损伤程度对碳纤维布加固混凝土框架结构抗震性能影响的研究
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摘要
目前,基于灾后损伤混凝土结构需要加固及损伤程度对加固后结构影响程度的研究尚属空白,按1/3缩尺模型,设计制作了钢筋混凝土框架试件。分别对3榀框架施加水平低周反复荷载,使其处于不同损伤状态(截面开裂、钢筋屈服),保持竖向荷载不变,对其进行碳纤维布加固,再对加固框架进行同样试验至破坏。基于试验结果,分析了损伤程度对加固框架开裂荷载、极限荷载、位移延性、裂缝宽度及碳纤维布应变滞后的影响;比较了碳纤维布加固不同损伤混凝土框架的抗震性能。结果表明,随着损伤程度的增加,碳纤维布加固后框架的最大裂缝宽度越大、碳纤维布应变滞后也越大;当损伤程度达到严重时,加固后的结构延性减小。总体上,碳纤维布加固的不同损伤钢筋混凝土框架均具有良好的抗震性能,为大震后损伤混凝土框架加固提供理论依据。
Based on present situation that the damaged RC frames need be strengthened after earthquake and the study of damaged degree effect on strengthen RC frame is less,the RC frame models with the scale 1/3 were designed and produced.Low-cyclic and repeated load was imposed on the three RC frame models,so that they were in different degrees of injury.Then,they were strengthened by CFRP in conditions of vertical-load holding,Last,the same experiments of the strengthened frames were done again,until the frame was failure.Based on the test data,the effects of damaged degree on cracking load,limit load,ductility,crack width and CFRP strain delay of strengthen frames were analyzed.The seismic properties of the different damaged RC frames strengthened by CFRP were compared.The results show that the longer the damaged degree,the widther the cracks and the more the CFRP strain delay.The ductility is less when the damaged degree of strengthened structure is critical.As a whole,the different damaged RC frames strengthened by CFRP have good seismic properties and performance.The theory basis was provided for strengthened RC frame after rare earthquake.
Based on present situation that the damaged RC frames need be strengthened after earthquake and the study of damaged degree effect on strengthen RC frame is less,the RC frame models with the scale 1/3 were designed and produced.Low-cyclic and repeated load was imposed on the three RC frame models,so that they were in different degrees of injury.Then,they were strengthened by CFRP in conditions of vertical-load holding,Last,the same experiments of the strengthened frames were done again,until the frame was failure.Based on the test data,the effects of damaged degree on cracking load,limit load,ductility,crack width and CFRP strain delay of strengthen frames were analyzed.The seismic properties of the different damaged RC frames strengthened by CFRP were compared.The results show that the longer the damaged degree,the widther the cracks and the more the CFRP strain delay.The ductility is less when the damaged degree of strengthened structure is critical.As a whole,the different damaged RC frames strengthened by CFRP have good seismic properties and performance.The theory basis was provided for strengthened RC frame after rare earthquake.
引文
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[2]JIANCHUN LI,BIJAN SAMALI,LIN YE,et al.Behaviour of concrete beam-column connections reinforcedwith hybrid FRP sheet[J].Composite Structures,2002,57(6):357-365.
[3]李贵炳,张爱晖,金伟良.钢筋混凝土梁加固时的既有荷载对其抗弯性能的影响[J].土木工程学报,2006,39(1):13-20.
[4]许成祥,李忠献,蔡卫东.考虑二次受力碳纤维布加固短柱的抗震试验[J].武汉理工大学学报,2002,24(7):27-30.
[5]BALSAMO A,COLOMBO A,MANFREDI G.Seismic behaviorof a full-scale RC frame repaired using CFRP laminates[J].Engineering Structures,2005,27(5):769-780.
[6]熊耀清,姚谦峰.CFRP加固RC框架结构振动台试验及损伤机理分析[J].北京交通大学学报,2006,30(1):25-29.
[7]王新玲,朱俊涛,吕林.碳纤维布加固完好混凝土框架结构抗震性能试验研究[J].郑州大学学报:工学版,2008,29(4):81-85.
[8]王亚勇,王言珂.汶川大地震建筑震害启示[J].建筑结构,2008,38(7):1-6.
[9]JGJ101—96建筑抗震试验方法规程[S].北京:中国建筑工业出版社,1997.
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