高低塔斜拉桥施工控制仿真计算
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摘要
复式提篮拱桥是近些年来在提篮拱桥基础上发展起来的一种新型拱桥结构型式。此类桥型结构新颖,受力及构造复杂,空间效应明显,国内外研究成果相对较少。因此,开展复式提篮拱桥力学性能分析研究具有重要的理论意义和实用价值。
本文根据平顶山市城东河路湛河桥主桥—复式提篮拱桥的结构特点,采用空间有限元法对该桥进行离散,用空间梁单元模拟系梁、端横梁、中横梁、纵梁和拱肋等构件,用板单元模拟桥面板,用只承受拉力的杆单元模拟吊杆,建立了该复式提篮拱桥的空间有限元计算模型,利用桥梁有限元计算程序ANSYS对该桥进行了初始平衡状态下的静力、稳定性分析,对桥梁的设计进行了成桥状态设计验算,同时探讨了吊杆损伤对该桥型静力、稳定性的影响。综合以上工作,本文得出以下结论:
(1)拱肋和系梁受力关于跨中对称。在吊杆位置系梁的轴力、剪力、弯矩都有较大的突变,拱肋的剪力也有较大的突变,弯矩和轴力变化不明显。由于端横梁的约束作用,系梁的弯矩图与固端梁相似,系梁整体处于全截面受压状态。拱肋受力以轴压力为主,除拱脚外其它位置所受弯矩和剪力都较小,但面外弯矩相对较大,拱脚及内、外拱肋连接处受力复杂,该桥型空间效应明显。
(2)吊杆受力关于跨中和纵轴对称,吊杆张力分布大致均匀。内拱吊杆最低安全系数为3.38,外拱吊杆最低安全系数为3.09,满足最小安全系数不得小于2.5的规定,且有较大安全储备。
(3)全桥变形以竖向变形为主,拱肋顶部发生了较大的横向变形。系梁最大竖向位移为一0.0283m,拱肋最大竖向位移为一0.0337m,最大横向位移为0.1m。该桥梁在荷载作用下位移都控制在规范规定的范围之内,满足设计规范正常使用极限状态下的变形要求。
(4)该桥梁的第1阶稳定系数在7.975^8.67之间,满足一般拱桥稳定系数大于4的要求,说明桥梁整体稳定性较好,该桥的失稳模态均以组合拱肋的面外扭转失稳为主,说明该桥拱肋的面外刚度相对面内刚度较小,对整个桥梁的稳定起控制作用,该桥的竖向失稳及桥面系横向失稳在较高阶中才出现,说明桥梁整体竖向刚度及桥面系横向刚度远大于拱肋的横向和扭转刚度。
Double X-arch bridge, is one of the new arch bridge types.This type of bridge is of novelty style with complex constitution and distinct spatial mechanics effect, and the research outcome about the double X-arch bridge has only a few in our country and overseas. Therefore, conducting the analyses of double X-arch bridges' mechanical properties takes on its important theoretical senses and practical values.
In this dissertation, the main bridge of Zhanhe bridge over Chengdong River in Pingdingshan City, a double X-arch bridge is discretized by the FEM according to its structural characteristics with the spatial beam element simulating the longitudinal tied beams,end floor beams, middle floor beams, axch ribs and the like, and with the plate element simulating the bridge deck, and with the truss element simulating the suspenders to erect the bridge's spatial mechanical computational finite element model. Suspenders' initial force is calculated by influence matrix method and optimized, which make the computed results of suspenders' responsive internal force, main structures' internal force and deformation consistent with the data of design; Finite element software ANSYS special for bridges' structure analyses was applied for analyses of this double X-arch bridge's mechanical properties of the static state, dynamic characteristics and stability on the initial equilibrium configuration, and the design of this double X-arch bridge was checked up in its completed stage. Moreover, the influences that the damage of the suspenders has brought on to this type of bridge's mechanical properties of the static state, dynamic characteristics and stability are discussed. Summarizing above work, this dissertation arrived at some conclusions as follows:
(1) The internal forces of arch ribs and longitudinal tied beams are in symmetry of the span centre. The axial forces and shearing forces and moments of longitudinal tied beams have sudden changes in the position of suspenders; the shearing forces of arch ribs also have sudden changes in the position of suspenders, but the moments &axial forces of arch ribs have no conspicuous changes. For the constrained action of end floor beams, the moment diagrams of longitudinal tied beams resemble like that of continuous beams with the full cross-section compressing except the under brim of span center cross-section with a little tension stress, whose stress still meet the require of A-type prestressed units. The internal forces of arch ribs give priority to compression force by contrast with shearing forces&moments within plane. Arch ribs of the bridge also bear great out-plane moments, which indicate double X-arch bridge has obvious spatial effect in mechanical properties.
