HRB500/HRB600钢筋作纵筋的混凝土框架梁端弯矩调幅试验研究
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摘要
为研究HRB500钢筋和HRB600钢筋作纵筋的混凝土框架梁端弯矩调幅规律,完成了12榀单层两跨混凝土框架静力加载试验。试验结果表明:由于受拉纵筋屈服强度提高,一方面梁端塑性铰出现推迟,塑性铰形成前会发生一定的弯矩调幅;另一方面锚固于节点内的梁端受拉纵筋应变渗透引起较大的梁端附加转角,加大了弯矩调幅能力。将试验框架梁端弯矩调幅分塑性铰形成前后两阶段进行考察,第一阶段弯矩调幅幅度为10.35%～33.42%,第二阶段弯矩调幅幅度为3.39%～30.5%。基于试验结果,建立了与梁端控制截面相对受压区高度呈幂函数减小趋势、与受拉纵筋屈服强度和受拉纵筋屈服时刻应变渗透引起的梁端附加转角呈线性增长趋势的第一阶段弯矩调幅系数计算公式;建立了与总塑性转角(塑性铰区范围内的塑性转角与应变渗透引起的梁端附加塑性转角之和)呈幂函数增长趋势、与受拉纵筋屈服强度呈线性减小趋势的第二阶段弯矩调幅系数计算公式。
To study the moment redistribution in the concrete frame beams reinforced with HRB500 and HRB600 steel bars, 12 single-layer and two-span reinforced concrete frames were tested. The test results showed that, due to the increase in the yield strength of the tensile longitudinal steel bars, the formation of the plastic hinges at beam ends was delayed. A certain extent of moment redistribution occurred before the formation of the plastic hinges. In addition, the strain penetration of the steel bars anchored in the joints caused larger additional rotations of beam ends, which increased the moment redistribution. The moment redistribution was investigated in two stages according to whether the plastic hinges were formed or not. The first-stage moment redistribution was between 10.35%～33.42% and the second-stage moment redistribution was between 3.39%～30.5%. Based on the test results, expressions for moment redistribution of the two stages were proposed. The first-stage moment redistribution decreased as a power function with an increase in the relative depth of the compression zone, and increased linearly as the yield strength of the tensile longitudinal reinforcement and the additional rotation at yielding increased. The second-stage moment redistribution increased as a power function with an increase in the total plastic rotation(the sum of the rotation of plastic hinges and the additional plastic rotation due to strain penetration), and decreased linearly as the yield strength of the tensile longitudinal reinforcement increased.
To study the moment redistribution in the concrete frame beams reinforced with HRB500 and HRB600 steel bars, 12 single-layer and two-span reinforced concrete frames were tested. The test results showed that, due to the increase in the yield strength of the tensile longitudinal steel bars, the formation of the plastic hinges at beam ends was delayed. A certain extent of moment redistribution occurred before the formation of the plastic hinges. In addition, the strain penetration of the steel bars anchored in the joints caused larger additional rotations of beam ends, which increased the moment redistribution. The moment redistribution was investigated in two stages according to whether the plastic hinges were formed or not. The first-stage moment redistribution was between 10.35%～33.42% and the second-stage moment redistribution was between 3.39%～30.5%. Based on the test results, expressions for moment redistribution of the two stages were proposed. The first-stage moment redistribution decreased as a power function with an increase in the relative depth of the compression zone, and increased linearly as the yield strength of the tensile longitudinal reinforcement and the additional rotation at yielding increased. The second-stage moment redistribution increased as a power function with an increase in the total plastic rotation(the sum of the rotation of plastic hinges and the additional plastic rotation due to strain penetration), and decreased linearly as the yield strength of the tensile longitudinal reinforcement increased.
引文
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[5]GB/T 50152―2012,混凝土结构试验方法标准[S].北京:中国建筑工业出版社,2012.Standard methods for testing of concrete structures[S].Beijing:China Architecture&Building Press,2010.(in Chinese)
[6]王英,周威,郑文忠.跨中集中荷载下两跨UPC矩形截面连续梁塑性铰性能[J].土木工程学报,2008,41(5):26―32.Wang Ying,Zhou Wei,Zheng Wenzhong.Performance of plastic hinge in a two-span continuous rectangular cross-section beam prestressed with unbonded tendons under concentrated load at mid span[J].China Civil Engineering Journal,2008,41(5):26―32.(in Chinese)
[7]郑文忠,王钧,韩宝权,等.内置H型钢预应力混凝土连续组合梁受力性能试验研究[J].建筑结构学报,2010,31(7):23―31.Zheng Wenzhong,Wang Jun,Han Baoquan,et al.Experimental research on mechanical behavior of continuous prestressed composite concrete beams with encased H-steel[J].Journal of Building Structures,2010,31(7):23―31.(in Chinese)
[8]解恒燕,郑文忠.内置钢箱-混凝土连续组合梁受力性能试验[J].哈尔滨工业大学学报,2010,42(2):186―192.Xie Hengyan,Zheng Wenzhong.Experimental research on mechanical behavior of continuous encased steel box concrete beam[J].Journal of Harbin Institute of Technology,2010,42(2):186―192.(in Chinese)
[9]Haskett M,Oehlers D J,Ali M S M,et al.Rigid body moment-rotation mechanism for reinforced concrete beam hinges[J].Engineering Structures,2009,31(5):1032―1041.
