铁路圆端空心墩抗震延性的拟静力试验研究
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摘要
为研究高烈度地区铁路圆端空心墩的延性抗震性能,对5个1:6缩尺模型进行了低周往复加载试验,分析了圆端空心墩损伤行为和塑性铰演化机理,探讨了不同设计参数桥墩的滞回性能、位移延性、强度/刚度及等效阻尼比等。结合损伤状态,基于位移延性对圆端空心墩抗震性能目标进行量化,并通过回归分析建立了强度/刚度退化与圆端空心墩性能目标的联系。鉴于已有模型不能很好估算圆端空心墩等效阻尼比,给出了基于试验数据的等效阻尼比公式。试验及分析结果表明:桥墩由于墩底倒角处混凝土压溃剥落、钢筋屈曲或拉断而发生弯曲破坏,墩身弯曲裂缝范围约占墩高的0.61～0.75;墩底实心段、倒角过渡段和墩身变截面的共同影响使得塑性铰区延长并整体上移;随着配箍率增加,桥墩延性有较大提升;在一定范围内增大轴压比可以提高桥墩抗弯能力,但过大的轴压会使墩底混凝土提前压溃而降低延性性能;在现行铁路规范允许位移延性比4.8下桥墩处于中等损伤状态,表明按规范设计的桥墩具有较好的抗震安全性。
To investigate the ductile performance of round-end hollow-section railway piers in intensive seismic zone, five 1:6 scaled models were tested under low-cyclic loading. The damage behavior and plastic hinge evolution mechanism were analyzed, as well as the hysteretic performance, displacement ductility,strength/stiffness and equivalent damping ratio of the specimens with different design parameters. The quantification for seismic performance object was implemented using displacement ductility combined with damage assessment. The relationship between seismic performance objectives and strength/stiffness degradation was also established through the regression analysis of test data. Due to the existing models being not appropriate to evaluate the equivalent damping ratio of round-end hollow piers, a proposed model was regressed based on the test results. The experimental and analytical results show that all specimens have a flexural failure due to concrete spalling, buckling or fracture of longitudinal rebar at the region of solid-to-hollow section, and the flexural crack distribution nearly covers 0.61 to 0.75 of the pier height. The plastic hinge region is extended and moves up wholly due to the existing of solid-section part, the transition part of solid-to-hollow section and variable hollow-section. With the increase of stirrup ratio, the displacement ductility capacity is obviously improved. The increased axial load ratio can improve the flexural capacity to some extent, but excessive axial load will lead to decreasing ductility for premature concrete crushing. The pier is at medium damage state under the ductility factor limitation of 4.8 in the current seismic code of railway engineering, which indicates seismic safety of piers designed using the code.
To investigate the ductile performance of round-end hollow-section railway piers in intensive seismic zone, five 1:6 scaled models were tested under low-cyclic loading. The damage behavior and plastic hinge evolution mechanism were analyzed, as well as the hysteretic performance, displacement ductility,strength/stiffness and equivalent damping ratio of the specimens with different design parameters. The quantification for seismic performance object was implemented using displacement ductility combined with damage assessment. The relationship between seismic performance objectives and strength/stiffness degradation was also established through the regression analysis of test data. Due to the existing models being not appropriate to evaluate the equivalent damping ratio of round-end hollow piers, a proposed model was regressed based on the test results. The experimental and analytical results show that all specimens have a flexural failure due to concrete spalling, buckling or fracture of longitudinal rebar at the region of solid-to-hollow section, and the flexural crack distribution nearly covers 0.61 to 0.75 of the pier height. The plastic hinge region is extended and moves up wholly due to the existing of solid-section part, the transition part of solid-to-hollow section and variable hollow-section. With the increase of stirrup ratio, the displacement ductility capacity is obviously improved. The increased axial load ratio can improve the flexural capacity to some extent, but excessive axial load will lead to decreasing ductility for premature concrete crushing. The pier is at medium damage state under the ductility factor limitation of 4.8 in the current seismic code of railway engineering, which indicates seismic safety of piers designed using the code.
