Performance-based seismic assessment of steel frames using endurance time analysis

• Finite element models of two high-rise steel frames are provided and calibrated.
• Seismic performance of the structures is compared using ETA, IDA, and THA.
• Advantages and disadvantages of ETA are compared with IDA in the structural collapse assessment.
• A new method is proposed to drive the collapse fragility curve for structures.
• Progressive collapse analysis of the frames is investigated using ETA method.

The current performance-based seismic assessment procedure can be computationally intensive as it requires a large number of time history analyses (THA) each requiring time intensive post-processing of results. This study proposes the endurance time analysis (ETA) method as an alternative method to THA and incremental dynamic analysis (IDA). ETA is a time history based dynamic pushover procedure that applies a set of gradually intensifying acceleration functions to the structure and monitors the performance of the building accordingly. In this paper, the application of ETA in the seismic assessment of multistory steel concentrically braced frames is compared with THA and IDA methods. Moreover, the progressive failure of the frames is investigated using the ETA method. The results of this analysis show that ETA can estimate THA as well as IDA, with considerably less computational effort.