ASSESSMENT OF SEISMIC RESPONSEPARAMETERS OF TALL BUILDINGS WITH TUBE IN TUBE STRUCTURAL SKELETON

In this research, the basic response parameters of the nonlinear dynamic behavior of steel tall buildings with tube in tube structural skeleton were studied. The studied model consists of an exterior braced-tube system and an interior framed-tube.A number of nonlinear dynamic time history analyses were conducted for the studied model under influencing of an ensemble of free field pulse type ground motions. The studied model is a 30-story steel tube in tube structure which contains several beam, bracing and column elements. The designation process has been completed for all of the elements, members sections and the connection zones based on the Iranian national building code (steel structures - part 10). The confirmations of the principle of strong column and weak beam in all connections and the assessment of strength of panel zones have been considered in the designation process. A number of diagonal girders are used in the skeleton of the studied structure to connect efficiently the exterior braced tube to the interior rigid framed tube systems. This improvement would cause an efficient and better distribution of lateral loads between the two resistant bents of the entire structure. The other helpful advantage is to attain to the minor stress ratios in member sections to achieve the more economical structure.