A Study on System Identification and Engineering Applicationof Strong Motion Records in Buildings

• Main Authors: Yu-Yen Chiu, 邱瑜燕
• Other Authors: G.C.Yao
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/c6qz3a

博士 === 國立成功大學 === 建築學系碩博士班 === 90 === The purpose of this research is to establish a new system identification method and the application of the identified system data. This method has the advantages of multiple checking and data sorting in analysis, and the error of estimation is small. The analyzed data come from two parts: first part is the building strong motion records in Taiwan with PGA greater than 80 gal from Ra-Li, Chi-Chi, and Chia-Yi earthquakes. Second part is nonlinear test data from shaking table tests. This includes input of pseudo white noise, TAP and TCU-078 ground motion. The analysis is constituted of: （1）Seventy-five pairs of building strong motion records are used to analyze the beginning of time-varying response of buildings in earthquakes by the AFMM method. Their frequencies and damping ratios are identified by the ARX model. Thirty-seven pairs among them are identified by the RARX (Recursive-ARX) model, to identified the frequencies and damping ratios in the time-varying response. （2）The 400 pairs of nonlinear laboratory test data are used to analyze the beginning of time-varying response of buildings in strong earthquakes by the AFMM method. By the ARX model, the frequencies and damping ratios are identified. Ninety-four pairs among them are identified by the RARX model to distinguish the frequencies and damping ratios of the time-varying response. （3）Three hundred eighty four time history records are used to analyze floor response spectrum. All of the analysis include the first and second mode resonant frequencies and the first anti-resonant frequencies. Assuming all the sample data are linear, dynamic, stochastic, lumped-parameter, discrete-time systems, conclusions can be summarized below: 1. The more asymmetric the structural form of a building is, the more the torsional effect exists. 2. The building strong motion records would be best examined by the AFMM method to observe whether there is a time-varying response region. ARX model for the linear time-invariant region system ID is suitable while the linear time-varying region is best analyzed by the RARX model. 3. Only at the upper floors, the fundamental anti-resonant frequency（ARF）will not move beyond the first resonant frequency in time-varying region. 4. The decrease trend of the first and second natural frequencies in damaged buildings is close to that of the fundamental anti-resonant frequency. 5. From the laboratory tests of RC frame-wall buildings, the appropriate structural behavior to choose the ARF approach in equipment protection is before the overlapping of the ARF and the fundamental frequencies take place.