Study on the Seismic Response Parameters of Steel Medium-Height Buildings with Framed-Tube Skeleton under Near-Fault Records

In this research, the performance abilities of tube type lateral load resistant framed systems are studied in order to assess the dynamic response properties of mid-rise steel structures under effects of far and near-field ground motions. For this purpose, three 10 story structural models with separated framed tube based skeletons were selected and designed. The structural models have been designed according to the Iranian seismic code 2800 (4th edition). The main criterion which was considered to select powerful ground motions for performing nonlinear time history analyses is the existence of energized coherent velocity pulses as well as high amplitude acceleration spikes in the time history of each earthquake record. Assessment of the analytical results should emphasize the importance of both lateral displacement and drift parameters which must be taken into account during the structural design phase. Furthermore, it was concluded that the maximum drift demand is more than 0.035 and the upper level of rotation of rigid connecting zones was obtained more than 5 percentages of a radian. As a general note, it was concluded that the seismic response parameters of mid-rise steel framed tube structures are intensively influenced by those strong earthquake records which contain powerful forward directivity effects and are able to emerge long period pulses in their time histories.