【作者】 公茂盛；

【导师】 谢礼立；

【作者基本信息】 中国地震局工程力学研究所 ， 防灾减灾工程及防护工程， 2005， 博士

【摘要】 结构强震反应观测是地震工程学的基础,是人们了解工程结构在地震作用下的反应及破坏过程、检验现有抗震设计理论与方法的主要手段之一。近几年,随着各国政府和地震工程界对结构强震反应观测的重视,结构反应观测台阵有了长足的发展。在我国,随着“十五”数字强震观测台网的建设,更多的高层建筑和重大建筑物布设了强震观测台阵。这些台阵一旦在强烈地震中获得反应记录,除了用于工程抗震研究外,还可以用来对结构模态参数进行识别,从而为震后结构健康诊断或震后安全评估提供基础依据。地震作用下结构模态参数的识别与破坏识别问题,也是世界地震工程领域备受关注的问题。本文就对基于结构地震反应记录的结构模态参数识别与应用问题进行了系统深入的研究。本文的主要研究内容摘要如下:1.结构强震反应记录HHT分析详细介绍了一种先进的非平稳信号处理方法—HHT(希尔伯特-黄变换)的意义及算法,针对该方法的具体算法,编制了一套计算程序。然后介绍一座7层钢筋混凝土建筑的概况和在几次地震中的地震反应记录和破坏情况,选择了3次主要的、有代表性地震的反应记录,利用HHT这一先进的数据处理方法,分析了该7层钢筋混凝土建筑物在3次地震中的地震反应记录。给出了幅值-频率-时间的三维分布关系,同时将得到的边际谱和FFT得到的傅立叶谱进行了对比,给出了一些有意义的结论。2.地震作用下结构系统参数识别提出了结构在小震和大震作用下模态参数的识别方法。若结构在地震作用下没有进入时变反应,整个过程都是线弹性反应,则利用整个记录来识别结构的模态参数。若结构进入了时变反应阶段,则将整个结构地震反应记录分为三段,第一段和第三段采用非时变参数识别方法,分别识别结构的模态参数,作为结构破坏前和破坏后的模态参数。第二段采用递归式识别方法,得到模态参数随时间变化的关系,可以观测模态参数在地震作用过程中的变化趋势及规律,也可以得到地震过程中结构的破坏起止时刻。利用一座7层钢筋混凝土建筑物及其在4次地震中的地震反应记录,利用本文方法和所编制的程序对其模态参数进行了详细的识别研究,得到了其小震地震反应的模态参数和大震地震反应的模态参数,特别是得到了结构的模态参数随时间的变化关系,分析结果显示本文所提方法非常有效,得到的结果也合理。3.结构自振周期统计分析提出了两类建筑结构基于地震反应记录的自振周期经验公式。分别选取了40座框剪结构形式的建筑物和36座钢结构形式的建筑物,利用这些建筑更多还原

【Abstract】 The structural earthquake response observation is the foundation of theearthquake engineering. The structural response and damage process underearthquake excitation are mainly be understood by this kind of observation. Theseismic design theories and methods of structures are also be examined by thestructural earthquake response observation. In recent years, all the governmentsof the world and earthquake engineering field have paid more and more attentionsto the structural earthquake response observation, which has been made quitegreat progress. In China, with the development of the digital strong earthquakeobservation, more and more high-rise and important buildings will be installedstrong earthquake response observation array. Once the observation systemobtained strong earthquake response records, the records can be used to structuralmodal parameter identification and engineering seismic research, and the resultscan be considered as fundamental data for structural health diagnosis and seismicsafety evaluation after earthquake. The structural modal parameters identificationand damage detection are always the concerned problems in the field ofearthquake engineering. The paper has made some researches of structural modalparameter identification and its applications under the excitation of earthquakesystematically and deeply. The main works of the paper are summarized asbelow:1. HHT Analysis of Structural Earthquake Response RecordsA new non-linear and non-stationary signal processing method-HHT(Hilbert-Huang Transform) with its meaning and arithmetic was introduceddetailedly in the paper. According to the arithmetic, a toolbox of HHT wasproduced and developed in the paper. Then a 7-storey steel concrete building andit earthquake response records and damage in several earthquakes wereintroduced. The HHT was used to deal with 3 main and representativeearthquakes response data and the amplitude-frequency-time distributions ofstructural earthquake response data were obtained. The HHT marginal spectrawere also given and compared with Fourier spectra and some significativeconclusions were made.2. System Identification of Structure under Excitation of EarthquakePresent the modal parameter system identification methods for structureunder excitation of small and severe earthquakes. If a structure were not intotime-varying response stage and the whole response were in linear elastic range,the modal parameters can be identified by using the whole earthquake responsetime-history. If the structure were surely into the time-varying response stage, thewhole earthquake response time-history was compartmentalized into threesegments. The first and the third segments were treated as time-invariant stage,and modal parameters identified from first and third segment were considered asthe intact and damaged cases of the structure respectively. For the secondsegment, the recursive identification method was used to identify the modalparameters and obtained the time-varying modal parameters from which thevariety property and law of the structural modal parameters could be found outduring the earthquake excitation. Also, the starting and end time point of thedamage could be observed clearly. According the method and thoughts of thepaper, a 7-storey RC building which had suffered 4 earthquakes and obtainedresponse data was used for the analysis. The modal parameters under theexcitation of small and severe earthquakes were identified and the time-varyingmodal parameters were also given in the paper. It is shown that the method of thepaper is very available and the results are accurate and reasonable.3. Statistical Analysis for Fundamental Periods of StructuresPresent experimental formulas for the fundamental periods of two types ofbuildings based on earthquake response data. A total of 40 RC frame-shear wallstructures and 36 moment resisting steel frame structures were used for thestatistical analysis. All the buildings had obtained earthquake response recordsduring one or more earthquakes. The fundamental periods of all the building inintact case were firstly identified, and then, the experimental formulas of the twotypes structures were given by non-linear regression method. The simpleexperimental formulas proposed in the paper can be used to for the code revision and structural earthquake-resistant design researches.4. Torsion Modal Parameter Identification using Earthquake DataPresent a method to decouple the lateral-torsional coupling earthquakeresponse and identify the torsion modal parameters. The torsional response time-history of structure under excitation of earthquake was decoupled from the lateralearthquake response data, and then the torsion modal parameters were identifiedfrom the torsional response data. The time-invariant and time-varying torsionmodal parameters were identified in the paper. A 7-storey RC building with itsearthquake response records was used for the analysis and some significativeconclusions were made.5. Damage Identification of Structure under Earthquake ExcitationBase on the structural simulation results of finite element model, the changesof structural modal parameters under different damage level were studied in thepaper. The relationship between the damage index and the change of modalfrequency was established, as well as the change of mode shape. Some empiricalequations between the damage index and modal frequency variety and modeshape variety were given by non-linear regression method. The equations can beused to predict the damage state once some building records the earthquakeresponse data. The modal parameters of intact structure need not to be knownprior to the earthquake, because the modal parameters before and after damagecan be identified simultaneously only using one-earthquake response records bythe methods of the paper.更多还原