CFRP加固组合梁承载力性能实验研究
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摘要
对碳纤维复合增强材料(CFRP)条带加固的混凝土-钢组合梁抗弯性能进行实验研究。在考虑CFRP条带加固长度和宽度两个变量的基础上,采用四点加载的方式,研究加固和未加固组合梁在加载过程中的承载力性能。通过分析试件的荷载-位移曲线和其破坏模态,揭示在加固前后混凝土试件的初裂荷载和极限承载力的变化规律,并分析组合梁各类破坏模态的产生机理。实验研究结果表明:采用CFRP条带加固的组合梁承载能力会提高,当CFRP加固长度为试件总长的60%时,承载力的提高效率最高。同时提出一桁架模型,用以分析加固前后组合梁中混凝土板、钢梁腹板以及FRP条带的内力,为该类加固梁的极限荷载预测提供了依据。
This paper presents the works of investigating the structural behaviors of composite beams before and after being strengthened with CFRP strips at the tension soffit. Seven samples were examined by the four-point bending loading tests. Among the seven samples,one was un-strengthened and the remaining six were strengthened by bonding CFRP strips of different numbers,width and length,respectively. All samples were tested beyond their ultimate failure. By recording the load-deflection data for the entire history,the first crack load,the CFRP debonding load or concrete longitudinal failure loads were identified. Meanwhile,the typical failure modes are documented and their respective mechanisms are analyzed. Comparing the strengthened beams with the reference one,the ultimate strength of composite beams strengthened by CFRP strips is significantly increased,and the most effective one is the beam strengthened by the CFRP strip of 60% beam length. In addition,a truss model is proposed to calculate the internal forces in the concrete,steel beam and FRP strips,from which the prediction for the failure load can be performed.
This paper presents the works of investigating the structural behaviors of composite beams before and after being strengthened with CFRP strips at the tension soffit. Seven samples were examined by the four-point bending loading tests. Among the seven samples,one was un-strengthened and the remaining six were strengthened by bonding CFRP strips of different numbers,width and length,respectively. All samples were tested beyond their ultimate failure. By recording the load-deflection data for the entire history,the first crack load,the CFRP debonding load or concrete longitudinal failure loads were identified. Meanwhile,the typical failure modes are documented and their respective mechanisms are analyzed. Comparing the strengthened beams with the reference one,the ultimate strength of composite beams strengthened by CFRP strips is significantly increased,and the most effective one is the beam strengthened by the CFRP strip of 60% beam length. In addition,a truss model is proposed to calculate the internal forces in the concrete,steel beam and FRP strips,from which the prediction for the failure load can be performed.
引文
[1]叶列平,冯鹏. FRP在工程结构中的应用与发展[J].土木工程学报,2006(3):24-36.
[2]Teng J G,Chen J F,Smith S T. Debonding failures in FRP-strengthened RC beams:Failure modes,existing research and future challenges[C]//Composites in Construction:A reality,Italy,American Society of Civil Engineers,2001:139-148.
[3]王文炜,李果.纤维增强塑料(FRP)在混凝土结构中的研究与应用[J].混凝土,2001(10):37-39.
[4]郑云,叶列平,岳清瑞. FRP加固钢结构的研究进展[J].工业建筑,2005(8):20-25,34.
[5]Tavakkolizadeh M,Saadatmanesh H. Strengthening of steel-concrete composite girders using carbon fiber reinforced polymers sheets[J].Journal of Structural Engineering,2003,129(1):30-40.
[6]Al-saidy A H,Klaiber F W,Wipf T J. Strengthening of steel-concrete composite girders using carbon fiber reinforced polymer plates[J].Construction and Building Materials,2007,21(2):295-302.
[7]邓军,黄培彦,李师庆. CFRP板加固钢-混凝土组合梁的塑性承载力分析[J].桥梁建设,2008(2):78-80,84.
[8]邓军,李师庆,黄培彦. CFRP板加固钢-混凝土组合梁的非线性有限元分析[J].华南理工大学学报(自然科学版),2008(6):35-39.
[9]焦铁涛,高尔新,彭福明. CFRP加固组合梁的应力与变形分析[J].钢结构,2008,23(1):13-15.
[10]霍君华,王连广.预应力CFRP布加固组合梁反拱变形计算[J].混凝土,2010(7):39-41.
[11]张凤.预应力CFRP布加固钢-混凝土组合梁受力分析[D].广西:广西科技大学,2013.
[12]陈伟宏,马景明,崔双双.用无机胶粘贴CFRP布加固损伤组合梁受弯性能[J].郑州大学学报(工学版),2014,35(5):79-83.
[13]霍君华.基于徐变效应预应力CFRP布加固组合梁变形分析[J].施工技术,2016(10):69-72.
[14]TeychennD C,Franklin R E,Erntroy H C,et al. Design of normal concrete mixes[M]. 2nd ed. Watford:Building Research Establishment,1997.
[15]Arlekar J N,Murty C R. Improved truss model for design of welded steel moment-resisting frame connections[J]. Journal of Structural Engineering,2004,130(3):498-510.
[2]Teng J G,Chen J F,Smith S T. Debonding failures in FRP-strengthened RC beams:Failure modes,existing research and future challenges[C]//Composites in Construction:A reality,Italy,American Society of Civil Engineers,2001:139-148.
[3]王文炜,李果.纤维增强塑料(FRP)在混凝土结构中的研究与应用[J].混凝土,2001(10):37-39.
[4]郑云,叶列平,岳清瑞. FRP加固钢结构的研究进展[J].工业建筑,2005(8):20-25,34.
[5]Tavakkolizadeh M,Saadatmanesh H. Strengthening of steel-concrete composite girders using carbon fiber reinforced polymers sheets[J].Journal of Structural Engineering,2003,129(1):30-40.
[6]Al-saidy A H,Klaiber F W,Wipf T J. Strengthening of steel-concrete composite girders using carbon fiber reinforced polymer plates[J].Construction and Building Materials,2007,21(2):295-302.
[7]邓军,黄培彦,李师庆. CFRP板加固钢-混凝土组合梁的塑性承载力分析[J].桥梁建设,2008(2):78-80,84.
[8]邓军,李师庆,黄培彦. CFRP板加固钢-混凝土组合梁的非线性有限元分析[J].华南理工大学学报(自然科学版),2008(6):35-39.
[9]焦铁涛,高尔新,彭福明. CFRP加固组合梁的应力与变形分析[J].钢结构,2008,23(1):13-15.
[10]霍君华,王连广.预应力CFRP布加固组合梁反拱变形计算[J].混凝土,2010(7):39-41.
[11]张凤.预应力CFRP布加固钢-混凝土组合梁受力分析[D].广西:广西科技大学,2013.
[12]陈伟宏,马景明,崔双双.用无机胶粘贴CFRP布加固损伤组合梁受弯性能[J].郑州大学学报(工学版),2014,35(5):79-83.
[13]霍君华.基于徐变效应预应力CFRP布加固组合梁变形分析[J].施工技术,2016(10):69-72.
[14]TeychennD C,Franklin R E,Erntroy H C,et al. Design of normal concrete mixes[M]. 2nd ed. Watford:Building Research Establishment,1997.
[15]Arlekar J N,Murty C R. Improved truss model for design of welded steel moment-resisting frame connections[J]. Journal of Structural Engineering,2004,130(3):498-510.