[10]Wibowo A,Wilson J,Lam N,et al.Yield Penetration Displacement of Lightly Reinforced Concrete Columns[J].Applied Mechanics&Materials,2016,845:119―125.
[11]陈明政,魏世宏,黄林青.三类预应力混凝土框架试验研究[J].工程力学,2008(增刊1):169―174.CheN Mingzheng,Wen Shihong,Huang Linqing.Test investigation of three types pre-stressed concrete frame[J].Engineering Mechanics,2008(Suppl 1):169―174.(in Chinese)
[12]王文炜,吴文清,李淑琴,等.简支梁转变为连续梁的弯矩调幅试验研究及其简化计算方法[J].工程力学,2010,27(5):147―152,158.Wang Wenwei,Wu Wenqing,Li Shuqin,et al.Experimental study and calculation method on moment redistribution induced by transforming simply supported beams into continuous beams[J].Engineering Mechanics,2010,27(5):147―152,158.(in Chinese)
[13]Zhao J,Sritharan S.Modeling of strain penetration effects in fiber-based analysis of reinforced concrete structures[J].Aci Structural Journal,2007,104(2):133―141.
[14]白绍良,傅剑平,汤华.框架中间层端节点梁筋直角弯折锚固端设计概念及方法的改进[J].重庆建筑工程学院学报,1994,16(3):1―12.Bai Shaoliang,Fu Jianping,Tang Hua.Improvements for the design concept and approach of the anchorage end90-degree bent beam reinforcement in frame exterior joints[S].Journal of Chongqing Architecture University,1994,16(3):1―12.(in Chinese)
[15]白绍良,傅剑平,周中元.末端带直角弯折的梁筋在端节点中的锚固性能试验研究[J].重庆建筑工程学院学报,1994,16(2):1―12.Bai Shaoliang,Fu Jianping,Zhou Zhongyuan.Experimental study on static anchorage behavior of beam bars with 90-degree hook in exterior joints of RC frames[S].Journal of Chongqing Architecture University,1994,16(2):1―12.(in Chinese)
[16]Farahbod F,Mostofinejad D.Experimental study of moment redistribution in RC frames strengthened with CFRP sheets[J].Composite Structures,2011,93(3):1168―1177.
[17]李龙起,周东华,廖文远,等.腹板开洞钢-混凝土连续组合梁塑性铰及内力重分布试验研究[J].工程力学,2015,32(11):123―131.Li Longqi,Zhou Donghua,Liao Wenyuan,et al.Experimental study on plastic hinge and international force redistribution for continuous steel-concrete composite beams with web openings[J].Engineering Mechanics,2015,32(11):123―131.(in Chinese)
[18]Lou T,Lopes S M R,Lopes A V.Factors affecting moment redistribution at ultimate in continuous beams prestressed with external CFRP tendons[J].Composites Part B,2014,66(11):136―146.
[19]Bagge N,O’Connor A,Elfgren L,et al.Moment redistribution in RC beams-A study of the influence of longitudinal and transverse reinforcement ratios and concrete strength[J].Engineering Structures,2014,80(5):11―23.
[20]Lou T,Lopes S M R,Lopes A V.Neutral axis depth and moment redistribution in FRP and steel reinforced concrete continuous beams[J].Composites Part B,2015,70(3):44―52.
[2]GB/T 1499.2―2018,钢筋混凝土用钢第2部分:热轧带肋钢筋[S].北京:中国标准出版社,2018Steel for the reinforcement of concrete-Part 2:Hot rolled ribbed bars[S].Beijing:Standards Press of China,2018.(in Chinese)
[3]Eligehausen R,Langer P.Rotation capacity of plastic hinges and allowable degree of moment redistribution.Universit?t Stuttgart-Universit?tsbibliothek,1987.
