ABSTRACT
This paper investigates the effects of the higher modes and the seismic frequency content on the accuracy of the inelastic static seismic (pushover) analysis of plane steel frames. Seven different frames designed by the EC8 are analyzed for lateral static load distributions along their hight and their complete inelastic response is compared against their dynamic one to 30 different historic seismic records of low, moderate and high frequency content. The effect of higher modes is taken into account by appropriately modifying the lateral load distribution leading to very good results. It is also found that the seismic frequency content significantly affects the accuracy of pushover analysis leading to very good results only for the cases of moderate frequency earthquakes. A simple remedy is proposed for the treatment of this frequency content effect.
