多破坏模式和二次受力影响下FRP加固RC梁抗弯承载力
|
摘要
针对实际工程应用中FRP加固RC梁存在多种破坏模式和二次受力影响等关键问题,提出采用能基本表征受压区混凝土实际应力-应变情况的Hognestad本构模型,以考虑受压区混凝土非线性应力变化。推导FRP加固RC梁受压混凝土等效应力和受压区高度各自对应的相关比值,并得出FRP拉断、钢筋屈服前、后受压区混凝土压碎这3种不同破坏模式下的梁正截面极限抗弯承载力计算公式,同时推导加固梁FRP最大、最小加固量的计算公式以定义各破坏模式间的临界状态,并考虑二次受力影响和滞后应变效应。研究结果表明:所推导的公式能有效表征加固梁的不同破坏模式及二次受力效应,所计算的承载力与试验值较吻合,可以用于RC梁加固设计和承载力分析。
With consideration of the different failure modes and the influence of secondary loading for FRP-strengthened RC beams, the Hognestad constitutive model that is close to actual stress-strain situations of concrete was used for the nonlinear changes in the compressive zone of concrete. The coefficients related to the equivalent stress of concrete under compression, as well as to the depth of compressive zone of concrete, were deduced based on the Hognestad model. Then the formulas of ultimate bending moments of RC beams were established with respect to three different failure modes i.e.,FRP tensile failure, reinforcement yield before and after concrete crushing. Meanwhile, the maximum and the minimum FRP amounts for beam reinforcement were given to define the critical conditions between different failure modes. The secondary loading effects with lag strains were also involved in the context. Lastly, the proposed formulas were validated by using some tested FRP-reinforced RC beams. The results show that the proposed formulas consider different failure modes and the influence of secondary loading. The ultimate loads calculated with the formula are in agreement with the experiments results, which indicates that the formula can be used to design the FRP reinforcement and analyze the corresponding ultimate load of RC beams.
With consideration of the different failure modes and the influence of secondary loading for FRP-strengthened RC beams, the Hognestad constitutive model that is close to actual stress-strain situations of concrete was used for the nonlinear changes in the compressive zone of concrete. The coefficients related to the equivalent stress of concrete under compression, as well as to the depth of compressive zone of concrete, were deduced based on the Hognestad model. Then the formulas of ultimate bending moments of RC beams were established with respect to three different failure modes i.e.,FRP tensile failure, reinforcement yield before and after concrete crushing. Meanwhile, the maximum and the minimum FRP amounts for beam reinforcement were given to define the critical conditions between different failure modes. The secondary loading effects with lag strains were also involved in the context. Lastly, the proposed formulas were validated by using some tested FRP-reinforced RC beams. The results show that the proposed formulas consider different failure modes and the influence of secondary loading. The ultimate loads calculated with the formula are in agreement with the experiments results, which indicates that the formula can be used to design the FRP reinforcement and analyze the corresponding ultimate load of RC beams.
引文
[1]GB 50367-2013,混凝土结构加固设计规范[S].GB 50367-2013,Code for design of strengthening concrete structure[S].
[2]王文炜,赵国藩.玻璃纤维布加固钢筋混凝土梁正截面抗弯承载力计算[J].建筑结构学报,2004,25(3):92-98.WANG Wenwei,ZHAO Guofan.Calculation of flexural capacity of RC beams strengthened with GFRP sheets[J].Journal of Building Structures,2004,25(3):92-98.
[3]蔺建廷.BFRP加固钢筋混凝土梁抗弯性能的试验研究[D].大连:大连理工大学土木工程学院,2009:1-30.LIN Jianting.Experimental research of reinforce concrete beams strengthened with basalt fiber polymer[D].Dalian:Dalian University of Technology.College of Civil Engineering,2009:1-30.
[4]LAML L,TENG.J G.Strength of RC cantilever slabs bonded with GFRP strips[J].Journal of Composites for Construction,2001,5(4):221-227.
[5]邢丽丽,孔祥清.外贴FRP加固钢筋混凝土梁结构性能研究进展[J].混凝土,2018(9):40-44.XING Lili,KONG Xiangqing.Research progress on structural performance of RC beams strengthened with externally bonded FRP sheets[J].Concrete,2018(9):40-44.
[6]CHEN W S,PHAMT M,SICHEMBE H,et al.Experimental study of flexural behaviour of RC beams strengthened by longitudinal and U-shaped basalt FRP sheet[J].Composites Part B:Engineering,2018,134:114-126.
