中、下承式拱桥吊索的模态分析与张力测定
详细信息    本馆镜像全文|  推荐本文 |  |   获取CNKI官网全文
摘要
中、下承式拱桥由于桥型优美是我国城市桥梁中应用发展很快的一种桥型,据有关资料介绍,我国现在已建成的中、下承式拱桥有300余座,目前仍在向更大跨径、更大规模的方向发展,应用区域和范围也在不断扩大。但是,近年来也连续出现了若干起中、下承式拱桥的垮塌事故,造成了严重的人员伤亡与经济损失。从这些事故分析中可以得出这样的结论:中、下承式拱桥的断桥与垮塌事故大多与吊索的健康状态有关,若能对拱桥吊索的健康状态进行经常及时地或实时在线地监测与诊断,多数中、下承式拱桥的重大事故是可以避免的。
     中、下承式拱桥主要由拱肋、桥面系(系杆梁)及吊索系3部分组成,其中吊索系不但是主要的传力(承力)构件,也是易损构件,主要的损伤包括:吊索中部分钢丝断裂、钢丝锈蚀、锚固失效等。无论哪一种损伤,都会引起吊索拉伸刚度的变化,而拱桥桥面系可视为由吊索弹性支承于拱肋上的一个超静定结构,部分吊索刚度的变化必然引起吊索系承受荷载的重新分配,即必然引起吊索系静张力的变化。因此,吊索的静张力是拱桥健康状况的敏感指标,可以根据吊索系静张力的实际测量值与拱桥健康档案中的吊索系静张力值之比较,来对拱桥的健康状况进行诊断与评估。
     当前,中、下承式拱桥吊索的张力测定方法主要有2种:直接法和间接法,在工程实际中主要使用间接法,振动法是间接法中最经常使用的一种方法。振动法测定吊索张力可以分为2个方面:张力计算公式;吊索振动频率的测试。目前,振动测试技术已经比较成熟,可以由振动信号十分精确地提取出吊索的振动频率。目前,振动法中测定吊索张力公式所用理论主要借助于斜拉桥斜拉索的张力测定理论。在斜拉索的张力测定中,由于斜拉索长度较大,其弯曲刚度和边界条件影响较小,一般可以忽略不计。中、下承式拱桥不同于斜拉桥,在中、下承式拱桥中,由于拱肋主要承受压力,失稳问题比较突出,矢高不可能太大,所以中、下承式拱桥吊索的长度一般较小。如果将斜拉索张力测定理论直接应用于吊索,特别是短吊索,则会产生较大误差,不能满足实际工程使用要求。吊索的张力测定必须考虑弯曲刚度和边界条件的影响。基于这一背景,本文的主要工作就是提出适合于中、下承式拱桥吊索张力测定的张力计算实用公式。
     在中、下承式拱桥吊索张力测定的理论研究中,当不考虑吊索弯曲刚度的影响时,吊索可以看成是一根张紧的弦,由于没有考虑弯曲刚度的影响,其张力与振动频率存在着简单的关系,张力计算十分方便。当只考虑吊索弯曲刚度的影响而将吊索两端的边界条件视为简支时,通过理论分析也可以直接推导出吊索张力与其横向振动频率关系的计算公式。当同时考虑吊索弯曲刚度和吊索两端固定支承的边界条件影响时,吊索的张力与吊索横向振动频率关系的方程是超越方程,无法直接导出张力计算显式公式。本文研究通过振动微
    
