预应力混凝土桁架梁桥的动力特性研究

发布时间：2018-07-26 19:31

【摘要】：随着经济的快速发展,我国的桥梁建设也得到了迅猛的发展,桥梁结构形式也逐渐多样化、大型化和轻型化。预应力混凝土桁架梁桥能充分发挥高强度材料的特征,促进结构轻型化,具有很好的跨越能力,同时又可以有效地避免混凝土开裂。此外,它还具有刚度大、耐久性好、重量轻、节约钢材和水泥、造型美观等优点,加之结构受力明确和构造简单、伸缩缝小的特点,在目前的桥梁建造中已经得到越来越多的推广和使用。基于其自重轻等特点,使其很容易受到风荷载、车辆荷载、地震荷载等动力荷载的影响,所以桥梁的动力特性研究系我们普遍关心的问题。桥梁结构基频反映了桥梁结构与冲击系数之间的关系,因此精确的基频计算直接影响冲击系数的大小。在规范条文里明确规定,桥梁的自振频率宜采用有限元方法计算。对于一些常规结构,规范提供了其基频估算公式,但预应力混凝土桁架梁桥的基频计算公式国内外规范尚缺乏,因此有必要研究预应力混凝土桁架梁桥的基频计算公式。针对上述问题,本文主要做了以下工作：(1)采用有限元软件Midas/Civil,以预应力混凝土桁架梁桥不同的跨度、宽度、弦杆刚度、腹杆刚度为设计参数,计算其结构基频。(2)研究各参数对结构基频影响的规律,确定敏感参数。(3)根据敏感参数对结构基频影响的规律,拟合预应力混凝土桁架梁桥的基频计算公式。(4)实测了武坚大桥与杨石桥两座实桥的结构基频,其实测值与本文公式计算值比较接近,说明本文提出的预应力混凝土桁架梁桥的基频计算公式可供工程设计参考。
[Abstract]:With the rapid development of economy, the construction of bridges in our country has been developed rapidly, and the forms of bridge structures are gradually diversified, large-scale and light. Prestressed concrete truss girder bridge can give full play to the characteristics of high strength materials, promote the lightweight of the structure, have good span ability, and can effectively avoid concrete cracking at the same time. In addition, it has the advantages of high stiffness, good durability, light weight, saving steel and cement, beautiful shape, etc. In addition, it has the advantages of clear structural force, simple structure, small expansion joint, etc. In the current bridge construction has been more and more popularized and used. Because of its light weight and other characteristics, it is easy to be affected by wind load, vehicle load, earthquake load and other dynamic loads, so the study of the dynamic characteristics of bridges is a common concern. The fundamental frequency of the bridge structure reflects the relationship between the bridge structure and the impact coefficient, so the accurate calculation of the fundamental frequency directly affects the magnitude of the impact coefficient. It is clearly stated in the code that the natural vibration frequency of the bridge should be calculated by finite element method. For some conventional structures, the code provides its fundamental frequency estimation formula, but the fundamental frequency calculation formula of prestressed concrete truss girder bridge is still lacking in domestic and foreign codes, so it is necessary to study the fundamental frequency calculation formula of prestressed concrete truss beam bridge. Aiming at the above problems, this paper mainly does the following work: (1) using the finite element software Midas / Civil, taking different span, width, chord stiffness and web stiffness of prestressed concrete truss girder bridge as design parameters, (2) the influence of each parameter on the fundamental frequency of the structure is studied, and the sensitive parameters are determined. (3) according to the law of the influence of the sensitive parameter on the fundamental frequency of the structure, Fitting the calculation formula of the fundamental frequency of prestressed concrete truss girder bridge. (4) measured the structural fundamental frequency of the two real bridges of Wujian Bridge and Yangshi Bridge, and the measured value is close to the calculated value of the formula in this paper. It shows that the calculation formula of foundation frequency of prestressed concrete truss girder bridge presented in this paper can be used as a reference for engineering design.
【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441;U448.21

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