钢纤维掺量对R-UHPC梁受弯性能影响的研究
|
摘要
以钢纤维掺量为主要参数,进行了5根R-UHPC梁的受弯性能试验.分析了试验梁的荷载-挠度曲线、截面应变和破坏状态.试验结果表明:UHPC材料根据其极限拉应变与钢筋屈服应变的关系,可分为U0类、U1类和U2类.U0类UHPC受拉应力-应变曲线无硬化段,当材料出现开裂,UHPC就退出工作,其抗弯极限承载力不应考虑UHPC的抗拉贡献.U1类、U2类有硬化段,材料开裂后,UHPC并未退出工作,尤其是U2类的R-UHPC梁,UHPC拉应力对梁抗弯极限承载力贡献率大于20%,在计算时需要考虑这部分贡献.从纤维掺量对UHPC抗拉性能出发,推导了R-UHPC梁抗弯极限承载力的计算方法,其结果稳定,且与实测值吻合较好.
5 R-UHPC beam flexural performance tests are carried out and compared with an ordinary concrete beam test, taking the steel fiber content as the main parameter. The load deflection curve, section strain and damage state of the test beams are analyzed. The results show that UHPC material can be divided into classes of U0, U1 and U2, according to the relationship of UHPC ultimate tensile strain and reinforced yield strain. The tensile stress-strain curve of U0 class has no strain hardening, and UHPC quits the job when the material starts cracking. Therefore, the contribution of U0 UHPC tensile stress should not be considered in calculation of flexural capacity. The tensile strain hardening occurred in U1 and U2 classes, and UHPC didn't quit the job after material cracking, especially for U2 class R-UHPC beam. The contribution rate of U2 UHPC tensile stress on ultimate flexural bearing capacity is more than 20%, thus it should be taken into consideration of the calculation result. Finally, the calculating method of ultimate flexural bearing capacity of R-UHPC beam was deduced from UHPC tensile properties of the fiber content influence, the results are stable, and agree well with the measured values.
5 R-UHPC beam flexural performance tests are carried out and compared with an ordinary concrete beam test, taking the steel fiber content as the main parameter. The load deflection curve, section strain and damage state of the test beams are analyzed. The results show that UHPC material can be divided into classes of U0, U1 and U2, according to the relationship of UHPC ultimate tensile strain and reinforced yield strain. The tensile stress-strain curve of U0 class has no strain hardening, and UHPC quits the job when the material starts cracking. Therefore, the contribution of U0 UHPC tensile stress should not be considered in calculation of flexural capacity. The tensile strain hardening occurred in U1 and U2 classes, and UHPC didn't quit the job after material cracking, especially for U2 class R-UHPC beam. The contribution rate of U2 UHPC tensile stress on ultimate flexural bearing capacity is more than 20%, thus it should be taken into consideration of the calculation result. Finally, the calculating method of ultimate flexural bearing capacity of R-UHPC beam was deduced from UHPC tensile properties of the fiber content influence, the results are stable, and agree well with the measured values.
引文
[1] 陈宝春,季韬,黄卿维,等.超高性能混凝土研究综述[J].建筑科学与工程学报,2014,31(3):1-24.
[2] YOO D Y,BANTHIA N,YOON Y S.Experimental and numerical study on flexural behavior of ultra-high-performance fiber-reinforced concrete beams with low reinforcement ratios[J].Canadian Journal of Civil Engineering,2017,44(1):18-28.
[3] YANG In-Hwan,JOH Chang-Bin,KIM Byung-Suk.Structural behavior of ultra high performance concrete beams subjected to bending[J].Engineering Structures,2010,32(11):3478-3487.
[4] HASGUL U,TURKER K,BIROL T,et al.Flexural behavior of ultra-high-performance fiber reinforced concrete beams with low and high reinforcement ratios[J].Structural Concrete,2018:1-14.
[5] KAHANJI C,ALI F,NADJAI A.Structural performance of ultra high performance fiber reinforced concrete beams[J].Structural Concrete,2017,18(2):249-258.
[6] XIA Jun,CHAN T,MACKIE K R,et al.Sectional analysis for design of ultra-high performance fiber reinforced concrete beams with passive reinforcement[J].Engineering Structures,2018,160:121-132.
