Seismic performance of high rise hybrid structures with moment frame configuration

The seismic design methods should pay special attention to the characteristics of ground motions especially in near fault. Near-field records are generally recognized by the sudden impulsive ground displacements in a short time domain in which contain large amount of kinetic energy. An important consequence of lateral displacement and story drift is the structural and non-structural damage. Many previous studies suggest that the mentioned parameters are sufficient to indicate the correlation between characteristics of the structural response and seismic risk. Framed tube system is one way to limit the movement of stories in high rise buildings. This structural system causes a similar behaviour of the whole resistant skeleton to a hollow tube, so that a significant increase is observed in lateral stiffness of the structure. In this study, the studied models are in the form of 20-story structures that are regular in plan and height. The resistant skeleton of the studied structures is designed according to the fourth edition of Standard No. 2800 as well as topics of the Iranian national building code. Based on the results obtained by conducting the nonlinear dynamic analyses, this study deals with the trend of variations in the target seismic response parameters subjected to the site-specific design spectrum according to the design provisions denoted in the Standard No. 2800. Topics and issues evaluated in this study include the lateral displacement, story drift and effect of the configuration of internal rigid frames in variation rates of the mentioned parameters. Based on the results, the maximum drift usually happened in the middle third of the structure height. Yet, the maximum response parameters of displacement and story drift were individually exposed to relative reduction and increase, regarding to replacement of the resistant skeleton from frame-tube into bundled-tube structure.