CFRP片材约束混凝土短柱徐变性能及极限承载力试验

Experiment on Creep Behaviors and Ultimate Bearing Capacity of Short Concrete Columns Confined with CFRP Laminates

通过不同形式轴压短柱试件727d徐变及极限承载力试验，研究长期持续荷载下徐变对CFRP约束混凝土柱极限承载力的影响。研究结果表明：CFRP约束混凝土柱的徐变发展趋势与素混凝土柱及钢筋混凝土柱基本相同；其徐变系数明显小于素混凝土柱，且混凝土强度等级愈低，徐变系数减小愈显著，而轴压比对徐变系数的影响较小，CFRP约束圆柱体的极限应变较CFRP约束棱柱体的极限应变大；长期荷载作用引起CFRP约束柱轴心受压极限变形降低4．5％～4．8％，引起无约束柱轴心受压柱极限变形降低23．2％～35．2％；CFRP能显著提高约束混凝土的极限承载力，且CFRP约束钢筋混凝土柱承载力的提高较CFRP约束素混凝土柱要小。

Through ultimate bearing capacity and creep property tests of all types of short columns after 727 days axial pressure sustained load, the effects of sustained load on the ultimate bearing capacity were researched. Test results indicatethat the creep development trend of CFRP-confined concrete column is basically the same as that of plain concrete columns and reinforced concrete columns, and the creep coefficient is evidently smaller than that of plain concrete columns. The lower is the concrete intensity, the creep coefficient will be decreased remarkably. However, the axial pressure ratio has smaller effect upon creep coefficient. The ultimate strain of CFRP-confined circular column is larger than that of CFRP-confined prismy column. Sustained load will result in reducing axial pressure ultimate distortion of CFRP-confined columns for 4.5%-4.8%, non-confined columns for 23.2%-35.2%. The ultimate bearing capacity of columns confined with CFRP laminates has increased observably, and the increasing range of CFRP-confined reinforced concrete columns will be less than that of CFRP-confined plain concrete columns.