某超限大跨度结构弹塑性地震反应分析

Analysis of the elasto-plastic seismic response of an ultra large span structure

大跨度结构的抗震分析方法主要有反应谱法、随机振动法和时程分析法,时程分析法比前两者有更高的精确度。以厦门铁路西站超限大跨度结构为背景,采用通用有限元软件ANSYS和ABAQUS建立精细化的三维分析模型,进行动力弹塑性时程分析,研究整体结构在强震作用下的动力响应和关键构件的损伤状况。分析结果表明,在罕遇地震作用下,结构的最大层间位移角小于规范限值;主塔柱在与网架结构高、低跨的连接部位,构件基本满足抗剪强度的要求,建议在塔柱中加入型钢钢骨,并增加柱腿之间连梁的配箍率,以提高柱的抗剪性能;支承网架的结构边柱在地震作用下也安全可靠;大跨度屋盖的关键构件处于弹性工作阶段,主桁架弦杆的水平和竖向位移均控制的好,钢屋盖在强震作用下具有足够的稳定性。总体来说,本结构能够在罕遇地震水平下实现"大震不倒",满足我国抗震规范的设防要求。

Seismic analysis methods of large-span structures mainly include response spectrum method, random vibration method and time history analysis method. Comparing with the first two methods, time history analysis method exhibits better accuracy. For the ultra large span structure of the Xiamen west railway station, ANSYS and ABAQUS were employed to perform three-dimensional analyses. Dynamic elasto-plastic time-history analysis was then conducted to study the dynamic response of the structure and the degree of damage of key structure members.The analysis results showed that maximal story drift of the structure under rare earthquakes can satisfy the requirement of seismic code. The joint regions where tower columns connect the grid structure with high and low spans basically can meet the shear resistance demand, and it was suggested that steel skeleton be embedded into tower columns to improve their shear performance. The side columns and steel roof are also safe under seismic action. The horizontal and vertical displacements of the main truss chords are well under control, and the steel roof is stable. Generally speaking, this building structure can fulfill the principle of ‘no collapse under seldom earthquake action＇ specified in the national seismic design code.