多类型长周期地震动作用下高层结构的动力行为与设计方法研究

发布时间：2018-08-30 09:39

【摘要】：远场类谐和地震动、近断层向前方向性地震动与近断层滑冲型地震动均属于长周期地震动，汶川、东日本大地震等震害表明，该类地震动对长周期结构具有较大的破坏作用，我国现行抗震规范由于未考虑长周期地震动而不能确保长周期结构的抗震安全。本文围绕三类长周期地震动，从地震动特性、高层结构动力响应特征与损伤破坏机理、结构抗震设计方法等方面展开研究与分析。主要研究工作内容包括：（1）系统对比分析远场类谐和地震动、近断层向前方向性地震动、近断层滑冲型地震动与普通地震动的特性差异。对比地震动的峰值、峰值比、持时及反应谱特性。基于希尔伯特-黄变换（HHT）理论，定义地震动累积能量谱、强频段、能量时间分布系数等概念，从地震动能量时频分布角度，对比三类长周期地震动与普通地震动的低频特性、宽频带特性以及脉冲特性。（2）设计并采用ABAQUS有限元软件建立代表短、中、长周期的框架结构与框架-剪力墙结构模型，分别以21条长周期地震动与3条普通地震动作为输入进行96次弹塑性地震响应时程分析，对比三类长周期地震动与普通地震动作用下的结构动力响应特征。同时，基于HHT对高层框架结构与框架-剪力墙结构的位移响应进行时频特性分析，进一步探讨四类地震动作用下的结构响应特点。（3）研究长周期地震动脉冲特征参数对高层结构动力响应的影响规律。首先，提出基于经验模态分解（EMD）的长周期地震动脉冲特征参数识别方法，，能够有效识别长周期地震动的脉冲速度峰值、脉冲周期与脉冲持时；然后，构建适用于三类长周期地震动的简化等效模型，并通过弹性及弹塑性反应谱验证该模型的合理性；最后，以12层框架结构为例，基于19次弹塑性时程反应计算结果，分析长周期地震动脉冲周期与脉冲持时对高层结构地震响应的影响规律。（4）研究对比三类长周期地震动作用下高层结构的损伤破坏机理。首先，分析长周期地震动最大瞬时输入能与弹塑性单自由度体系最大位移响应的相关性。在此基础上，提出瞬时输入能比的概念，并基于该指标对比分析三类长周期地震动作用下结构的地震破坏模式。接着，基于提出的逐步损伤分析法（SDA），以12层框架结构为例，通过54次弹塑性时程反应分析，对比三类长周期地震动作用下高层结构的损伤演化特性。最后，基于EMD分析了长周期地震动中控制高层结构非线性地震动响应的IMF分量，提出有效长周期地震动的概念，定义了有效峰值与有效峰值率，揭示了长周期地震动作用下高层结构的类共振作用机理；同时，提出长周期地震动能量梯度的概念，分析了三类长周期地震动的能量梯度分布规律，揭示了长周期地震动对高层结构的脉冲作用机理。（5）研究考虑长周期地震动影响的结构抗震设计方法。首先，分析我国现行抗震规范中烈度、设计地震动参数、设计反应谱以及时程分析法在考虑长周期地震动影响时所存在的问题。然后，基于100条长周期地震动记录，构造400个弹塑性单自由度体系，研究并提出适用于三类长周期地震动的抗震分析用强度指标。接着，对比分析了中、美、日、欧抗震设计谱理论及其在考虑长周期地震动影响方面的适用性。其次，分析了长周期地震动的频谱特征周期与非平稳特性，为进行长周期地震动地震危险性分析提供基础。探讨了结构周期的划分方法，分析了基于地震动瞬态效应划分结构周期的可行性。最后，给出现阶段考虑长周期地震动影响的结构抗震设计建议。
[Abstract]:Far-field quasi-harmonic ground motion, near-fault forward ground motion and near-fault slip-and-thrust ground motion belong to long-period ground motion. Earthquake disasters such as Wenchuan and East Japan Earthquakes show that such ground motions have great damage to long-period structures. The current seismic code in China can not ensure long-period ground motion because it does not consider long-period ground motion. In this paper, three types of long-period ground motions are studied and analyzed, including ground motion characteristics, dynamic response characteristics and damage mechanism of high-rise structures, and seismic design methods of structures.
(1) Comparing the characteristics of far-field harmonic and ground motions, near-fault forward motion, near-fault slip-and-thrust ground motions and ordinary ground motions. Comparing the peak value, peak ratio, duration and response spectrum characteristics of ground motions. Based on Hilbert-Huang transform (HHT) theory, the cumulative energy spectrum, strong frequency band and energy-time division of ground motions are defined. From the point of view of time-frequency distribution of ground motion energy, the low-frequency characteristics, broadband characteristics and pulse characteristics of three kinds of long-period ground motions are compared with those of ordinary ground motions.
(2) Design and use ABAQUS finite element software to build the frame structure and frame-shear wall structure models which represent short, medium and long periods, respectively, with 21 long-period ground motions and 3 ordinary ground motions as input to carry out 96 elasto-plastic seismic response time-history analysis, and compare the three types of long-period ground motions with ordinary ground motions. At the same time, the time-frequency characteristics of displacement response of high-rise frame structure and frame-shear wall structure are analyzed based on HHT, and the structural response characteristics under four types of earthquake are further discussed.
(3) The influence of the characteristic parameters of long-period ground motions on the dynamic response of high-rise structures is studied. Firstly, a method of identifying the characteristic parameters of long-period ground motions based on empirical mode decomposition (EMD) is proposed, which can effectively identify the peak velocity, pulse period and pulse duration of long-period ground motions. The simplified equivalent model of long-period ground motion is validated by the elastic and elastic-plastic response spectrum. Finally, based on 19 times elastic-plastic time-history response calculation results of 12-storey frame structures, the influence of long-period ground motion pulse period and pulse duration on the seismic response of high-rise structures is analyzed.
(4) The damage mechanism of high-rise structures subjected to three kinds of long-period ground motions is studied and compared. Firstly, the correlation between the maximum instantaneous input energy of long-period ground motions and the maximum displacement response of elastic-plastic single-degree-of-freedom system is analyzed. Then, based on the proposed SDA method, the damage evolution characteristics of high-rise structures subjected to three kinds of long-period ground motions are compared by 54 times elastic-plastic time-history analysis. Finally, the nonlinear control of high-rise structures under long-period ground motions is analyzed by EMD. The concept of effective long-period ground motion is proposed, the effective peak value and effective peak rate are defined, and the resonance-like mechanism of high-rise structures under long-period ground motion is revealed. The mechanism of long-period ground motion on high rise structures is revealed.
(5) The seismic design method of structures considering the effect of long-period ground motion is studied. Firstly, the seismic intensity, design ground motion parameters, design response spectrum and time-history analysis method in the current seismic code of China are analyzed. Then, 400 elastic-plastic single selves are constructed based on 100 long-period ground motion records. Then, the seismic design spectrum theory of China, the United States, Japan and Europe and its applicability in considering the influence of long-period ground motion are compared and analyzed. Secondly, the spectral characteristic period and non-stationary characteristics of long-period ground motion are analyzed for long-period ground motion. The method of dividing the period of structure is discussed, and the feasibility of dividing the period of structure based on the transient effect of ground motion is analyzed.
【学位授予单位】：西安建筑科技大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：TU973.31

【参考文献】