引文
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[2]Yeh Y K,Mo Y L,Yang C Y.Seismic performance of rectangular hollow bridge columns[J].Journal of Structural Engineering,2002,128(1):60-68
[3]Mo Y L,Wong D C,Maekawa K.Seismic performance of hollow bridge columns[J].ACI Structural Journal,2003,100(3):337-348
[4]Yeh Y K,Mo Y L,Yang CY.Full-scale tests on rectangular hollow bridge piers[J].Materials and Structures,2002,35(2):117-125
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[6]Shin M,Choi YY,Sun CH,et al.Shear strength model for reinforced concrete rectangular hollow piers[J].Engineering Structures,2013,56:958-969
[7]Cassese P,Ricci P,Verderame G M.Experimental study on the seismic performance of existing reinforced concrete bridge piers with hollow rectangular section[J].Engineering Structures,2017,144(8):88-106
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[10]孙治国,王东升,郭迅,等.地震作用下RC薄壁空心墩抗剪强度比较研究[J].土木工程学报,2013,46(12):81-89(Sun Zhiguo,Wang Dongsheng,Guo Xun,et al.Comparative study on shear strength of RC thin-walled hollow bridge piers under seismic effect[J].China Civil Engineering Journal,2013,46(12):81-89(in Chinese))
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[14]Turmo J,Ramos G,Aparicio A C.Shear truss analogy for concrete members of solid and hollow circular cross section[J].Engineering Structures,2009,31(2):455-465
[15]Lignola G P,Prota A,Manfredi G,et al.Unified theory for confinement of RC solid and hollow circular columns[J].Composites Part B:Engineering,2008,39(7-8):1151-1160
[16]GB 50111-2006铁路工程抗震设计规范[S].北京:中国计划出版社,2009(GB 50111-2006 Code for seismicdesign of railway engineering[S].Beijing:China Planning Press,2009(in Chinese))
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[19]JGJ 101-96建筑抗震试验方法规程[S].北京:中国建筑工业出版社,2008(JGJ 101-96 Specification of testing methods for earthquake resistant building[S].Beijing:China Architecture&Building Press,2008(in Chinese))
[20]蒋丽忠,邵光强,姜静静,等.高速铁路圆端形实体桥墩抗震性能试验研究[J].土木工程学报,2013,46(3):86-95(Jiang Lizhong,Shao Guangqiang,Jiang Jingjing,et al.Experimental study on seismic performance of solid piers with rounded cross-section in high-speed railway[J].China Civil Engineering Journal,2013,46(3):86-95(in Chinese))
[21]Park R.Evaluation of ductility of structures and structural assemblages from laboratory testing[J].Bulletin of the New Zealand National Society for Earthquake Engineering,1989,22(3):155-166
[22]王东升,李宏男,赵颖华,等.钢筋混凝土桥墩基于位移的抗震设计方法[J].土木工程学报,2006,39(10):80-86(Wang Dongsheng,Li Hongnan,Zhao Yinghua,et al.Displacement-based seismic design method of RCbridge piers[J].China Civil Engineering Journal,2006,39(10):80-86(in Chinese))
[23]刘艳辉,赵世春,强士中.城市高架桥抗震性能水准的量化[J].西南交通大学学报,2010,45(1):54-58,64(Liu Yanhui,Zhao Shichun,Qiang Shizhong.Quantification of seismic performance levels for urban viaduct[J].Journal of Southwest Jiaotong University,2010,45(1):54-58,64(in Chinese))
[24]宋晓东.桥梁高墩延性抗震性能的理论和试验研究[D].上海:同济大学,2004(Song Xiaodong.Theoretical and experimental study on ductility seismic performance of reinforced concrete high piers[D].Shanghai:Tongji University,2004(in Chinese))
[25]Hose Y,Silva P,Seible F.Development of a Performance evaluation database for concrete bridge components and systems under simulated seismic loads[J].Earthquake Spectra,2000,16(2):413-442
[26]佐雪.基于拟静力与振动台试验的铁路圆端空心墩抗震性能研究[D].成都:西南交通大学,2018(Zuo Xue.Research on seismic ductility of round-end hollow piers based on quasi-static test and shaking table test[D].Chengdu:Southwest Jiaotong University,2018(in Chinese))
