CFRP加固高强钢筋混凝土梁抗剪承载力计算
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摘要
为深入探讨高强混凝土结构用碳纤维布(简称CFRP)增强系列问题,对基于碳纤维布拉断的高强钢筋混凝土加固梁进行了抗剪性能试验研究,考虑了加固量、加固形式、剪跨比、预损伤程度、配箍率等参数的影响.试验结果表明,经碳纤维布加固的高强混凝土梁抗剪承载力提高较多,加固效果明显;预损伤对加固梁的抗剪承载力影响不大;剪跨比、加固量综合起来影响着碳纤维布的受力程度,从而影响到碳纤维布的有效应变,最终决定了试验梁的抗剪承载力.基于有效应变模型,提出了与试验结果相吻合的碳纤维布抗剪承载力计算方法,并结合我国碳纤维布加固混凝土结构规程,提出了高强钢筋混凝土梁用碳纤维布进行抗剪加固的设计方法.
In-depth experimental studies on the shear performances of high strength RC beams bonded with CFRP were carried out,in which numerous influencing factors were properly considered,including the amount of CFRP sheets in use,the reinforcement ways,the shear span ratio,the damage degree and the shear reinforcement ratio.The results indicate that the shear capacities of the repaired beams are obviously increased.Damages in advance have little influences on the shear capacities of the beams.Shear span ratio and the shear reinforcement amount of CFRP sheets are the two important factors impacting the effective strain of CFRP strips and thus finally determine the shear capacities.Based on the effective strain model,a calculational expression of shear capacity is established which predicts identical results with the experimental ones.Combined with the national regulations in concrete structures strengthened with CFRP,design proposal of high strength RC beams bonded with CFRP for shear reinforcement is finally derived.
In-depth experimental studies on the shear performances of high strength RC beams bonded with CFRP were carried out,in which numerous influencing factors were properly considered,including the amount of CFRP sheets in use,the reinforcement ways,the shear span ratio,the damage degree and the shear reinforcement ratio.The results indicate that the shear capacities of the repaired beams are obviously increased.Damages in advance have little influences on the shear capacities of the beams.Shear span ratio and the shear reinforcement amount of CFRP sheets are the two important factors impacting the effective strain of CFRP strips and thus finally determine the shear capacities.Based on the effective strain model,a calculational expression of shear capacity is established which predicts identical results with the experimental ones.Combined with the national regulations in concrete structures strengthened with CFRP,design proposal of high strength RC beams bonded with CFRP for shear reinforcement is finally derived.
引文
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[8]HSU T T.Unified Theory of Reinforced Concrete[M].Florida:CRC Press,1993
[9]COLLINS M P.Toward a rational theory for RCmembers in shear[J].Journal of the StructuralDivision ASCE,1998,124(12):1375-1417
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[11]DENIAUD C,CHENG J J R.Review of sheardesign methods for reinforced concrete beamsstrengthened with fiber reinforced polymer sheets[J].Canadian Journal of Civil Engineering,2001,28:271-281
[12]DENIAUD C,CHENG J J R.Shear behavior ofreinforced concrete T-beams with externally bondedfiber-reinforced polymer sheets[J].ACI StructuralJournal,2001,98(3):386-394
