POST-EARTHQUAKE DAMAGE ASSESSMENT OF MOMENT RESISTING STEEL FRAMES

The assessment of damage in structures that have suffered one or more earthquakes is of paramount importance to better understand the post-earthquake effective behaviour, and eventually to define the more appropriate design strategies for retrofitting and repairing. The paper, which is focused on moment-resisting (MR) steel frames, deals with post-earthquake assessment after one or more seismic events. A procedure combining non-linear time-history finite element analysis with the low-cyclic fatigue theory have been applied to appraise the damage level of each frame component and then the residual load carrying capacity have been evaluated via the incremental static analysis of the damaged frames. It is worth underlining that, on the basis of the discussed numerical results, the damage measurement and the residual load carrying capacity, which are often neglected in routine design, appear very useful to increase the knowledge on the effective safety level of the frame after one or more earthquake.