基于结构动力特性的钢筋混凝土框架结构损伤研究

发布时间：2018-09-09 19:47

【摘要】：性能化抗震设计的重要基础是确定表征结构抗震反应的指标,合理的结构反应指标能够评价结构在不同水准地震作用下的性能。同时,合理的结构反应指标也能够评价结构的损伤程度,能够作为决策者对结构震后处理的决策依据。结构的频率、振型等动力特性是结构本身的基本属性,随着地震荷载增强,结构进入弹塑性阶段,结构构件发生损伤时,结构动力特性也在发生改变。因此,本文重点探讨基于结构动力特性改变的损伤参数。本文通过弹塑性静力推覆过程中结构动力特性的变化来进行结构损伤评估,提出基于频率下降率损伤指标、考虑频率余量的损伤指标以及根据各阶振型相对质量计算的组合频率损伤指标。考虑到当前主流分析软件无法得到弹塑性推覆过程中结构的动力特性,本文对IDARC程序进行了改编,使之能够输出结构静力推覆过程中每一步的各阶频率及振型。本文建立了一10层框架模型,并取其中一榀进行分析。应用改编IDARC程序,通过逐步增加水平力计算结构响应,并在每步计算动力特性的改变,结果表明,结构各阶频率在推覆过程中均会下降,但结构低阶振型变化较小。计算基于动力特性的损伤参数指标的变化历程,并与基于位移延性、基于Park-Ang模型等几种损伤参数进行对比,发现基于动力特性的损伤参数能较好地识别结构屈服阶段和失效阶段。本文提出的基于频率的损伤指标能够反映结构的整体破坏历程,对结构的各个阶段较好的识别,提出的组合频率损伤指标一定程度上能够综合反映前几阶振型对损伤的贡献。本文通过考察结构推覆全过程中动力特性变化这一视角,并计算相应的频率损伤指标,对结构的破坏历程和损伤表征方法进行了综合研究,为结构的整体损伤评估提供了新的途径。
[Abstract]:The important foundation of performance-based seismic design is to determine the index of seismic response of structure, and reasonable structural response index can evaluate the performance of structure under different earthquake levels. At the same time, the reasonable structural response index can also evaluate the damage degree of the structure, and can be used as the decision basis of the decision maker for the post-earthquake treatment of the structure. The dynamic characteristics of structure, such as frequency and mode, are the basic properties of the structure itself. With the increase of seismic load, the structure enters the elastic-plastic stage, and the dynamic characteristics of the structure also change when the structural members are damaged. Therefore, the damage parameters based on the dynamic characteristics of the structure are discussed in this paper. In this paper, the structural damage assessment is carried out through the change of the dynamic characteristics of the structure during the elastoplastic static force push-over process, and the damage index based on the frequency drop rate is proposed. The damage index of frequency margin and the combined frequency damage index calculated according to the relative mass of various modes are considered. Considering that the current mainstream analysis software can not obtain the dynamic characteristics of the structure in the process of elastoplastic nappe, the IDARC program is adapted to output the frequencies and modes of each step in the static push process of the structure. In this paper, a 10-story frame model is established and one of them is analyzed. By adapting the IDARC program, the structural response is calculated by increasing the horizontal force step by step, and the change of the dynamic characteristics is calculated at each step. The results show that the frequency of each order of the structure will decrease in the process of nappe, but the change of the low-order mode of the structure will be small. The change history of damage parameters based on dynamic characteristics is calculated and compared with several damage parameters based on displacement ductility and Park-Ang model. It is found that the damage parameters based on dynamic characteristics can better identify the yield stage and failure stage of the structure. The damage index based on frequency presented in this paper can reflect the whole damage history of the structure, and better identify each stage of the structure. To some extent, the combined frequency damage index can reflect the contribution of the previous vibration modes to the damage to a certain extent. In this paper, the damage history and damage characterization method of the structure are comprehensively studied by examining the dynamic characteristics change during the whole process of the structure nappe, and calculating the corresponding frequency damage index. It provides a new approach for structural damage assessment.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU375.4;TU317

【引证文献】