方形螺旋箍筋GFRP筋混凝土柱轴压性能研究

AXIAL COMPRESSIVE PROPERTIES OF GFRP REINFORCED CONCRETE COLUMNS WITH SQUARE SPIRAL STIRRUPS

通过设计5根配置螺旋箍筋和3根配置普通箍筋方形截面玻璃纤维筋(GFRP)混凝土柱(200 mm×200 mm×600 mm)的轴心受压试验,重点分析方形截面GFRP筋混凝土柱的极限承载力和延性等在不同箍筋形式下的变化规律,研究螺旋箍筋对方形截面GFRP筋混凝土柱的轴压性能的影响。试验结果表明:GFRP纵筋承载力占GFRP筋混凝土柱极限承载力的3%~7%;配置螺旋箍筋的GFRP筋混凝土柱的极限承载力比配置普通箍筋的增加了0.8%~1.6%,延性增加了13%~33%;缩小箍筋间距可以防止纵筋过早屈曲破坏,同时可提高GFRP筋混凝土柱的延性和承载力;把GFRP筋受压承载力设置为其极限抗拉强度的0.35倍,可以准确预测GFRP筋混凝土柱的极限承载力。

Through the axial compression test of five GFRP columns(200 mm×200 mm×600 mm)with spiral stirrups and three GFRP columns(200 mm×200 mm×600 mm)with ordinary stirrups,the change rule of ultimate bearing capacity and ductility of GFRP columns with square sections under different stirrups is analyzed,so as to study the influence of spiral stirrups on the axial compression performance of GFRP columns with square sections.The test results indicate that the load-carrying capacity of longitudinal GFRP bars accounted for 3%~7%of the ultimate load-carrying capacity of the columns.The ultimate load-carrying capacity and ductility of GFRP columns with spiral stirrups increased by 0.8%~1.6%and 13%~33%,respectively,compared to GFRP hoops.Reducing the stirrup spacing may prevent the buckling failure of the longitudinal bars and increase the ductility and load-carrying capacity of the GFRP-RC columns.It has been found that setting the GFRP compressive strength to 35%of the GFRP maximum tensile strength yields a reasonable estimation of ultimate load-carrying capacity of GFRP-RC columns.