), 覃石生 广西大学 土木建筑工程学院，南宁 530004
收稿日期:2019-10-11出版日期:2021-03-01发布日期:2021-04-02通讯作者:邱辰E-mail:303494977@qq.com作者简介:谢肖礼(1963-)，男，广西省桂平市人，教授，博士生导师，从事力学、结构仿真及非线性、大跨度高性能桥梁等研究工作．基金资助:新型桥梁技术开发及应用(桂科AB18126047);广西防灾减灾与工程安全重点实验室系统性研究项目(2016ZDX0001)Research and Test Verification of Dynamic Characteristics of Deck V-Arch Bridge
XIE Xiaoli, PANG Mulin, QIU Chen(), QIN Shisheng College of Civil Engineering and Architecture, Guangxi University, Nanning 530004, China
Received:2019-10-11Online:2021-03-01Published:2021-04-02Contact:QIU Chen E-mail:303494977@qq.com摘要/Abstract
摘要： 为解决上承式拱桥跨径增大后自振频率快速下降的问题，提出一种新的上承式加V拱桥结构体系．将V形构件设于主梁和拱圈间以增大拱桥的刚度，进而提高结构的自振频率．通过适时的结构体系转换，实现一期恒载由拱圈承担，二期恒载及活载由一个主梁为上弦杆、拱圈为下弦杆、V形构件为腹杆并带多点弹性约束的变高桁架来承担，整个结构同时兼具拱和桁架的优点．为验证上承式加V拱桥动力特性研究和计算的正确性，修建跨径为10 m的试验桥，通过脉动试验测试桥梁首次发生面内竖弯的自振频率；利用有限元软件对其刚度和动力特性进行计算，分析V形构件刚度对结构动力特性以及V形构件数量对结构温度应力的影响，并研究体系转换的必要性．结果表明：结构首次发生面内竖弯的自振频率试验值与计算值相差较小，且振型与有限元分析相吻合．在增加材料很少甚至不增加材料的情况下，结构的自振频率得到明显提高，尤其是面内自振频率．V形构件的刚度存在一个合理的设置范围，V形构件的个数应以能使其与主梁或拱圈所构成的三角形的内角在45°～60°之间为宜．加V形构件后的上承式拱桥结构刚度大幅提高，且在L/4(L为桥梁跨径)处，列车静活载所产生的上挠度几乎为0.经过体系转换后二次成桥的成桥方法可使上承式加V拱桥充分发挥拱受力的优越性．
关键词: 上承式拱桥, 动力特性, 试验, 有限元, 刚度, 高速铁路桥
Abstract: To solve the problem that the natural frequency of deck arch bridges would decrease rapidly when the span increases, a novel arch bridge structure named deck V-arch bridge is proposed. The V-shaped members are added between the main girders and the arch ribs to increase the stiffness of the arch bridge, thereby increasing the natural frequency of the structure. Through the timely conversion of the structural system, the first-phase dead load is carried by the arch ribs, while the second-phase dead load and live load are carried by the variable height truss with main girders as upper chords, arch ribs as lower chords, and V-shaped members as webs, with multi-point elastic constraints. The entire structure has the advantages of arch and truss. In order to verify the correctness of the research and calculation of the dynamic characteristics of the deck V-arch bridge, a test bridge with a span of 10 m is built. The first natural frequency of the vertical bending in the plane of the bridge is tested by utilzing the pulsation test. The stiffness and dynamic characteristics are calculated by utilizing the finite element software. The influence of V-shaped member stiffness on the natural frequency and that of the number of V-shaped members on the temperature stress of the structure are analyzed. The necessity of system transformation is studied. The results show that the difference between test value and calculated value of the first natural frequency of vertical bending in the plane is small. The mode shape is in good agreement with the finite element analysis. With little or no additional material, the natural frequency of the structure is significantly increased, especially the in-plane frequency. The stiffness of the V-shaped members has a reasonable setting range. When the inner angles of the triangle formed by the main girders or the arch ribs are between 45 ℃ and 60 ℃,the number of V-shaped web members is suitable. The structural stiffness of deck arch bridge with V-shaped members is greatly improved, and at the position of L/4 (L is the span of the bridge), the upward deflection generated by the static live load of the train is approximately zero. After the transformation of the structural system, the deck V-arch bridge can fully exert the superiority of the arch force.
Key words: deck arch bridge, dynamic characteristics, test, finite element, stiffness, high-speed railway bridge
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