纤维布约束超高性能混凝土短柱轴压性能

Study on axial compression performance research on UHPC short columns confined by fiber reinforced polymer

基于18根纤维布约束混凝土短柱试验,以纤维布类型、约束纤维布层数和核心混凝土种类作为试验变量。从破坏形态、极限强度提高率、约束比、应变硬化FRP层数阈值进行分析。试验结果表明:超高性能混凝土在纤维布约束下破坏为延性破坏,且完整性良好;碳纤维布比玻璃纤维布能更好地提高超高性能混凝土短柱的极限强度;约束比随着纤维布层数增加而增大,碳纤维布的约束比大于玻璃纤维布;随着核心混凝土强度的提高,出现应变硬化现象所需要的最小约束比随之增大,表现为需要纤维布层数阈值越来越大;极限强度比rσ及极限应变与核心混凝土强度呈负相关,且都随着纤维布层数的增加而增大。

Based on the experimental study of 18 fiber reinforced polymer(FRP) confined concrete short columns, type of FRP, FRP layers and the types of core concrete were taken as experimental variables. The failure modes, ultimate strength increased rate, confinement ratio, the strain hardening FRP layers threshold analysis results were analyzed. Experimental results show that: FRP confined ultra-high performance concrete(UHPC) short columns feature ductile failure and have good integrity when it is destroyed;the UHPC short columns is better strengthened by carbon fiber reinforced polymer(CFRP) than by glass fiber reinforced polymer(GFRP);the confinement ratio increases with the number of layers of FRP, and the confinement ratio of CFRP is higher than GFRP;with the increase of the strength of core concrete, the minimum confinement ratio required increases for appearing strain hardening, which is reflected by the increase of the strain hardening FRP layers threshold;the ultimate strength ratio(rσ) and ultimate strain of FRP confined concrete short column are negatively correlated with the strength of core concrete and increase with the number of layers of FRP.