    郑州大学硕士学位论文
    分方程导出频率方程,引入无量纲参数化简吊索的张力与其横向振动频率之间关系的超越
    方程,采用数值计算和曲线拟合方法,在不同的无量纲参数杏取值范围内得到吊索张力与
    吊索横向振动频率简单的函数关系,文中给出了吊索张力计算的显式公式。
     本文给出的当采用吊索第1阶横向振动频率时,吊索张力计算的实用计算公式为:
    一‘五Z,2[。·82犯一:贪)2」,(。·、一)
     .,一、,「一______‘。、,飞
    ‘’一4m(了】‘,‘「。’“吕‘一‘Z”‘,j’(了{」’(”<““。,
    一(厂/,2「1·
    l一4 .3r4二
     厂
    {
     (20<睿)
    式中,;=z擂,一篇,二为吊索的弯曲刚度,脚为吊索的线质量密度,z为吊索的
    计算长度,石为实测的吊索第1阶横向振动频率,T为吊索的计算张力。本文还给出了采
    用吊索第3阶横向振动频率的张力实用计算公式。本文利用京珠国道郑州黄河特大桥主桥
    的吊索参数,将本文提出的2组吊索张力计算实用公式的计算结果和采用考虑杆件几何刚
    度(考虑张力影响)的有限元法的计算结果进行了对比,计算结果表明该实用公式具有很
    高的计算精度。
     在基于振动法具体进行吊索张力测定时,可首先对吊索进行振动测试,通过对振动信
    号的处理,提取出吊索的振动频率,代入相应的张力计算公式,即可得到实测张力值。由
    于参数咨中含有未知的吊索张力T,在吊索张力测定时要进行迭代计算:可以先假设杏的
    范围,由对应计算公式计算得到吊索张力,然后计算新的咨值。如果咨值在假设的范围内,
    得到的吊索张力值是准确的;如果咨值不在假设范围内,根据咨值选用新的计算公式进行
    迭代计算。一般进行2次迭代计算,就可以得到准确的吊索张力计算值。
     为了检验本文提出的中、下承式拱桥吊索张力测定实用计算公式的准确性,作者在京
    珠国道郑州黄河特大桥主桥施工现场进行了吊索张力测定试验。在吊索的振动频率测试
    中,采用了环境随机激励方式,利用功率谱峰值法处理振动信号,得到吊索的第1阶横向
    振动频率,代入本文实用计算公式,得出了吊索张力,通过与现场吊索的张拉力值比较,
    验证了本文公式的正确性。
     本文通过有限元法的数值验证和下承式拱桥施工现场的实践检验,证明了本文提出
Because of its graceful bridge type, through and half through arch bridges are a kind of bridge with quicker development and application among all of the city bridges in our country. According to related documents and materials, there have been more than 300 through and half through arch bridges built in our country, which develop in the direction of larger span and scale, and the area of use is expanding gradually. However, in recent years, some accidents of through and half through arch bridges' collapses engendered severe casualties and economic loss related. Such a conclusion can be derived from these accidents' analyses breaking up and collapse of through and half through arch bridges mostly relating with the health condition of suspenders; if timely and real time online monitoring and diagnoses are conducted, a majority of serious accidents can be avoided.
    Through and half through arch bridges are mostly made up of arch ribs and floor systems ( tied beams ) and systems of suspenders. Suspender is not only a primary carrying member, but also a member vulnerable to rained. The primary damages of suspenders are rupture of some steel wires, corrosion of steel wires, lapse of anchors, and the like. Every kind of damages will bring variance of suspender's stretch stiffness. The floor system is regarded as an indeterminate structure elastically supported on arch ribs. The stiffness variance of some suspenders certainly induces the redistribution of loads. In other words, it causes the variance of static tensile forces of suspenders. The static tensile force of suspenders is a sensitive index of health condition of arch bridge. The health condition of arch bridge can be diagnosed and evaluated by comparison of the values of tension measurement of suspenders and the values of static tensile forces in the health archive of arch bridge.
    Currently, two methods of tension measurement, direct method and indirect method, are used in the tension measurement of suspender of through and half through arch bridges. Indirect method is mainly used in practical engineering applications. Vibration method is one of the indirect methods, which is mostly put into use. Two respects of tension measurement of suspenders by using vibration method might be involved: tension formula and measurement of vibration frequency. Now the vibration measuring technique has been already developed successfully. The vibration frequency of the suspender can be accurately obtained from the vibration signals. Theory of tension measurement of suspenders mainly depends on the theory of tension measurement of cables of cable-stayed bridge by using vibration method. Since the length of cables is relatively large, the effect of the flexural stiffness and boundary conditions is small on the tension measurement of cable-stayed bridge and can be neglected. Through and half through arch
     bridges are different from cable-stayed bridge. As the arch ribs of through and half through arch bridges bear compression, the bucking problem is comparatively obvious, and the value of rise of arch can not be too large. Generally the length of suspenders of through and half through arch bridges are relatively small. If the theory of tension measurement of cable-stayed bridge is directly applied to the tension measurement of suspenders, especially short suspenders,
    
