BFRP约束损伤混凝土棱柱体轴压力学性能研究

Axial Compression Behavior of Pre⁃damaged Concrete Prisms Confined with BFRP

为研究玄武岩纤维增强复合材料(Basalt Fiber Reinforced Polymer,BFRP)约束有初始损伤的混凝土棱柱体的轴压力学性能,对37个边长150 mm、高300 mm的混凝土棱柱体进行了轴压试验,其中包括34个BFRP约束混凝土试件和3个素混凝土试件,试验变量为BFRP层数(1、2、3、4和6层)和初始损伤程度(轻微、中等和严重损伤),试验结果表明:BFRP约束棱柱体的抗压强度和轴向变形能力随FRP约束层数的增加而提高,特别对变形能力的提高更为明显;初始损伤程度对BFRP约束试件的峰值点以及极限点的强度影响较明显,但对极限应变影响较小;当BFRP层数为2层及以下时,BFRP约束棱柱体的应力—应变曲线有明显软化段,当BFRP层数为4层及以上时,应力—应变曲线开始有明显强化段。基于试验结果,提出了考虑初始损伤影响的BFRP约束混凝土棱柱体的强度模型和应变模型,并分别给出了弱约束和强约束下的应力—应变关系模型,模型预测结果与试验结果吻合良好。

In order to study the axial compression behavior of pre-damaged concrete prisms confined by basalt fiber reinforced polymers(BFRPs),thirty-seven concrete prisms,with a side length of 150 mm and a height of 300 mm,were tested under axial compression,including thirty-four BFRP-con⁃fined specimens and three plain concrete specimens.The test variables were the number of BFRP lay⁃ers(one,two,three,four,and six layers)and the initial damage(slight,moderate and severe dam⁃age).The test results show that the compression strength and axial deformation capacities of the BFRP-confined prisms increase with the increase of FRP layers,in which the improvement of the de⁃formation capacity is more obvious.The initial damage levels have an obvious influence on the peak and ultimate values of strength for BFRP-confined specimens but have little effect on the ultimate strain.When the BFRP layers are two or less,the stress-strain curves of BFRP-confined prisms have a softening section.When the BFRP layers are four or more,the stress-strain curves start to have an obvious strengthening section.Based on the test results,strength and strain models of the BFRP-con⁃fined concrete prisms considering the influences of initial damage were proposed,and the stress-strain relationship models under weak confinement and strong confinement were also presented.The model predicted results are in good agreement with the test results.