5组不同合成纤维加固混凝土柱的轴压性能研究

Study on axial compressive behavior of concrete columns strengthened with synthetic fibers

共设计了5组纤维加固混凝土柱试件,研究了无纤维加固、玻璃纤维加固(GFRP)、碳纤维加固(CFRP)和碳纤维+玻璃纤维加固(JFRP、NFRP)混凝土柱的破坏形貌和轴压性能。结果表明,经过碳纤维、玻璃纤维和合成纤维加固处理后,混凝土柱的峰值应力、最大拉应变和纵向最大压应变都出现不同程度增大;合成纤维加固混凝土柱的峰值应力相较无加固试件明显增大,且合成纤维加固试件的最大拉应变和纵向最大压应变明显高于其他试件。由于纤维加固后,纤维可以对混凝土起到环向约束作用而增加钢筋应变,且合成纤维和碳纤维对混凝土柱的约束作用相近,而玻璃纤维对混凝土的约束作用相对较弱。纤维布加固混凝土柱有助于提升混凝土柱的环向约束,且混凝土柱的横向变形受到明显抑制,纤维对混凝土柱的纵向约束效果从高至低顺序依次为:JFRP、NFRP、GFRP、CFRP,且都高于未加固混凝土柱。

Five groups of fiber reinforced concrete column specimens were designed to study the failure morphology and axial compression performance of concrete columns strengthened with non fiber,glass fiber(GFRP),carbon fiber(CFRP)and carbon fiber&glass fiber(JFRP、NFRP).The results show that the peak stress,the maximum tensile strain and the maximum longitudinal compressive strain of concrete columns increase in varying degrees after carbon fiber,glass fiber and synthetic fiber reinforcement;the peak stress of concrete columns strengthened with synthetic fiber is significantly higher than that of the specimens without reinforcement,and the maximum tensile strain and the maximum longitudinal compressive strain of the specimens strengthened with synthetic fiber are significantly higher than those of other specimens.After the fiber reinforcement,the fiber can play a hoop restraining role on the concrete and increase the steel strain,and the restraining effect of synthetic fiber and carbon fiber on the concrete column is similar,while the restraining effect of glass fiber on the concrete is relatively weak.Strengthening concrete columns with fiber sheets helps to improve the circumferential restraint of concrete columns,and the lateral deformation of concrete columns is significantly restrained.The longitudinal restraint effect of fiber on concrete columns is in the order of JFRP>NFRP>GFRP>CFRP,which is higher than that of unreinforced concrete columns.