| dc.description.abstract | In Taiwan, steel structures have been under development for nearly forty years. Due to the revision of building codes and the attenuation of the materials strength and beam-culmn joint performance of building caused by the earthquake during the period, there are doubts about the lack of seismic performance of steel structures. In addition, high-rise buildings are involved in higher modal reactions, not only using inelastic static pushover analysis, but also inelastic dynamic time-history analysis to examine unexpected large displacement reactions. This study will establish a method for seismic evaluation and retrofit of high-rise steel structure building, and understand the characteristics of high-rise building responses and common retrofit methods.
This study will establish four models, 15th, 20th, 28th and 35th floor high-rise steel structures, all designed in the past specifications (1982,1994), it is expected that these four models need to be retrofit. Referring to the Taiwan and U.S.A. specifications for seismic performance evaluation procedures and standards, establish a recommended seismic capacity evaluation method, and evaluate the design case and a real case. After evaluation, retrofit was performed using buckling restrained braces and nonlinear viscous dampers. Then, the inelastic static pushover analysis and inelastic dynamic time-history analysis were used to compare the changes in intensity and displacement.
The results of this study show that the two horizontal component earthquake records should not be used separately. Because frequency and the duration of the earthquake records is the same, and the frequency is a major cause of structural response, it is recommended to consider the relation of two horizontal component earthquake records. In the story drift, of a 15-story steel structure, the use of inelastic static pushover analysis is similar to inelastic dynamic time-history analysis reaction, and the higher-rise steel structure has a high-modal effect, so more than 15 floors of steel structure should enter the inelastic dynamic time-history. In addition, the higher steel structure building, the lower efficiency of the control using the buckling restrained braces, and the higher efficiency of using the nonlinear viscous damper in the steel structure of the higher steel structure building. But the nonlinear viscous damper difficult to control, recommended to enter the inelastic dynamic time-history analysis. Each building evaluation and retrofit is a different case. It is necessary to understand the building requirements and the advantages and disadvantages of each retrofit strategy in order to effectively retrofit the design. | en_US |