铁路大跨度混凝土拱桥徐变变形控制因素研究
|
摘要
研究目的:混凝土拱桥具有较大的横竖向刚度、良好的环境适应性和较高的经济价值,在山区大跨度铁路桥梁建设中得到推广应用。然而,受拱结构的受力特点和混凝土的材料特性影响,混凝土拱桥在后期运营过程中会出现徐变下挠变形,直接影响线路的平顺度,进而影响行车的安全性和舒适性。本文以一座在建的铁路大跨度混凝土拱桥为研究对象,从分析混凝土徐变机理及影响因素出发,选取工法、加载龄期、铺轨时间以及拱上结构形式等因素作为变量,基于CEB-FIP(1990)徐变本构模型开展结构的徐变变形研究,分析不同因素下混凝土拱桥的徐变变形情况,探究徐变变形控制的主要因素。研究结论:(1)平衡加载法的受力模式使得拱圈顶底板应力差较大,导致后期徐变变形较大;(2)悬臂拼装法可以节省施工工期,但预制时间较短也会导致后期的徐变变形较大;(3)延长混凝土龄期和减少拱上结构重量对抑制后期徐变下挠有一定的帮助,但效果并不明显;(4)延迟铺轨对减小长期徐变下挠有明显的改善;(5)在以上四种影响拱圈后期收缩徐变的因素中,工法和铺轨时间对后期混凝土收缩徐变影响较大,可作为大跨度拱桥徐变变形控制技术的关键因素;(6)本文研究可为类似结构的设计提供参考和借鉴。
Research purposes: Due to its high transverse vertical stiffness,good environmental adaptability and high economic advantages,concrete arch bridges have been widely used in the construction of large-span railway bridges in mountainous areas. However,due to the mechanical characteristics of arch structure and the material properties of concrete,creep deflection will appear in the later operation which directly affects the driving safety and comfort. Based on a long-span concrete arch bridge under construction,the mechanism and influence factors of creep are analyzed.With construction method,age,time of track-laying and arch structure selected as variables,the study on creep deformation is carried out based on the CEB-FIP creep constitutive model( 1990),and the main factors of creep deformation control can be obtained.Research conclusions:( 1) Balanced loading method makes the stress difference between the roof and floor of the arch ring larger which lead to the larger later creep deformation.( 2) Cantilever assembly method can save the construction period,but the short prefabrication time will also lead to large creep deformation.( 3) Prolonging the concrete age and reducing the weight of the arch structure are helpful for restraining the creep deformation,but the effect is not obvious.( 4) Delayed track laying can reduce creep deformation obviously.( 5) Construction method and track laying time among the above four factors have a great influence on the later shrinkage and creep of concrete,which can be used as the key factors in the creep deformation control technology of long-span arch bridge.( 6) The research results can provide reference and basis for the design of similar structures.
Research purposes: Due to its high transverse vertical stiffness,good environmental adaptability and high economic advantages,concrete arch bridges have been widely used in the construction of large-span railway bridges in mountainous areas. However,due to the mechanical characteristics of arch structure and the material properties of concrete,creep deflection will appear in the later operation which directly affects the driving safety and comfort. Based on a long-span concrete arch bridge under construction,the mechanism and influence factors of creep are analyzed.With construction method,age,time of track-laying and arch structure selected as variables,the study on creep deformation is carried out based on the CEB-FIP creep constitutive model( 1990),and the main factors of creep deformation control can be obtained.Research conclusions:( 1) Balanced loading method makes the stress difference between the roof and floor of the arch ring larger which lead to the larger later creep deformation.( 2) Cantilever assembly method can save the construction period,but the short prefabrication time will also lead to large creep deformation.( 3) Prolonging the concrete age and reducing the weight of the arch structure are helpful for restraining the creep deformation,but the effect is not obvious.( 4) Delayed track laying can reduce creep deformation obviously.( 5) Construction method and track laying time among the above four factors have a great influence on the later shrinkage and creep of concrete,which can be used as the key factors in the creep deformation control technology of long-span arch bridge.( 6) The research results can provide reference and basis for the design of similar structures.
引文
[1]赵人达,张正阳.我国钢管混凝土劲性骨架拱桥发展综述[J].桥梁建设,2016(6):45-49.Zhao Renda, Zhang Zhengyang. A Summary of Development of Concrete-Filled Steel Tube Framed Arch Bridges in China[J]. Bridge Construction,2016(6):45-49.
[2]朱颖,徐勇,陈列,等.沪昆客运专线北盘江特大桥桥位、线路高程及桥式方案比选[J].高速铁路技术,2013(4):1-6.Zhu Ying,Xu Yong,Chen Lie,etc. Altenative Solution of BEipanjiang Bridge Site,Route Height and Bridge Type on Shanghai-Kunming Passenger Dedicated Railway[J]. High Speed Railway Technology,2013(4):1-6.