(2) Internal forces of suspenders are in symmetry of the span centre and tension values of the suspenders are also relatively even. The safety factors of suspenders under eachconsidered load case in static state, with safety factor3.38 of inside suspenders and with minimum safety factor3.09 of outboard suspenders, which meet the requires in bridge design codes of large than 2.5 and have a comfortable margin.
(3) The vertical displacement plays a dominant role in the integral deformation of this bridge and greater transverse displacement happens in the vault of arch ribs. In each considered load case in static state, the maximal vertical displacement of tied beams is -0.0283m, the maximal vertical and transverse displacement of arch ribs is -0.0337m and0.1m. The deformation of each members of this bridge in each considered load case are within the specialized range of bridge design codes, so that the deformation of each members of this bridge fulfils the deformation require of Serviceability limit-State.
(4) The bridge's 1 St order stability factors under considered cases are between 7.975 and8.67, which meet the require of large than 4and indicate the bridge has highly stability,the bridge's 1 St order buckling modes are all out-plane torsional buckling modes of compositearches which indicates the arches' stiffness out of plane is relatively smaller than that in plane and controls the stability of the bridge. The bridge's vertical buckling and the deck system's transverse buckling appear in the high order buckling modes, which indicates that the bridge's vertical stiffness and the deck system's transverse stiffness are much larger than the transverse and torsional stiffness of the composite arches.
本文根据平顶山市城东河路湛河桥主桥—复式提篮拱桥的结构特点,采用空间有限元法对该桥进行离散,用空间梁单元模拟系梁、端横梁、中横梁、纵梁和拱肋等构件,用板单元模拟桥面板,用只承受拉力的杆单元模拟吊杆,建立了该复式提篮拱桥的空间有限元计算模型,利用桥梁有限元计算程序ANSYS对该桥进行了初始平衡状态下的静力、稳定性分析,对桥梁的设计进行了成桥状态设计验算,同时探讨了吊杆损伤对该桥型静力、稳定性的影响。综合以上工作,本文得出以下结论:
(1)拱肋和系梁受力关于跨中对称。在吊杆位置系梁的轴力、剪力、弯矩都有较大的突变,拱肋的剪力也有较大的突变,弯矩和轴力变化不明显。由于端横梁的约束作用,系梁的弯矩图与固端梁相似,系梁整体处于全截面受压状态。拱肋受力以轴压力为主,除拱脚外其它位置所受弯矩和剪力都较小,但面外弯矩相对较大,拱脚及内、外拱肋连接处受力复杂,该桥型空间效应明显。
(2)吊杆受力关于跨中和纵轴对称,吊杆张力分布大致均匀。内拱吊杆最低安全系数为3.38,外拱吊杆最低安全系数为3.09,满足最小安全系数不得小于2.5的规定,且有较大安全储备。
(3)全桥变形以竖向变形为主,拱肋顶部发生了较大的横向变形。系梁最大竖向位移为一0.0283m,拱肋最大竖向位移为一0.0337m,最大横向位移为0.1m。该桥梁在荷载作用下位移都控制在规范规定的范围之内,满足设计规范正常使用极限状态下的变形要求。
(4)该桥梁的第1阶稳定系数在7.975^8.67之间,满足一般拱桥稳定系数大于4的要求,说明桥梁整体稳定性较好,该桥的失稳模态均以组合拱肋的面外扭转失稳为主,说明该桥拱肋的面外刚度相对面内刚度较小,对整个桥梁的稳定起控制作用,该桥的竖向失稳及桥面系横向失稳在较高阶中才出现,说明桥梁整体竖向刚度及桥面系横向刚度远大于拱肋的横向和扭转刚度。
Double X-arch bridge, is one of the new arch bridge types.This type of bridge is of novelty style with complex constitution and distinct spatial mechanics effect, and the research outcome about the double X-arch bridge has only a few in our country and overseas. Therefore, conducting the analyses of double X-arch bridges' mechanical properties takes on its important theoretical senses and practical values.
