三塔两主跨悬索桥瞬态地震响应分析动态子结构方法的研究

发布时间：2018-03-18 05:38

本文选题：悬索桥　切入点：地震响应　出处：《南京理工大学》2014年博士论文　论文类型：学位论文

【摘要】：悬索桥通过构造桥塔-主缆-吊索体系,将桥面荷载依次顺序传递给吊索、主缆和桥塔,巧妙地将可能发生的大幅度桥梁挠曲变形,转化为微小的缆索张拉变形和桥塔压缩变形,实现了大跨度桥梁的跨越,成为现代大跨度桥梁的主选桥型。泰州长江公路大桥以其独特的三塔两主跨悬索桥型,实现了约3000米的主桥跨度,避免了采用斜拉桥-悬索桥组合桥型或者双悬索桥拼接桥型对主航道的压缩,节约建设成本和周期,结构轻盈优美,成为大跨度悬索桥型的一个重要发展方向。大跨度悬索桥使用寿命长,寿命期间遭遇地震的可能性增大,进行地震响应分析对设计和使用都是必要的。由于悬索桥结构体量大,地震响应的时程分析面临计算复杂,计算时间过长的困难。一般情况下,不得不将计算时间迭代步长取到0.1s,从而难以准确把握地震波传播特征和地震响应特征,丧失了重要的变形和内力等重要信息,对设计和使用大跨度悬索桥带来了一定的盲目性。但是,若对大跨度悬索桥作瞬态地震响应分析,计算时间步长将至少取到毫秒量级。对于大型商用有限元分析软件而言,在计算过程所消耗计算机资源将难以承受。计算时间过长的问题,事实上导致了计算分析不能有效地实现。因此,发展精确、高效率的大跨度悬索桥瞬态地震响应分析计算方法迫在眉睫。本文针对三塔两主跨悬索桥,以泰州长江公路大桥为例,研究分析主缆和边缆、加劲梁和桥塔、垂直吊索瞬态地震响应的动态子结构方法。采用组合单元法,研究分析大跨度悬索桥瞬态地震响应分析的动态子结构方法。根据具体地震分析数据,输入多点地震激励,对泰州长江公路大桥进行瞬态地震响应计算,计算地震波在桥中的传播和桥梁的长期地震响应。研究瞬态地震响应基本特征,获得地震响应数据,为该桥梁的使用维护和今后三塔两主跨悬索桥的设计研究,提供了重要的技术依据。本文的主要工作和创新点归纳如下：(1)考虑桥塔和缆索的水平位移,以及弹性索的张拉作用,提出了适用于三塔两主跨悬索桥的挠度理论。计算了单跨满载下泰州长江公路大桥的静态变形和桥梁静态内力,并提出了供工程设计师使用的简化挠度理论。(2)基于有限位移理论,建立了能够考虑初应力和几何非线性效应的缆索单元、梁单元、吊索单元和弹簧单元的质量阵、刚度阵和内力阵。分别提出了适用于大跨度缆索、大跨度加劲梁和吊索瞬态地震响应分析的动态子结构方法,数值研究了方法的收敛性和瞬态地震响应计算的有效性。(3)对三塔两主跨悬索桥采用组合单元法,组合使用所建立的缆索单元、梁单元、吊索单元和弹簧单元,提出了瞬态地震响应计算的动态子结构方法。具体计算了多点激励下泰州长江公路大桥的地震波传播和长期地震响应,计算结果表明,该动态子结构方法可有效节约计算过程的内存占用,提高计算速度达16倍以上。(4)计算得到了泰州长江公路大桥瞬态地震响应的基本特征：①在多点地震激励下,悬索桥中存在多种类型的变形波和内力波,波速差别大,全桥变形波形十分复杂；②吊索变形的不一致性十分明显,吊索倾斜明显；③靠近塔边的长吊索容易发生剧烈水平抛出现象,抛出量可达到0.8m,个别吊索发生了类似于共振的现象；④边塔和中塔底部出现了较大的弯矩,中塔底部的弯矩值高达2500MNm,是边塔的5倍,也是最不利工况下中塔塔底静弯矩的5倍。
[Abstract]:Through the construction of tower suspension bridge main cable and cable system, will transfer the deck loads in order to cable, cable and tower, deformation of bridge deflection greatly cleverly possible, into tiny cable tension deformation and compression deformation of tower, the large span bridge across the main bridge has become a modern long span bridge. The Taizhou Yangtze River Highway Bridge with its unique three tower and two span suspension bridge, which has about 3000 meters of the main span, avoid the suspension bridge bridge or suspension bridge bridge of double stitching main channel compression of cable-stayed bridge, save construction cost and cycle structure, light and graceful, become an important development direction of long-span suspension bridge. The long-span suspension bridge with long service life, life during the possibility of encountering earthquake increases, the earthquake response analysis of the design and use are necessary. Due to the suspension bridge The structure of a large amount of seismic response time history analysis with computational complexity, long computation time difficult. Under normal circumstances, will have to calculate the iterative time step to 0.1s, and it is difficult to accurately grasp the characteristics of seismic response and seismic wave propagation characteristics, the loss of important deformation and internal force of the important information, brings certain blindness for the design and application of long span suspension bridge. However, if the long-span suspension bridge for earthquake transient response analysis, calculation time step will take at least one millisecond. For the large commercial finite element analysis software, the calculation process of the consumption of computer resources will be difficult to bear. The calculation time is too long, in fact led to calculation and analysis can not effectively implement. Therefore, the development of accurate and efficient long-span suspension bridge