Simplified collapse capacity assessment of earthquake excited regular frame structures vulnerable to P-delta

In this paper the prediction of the global collapse capacity of earthquake excited regular moment-resisting frame structures is discussed. The addressed flexible planar frame structures with non-deteriorating inelastic component behavior are vulnerable to the destabilizing effect of gravity loads. A simplified collapse assessment methodology based on pushover analyses, equivalent single-degree-of-freedom systems, and a collapse capacity spectrum is proposed. This methodology, which is referred to as collapse capacity spectrum methodology, is examined for a series of frame structures covering a wide range of structural parameters. Therefore, the global collapse capacity of these structures derived with this methodology and with the computationally expensive incremental dynamic analysis procedure is set in contrast. From the outcomes it can be concluded that in the initial design process the collapse capacity spectrum methodology is an appropriate tool to assess reliably the median and the dispersion of collapse capacity of P-delta sensitive regular moment-resisting frame structures subjected to severe earthquake excitation.

► Earthquake induced sidesway collapse of inelastic frames vulnerable to P-delta is assessed.
► The efficient collapse capacity spectrum methodology is proposed to predict collapse.
► This methodology renders sufficient accurate estimates of the collapse fragility.