[7]吴刚.FRP加固钢筋混凝土结构的试验研究与理论分析[D].南京:东南大学土木工程学院,2002:1-25.WU Gang.Experimental study and theoretical analysis on strengthening concrete structures with FRP[D].Nanjing:Southeast University.College of Civil Engineering,2002:1-25.
[8]GB 50010-2010,混凝土结构设计规范[S].GB 50010-2010,Code for design of concrete structures[S].
[9]东南大学,天津大学,同济大学,等.混凝土结构设计原理(上册)[M].5版.北京:中国建筑工业出版社,2012:35-65.Southeast University,Tianjing University,Tongji University,et al.Concrete structures[M].5th ed.Beijing:China Construction Industry Press,2012:35-65.
[10]王滋军,刘伟庆,姚秋来,等.考虑二次受力的碳纤维加固钢筋混凝土梁抗弯性能的试验研究[J].工业建筑,2004,34(7):85-87.WANG Zijun,LIU Weiqing,YAO Qiulai,et al.Yunxiang.Experimental research on the flexural behavior of RC beams strengthened by carbon fiber sheet under quadratic loading[J].Industrial Construction,2004,34(7):85-87.
[11]ACI Committee-440.2R-02.Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures[R].ACI:Farmington HillsMich,45.
[12]郑建军,廖永石,朱彦鹏.FRP加固梁抗弯计算和试验分析[J].低温建筑技术,2010,32(9):38-40.ZHENG Jianjun,LIAO Yongshi,ZHU Yanpeng.The experimental analysis and calculation of flexural capacity of RCbeams strengthened with FRP sheets[J].Low Temperature Architecture Technology,2010,32(9):38-40.
[13]张丹伟.纤维布加固钢筋混凝土梁受弯性能分析[D].郑州:郑州大学水利与环境学院,2013:1-50.ZHANG Danwei.Analysis of reinforced concrete beam strengthened with FRP on flexural behavior[D].Zhengzhou:Zhengzhou University.College of Water Conservancy&Environmental Engineering,2013:1-50.
[14]杨玫.碳纤维布加固高强钢筋混凝土梁抗弯性能研究[D].大连:大连理工大学土木工程学院,2005:20-60.YANG Mei.Study on flexural behavior of high-strength reinforced concrete beams strengthened with CFRP[D].Dalian:Dalian University of Technology.College of Civil Engineering,2005:20-60.
[15]赵鸣,赵海东,张誉.碳纤维片材加固钢筋混凝土梁受弯试验研究[J].结构工程师,2002(2):52-58.ZHAO Ming,ZHAO Haidong,ZHANG Yu.Experimental study on flexural RC members strengthened with CFRP fabrics[J].Structural Engineers,2002(2):52-58.
[16]张国东.CFRP加固钢筋混凝土受弯构件正截面基本性能的试验研究[D].哈尔滨:哈尔滨工业大学土木工程学院,2003:1-45.ZHANG Guodong.Experimental study on the basic properties of reinforced concrete flexural members strengthened with CFRP[D].Harbin:College of Harbin Technology.College of Civil Engineering,2003:1-45.
[17]赵璟.考虑二次受力的BFRP加固钢筋混凝土梁抗弯性能的研究[D].杭州:浙江工业大学建筑工程学院,2012:10-40.ZHAO Jing.Study on the bending behavior of RC beams strengthened with BFRP considering the secondary loading[D].Hangzhou:Zhejiang University of Technology.College of Civil Engineering and Architecture,2012:10-40.
[18]黄楠.二次受力下CFRP布加固钢筋混凝土梁的抗弯性能研究[D].宁波:宁波大学建筑工程与环境学院,2015:10-45.HUANG Nan.The research of flexural behaviors of RC beams strengthened with CFRP under secondary loading[D].Ningbo:Ningbo University.Faculty of Architectural,Civil Engineering And Environment,2015:10-45.
[2]王文炜,赵国藩.玻璃纤维布加固钢筋混凝土梁正截面抗弯承载力计算[J].建筑结构学报,2004,25(3):92-98.WANG Wenwei,ZHAO Guofan.Calculation of flexural capacity of RC beams strengthened with GFRP sheets[J].Journal of Building Structures,2004,25(3):92-98.
[3]蔺建廷.BFRP加固钢筋混凝土梁抗弯性能的试验研究[D].大连:大连理工大学土木工程学院,2009:1-30.LIN Jianting.Experimental research of reinforce concrete beams strengthened with basalt fiber polymer[D].Dalian:Dalian University of Technology.College of Civil Engineering,2009:1-30.