[3]谢肖礼,秦荣.收缩徐变对钢管混凝土拱桥影响的理论研究[J].桥梁建设,2001(4):1-4.Xie Xiaoli,Qin Rong. The Theoretic Research on the Effect of Creep and Shrinkage of CFST Arch Bridge[J]. Bridge Construction,2001(4):1-4.
[4]王存国,黄纳新,崔阳华.广深港客运专线连续梁拱后期变形预估研究[J].铁道工程学报,2014(2):67-71.Wang Cunguo,Huang Naxin,Cui Yanghua. Study by Prediction for Post Deformation of Continuous Beamarch Bridge on Guangzhou-Shenzhen-Hongkong Passenger Dedicated Railway[J]. Journal of Railway Engineering Society,2014(2):67-71.
[5]马伊硕.徐变对大跨度钢管混凝土拱桥静力及动力可靠性的影响研究[D].北京:北京交通大学,2013.Ma Yishuo. Creep Influence on Static and Dynamic Reliability of Long-span Concrete Filled Steel Tube Arch Bridges[D]. Beijing:Beijing Jiaotong University,2013.
[6]张进.采用组合法施工的钢筋混凝土拱桥徐变收缩影响研究[D].重庆:重庆交通大学,2015.Zhang Jin. Study on Effect Creep and Shrinkage of RC Arch Bridge Utilizing Combined Construction Method[D]. Chongqing:Chongqing Jiaotong University,2015.
[7]谢海清.特大跨度铁路劲性骨架混凝土拱桥结构选型及关键力学问题研究[D].成都:西南交通大学,2012.Xie Haiqing. Study on Structural Type Selection and Mechanical Behaviors of Long-span Railway Concrete Arch Bridge with Rigid Skeleton[D]. Chengdu:Southwest Jiaotong University,2012.
[8]林春姣,郑皆连.南盘江特大桥拱圈混凝土斜拉扣挂法施工分析[J].桥梁建设,2016(5):116-121.Lin Chunjiao,Zheng Jielian. Analysis of Construction of Main Arch Rib Concrete of Nanpan River Bridge Using Fastening Stay Method[J]. Bridge Construction,2016(5):116-121.
[2]朱颖,徐勇,陈列,等.沪昆客运专线北盘江特大桥桥位、线路高程及桥式方案比选[J].高速铁路技术,2013(4):1-6.Zhu Ying,Xu Yong,Chen Lie,etc. Altenative Solution of BEipanjiang Bridge Site,Route Height and Bridge Type on Shanghai-Kunming Passenger Dedicated Railway[J]. High Speed Railway Technology,2013(4):1-6.
[3]谢肖礼,秦荣.收缩徐变对钢管混凝土拱桥影响的理论研究[J].桥梁建设,2001(4):1-4.Xie Xiaoli,Qin Rong. The Theoretic Research on the Effect of Creep and Shrinkage of CFST Arch Bridge[J]. Bridge Construction,2001(4):1-4.
[4]王存国,黄纳新,崔阳华.广深港客运专线连续梁拱后期变形预估研究[J].铁道工程学报,2014(2):67-71.Wang Cunguo,Huang Naxin,Cui Yanghua. Study by Prediction for Post Deformation of Continuous Beamarch Bridge on Guangzhou-Shenzhen-Hongkong Passenger Dedicated Railway[J]. Journal of Railway Engineering Society,2014(2):67-71.
[5]马伊硕.徐变对大跨度钢管混凝土拱桥静力及动力可靠性的影响研究[D].北京:北京交通大学,2013.Ma Yishuo. Creep Influence on Static and Dynamic Reliability of Long-span Concrete Filled Steel Tube Arch Bridges[D]. Beijing:Beijing Jiaotong University,2013.
[6]张进.采用组合法施工的钢筋混凝土拱桥徐变收缩影响研究[D].重庆:重庆交通大学,2015.Zhang Jin. Study on Effect Creep and Shrinkage of RC Arch Bridge Utilizing Combined Construction Method[D]. Chongqing:Chongqing Jiaotong University,2015.
[7]谢海清.特大跨度铁路劲性骨架混凝土拱桥结构选型及关键力学问题研究[D].成都:西南交通大学,2012.Xie Haiqing. Study on Structural Type Selection and Mechanical Behaviors of Long-span Railway Concrete Arch Bridge with Rigid Skeleton[D]. Chengdu:Southwest Jiaotong University,2012.
[8]林春姣,郑皆连.南盘江特大桥拱圈混凝土斜拉扣挂法施工分析[J].桥梁建设,2016(5):116-121.Lin Chunjiao,Zheng Jielian. Analysis of Construction of Main Arch Rib Concrete of Nanpan River Bridge Using Fastening Stay Method[J]. Bridge Construction,2016(5):116-121.