    
    a larger error will be produced and it can not satisfy the requirements of practical engineering applications. The effect of the flexural stiffness and boundary conditions must be taken into account during tension measurement of suspenders. On the basis of this background, the raise of practical calculating formulae of suspender's tension suitable for the tension measurement of suspenders in through and half through arch bridges is the major contents of this dissertation.
    In the theoretical research of tension measurement of suspenders of through and half through arch bridges, when the influence of the flexural stiffness of suspenders is not taken into account, the suspenders can be regarded as a tensioned string. Sin
引文
[1] 宋勤.重庆市綦江县虹桥特大垮塌事故的原因和教训[J].施工技术,1999,28(10):54.
    [2] 魏建东.宜宾小南门大桥的抢修加固与恢复工程[J].公路,2003,(4):34~38.
    [3] 方志,张智勇.斜拉桥的索力测试[J].中国公路学报,1997,10(1):51~58.
    [4] 李国豪.桥梁结构的稳定与振动[M].北京:中国铁道出版社,1992.
    [5] 郭向荣,陈淮.弹性支承对斜拉桥拉索自振特性的影响[J].郑州工业大学学报,2000,21(1):34~36.
    [6] 蔡敏,蔡键,李彬,李万恒.环境因素对斜拉桥斜索自振频率的影响[J].合肥工业大学学报(自然科学版),1999,22(5):36~39.
    [7] 骆宁安,王卫锋,韩大建.广州体育馆拉索索力测试方法及其应用[J].华南理工大学学报(自然科学版),2002,30(2):73~75.
    [8] 何祖发,郭良友.脉动法在测量斜拉桥索力中的应用[J].城市道桥与防洪,1996,(2):32~36.
    [9] 吴海军,陈思甜,龚尚龙,许羿,施尚伟.斜拉桥索力测试方法研究[J].重庆交通学院学报,2001,20(4):23~25,37.
    [10] 任伟新.环境振动系统识别方法的比较分析[J].福州大学学报(自然科学版),2001,29(6):80~86.
    [11] 陈刚,任伟新.基于环境振动的斜拉桥拉索基频识别[J].地震工程与工程振动,2003,23(3):100~106.
    [12] 陈刚.振动法测索力与实用公式[D].福州:福州大学硕士学位论文,2004.
    [13] Irvine H M, Caughey T K. The linear theory of free vibration of a suspended cable [C]. Proc., Royal Soc., London, England, Series A, Vol. 341.
    [14] 陈水生,孙炳楠,胡隽.粘弹性阻尼器对斜拉桥拉索的振动控制研究[J].土木工程学报,2002,35(6):59~65.
    [15] 陈水生,孙炳楠,胡隽.斜拉索受轴向激励引起的面内参数振动分析[J].振动工程学报,2002,15(2):144~149.
    [16] 王卫锋,徐郁峰,韩大建,王卫兵.崖门大桥施工中的索力测试技术[J].桥梁建设,2003,(1):23~26.
    [17] 李桂华,许士斌,吴晓媛,时战,白水源.大型桥梁动力特性检测方法[J].应用力学学报,1996,13(1):48~52.
    [18] 张运波,沈锐利.单索结构振动特性的有限元分析[J].公路,2002,(10):46~49.
    
    
    [19] 吴海涛,郭良友.宁波招宝山大桥重建工程索力测试[J].桥梁建设,2001,(3):61~63.
    [20] 兰海,史家钧.大跨斜拉桥结构的综合监测[J].结构工程师,2000,(2):5~11.
    [21] 许汉铮,黄平明.带减振架的吊索索力测试研究[J].公路,2003,(8):76~78.
    [22] 许俊,史家钧.济南黄河公路大桥主桥换索过程的索力监测[J].同济大学学报,1998,26(4):471~475.
    [23] 王卫锋,韩大建.斜拉桥的索力测试及其参数识别[J].华南理工大学学报(自然科学版),2001,29(1):18~21.
    [24] 陈岩,胡时胜,宋力.斜拉桥桥索张力测量[J].实验力学,1997,12(3):347~350.
    [25] 王代华,刘建胜.斜拉桥桥索张力检测理论与实验研究[J].工程力学(增刊),1999:334~338.
    [26] 刘建胜,王代华.斜拉桥桥索张力在线监测系统及斜拉桥健康状态识别的研究[J].工程力学,2000,17(2):713~717.
    [27] 黄勇,蔡键,蔡敏.斜拉桥斜索频率检测的温度修正[J].华东公路,1999,(6):13~15.
    [28] 陈文革,蔡键.斜拉桥索力的测试方法[J].华东公路,1998,(1):61~63.
    [29] 贺修泽,付晓宁.斜拉索的索力测试[J].中外公路,2002,22(6):38~39.
    [30] 邵长江,喻梅.振动法测斜拉索索力[J].四川建筑,2003,23(1):54~55.
    [31] 欧阳东,蔡敏,李义.振动频率法测量索力过程中的波形修正[J].合肥工业大学学报(自然科学版),2003,26(6):1171~1173.
    [32] 张小林.振动频谱法在索力测试中的应用[J].甘肃科学学报,2003,15(3):100~104
    [33] Yen Wen-Huei P, Mehrabi Armin B, Tabatabai Habib. Evaluation of stay cable tension using a non-destructive vibration technique[C]. Structures Congress - Proceedings, 1997, 1: 503~507.
    [34] Shimada Tadayuki. Estimating method of cable tension from natural frequency of high mode[J]. Proceedings of the Japan Society of Civil Engineers, 1994, (501): 163~171.
    [35] Zheng G, Ko J M, Ni Y Q. Multimode-based evaluation of cable tension force in cable-supported bridges[J]. Proceedings of SPIE - The International Society for Optical Engineering, 2001, 4330: 511~522.
    [36] Zui Hiroshi, Nishikawa Tohru, Hamazaki Yoshihiro, Shinke Tohru. Basic study on simultaneous identification of cable tension and flexural rigidity by extended Kalman filter[J]. Structural Engineering/Earthquake Engineering, 1998, 15 (1): 97~106.
    [37] Yamagiwa Ichiro, Utsuno Hideo, Sugii Kenichi, Honda Yuji. Simultaneous identification of tension and flexural rigidity of cables[R]. Research and Development Kobe Steel
    