[4]LAML L,TENG.J G.Strength of RC cantilever slabs bonded with GFRP strips[J].Journal of Composites for Construction,2001,5(4):221-227.
[5]邢丽丽,孔祥清.外贴FRP加固钢筋混凝土梁结构性能研究进展[J].混凝土,2018(9):40-44.XING Lili,KONG Xiangqing.Research progress on structural performance of RC beams strengthened with externally bonded FRP sheets[J].Concrete,2018(9):40-44.
[6]CHEN W S,PHAMT M,SICHEMBE H,et al.Experimental study of flexural behaviour of RC beams strengthened by longitudinal and U-shaped basalt FRP sheet[J].Composites Part B:Engineering,2018,134:114-126.
[7]吴刚.FRP加固钢筋混凝土结构的试验研究与理论分析[D].南京:东南大学土木工程学院,2002:1-25.WU Gang.Experimental study and theoretical analysis on strengthening concrete structures with FRP[D].Nanjing:Southeast University.College of Civil Engineering,2002:1-25.
[8]GB 50010-2010,混凝土结构设计规范[S].GB 50010-2010,Code for design of concrete structures[S].
[9]东南大学,天津大学,同济大学,等.混凝土结构设计原理(上册)[M].5版.北京:中国建筑工业出版社,2012:35-65.Southeast University,Tianjing University,Tongji University,et al.Concrete structures[M].5th ed.Beijing:China Construction Industry Press,2012:35-65.
[10]王滋军,刘伟庆,姚秋来,等.考虑二次受力的碳纤维加固钢筋混凝土梁抗弯性能的试验研究[J].工业建筑,2004,34(7):85-87.WANG Zijun,LIU Weiqing,YAO Qiulai,et al.Yunxiang.Experimental research on the flexural behavior of RC beams strengthened by carbon fiber sheet under quadratic loading[J].Industrial Construction,2004,34(7):85-87.
[11]ACI Committee-440.2R-02.Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures[R].ACI:Farmington HillsMich,45.
[12]郑建军,廖永石,朱彦鹏.FRP加固梁抗弯计算和试验分析[J].低温建筑技术,2010,32(9):38-40.ZHENG Jianjun,LIAO Yongshi,ZHU Yanpeng.The experimental analysis and calculation of flexural capacity of RCbeams strengthened with FRP sheets[J].Low Temperature Architecture Technology,2010,32(9):38-40.
[13]张丹伟.纤维布加固钢筋混凝土梁受弯性能分析[D].郑州:郑州大学水利与环境学院,2013:1-50.ZHANG Danwei.Analysis of reinforced concrete beam strengthened with FRP on flexural behavior[D].Zhengzhou:Zhengzhou University.College of Water Conservancy&Environmental Engineering,2013:1-50.
[14]杨玫.碳纤维布加固高强钢筋混凝土梁抗弯性能研究[D].大连:大连理工大学土木工程学院,2005:20-60.YANG Mei.Study on flexural behavior of high-strength reinforced concrete beams strengthened with CFRP[D].Dalian:Dalian University of Technology.College of Civil Engineering,2005:20-60.
[15]赵鸣,赵海东,张誉.碳纤维片材加固钢筋混凝土梁受弯试验研究[J].结构工程师,2002(2):52-58.ZHAO Ming,ZHAO Haidong,ZHANG Yu.Experimental study on flexural RC members strengthened with CFRP fabrics[J].Structural Engineers,2002(2):52-58.
[16]张国东.CFRP加固钢筋混凝土受弯构件正截面基本性能的试验研究[D].哈尔滨:哈尔滨工业大学土木工程学院,2003:1-45.ZHANG Guodong.Experimental study on the basic properties of reinforced concrete flexural members strengthened with CFRP[D].Harbin:College of Harbin Technology.College of Civil Engineering,2003:1-45.
[17]赵璟.考虑二次受力的BFRP加固钢筋混凝土梁抗弯性能的研究[D].杭州:浙江工业大学建筑工程学院,2012:10-40.ZHAO Jing.Study on the bending behavior of RC beams strengthened with BFRP considering the secondary loading[D].Hangzhou:Zhejiang University of Technology.College of Civil Engineering and Architecture,2012:10-40.
[18]黄楠.二次受力下CFRP布加固钢筋混凝土梁的抗弯性能研究[D].宁波:宁波大学建筑工程与环境学院,2015:10-45.HUANG Nan.The research of flexural behaviors of RC beams strengthened with CFRP under secondary loading[D].Ningbo:Ningbo University.Faculty of Architectural,Civil Engineering And Environment,2015:10-45.