Seismic capacity and possibility of collapse of tall steel buildings with outrigger system using failure curves and damage profiles]

forms of the outrigger or belt truss structure have high performance in reducing the response of tall structures against side loads. However outriggers system are not considered as a seismic system in design codes. In this paper seismic behavior of tall buildings with outriggers will be checked and the effect of adding outrigger on the seismic behavior of steel tall structures in term of capacity of seismic intensity corresponding to the level of performance of collapse, Distribution of seismic requirements in high of structures demand curves corresponding to the general instability of structures and Fragility curves will be studied. Therefore, in the first three buildings of 20, 25 and 30 floors in three dimensions are designed so that the effects of outriggers not considered in the initial design and in terms of members resistance and the relative displacement (drift) have passed some regulations.
To do this, the three structures is designed using 3D model So that the effects of outrigger are not considered in the initial design and in terms of resistance members as well as the relative displacement of stories have passed limits of design code. and then one of main frame of structure is analyzed using “Opensees” software and moment frame structural system and CBF with regard to inelastic behavior in both the presence and absence of outrigger checked by IDA analysis. The results show