Power based seismic collapse criterion for ductile and non-ductile framed structures

In performance-based earthquake engineering design, quantification of the collapse capacity of a structure is of paramount requirement for the development of collapse fragility models. Different methods for predicting collapse provide varying estimates. Consequently, performance design is highly sensitive to the method employed to quantify the collapse capacity. Recently, new energy-based methods have emerged as alternatives to the conventionally used criterion with the aim of objectively quantifying structural collapse. Although these new energy-based criteria are much more robust than the conventional ones, they inherently rely on the occurrence of large deformations. This makes them lagging indicators of collapse resulting in un-conservative results. Moreover, they mainly focus on describing P–Δ instability governed collapse mechanisms, which typically occur in ductile structures. As an improvement, this study presents a new power balance-based numerical collapse criterion that tracks the rate at which energy is supplied and dissipated in the structure. It acts as a leading indicator and successfully predicts seismic collapse in framed structures under both gravity load and sidesway collapse mechanisms. This is illustrated using a wide range of validated collapse simulations. It is found that the probability of collapse predicted using the power criterion falls between that derived from the IM/DM (intensity measure/damage measure) based rules and the energy-based criterion.