量与损伤程度和加固材料的弹性模量有关,并与持荷大小有关.在试验条件下,带损伤的加固柱长期轴向变形呈稳定态势,并可以用修正现有混凝土徐变计算公式推算.

Despite the significant importance, long-term seismic behavior of reinforced concrete （RC） columns retrofitted with fiber-reinforced plastic （FRP） has received little attention. In this paper, the residual performance of FRP retrofitted columns damaged after simulated seismic loading is studied. Eight model columns with a shear aspect ratio of 5.0 were tested first under cyclic lateral force and a constant load equal to 20% of the column gross axial load capacity. The main parameters considered were the type of FRP jacket and peak drift ratio where the lateral loading was interrupted. Glass-fiber-reinforced plastic （GFRP） and Carbon-fiber-reinforced plastic （CFRP） were both used for retrofitting. Five of the model columns were subjected to long-term axial loading after subjected to limited damage by lateral cyclic loading. The deformation of retrofitted columns under long-term axial loading depended on the previous damage intensity and the modulus of FRP. Under the testing condition of this study, the long-term axial deformation of retrofitted column tends to be stable, despite subjected simulated earthquake damage.