现代木结构拱桥力学性能分析与试验研究

发布时间：2018-09-10 06:14

【摘要】：现代木结构的优越性已是有目共睹,并且在国外得到了广泛的应用,然而在国内却属于新型、稀奇结构,尤其是重型木结构实为少数。本文首先结合我国森林资源、市场需求等情况分析了现代木结构在我国发展的前景,认为现代木结构在我国的发展是可行的,同时也是必要的。其次以中南林业科技大学所建张家界现代木结构拱桥为依托,利用有限元软件,计算分析了各种荷载组合下该桥力学性能及其稳定性,探索了中国人行天桥对其适用性,同时结合静载试验对该桥施工质量、承载能力力以及运营情况作了评定。然后通过改变边界条件将原结构改为无铰拱桥,研究了边界条件对结构静力性能的影响；并以边界条件、拱肋刚度、横向联系布置及其刚度等因素为参数,研究了该桥自振特性的参数敏感性。研究分析结果表明： (1)张家界现代木结构拱桥恒载相对于活载比例小,活载对该桥作用效应较明显,结构受力和变形较为合理,各种荷载组合下稳定性能较好；该桥依据美国现代木结构设计规范设计,但其强度和刚度能够满足我国人行天桥设计规范的要求。 (2)荷载试验表明该桥施工质量以及运营状态较好,具有良好的动力特性。 (3)该桥拱肋同时承受轴力和弯矩,轴力图和弯矩图在拱肋与立柱连接处发生变化。轴力从拱脚到拱顶逐渐减小。纵梁弯矩及轴力在横梁处分割成段,每段弯矩图与简支梁在均布荷载作用下弯矩图相似。 (4)相对于该桥结构形式而言,无铰拱桥在变形、受力上更为合理,使得国内强度等级稍低的木材作为大跨度重型木结构用材成为可能,然而三铰拱桥在材料加工、制作及其运输与拼装等方面占据优势,因此该桥最终选取三铰拱桥的结构形式。 (5)拱肋和横向联系的刚度对结构自振特性影响不明显,边界条件和横向联系的布置分别对现代木结构拱桥面内和面外的振动频率与振型序列影响较为突出。
[Abstract]:The superiority of modern wood structure is obvious to all and has been widely used in foreign countries. However, it is a new and rare structure in China, especially for heavy wood structure. In this paper, the prospect of the development of modern wood structure in China is analyzed according to the situation of forest resources and market demand. It is considered that the development of modern wood structure in China is feasible and necessary at the same time. Secondly, based on the modern wooden arch bridge of Zhangjiajie built by the Central South Forestry Science and Technology University, the mechanical properties and stability of the bridge under various load combinations are calculated and analyzed by using finite element software, and the applicability of the Chinese footbridge to the bridge is explored. At the same time, combined with static load test, the construction quality, bearing capacity and operation of the bridge are evaluated. Then, by changing the boundary condition from the original structure to a hingless arch bridge, the influence of the boundary condition on the static performance of the structure is studied, and the parameters of the boundary condition, the stiffness of the arch rib, the transverse connection arrangement and the stiffness are taken as parameters. The parameter sensitivity of the bridge's natural vibration characteristics is studied. The results show that: (1) the ratio of dead load to live load of modern wooden arch bridge in Zhangjiajie is small, the effect of live load on the bridge is obvious, the force and deformation of structure are reasonable, and the stability under various load combinations is better; The bridge is designed according to the American modern timber structure design code, but its strength and stiffness can meet the requirements of the design code for the footbridge in China. (2) the load test shows that the bridge is of good construction quality and running condition. (3) the arch rib of the bridge bears both axial force and bending moment, and the axial force and bending moment diagram change at the joint of arch rib and column. The axial force gradually decreases from the arch to the vault. The bending moment and axial force of longitudinal beam are divided into sections at the crossbeam. The moment diagram of each section is similar to that of simply supported beam under uniform load. (4) compared with the structural form of the bridge, the deformation and force of the unhinged arch bridge are more reasonable. This makes it possible for domestic timber with lower strength grades to be used as materials for large-span heavy-duty timber structures. However, three-hinged arch bridges have advantages in material processing, manufacture, transportation and assembly, etc. Therefore, the structure form of three-hinged arch bridge is selected finally. (5) the stiffness of arch rib and transverse connection has no obvious influence on the natural vibration characteristics of the structure. The influence of boundary condition and transverse connection on the vibration frequency and vibration pattern sequence in and out of plane of modern wooden arch bridge is obvious.
【学位授予单位】：中南林业科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U448.22;U441

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