In this dissertation, the main bridge of Zhanhe bridge over Chengdong River in Pingdingshan City, a double X-arch bridge is discretized by the FEM according to its structural characteristics with the spatial beam element simulating the longitudinal tied beams,end floor beams, middle floor beams, axch ribs and the like, and with the plate element simulating the bridge deck, and with the truss element simulating the suspenders to erect the bridge's spatial mechanical computational finite element model. Suspenders' initial force is calculated by influence matrix method and optimized, which make the computed results of suspenders' responsive internal force, main structures' internal force and deformation consistent with the data of design; Finite element software ANSYS special for bridges' structure analyses was applied for analyses of this double X-arch bridge's mechanical properties of the static state, dynamic characteristics and stability on the initial equilibrium configuration, and the design of this double X-arch bridge was checked up in its completed stage. Moreover, the influences that the damage of the suspenders has brought on to this type of bridge's mechanical properties of the static state, dynamic characteristics and stability are discussed. Summarizing above work, this dissertation arrived at some conclusions as follows:
(1) The internal forces of arch ribs and longitudinal tied beams are in symmetry of the span centre. The axial forces and shearing forces and moments of longitudinal tied beams have sudden changes in the position of suspenders; the shearing forces of arch ribs also have sudden changes in the position of suspenders, but the moments &axial forces of arch ribs have no conspicuous changes. For the constrained action of end floor beams, the moment diagrams of longitudinal tied beams resemble like that of continuous beams with the full cross-section compressing except the under brim of span center cross-section with a little tension stress, whose stress still meet the require of A-type prestressed units. The internal forces of arch ribs give priority to compression force by contrast with shearing forces&moments within plane. Arch ribs of the bridge also bear great out-plane moments, which indicate double X-arch bridge has obvious spatial effect in mechanical properties.
(2) Internal forces of suspenders are in symmetry of the span centre and tension values of the suspenders are also relatively even. The safety factors of suspenders under eachconsidered load case in static state, with safety factor3.38 of inside suspenders and with minimum safety factor3.09 of outboard suspenders, which meet the requires in bridge design codes of large than 2.5 and have a comfortable margin.
(3) The vertical displacement plays a dominant role in the integral deformation of this bridge and greater transverse displacement happens in the vault of arch ribs. In each considered load case in static state, the maximal vertical displacement of tied beams is -0.0283m, the maximal vertical and transverse displacement of arch ribs is -0.0337m and0.1m. The deformation of each members of this bridge in each considered load case are within the specialized range of bridge design codes, so that the deformation of each members of this bridge fulfils the deformation require of Serviceability limit-State.
(4) The bridge's 1 St order stability factors under considered cases are between 7.975 and8.67, which meet the require of large than 4and indicate the bridge has highly stability,the bridge's 1 St order buckling modes are all out-plane torsional buckling modes of compositearches which indicates the arches' stiffness out of plane is relatively smaller than that in plane and controls the stability of the bridge. The bridge's vertical buckling and the deck system's transverse buckling appear in the high order buckling modes, which indicates that the bridge's vertical stiffness and the deck system's transverse stiffness are much larger than the transverse and torsional stiffness of the composite arches.
引文
[1] 严志刚,盛洪飞.钢管混凝土拱桥的发展优势[J].东北公路,2002,25(1):31～33.
[2] 陈宝春.钢管混凝土拱桥设计与施工[M].北京:人民交通出版社,1999.
[3] 金成棣.预应力混凝土梁拱组合桥梁——设计研究与实践[M].北京:人民交通出版社,2001.
[4] 江同心,华有恒.关于钢管混凝土拱桥若干问题的探讨[J].桥梁建设, 2001,(1):24～27,31.
[5] 项贻强,李新生,申永刚,薛静平.空间梁拱组合式桥梁的分析理论及试验研究[J].中国公路报,2002,15(1):67～71.
