桥梁结构双重挡块防落梁构造设计研究

发布时间：2018-05-03 10:58

本文选题：简支梁桥 + 双重挡块　；参考：《烟台大学》2017年硕士论文

【摘要】：近年来,我国境内地震活动较为活跃,地震中许多桥梁结构受到损毁,如何确保在地震发生后,桥梁线路依然能够安全可靠的通行,成为当前工程研究中极为关注的问题。挡块是桥梁横桥向保护支座限制主梁位移的主要构件,也是震区横桥向抗震的重要构造措施。现有横桥向抗震挡块多为单道防线设计,无法同时满足抗震设计中对构造装置耗能与限位的双重要求。本文对当前桥梁结构横桥向限位挡块抗震设计与研究中存在的问题进行思考,在现有限位挡块的基础上,以“多道防线、功能分离、逐级生效”为原则,参考当前较为流行的延性抗震思路,设计了新的横桥向抗震构造装置。使其既能限制主梁横桥向位移,又能消散地震力,降低桥梁下部结构的地震反应。本文主要完成了以下工作:(1)提出了新型双重挡块防落梁的抗震构造装置。内侧为刚度较小的耗能挡块,利用钢构件的塑性变形消散地震作用;外侧为刚度与承载力较大刚性限位挡块,利用其强大的稳固性限制主梁在横桥向产生较大的相对位移。耗能挡块与刚性挡块共同作用,能够有效的发挥挡块在横桥向的抗震减震功能。(2)采用非线性时程分析法,分别从刚度以及初始间距两个方面研究了其对普通单挡块地震反应的影响。研究发现:忽略挡块与主梁的碰撞会低估桥梁结构的地震反应,且碰撞力受碰撞刚度的影响较大;随挡块刚度的增大,碰撞力呈现先增大后又减小的变化趋势,存在一个可以导致桥梁下部结构地震作用最大的刚度值;刚度越大挡块限位能力越强;普通单挡块结构的初始间距对挡块的地震反应受输入地震波影响较大,很难确定统一的最佳初始间距。(3)采用Midas-Civil软件建立了含双重挡块结构的有限元模型,通过与相同条件下的普通挡块进行对比分析其抗震性能,并研究了内挡块刚度、初始间距对双重挡块抗震性能的影响。分析发现:双重挡块抗震性能受内挡块刚度以及输入地震波的影响较大,较小刚度的耗能构件仅能消散较少的地震作用,过大刚度的内挡块会与主梁产生较大碰撞力,影响装置的抗震性能,最佳内挡块刚度在不同地震波作用下并不统一。但总的来讲,采用合适刚度非线性内挡块的双重挡块结构能够有效地降低桥梁墩底的地震作用。在保证内挡块足够耗能空间的前提下,内挡块初始间距对双重挡块抗震性能的影响较小。(4)通过改变桥梁墩高,研究了墩高对双重挡块抗震的影响,同时分析了不同墩高下内挡块初始间距的变化影响。在挡块结构相同的情况下,桥墩越高,挡块与主梁的碰撞力越小;在保证内挡块足够耗能空间的前提下,墩高变化对内挡块初始间距选择的影响较小;主梁位移量受墩高变化的影的变化量较小,挡块的限位功能可忽略墩高的影响。
[Abstract]:In recent years, seismicity is active in China, and many bridge structures have been damaged in earthquake. How to ensure the safe and reliable passage of bridge lines after the earthquake has become a problem of great concern in current engineering research. The block block is the main component which limits the displacement of the main beam in the transverse protection support of the bridge, and it is also an important structural measure for the earthquake resistance of the transverse bridge in the earthquake area. Most of the existing cross-bridge seismic blocks are designed by single line of defense, which can not meet the dual requirements of energy consumption and limit in seismic design at the same time. In this paper, the problems existing in the seismic design and research of the horizontal limit block of the bridge structure are considered. On the basis of the existing limited block, the principle of "multi-line defense line, function separation, step by step effect" is taken as the principle. Referring to the popular idea of ductile earthquake resistance at present, a new transverse bridge aseismic structure is designed. It can not only limit the displacement of the bridge but also dissipate the seismic force and reduce the seismic response of the bridge structure. The main work of this paper is as follows: 1) A new type of anti-seismic structure of double block anti-falling beam is put forward. The inner side is a small energy dissipation block, and the plastic deformation of the steel member dissipates the seismic action, while the outside is a rigid limit block with large stiffness and bearing capacity, which limits the relative displacement of the main beam in the transverse direction by its strong stability. The joint action of energy dissipation block and rigid block can effectively exert the seismic and seismic absorption function of the block in the transverse direction of the bridge. The nonlinear time-history analysis method is used. The effects of stiffness and initial spacing on the seismic response of single block are studied respectively. It is found that ignoring the collision between the block and the main beam will underestimate the seismic response of the bridge structure, and the impact force will be greatly affected by the impact stiffness, and the impact force will increase first and then decrease with the increase of the block stiffness. There is a stiffness value which can lead to the maximum seismic action of the bridge substructure; the greater the stiffness, the stronger the limiting capacity of the block. The initial spacing of the common single-block structure is greatly affected by the seismic response of the retaining block, and the influence of the initial spacing of the common single-block structure on the seismic response of the retaining block is greater. It is difficult to determine the uniform optimal initial spacing. (3) the finite element model of the structure with double retaining blocks is established by using Midas-Civil software. The seismic performance of the block is compared with that of the common block under the same conditions, and the stiffness of the inner retaining block is studied. The effect of initial spacing on seismic performance of double block. It is found that the aseismic performance of double retaining blocks is greatly affected by the internal block stiffness and the input seismic wave. The energy dissipation members with smaller stiffness can only dissipate less seismic action, and the inner retaining block with too large stiffness will produce a large collision force with the main beam. The optimum block stiffness is not uniform under different seismic waves. But in general, the double block structure with suitable stiffness and nonlinear internal retaining block can effectively reduce the seismic action at the bottom of the bridge pier. On the premise of ensuring enough energy dissipation space, the influence of the initial spacing of the inner block on the seismic performance of the double retaining block is small. 4) by changing the height of the bridge pier, the influence of the pier height on the earthquake resistance of the double retaining block is studied. At the same time, the influence of the initial spacing of the inner block at different piers is analyzed. In the case of the same block structure, the higher the pier, the smaller the collision force between the retaining block and the main beam, and the smaller the influence of the change of the pier height on the selection of the initial spacing of the inner retaining block under the premise of ensuring enough energy dissipation space of the inner block. The displacement of the main beam is influenced by the height of the pier and the influence of the height of the pier can be neglected.
【学位授予单位】：烟台大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U442.55

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