[27]Chopra A K.Dynamics of structures[D].Prentice Hal:University of California at berkeley,2006
[28]Kowalsky M J.Displacement based design:a methodology for seismic design applied to RC bridge piers[D].San Diego,CA:University of California,1994
[29]Priestley M J N.Myths and fallacies in earthquake engineering,revisited[M].Pavia,Italy:IUSS press,2003
[30]Iwan W D,Guyader A.A study of the accuracy of the capacity spectrum method in engineering analysis[C]//Proc,3rd US-Japan Workshop on Performance-Based Earthquake Engineering Methodology for Reinforced Concrete Building Structures.Seattle,Washington:Pacific Earthquake Engineering Research Center,2001
[31]Hwang J.Evaluation of equivalent linear analysis method of bridge isolation[J].Journal of Structural Engineering,1996,122(8):972-976
[32]Elmenshawi A,Brown T.Hysteretic energy and damping capacity of flexural elements constructed with different concrete strengths[J].Engineering Structures,2010,32(1):297-305
[2]Yeh Y K,Mo Y L,Yang C Y.Seismic performance of rectangular hollow bridge columns[J].Journal of Structural Engineering,2002,128(1):60-68
[3]Mo Y L,Wong D C,Maekawa K.Seismic performance of hollow bridge columns[J].ACI Structural Journal,2003,100(3):337-348
[4]Yeh Y K,Mo Y L,Yang CY.Full-scale tests on rectangular hollow bridge piers[J].Materials and Structures,2002,35(2):117-125
[5]Calvi G M,Pavese A,Rasulo A,et al.Experimental and numerical studies on the seismic response of RC hollow bridge piers[J].Bulletin of Earthquake Engineering,2005,3(3):267-297
[6]Shin M,Choi YY,Sun CH,et al.Shear strength model for reinforced concrete rectangular hollow piers[J].Engineering Structures,2013,56:958-969
[7]Cassese P,Ricci P,Verderame G M.Experimental study on the seismic performance of existing reinforced concrete bridge piers with hollow rectangular section[J].Engineering Structures,2017,144(8):88-106
[8]宗周红,陈树辉,夏樟华.钢筋混凝土箱型高墩双向拟静力试验研究[J].防灾减灾工程学报,2010,30(4):369-374(Zong Zhouhong,Chen Shuhui,Xia Zhanghua.Bi-axial quasi-static testing research of high hollow reinforced concrete piers[J].Journal of Disaster Prevention and Mitigation Engineering,2010,30(4):369-374(in Chinese))
[9]罗征.钢筋混凝土矩形空心墩抗震性能试验研究[D].上海:同济大学,2012(Luo Zheng.Experimental study on seismic performance of reinforced concrete columns[D].Shanghai:Tongji University,2012(in Chinese))
[10]孙治国,王东升,郭迅,等.地震作用下RC薄壁空心墩抗剪强度比较研究[J].土木工程学报,2013,46(12):81-89(Sun Zhiguo,Wang Dongsheng,Guo Xun,et al.Comparative study on shear strength of RC thin-walled hollow bridge piers under seismic effect[J].China Civil Engineering Journal,2013,46(12):81-89(in Chinese))
[11]韩强,周雨龙,杜修力.钢筋混凝土矩形空心桥墩抗震性能[J].工程力学,2015,32(3):28-40(Han Qiang,Zhou Yulong,Du Xiuli.Seismic performance of reinforced concrete rectangular hollow bridge columns[J].Engineering Mechanics,2015,32(3):28-40.(in Chinese))
[12]Zahn F A,Park R,Priestley M J N.Flexural strength and ductility of circular hollow reinforced concrete piers without confinement on inside face[J].ACI Structural Journal,1990,87(2):156-166
[13]Yeh Y K,Mo Y L,Yang C Y.Seismic performance of hollow circular bridge piers[J].ACI Structural Journal,2001,98(6):862-871
[14]Turmo J,Ramos G,Aparicio A C.Shear truss analogy for concrete members of solid and hollow circular cross section[J].Engineering Structures,2009,31(2):455-465
[15]Lignola G P,Prota A,Manfredi G,et al.Unified theory for confinement of RC solid and hollow circular columns[J].Composites Part B:Engineering,2008,39(7-8):1151-1160
