Operational Modal Analysis Of High-rise Building Under Ambient Excitation And Finite Element Modeling Analysis

High-rise buildings play an important role in the rapid development of urbanization in our country. Whether early for reasonable design of high-rise building, or late on the health monitoring and damage identification, it is necessary to fully understand the dynamic characteristics of engineering structures.The modal parameters of engineering structures are very important to the dynamic characteristics. In this thesis, a research on the operational modal parameter identification based on the LMS Test.Lab for10high-rise buildings under ambient excitation was carried out, meanwhile, the corresponding finite element model of the10high-rise buildings was established by SAP2000for modal analysis. To sum up, the main research content is as follows:(1)Based on the brief introduction of the theoretical background and significance of the modal parameter identification,a literature review of the research status at domestic and abroad on operational modal parameter identification of high-rise building was conducted, meanwhile, an overview of this thesis is presented;(2)A brief description of the tested10high-rise building was introduced. The calculation principles of the random vibration signal analysis software LMS Test.Lab was introduced, and the software was used to identify the modal parameters of the10high-rise buildings. Xiangyun Garden A#building was taken as an example, the modal parameter identification process, the modal frequency and modal vibration mode were explained in detail.(3)How to quickly build a reasonable high-rise building model in SAP2000following the existing PKPM model was detailed introduced. Considering the influence of mass and stiffness of the infilled wall on modal analysis, three kinds of SAP2000models were established. They are as following:Model1--Regardless of the infilled wall; Model2--only consider the mass of infilled wall; Model3--Considering both of the mass and stiffness of the infilled wall. The modal frequency and the corresponding modal vibration mode of the three models calculated and analyzed by PKPM. SAP2000and LMS Test.Lab are compared.(4)The influence factors and the existing calculation method for the natural vibration period of high-rise buildings was introduced. The empirical formula of natural vibration periods in UBC-97,NBCC-1995,KBC-1988,BSLJ-1994,AS1170-2 and GB50011-2010were analyzed and these formulas were applied to calculate the natural vibration periods of the10high-rise buildings. The Response Spectrum Curve in Chinese Code for seismic design of building (GB50011-2010) was taken as an example, then the rationality of choosing earthquake influence coefficient a value according to the natural vibration period estimated by the national code was evaluated.