马高1,2,3,陈晓煌1.BFRP约束损伤混凝土轴压试验与应力-应变关系[J].湖南大学学报:自然科学版,2020,(1):36~44
BFRP约束损伤混凝土轴压试验与应力-应变关系
Axial Compression Test and Stress-strain Relationshipof BFRP-confined Predamaged Concrete
  
DOI:
中文关键词:  FRP约束  初始损伤  强度模型  极限应变模型  应力-应变关系模型
英文关键词:FRP-confinement  predamage  strength model  ultimate strain model  stress-strain model
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作者单位
马高1,2,3,陈晓煌1 (1. 湖南大学 土木工程学院湖南 长沙 410082 2. 工程结构损伤诊断湖南省重点实验室(湖南大学)湖南 长沙 410082 3. 桥梁结构安全控制湖南省工程实验室(长沙理工大学)湖南 长沙410076) 
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中文摘要:
      为研究BFRP(玄武岩纤维增强复合材料)层数、初始损伤对FRP约束混凝土轴压力学性能的影响,对14个素混凝土圆柱体进行轴压预加载,考虑3种初始损伤等级,随后采用3种BFRP层数包裹加固并再次进行轴压试验. 试验发现BFRP约束损伤混凝土的极限强度、极限应变分别为未约束混凝土的1.18~1.81倍和5.94~10.55倍;但与BFRP约束完好混凝土比较,其极限强度和初始弹性模量分别下降了7%~15%和38%~55%,极限应变则无明显差别. 损伤混凝土经BFRP约束后其抗压强度和变形能力仍得到了改善,但损伤会降低BFRP约束混凝土的强度和初始弹性模量,且降低程度随损伤的增大而更明显. 直接套用现有的FRP约束完好混凝土力学模型对损伤结构进行加固设计,会偏于不安全. 基于试验结果和收集的文献数据,提出了可以考虑初始损伤影响的BFRP约束混凝土的强度模型、初始弹性模量模型和应力-应变关系模型,模型预测结果与试验结果吻合良好.
英文摘要:
      To investigate the effects of basalt fiber-reinforced polymer (BFRP) layers and predamage levels on the axial compression behavior of BFRP-confined concrete,fourteen plain concrete cylinders were pre-loaded under axial compression loading. Three predamaged levels were considered. The predamaged cylinders were wrapped with three different BFRP layers and subjected to axial compression loading again. It is found that the ultimate strength and ultimate strain of the BFRP-confined predamaged concrete were 1.18~1.81 times and 5.94~10.55 times of those of the unconfined concrete,respectively. However,compared with the BFRP-confined undamaged concrete,the ultimate strength and initial elastic modulus of the BFRP-confined predamaged concrete were reduced by 7%~15% and 38%~55%,respectively,while the ultimate strain had little difference. The test results showed that the compression strength and deformation capacities of the damaged concrete exhibited good repair effect after BFRP confinement. However,the strength and initial elastic modulus of the BFRP-confined concrete tended to decrease with an increase of predamage level. Therefore,it will be unsafe to apply the existing mechanical model of FRP-confined undamaged concrete to the retrofit design of damaged structures. Based on the experimental results and collected literature data,a strength model,initial elastic modulus model and stress-strain relationship model of BFRP-confined concrete were proposed with considering the effect of predamage levels. The proposed models showed a good agreement with the experimental results.
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