seismic response analysis method of transient calculation is imminent. Aiming at the three tower and two span suspension On the bridge, the Taizhou Yangtze River Highway Bridge as an example, research and analysis of the main cable and side cable, stiffening girder and pylon, dynamic substructure method of vertical sling transient seismic. By using the composite element method, analysis of dynamic substructure analysis method of long span suspension bridge transient seismic response. According to the specific analysis of seismic data, multi point input earthquake response calculation of transient earthquake on Taizhou Yangtze River Highway Bridge, the seismic response analysis of long term seismic wave propagation and the bridge in the middle of the bridge. The fundamental characteristics of the transient response to earthquake, earthquake response data, design and research for the bridge maintenance and the future of three tower and two span suspension bridge, provides an important basis for the main work of this paper is as follows: (1) considering the horizontal displacement of tower and cable, cable tension and elastic effect, put forward for the three tower two span suspension The bridge deflection theory. The static deformation and internal force of single span bridge static load under the Taizhou Yangtze River Highway Bridge is calculated, and a simplified deflection theory for engineering designers use. (2) based on the finite displacement theory, established to consider the initial stress of cable element, and the geometric nonlinear effect of beam element, the mass matrix of sling element and spring element, stiffness matrix and internal force matrix. Are proposed for large span cable, dynamic substructure analysis method of long span stiffening girder and suspender transient seismic response, a numerical study of the validity of the calculation method and the convergence of the transient response of the earthquake. (3) of three tower and two span suspension bridge the composite element method, cable element, using a combination of the beam element, cable elements and spring elements, dynamic substructure method was proposed to calculate the transient seismic response. The multipoint excitation of Yangtze River in Taizhou Seismic wave propagation and seismic response of long highway bridge, the calculation results show that the dynamic substructure method can effectively save the calculation process memory footprint, improve computing speed more than 16 times. (4) calculated by the Taizhou Yangtze River Highway Bridge transient seismic response characteristics in multiple seismic excitations, there wave deformation and internal force wave of various types of suspension bridge, the velocity difference is big, the whole bridge deformation waveform is very complicated; the inconsistency of the sling deformation is very obvious, the sling was tilted; the tower near the edge of the long sling prone to violent horizontal throw phenomenon, throws capacity can reach 0.8m, was similar to the resonance phenomenon the Bianta individual slings; and at the bottom of the tower appeared in the big moment, in the moment of tower bottom value is 5 times as high as 2500MNm, Bianta, 5 times is the most unfavorable condition in the bottom bending moment.

【学位授予单位】：南京理工大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：U442.55;U448.25

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