碳纤维布加固混凝土框架受力性能
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摘要
为了避免纤维布拉断、剥离等提前破坏模式,提出了铝角钢/FRP加固框架结构梁、柱端部的新型加固方法.介绍了两跨两层框架试件的几何、配筋、加固过程和试验方法.通过比较分析,选择合适的应力-应变模型以模拟FRP对混凝土的约束效应,截面的弯矩-曲率关系近似地采用带软化段的四折线型,对加固后的框架进行非线性分析,与试验结果作了对比.最后,研究了混凝土约束效应、加固长度、合理选择待加固杆件对加固框架受力性能的影响.数值分析结果与试验结果吻合良好,FRP产生的约束效应对框架受力有较大影响,适当选择加固长度和加固量,可以实现塑性铰或破坏面位置的转移,特别加强薄弱的杆件,可以取得显著的加固效果.
To avoid the premature failure modes,such as peeling and rapture of laminates,a new strengthening method using aluminum angle and CFRP(carbon fiber reinforced polymer)sheets systems is proposed,which can strengthen the ends of beams and columns of RC frames.Firstly,the reinforcement,aluminum angle and CFRP sheets details of two spans,two levels RC frame specimen and the test setup are introduced.Secondly,a stress-strain model fitting to FRP-confined concrete is selected.The moment-curvature relationships are simplified into quadrilinear form with curvature-softening behaviour,and nonlinear static analysis is carried out to examine the behaviour of the frame specimen.Lastly,the effects of confined concrete,selecting length and members to reinforce on the behaviour of the strengthened frames are studied.The numerical results agree well with the test results and show that the effect of confined concrete on the performance of the strengthened frames shouldn't be ignored,the position of plastic hinges and failure sections could be shifted from the ends of beams or columns by proper selection of strengthening length and content of FRP sheets,and rational selection of strengthening members could notably improve the performance of strengthened frames.
To avoid the premature failure modes,such as peeling and rapture of laminates,a new strengthening method using aluminum angle and CFRP(carbon fiber reinforced polymer)sheets systems is proposed,which can strengthen the ends of beams and columns of RC frames.Firstly,the reinforcement,aluminum angle and CFRP sheets details of two spans,two levels RC frame specimen and the test setup are introduced.Secondly,a stress-strain model fitting to FRP-confined concrete is selected.The moment-curvature relationships are simplified into quadrilinear form with curvature-softening behaviour,and nonlinear static analysis is carried out to examine the behaviour of the frame specimen.Lastly,the effects of confined concrete,selecting length and members to reinforce on the behaviour of the strengthened frames are studied.The numerical results agree well with the test results and show that the effect of confined concrete on the performance of the strengthened frames shouldn't be ignored,the position of plastic hinges and failure sections could be shifted from the ends of beams or columns by proper selection of strengthening length and content of FRP sheets,and rational selection of strengthening members could notably improve the performance of strengthened frames.
引文
[1]Parvin A,G ranata P.Use of FRP overlays at beam-col-umn connections[C]//Proceedings of the Second Interna-tional Conference on Composites in Infrastructure.Tucson,AZ,1998,1:213-20.
[2]Balsamo A,Colombo A,M anfred i G,et al.Se ism ic be-havior of a fu ll-scale RC fram e repaired using CFRP lam i-nates[J].Engineering Structures,2005,27(5):769-780.
[3]王步,夏春红,王溥.碳纤维布加固混凝土框架抗震性能试验研究[J].施工技术,2004,33(6):6-15.W ang Bu,X ia Chunhong,W ang Pu.Experim ent studyon se ism ic behaviour of RC fram es strengthened by CFRPsheets[J].Construction Technolog,y 2004,33(6):6-15.(in Ch inese)
[4]江卫国,陈忠范,程文瀼.CFRP布加固框架梁柱端部受弯承载力的试验研究[J].特种结构,2006,2(23):91-94.JiangW e iguo,Chen Zhongfan,Cheng W enrang.Experi-m ental study on bent capac ity of beam-column connectionstrengthened w ith CFRPs[J].Special Structures,2006,2(23):91-94.(in Ch inese)
[5]M iyauch i K,Shahawy M.Behavior of concrete columnsconfined by fiber composites[J].Journal of StructuralEngineering ASCE,1997,123(5):583-590.