    Engineering Reports, 1999, 49 (2): 12~15.
    [38] Ni Y Q, Ko J M, Zheng G. Dynamic analysis of large-diameter sagged cables taking into account flexural rigidity[J]. Journal of Sound and Vibration, 2002, 257 (2): 301~319.
    [39] Al-Qassab M, Nair S. Wavelet-Galerkin method for the free vibrations of an elastic cable carrying an attached mass[J]. Journal of Sound and Vibration, 2004, 270 (1-2): 191~206.
    [40] Srinil Narakorn, Rega Giuseppe, Chucheepsakul Somchai. Large Amplitude Three-Dimensional Free Vibrations of Inclined Sagged Elastic Cables[J]. Nonlinear Dynamics, 2003, 33 (2), 129~154.
    [41] Russell J C, Lardner T J. Experimental determination of frequencies and tension for elastic cables[J]. Journal of Engineering Mechanics, ASCE, 1998, 10 (124): 1067~1072.
    [42] Kroneberger-Stanton K J, Hartsough B R. Monitor for indirect measurement of cable vibration frequency and tension[J]. Transactions of the ASAE, 1992, 1 (35): 341~346.
    [43] 许汉铮,黄平明.大跨径悬索桥主缆锚跨张力控制[J].长安大学学报(自然科学版),2002,22(5):32~34,41.
    [44] 施正友.自振频率法确定悬索拉力方法初探[J].青海水力发电,1997,(3):30~31.
    [45] 余岭,朱若燕.大型桥梁吊杆自振频率测试与分析[J].湖北工学院学报,1995,10(增刊):70~74.
    [46] 冯仲仁,靳敏超,胡春宇,连岳泉.武汉市晴川桥吊杆索力测试分析[J].武汉理工大学学报,2002,24(12):49~51.
    [47] 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(4):1~3.
    [48] 张开银,向木生.钢丝绳拉力测量过程中应注意的问题[J].振动、测试与诊断,1999,19(1):20~25.
    [49] 张开银,沈典栋,王建强.随机干扰作用下扣索拉力的测量技术[J].武汉交通科技大学学报,1998,22(5):457~460.
    [50] 张建刚,张开银,沈典栋.随机激励作用下拉索内力的测量[J].中山大学学报论丛,2000,20(1):19~23.
    [51] 张航,龚良甫.扣索张力的最小二乘修正技术[J].重庆交通学院学报,2001,21(3):87~89.
    [52] 汤国栋,杨弘,朱正刚,陈兵,梁利辉.桥梁吊杆及拉索的健康诊断[J].公路,2002,(9):36~41.
    [53] 唐亚鸣,张河.大型桥梁拉索损伤与健康监测[J].桥梁建设,2002,(5):79~82.
    [54] 欧维义.数学物理方程(修订版)[M].长春:吉林大学出版社,1997.
    
    
    [55] Zui H, Shinke T, Namita Y. Practical formulas for estimation of cable tension by vibration method[J]. Journal of Structural Engineering, 1996, 122 (6): 651~656.
    [56] 宋一凡.公路桥梁荷载试验与结构评定[M].北京:人民交通出版社,2002.
    [57] 曹树谦,张文德,萧龙翔.振动结构模态分析:理论、实验与应用[M].天津:天津大学出版社,2001.
    [58] 史家钧,章关永.用随机振动法测量曼谷Rama Ⅸ斜拉桥的索力[J].土木工程学报,1992,25(2):68~71.
    [59] 林志宏,徐郁峰.频率法测量斜拉桥索力的关键技术[J].中外公路,2003,23(5):1~4

© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号

地址:北京市海淀区学院路29号 邮编:100083

电话:办公室:(+86 10)66554848;文献借阅、咨询服务、科技查新:66554700