[6] 李乔,李丽.异型拱桥结构内力分析[J].公路交通科技,2001,18(1):31～35.
[7] 陈兵,朱正刚,罗特军.中、下承式拱桥吊杆体系研究[J].四川建筑,2002, 22(4):29～30,32.
[8] 田学民,李乔,张清华.尼尔森体系提篮拱桥的内力分布[J].西南交通大学学报,2002, 37(5):505～509.
[9] Ren Wei-Xin, Harik I E. Experimental and Numerical Modal Analysis of a Steel Arch Bridge[C], Proc. of 2th International Conference on Advances in Structural Engineering and Mechanics. Pusan, Korea. 2002.13～21.
[10] Yabuki Tetsuya, Kuranishi Shigeru. Evaluation of stability for deck-type steel arch bridges[J].Structural Engineering/Earthquake Engineering,1993,10(3): 117～127.
[11] 李宏辉.九曲河提篮拱桥受力特性分析[D].成都:西南交通大学,2002.
[12] 程海根,强士中.钢管混凝土提篮拱动力特性分析[J].公路交通科技,2002, 19(3): 63～65.
[13] 汤国栋.拱桥吊杆的安全忧虑与对策.第一届全国公路科技创新高层论坛论文集[C].北京:外文出版社,2002.
[14] 钟轶峰 , 邓朝荣 , 殷学纲 . 提篮拱桥吊索静张力测试与计算 [J]. 重庆建筑大学学报,2003,25(2):54～57,72.
[15] 殷学纲,姚建军.中承式拱桥的吊索损伤对吊索系张力的影响[J].中国公路学报,2004,17(1):45～48.
[16] 谢幼藩,陈克济。拱桥面内稳定计算探讨[J].西南交通大学学报,1982,17(1):16-21.
[17] 项海帆,高等桥梁结构理论[M],人民交通出版社,2001(4).
[18] 邱文亮,钢管混凝土拱桥拱肋侧倾角对稳定性能的影响[J].公路交通科技,2004.
[19] 叶建龙,孙建渊,席广恒.梁拱组合桥柔性吊杆张拉力的确定及分析[J].东北公路,2000,23(1):44～47.
[20] 殷学纲,姚建军.中承式拱桥的吊索损伤对吊索系张力的影响[J].中国公路学报,2004,17(1):45～48.
[21] 张维国,贾乃波,刘祥高,周绍峰.再谈系杆拱桥吊杆初始张拉力的计算方法[J].水利水电科技进展,2002,22(3):26～28,70.
[22] 顾安邦,徐君兰.中、下承式拱桥短吊杆结构行为分析[J].重庆交通学院学报,2002, 21(5):1～3.
[23] Lin.T.Y and Burns N.H. Design of Pressressed concrete structures 3rd edition ,John wiley and sons, New York,1981.
[24] Nazmy A S. Stability and load-carrying capacity of three- dimensional long-span steel arch bridges[J].Computers & Structures, 1997,65(6):857～868.
[25] 孙建渊,李国平,石洞,朱敏.梁拱组合桥吊杆多次张拉的分析研究[J].华东公路,1999, (5):30～33.
[26] 陈大庆.系杆拱桥刚性吊杆一次张拉设计[J].华东公路,1999,(5):45～47.
[27] 楚海建,何结兵,顾爱军,梁金栋.系杆拱桥吊杆一次张拉方案的优化设计[J].华东公路,2002,(1):46～48.
[28] 彭宣茂.系杆拱桥吊杆初始张拉力的计算方法[J].水利水电科技进展, 2000,20(6): 32～33,38,69.
[29] 虞建成,邵容光,王小林.系杆拱桥吊杆初始张拉力及施工控制[J].东南大学学报,1998,28(3):112～116.
[30] 梅尧坤,李丽君.单拱面预应力混凝土系杆拱桥设计简介[J].桥梁建设, 1994,(2): 25～27.
[2] 陈宝春.钢管混凝土拱桥设计与施工[M].北京:人民交通出版社,1999.
[3] 金成棣.预应力混凝土梁拱组合桥梁——设计研究与实践[M].北京:人民交通出版社,2001.