[7] QI Jianan,WANG Jingquan,MA Zhongguo John.Flexural response of high-strength steel-ultra-high-performance fiber reinforced concrete beams based on a mesoscale constitutive model:Experiment and theory[J].Structural Concrete,2017:719-734.
[8] 刘超,黄钰豪,马汝杰,等.高应变强化超高性能混凝土T形梁抗弯承载力[J].同济大学学报:自然科学版,2018,46(6):744-750.
[9] GOWRIPALAN N,GILBERT R.Design guidelines for ductal prestressed concrete beams[S].[s.n.]:VSL Pty Ltd.,2000.
[10] AFGC,SETRA.Ultra High performance fibre reinforced concretes[S].Paris:Association Fran?aise de Génie Civil (AFGC) and SETRA Working Group,2013.
[11] Maintenance Construction Sécurite,cole Polytechnique Fédérale de Lausanne.Ultra-high performance fibre reinforced cement-based composites (UHPFRC):SIA 2052:201 [S].Lausanne:[s.n.],2016.
[12] SU Jiazhan,DU Renyuan,CHEN Baochun,et al.Research on flexural behavior of the externally prestressed UHPC box girder[J].Journal of Asian Concrete Federation,2017,3(2):82-89.
[13] 方志,郑辉,杨剑,等.超高性能混凝土结构的设计方法[J].建筑科学与工程学报,2017,34(5):59-67.
[14] 沈秀将.活性粉末混凝土(RPC)受拉性能试验研究[D].福州:福州大学,2015.
[2] YOO D Y,BANTHIA N,YOON Y S.Experimental and numerical study on flexural behavior of ultra-high-performance fiber-reinforced concrete beams with low reinforcement ratios[J].Canadian Journal of Civil Engineering,2017,44(1):18-28.
[3] YANG In-Hwan,JOH Chang-Bin,KIM Byung-Suk.Structural behavior of ultra high performance concrete beams subjected to bending[J].Engineering Structures,2010,32(11):3478-3487.
[4] HASGUL U,TURKER K,BIROL T,et al.Flexural behavior of ultra-high-performance fiber reinforced concrete beams with low and high reinforcement ratios[J].Structural Concrete,2018:1-14.
[5] KAHANJI C,ALI F,NADJAI A.Structural performance of ultra high performance fiber reinforced concrete beams[J].Structural Concrete,2017,18(2):249-258.
[6] XIA Jun,CHAN T,MACKIE K R,et al.Sectional analysis for design of ultra-high performance fiber reinforced concrete beams with passive reinforcement[J].Engineering Structures,2018,160:121-132.
[7] QI Jianan,WANG Jingquan,MA Zhongguo John.Flexural response of high-strength steel-ultra-high-performance fiber reinforced concrete beams based on a mesoscale constitutive model:Experiment and theory[J].Structural Concrete,2017:719-734.
[8] 刘超,黄钰豪,马汝杰,等.高应变强化超高性能混凝土T形梁抗弯承载力[J].同济大学学报:自然科学版,2018,46(6):744-750.
[9] GOWRIPALAN N,GILBERT R.Design guidelines for ductal prestressed concrete beams[S].[s.n.]:VSL Pty Ltd.,2000.
[10] AFGC,SETRA.Ultra High performance fibre reinforced concretes[S].Paris:Association Fran?aise de Génie Civil (AFGC) and SETRA Working Group,2013.
[11] Maintenance Construction Sécurite,cole Polytechnique Fédérale de Lausanne.Ultra-high performance fibre reinforced cement-based composites (UHPFRC):SIA 2052:201 [S].Lausanne:[s.n.],2016.
[12] SU Jiazhan,DU Renyuan,CHEN Baochun,et al.Research on flexural behavior of the externally prestressed UHPC box girder[J].Journal of Asian Concrete Federation,2017,3(2):82-89.
[13] 方志,郑辉,杨剑,等.超高性能混凝土结构的设计方法[J].建筑科学与工程学报,2017,34(5):59-67.
[14] 沈秀将.活性粉末混凝土(RPC)受拉性能试验研究[D].福州:福州大学,2015.