[13]CHEN J F,TENG J G.Shear capacity offiber-reinforced polymer-strengthened reinforcedconcrete beams:fiber reinforced polymer rupture[J].Journal of Structural Engineering,2003,129(3):615-625
[14]中国工程建设标准化协会.CECS146:2003碳纤维片材加固混凝土结构技术规程[M].北京:中国计划出版社,2003
[15]中国工程建设标准化协会.CECS 104:99高强混凝土结构技术规程[M].北京:中国工程建设标准化协会,1999
[16]李松辉.碳纤维布加固桥梁的设计理论研究[D].大连:大连理工大学,2003
[17]曹双寅,滕锦光,陈健飞,等.外贴纤维布加固梁斜截面纤维应变分布的试验研究[J].土木工程学报,2003,36(11):6-11
[18]周英武,王苏岩,李宏男.钢筋混凝土梁斜裂缝倾角的理论与试验分析[J].大连理工大学学报,2008,48(2):235-239(ZHOU Ying-wu,WANG Su-yan,LI Hong-nan.Theoretical and experimental analyses of criticalshear angle of RC beam[J].Journal of DalianUniversity of Technology,2008,48(2):235-239)
[19]CHEN J F,TENG J G.Shear capacity ofFRP-strengthened RC beams:FRP debonding[J].Construction and Building Materials,2003,17:27-41
[2]杜婷,郭太平,林怀立,等.混凝土材料的研究现状和发展应用[J].混凝土,2006,5:7-9
[3]赵彤,刘明国,谢剑.碳纤维布用于改善斜向受力高强混凝土柱抗震性能的研究[J].土木工程学报,2002,35(3):13-19
[4]王苏岩,韩克双,曲秀华.CFRP加固高强混凝土柱改善延性的试验研究[J].世界地震工程,2005,21(3):7-10
[5]TRIANTAFILLOU T C.Shear strengthening ofreinforced beams using epoxy-bonded FRP composites[J].ACI Structural Journal,1998,95(2):386-394
[6]TRIANTAFILLOU T C,COSTAS P A.Design ofconcrete flexural members strengthened in shear withFRP[J].Journal of Composites for Construction,2000,4(11):198-205
[7]AL-NAHLAWI G J,WIGHT J K.Beam analysisusing concrete tensile strength in truss models[J].ACI Structural Journal,1992,89:284-289
[8]HSU T T.Unified Theory of Reinforced Concrete[M].Florida:CRC Press,1993
[9]COLLINS M P.Toward a rational theory for RCmembers in shear[J].Journal of the StructuralDivision ASCE,1998,124(12):1375-1417
[10]VECCHIO F J,COLLINS M P.The modifiedcompression-filed theory for reinforced concreteelements subjected to shear[J].ACI StructuralJournal,1986,83:386-394
[11]DENIAUD C,CHENG J J R.Review of sheardesign methods for reinforced concrete beamsstrengthened with fiber reinforced polymer sheets[J].Canadian Journal of Civil Engineering,2001,28:271-281
[12]DENIAUD C,CHENG J J R.Shear behavior ofreinforced concrete T-beams with externally bondedfiber-reinforced polymer sheets[J].ACI StructuralJournal,2001,98(3):386-394
[13]CHEN J F,TENG J G.Shear capacity offiber-reinforced polymer-strengthened reinforcedconcrete beams:fiber reinforced polymer rupture[J].Journal of Structural Engineering,2003,129(3):615-625
[14]中国工程建设标准化协会.CECS146:2003碳纤维片材加固混凝土结构技术规程[M].北京:中国计划出版社,2003
[15]中国工程建设标准化协会.CECS 104:99高强混凝土结构技术规程[M].北京:中国工程建设标准化协会,1999
[16]李松辉.碳纤维布加固桥梁的设计理论研究[D].大连:大连理工大学,2003
[17]曹双寅,滕锦光,陈健飞,等.外贴纤维布加固梁斜截面纤维应变分布的试验研究[J].土木工程学报,2003,36(11):6-11
[18]周英武,王苏岩,李宏男.钢筋混凝土梁斜裂缝倾角的理论与试验分析[J].大连理工大学学报,2008,48(2):235-239(ZHOU Ying-wu,WANG Su-yan,LI Hong-nan.Theoretical and experimental analyses of criticalshear angle of RC beam[J].Journal of DalianUniversity of Technology,2008,48(2):235-239)
[19]CHEN J F,TENG J G.Shear capacity ofFRP-strengthened RC beams:FRP debonding[J].Construction and Building Materials,2003,17:27-41
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