[4] 江同心,华有恒.关于钢管混凝土拱桥若干问题的探讨[J].桥梁建设, 2001,(1):24～27,31.
[5] 项贻强,李新生,申永刚,薛静平.空间梁拱组合式桥梁的分析理论及试验研究[J].中国公路报,2002,15(1):67～71.
[6] 李乔,李丽.异型拱桥结构内力分析[J].公路交通科技,2001,18(1):31～35.
[7] 陈兵,朱正刚,罗特军.中、下承式拱桥吊杆体系研究[J].四川建筑,2002, 22(4):29～30,32.
[8] 田学民,李乔,张清华.尼尔森体系提篮拱桥的内力分布[J].西南交通大学学报,2002, 37(5):505～509.
[9] Ren Wei-Xin, Harik I E. Experimental and Numerical Modal Analysis of a Steel Arch Bridge[C], Proc. of 2th International Conference on Advances in Structural Engineering and Mechanics. Pusan, Korea. 2002.13～21.
[10] Yabuki Tetsuya, Kuranishi Shigeru. Evaluation of stability for deck-type steel arch bridges[J].Structural Engineering/Earthquake Engineering,1993,10(3): 117～127.
[11] 李宏辉.九曲河提篮拱桥受力特性分析[D].成都:西南交通大学,2002.
[12] 程海根,强士中.钢管混凝土提篮拱动力特性分析[J].公路交通科技,2002, 19(3): 63～65.
[13] 汤国栋.拱桥吊杆的安全忧虑与对策.第一届全国公路科技创新高层论坛论文集[C].北京:外文出版社,2002.
[14] 钟轶峰 , 邓朝荣 , 殷学纲 . 提篮拱桥吊索静张力测试与计算 [J]. 重庆建筑大学学报,2003,25(2):54～57,72.
[15] 殷学纲,姚建军.中承式拱桥的吊索损伤对吊索系张力的影响[J].中国公路学报,2004,17(1):45～48.
[16] 谢幼藩,陈克济。拱桥面内稳定计算探讨[J].西南交通大学学报,1982,17(1):16-21.
[17] 项海帆,高等桥梁结构理论[M],人民交通出版社,2001(4).
[18] 邱文亮,钢管混凝土拱桥拱肋侧倾角对稳定性能的影响[J].公路交通科技,2004.
[19] 叶建龙,孙建渊,席广恒.梁拱组合桥柔性吊杆张拉力的确定及分析[J].东北公路,2000,23(1):44～47.
[20] 殷学纲,姚建军.中承式拱桥的吊索损伤对吊索系张力的影响[J].中国公路学报,2004,17(1):45～48.
[21] 张维国,贾乃波,刘祥高,周绍峰.再谈系杆拱桥吊杆初始张拉力的计算方法[J].水利水电科技进展,2002,22(3):26～28,70.
[22] 顾安邦,徐君兰.中、下承式拱桥短吊杆结构行为分析[J].重庆交通学院学报,2002, 21(5):1～3.
[23] Lin.T.Y and Burns N.H. Design of Pressressed concrete structures 3rd edition ,John wiley and sons, New York,1981.
[24] Nazmy A S. Stability and load-carrying capacity of three- dimensional long-span steel arch bridges[J].Computers & Structures, 1997,65(6):857～868.
[25] 孙建渊,李国平,石洞,朱敏.梁拱组合桥吊杆多次张拉的分析研究[J].华东公路,1999, (5):30～33.
[26] 陈大庆.系杆拱桥刚性吊杆一次张拉设计[J].华东公路,1999,(5):45～47.
[27] 楚海建,何结兵,顾爱军,梁金栋.系杆拱桥吊杆一次张拉方案的优化设计[J].华东公路,2002,(1):46～48.
[28] 彭宣茂.系杆拱桥吊杆初始张拉力的计算方法[J].水利水电科技进展, 2000,20(6): 32～33,38,69.
[29] 虞建成,邵容光,王小林.系杆拱桥吊杆初始张拉力及施工控制[J].东南大学学报,1998,28(3):112～116.
[30] 梅尧坤,李丽君.单拱面预应力混凝土系杆拱桥设计简介[J].桥梁建设, 1994,(2): 25～27.