[4]GB/T 228.1―2010,金属材料拉伸试验第1部分:室温试验方法[S].北京:中国建筑工业出版社,2010.Metallic materials-tensile testing-Part 1:Method of test at room temperature[S].Beijing:China Architecture&Building Press,2010.(in Chinese)
[5]GB/T 50152―2012,混凝土结构试验方法标准[S].北京:中国建筑工业出版社,2012.Standard methods for testing of concrete structures[S].Beijing:China Architecture&Building Press,2010.(in Chinese)
[6]王英,周威,郑文忠.跨中集中荷载下两跨UPC矩形截面连续梁塑性铰性能[J].土木工程学报,2008,41(5):26―32.Wang Ying,Zhou Wei,Zheng Wenzhong.Performance of plastic hinge in a two-span continuous rectangular cross-section beam prestressed with unbonded tendons under concentrated load at mid span[J].China Civil Engineering Journal,2008,41(5):26―32.(in Chinese)
[7]郑文忠,王钧,韩宝权,等.内置H型钢预应力混凝土连续组合梁受力性能试验研究[J].建筑结构学报,2010,31(7):23―31.Zheng Wenzhong,Wang Jun,Han Baoquan,et al.Experimental research on mechanical behavior of continuous prestressed composite concrete beams with encased H-steel[J].Journal of Building Structures,2010,31(7):23―31.(in Chinese)
[8]解恒燕,郑文忠.内置钢箱-混凝土连续组合梁受力性能试验[J].哈尔滨工业大学学报,2010,42(2):186―192.Xie Hengyan,Zheng Wenzhong.Experimental research on mechanical behavior of continuous encased steel box concrete beam[J].Journal of Harbin Institute of Technology,2010,42(2):186―192.(in Chinese)
[9]Haskett M,Oehlers D J,Ali M S M,et al.Rigid body moment-rotation mechanism for reinforced concrete beam hinges[J].Engineering Structures,2009,31(5):1032―1041.
[10]Wibowo A,Wilson J,Lam N,et al.Yield Penetration Displacement of Lightly Reinforced Concrete Columns[J].Applied Mechanics&Materials,2016,845:119―125.
[11]陈明政,魏世宏,黄林青.三类预应力混凝土框架试验研究[J].工程力学,2008(增刊1):169―174.CheN Mingzheng,Wen Shihong,Huang Linqing.Test investigation of three types pre-stressed concrete frame[J].Engineering Mechanics,2008(Suppl 1):169―174.(in Chinese)
[12]王文炜,吴文清,李淑琴,等.简支梁转变为连续梁的弯矩调幅试验研究及其简化计算方法[J].工程力学,2010,27(5):147―152,158.Wang Wenwei,Wu Wenqing,Li Shuqin,et al.Experimental study and calculation method on moment redistribution induced by transforming simply supported beams into continuous beams[J].Engineering Mechanics,2010,27(5):147―152,158.(in Chinese)
[13]Zhao J,Sritharan S.Modeling of strain penetration effects in fiber-based analysis of reinforced concrete structures[J].Aci Structural Journal,2007,104(2):133―141.
[14]白绍良,傅剑平,汤华.框架中间层端节点梁筋直角弯折锚固端设计概念及方法的改进[J].重庆建筑工程学院学报,1994,16(3):1―12.Bai Shaoliang,Fu Jianping,Tang Hua.Improvements for the design concept and approach of the anchorage end90-degree bent beam reinforcement in frame exterior joints[S].Journal of Chongqing Architecture University,1994,16(3):1―12.(in Chinese)
[15]白绍良,傅剑平,周中元.末端带直角弯折的梁筋在端节点中的锚固性能试验研究[J].重庆建筑工程学院学报,1994,16(2):1―12.Bai Shaoliang,Fu Jianping,Zhou Zhongyuan.Experimental study on static anchorage behavior of beam bars with 90-degree hook in exterior joints of RC frames[S].Journal of Chongqing Architecture University,1994,16(2):1―12.(in Chinese)
[16]Farahbod F,Mostofinejad D.Experimental study of moment redistribution in RC frames strengthened with CFRP sheets[J].Composite Structures,2011,93(3):1168―1177.
[17]李龙起,周东华,廖文远,等.腹板开洞钢-混凝土连续组合梁塑性铰及内力重分布试验研究[J].工程力学,2015,32(11):123―131.Li Longqi,Zhou Donghua,Liao Wenyuan,et al.Experimental study on plastic hinge and international force redistribution for continuous steel-concrete composite beams with web openings[J].Engineering Mechanics,2015,32(11):123―131.(in Chinese)
[18]Lou T,Lopes S M R,Lopes A V.Factors affecting moment redistribution at ultimate in continuous beams prestressed with external CFRP tendons[J].Composites Part B,2014,66(11):136―146.
[19]Bagge N,O’Connor A,Elfgren L,et al.Moment redistribution in RC beams-A study of the influence of longitudinal and transverse reinforcement ratios and concrete strength[J].Engineering Structures,2014,80(5):11―23.
[20]Lou T,Lopes S M R,Lopes A V.Neutral axis depth and moment redistribution in FRP and steel reinforced concrete continuous beams[J].Composites Part B,2015,70(3):44―52.