高烈度区铁路悬索桥地震分析研究

发布时间：2018-12-05 14:45

【摘要】：桥梁作为交通运输线上的关键工程,在整个交通运输线上起着至关重要的作用,如果受到强烈地震的破坏导致交通中断,带来的人员伤亡和经济损失将十分惨重,并且使得大地震后的抢险救灾和重建工作无法顺利进行,后果将不堪设想。伴随着我国当前大力扩展和改造铁路基础建设,铁路悬索桥的修建势在必行。高烈度区需要修建的铁路悬索桥有跨度大、恒载和列车活载较大等特点,其地震响应分析和抗震设计方面的深入研究亦迫在眉睫。本文借助有限元计算软件Midas Civil,对某高烈度区铁路悬索桥建立三维空间有限元模型,用梁单元、只受拉单元和板单元建模,对悬索桥的结构动力特性进行数值分析。采用线性和非线性时程分析法,分别在四种地震荷载组合下对该铁路悬索桥进行地震响应分析,并对计算结果进行对比,主要考察的结构体系的响应指标包括：梁端顺桥向位移、跨中竖向位移、主塔塔顶位移、主塔塔底轴力和弯矩等。还运用非线性时程分析对主梁重量不同的铁路悬索桥进行地震响应分析。研究结果表明：(1)铁路悬索桥自振周期较长,结构柔性特性显著；(2)对比线性与非线性时程分析结果,以非线性时程分析得出的结论进行铁路悬索桥的设计和研究偏于安全,亦即非线性特性对铁路悬索桥地震响应影响比较明显；(3)在地震荷载工况组合中加入竖向地震力后,对梁端顺桥向位移、塔顶顺桥向位移和塔底弯矩的最大值影响很小,而对跨中竖向位移和塔底轴力的最大值影响较大,铁路悬索桥设计时,竖向地震力的影响不能忽略；(4)铁路悬索桥地震响应对于主梁重量的变化并不敏感,虽然主梁重量改变时,铁路悬索桥地震响应指标会按一定趋势变化,但变化幅度不大。
[Abstract]:As a key project on the transportation line, bridge plays a vital role in the whole transportation line. If the damage caused by a strong earthquake results in traffic disruption, the casualties and economic losses will be very heavy. And make the rescue and reconstruction work after the earthquake can not be carried out smoothly, the consequences will be unthinkable. With the expansion and reconstruction of railway infrastructure, the construction of railway suspension bridge is imperative. The railway suspension bridges needed to be built in high intensity areas have the characteristics of long span, large dead load and large live load of trains, so it is urgent to study the seismic response analysis and seismic design of railway suspension bridges. In this paper, a three-dimensional finite element model of a railway suspension bridge with high intensity is established by means of the finite element calculation software Midas Civil,. The dynamic characteristics of the suspension bridge are numerically analyzed by using the beam element, only the tensile element and the plate element. The linear and nonlinear time-history analysis methods are used to analyze the seismic response of the railway suspension bridge under four kinds of seismic loads, and the calculated results are compared. The main response indexes of the structural system are as follows: bridge displacement, mid-span vertical displacement, top displacement of main tower, axial force and bending moment at bottom of main tower, etc. The nonlinear time history analysis is also used to analyze the seismic response of railway suspension bridges with different main girder weight. The results show that: (1) the natural vibration period of railway suspension bridge is longer and the flexible characteristic of the structure is remarkable; (2) compared with the results of linear and nonlinear time-history analysis, the design and research of railway suspension bridge is more safety based on the conclusion of nonlinear time-history analysis, that is, the nonlinear characteristic has obvious influence on the seismic response of railway suspension bridge; (3) after adding vertical seismic force to the combination of seismic load conditions, the maximum value of beam end bridge displacement, tower top forward bridge displacement and tower bottom bending moment is very small, but the maximum value of span center vertical displacement and tower bottom axial force is more significant. In the design of railway suspension bridge, the influence of vertical seismic force can not be ignored. (4) the seismic response of railway suspension bridge is not sensitive to the change of main beam weight, although the seismic response index of railway suspension bridge will change according to a certain trend when the main girder weight changes, but the change range is not large.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U442.55;U448.25

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