[6]吴刚,吕志涛.纤维增强复合材料(FRP)约束混凝土矩形柱应力-应变关系的研究[J].建筑结构学报,2004,25(3):99-106.W u Gang,LüZh itao.Study on the stress-strain relation-sh ip of FRP-confined concrete rectangu lar columns[J].Journal ofBuilding Structures,2004,25(3):99-106.(in Ch inese)
[7]HarajliM H.Behavior of gravity load-designed rectangu-lar concrete columns confined w ith fiber re inforced poly-m er sheets[J].Journal of Composites for Construction,2005,9(1):4-14.
[8]过镇海,张秀琴,翁义军.箍筋约束混凝土的强度与变形[C]//城乡建设部抗震办公室,等.唐山地震十周年中国抗震防灾论文集.北京,1986:143-150.
[9]W u Y F,Oehlers D J,G riffith M C.Rational defin itionof the flexural deform ation capac ity ofRC column sections[J].Engineering Structures,2004,26(5):641-650.
[10]清华大学抗震工程研究室.钢筋混凝土结构的抗震性能[M].北京:清华大学出版社,1981.
[11]L ivesley R K.Matrix m ethods of structural analysis[M].2nd ed.New York:Pergamon Press,1975.
[2]Balsamo A,Colombo A,M anfred i G,et al.Se ism ic be-havior of a fu ll-scale RC fram e repaired using CFRP lam i-nates[J].Engineering Structures,2005,27(5):769-780.
[3]王步,夏春红,王溥.碳纤维布加固混凝土框架抗震性能试验研究[J].施工技术,2004,33(6):6-15.W ang Bu,X ia Chunhong,W ang Pu.Experim ent studyon se ism ic behaviour of RC fram es strengthened by CFRPsheets[J].Construction Technolog,y 2004,33(6):6-15.(in Ch inese)
[4]江卫国,陈忠范,程文瀼.CFRP布加固框架梁柱端部受弯承载力的试验研究[J].特种结构,2006,2(23):91-94.JiangW e iguo,Chen Zhongfan,Cheng W enrang.Experi-m ental study on bent capac ity of beam-column connectionstrengthened w ith CFRPs[J].Special Structures,2006,2(23):91-94.(in Ch inese)
[5]M iyauch i K,Shahawy M.Behavior of concrete columnsconfined by fiber composites[J].Journal of StructuralEngineering ASCE,1997,123(5):583-590.
[6]吴刚,吕志涛.纤维增强复合材料(FRP)约束混凝土矩形柱应力-应变关系的研究[J].建筑结构学报,2004,25(3):99-106.W u Gang,LüZh itao.Study on the stress-strain relation-sh ip of FRP-confined concrete rectangu lar columns[J].Journal ofBuilding Structures,2004,25(3):99-106.(in Ch inese)
[7]HarajliM H.Behavior of gravity load-designed rectangu-lar concrete columns confined w ith fiber re inforced poly-m er sheets[J].Journal of Composites for Construction,2005,9(1):4-14.
[8]过镇海,张秀琴,翁义军.箍筋约束混凝土的强度与变形[C]//城乡建设部抗震办公室,等.唐山地震十周年中国抗震防灾论文集.北京,1986:143-150.
[9]W u Y F,Oehlers D J,G riffith M C.Rational defin itionof the flexural deform ation capac ity ofRC column sections[J].Engineering Structures,2004,26(5):641-650.
[10]清华大学抗震工程研究室.钢筋混凝土结构的抗震性能[M].北京:清华大学出版社,1981.
[11]L ivesley R K.Matrix m ethods of structural analysis[M].2nd ed.New York:Pergamon Press,1975.
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