[16]GB 50111-2006铁路工程抗震设计规范[S].北京:中国计划出版社,2009(GB 50111-2006 Code for seismicdesign of railway engineering[S].Beijing:China Planning Press,2009(in Chinese))
[17]刘林.高墩大跨铁路桥梁抗震设计与减震控制研究[D].北京:北京交通大学,2004(Liu Lin.Research on seismic design and seismic isolation and reduction control of high-pier and long-span railway bridges[D].Beijing:Beijing Jiaotong University,2004(in Chinese))
[18]蒋丽忠,邵光强,王辉,等.高速铁路圆端形空心桥墩抗震性能试验研究[J].工程力学,2014,31(3):72-82(Jiang Lizhong,Shao Guangqiang,Wang Hui,et al.Experimental study on seismic performance of hollow piers with rounded rectangular cross section in high-speed railways[J].Engineering Mechanics,2014,31(3):72-82(in Chinese))
[19]JGJ 101-96建筑抗震试验方法规程[S].北京:中国建筑工业出版社,2008(JGJ 101-96 Specification of testing methods for earthquake resistant building[S].Beijing:China Architecture&Building Press,2008(in Chinese))
[20]蒋丽忠,邵光强,姜静静,等.高速铁路圆端形实体桥墩抗震性能试验研究[J].土木工程学报,2013,46(3):86-95(Jiang Lizhong,Shao Guangqiang,Jiang Jingjing,et al.Experimental study on seismic performance of solid piers with rounded cross-section in high-speed railway[J].China Civil Engineering Journal,2013,46(3):86-95(in Chinese))
[21]Park R.Evaluation of ductility of structures and structural assemblages from laboratory testing[J].Bulletin of the New Zealand National Society for Earthquake Engineering,1989,22(3):155-166
[22]王东升,李宏男,赵颖华,等.钢筋混凝土桥墩基于位移的抗震设计方法[J].土木工程学报,2006,39(10):80-86(Wang Dongsheng,Li Hongnan,Zhao Yinghua,et al.Displacement-based seismic design method of RCbridge piers[J].China Civil Engineering Journal,2006,39(10):80-86(in Chinese))
[23]刘艳辉,赵世春,强士中.城市高架桥抗震性能水准的量化[J].西南交通大学学报,2010,45(1):54-58,64(Liu Yanhui,Zhao Shichun,Qiang Shizhong.Quantification of seismic performance levels for urban viaduct[J].Journal of Southwest Jiaotong University,2010,45(1):54-58,64(in Chinese))
[24]宋晓东.桥梁高墩延性抗震性能的理论和试验研究[D].上海:同济大学,2004(Song Xiaodong.Theoretical and experimental study on ductility seismic performance of reinforced concrete high piers[D].Shanghai:Tongji University,2004(in Chinese))
[25]Hose Y,Silva P,Seible F.Development of a Performance evaluation database for concrete bridge components and systems under simulated seismic loads[J].Earthquake Spectra,2000,16(2):413-442
[26]佐雪.基于拟静力与振动台试验的铁路圆端空心墩抗震性能研究[D].成都:西南交通大学,2018(Zuo Xue.Research on seismic ductility of round-end hollow piers based on quasi-static test and shaking table test[D].Chengdu:Southwest Jiaotong University,2018(in Chinese))
[27]Chopra A K.Dynamics of structures[D].Prentice Hal:University of California at berkeley,2006
[28]Kowalsky M J.Displacement based design:a methodology for seismic design applied to RC bridge piers[D].San Diego,CA:University of California,1994
[29]Priestley M J N.Myths and fallacies in earthquake engineering,revisited[M].Pavia,Italy:IUSS press,2003
[30]Iwan W D,Guyader A.A study of the accuracy of the capacity spectrum method in engineering analysis[C]//Proc,3rd US-Japan Workshop on Performance-Based Earthquake Engineering Methodology for Reinforced Concrete Building Structures.Seattle,Washington:Pacific Earthquake Engineering Research Center,2001
[31]Hwang J.Evaluation of equivalent linear analysis method of bridge isolation[J].Journal of Structural Engineering,1996,122(8):972-976
[32]Elmenshawi A,Brown T.Hysteretic energy and damping capacity of flexural elements constructed with different concrete strengths[J].Engineering Structures,2010,32(1):297-305