Modeling sensitivity analysis of special concentrically braced frames under short and long duration ground motions

Modeling and simulation of the seismic response of special concentrically braced steel frames (SCBFs) through collapse involves several sources of epistemic uncertainties, e.g. braces low-cycle fatigue model, that could affect the seismic performance assessment. However, longer duration earthquakes, e.g. from subduction zones rupture, could have more damaging effect on SCBFs when associated with the brace fatigue life. The objective of this study is to investigate the influence of modeling parameters on the seismic response of SCBFs as it relates to the earthquake duration. Different OpenSEES modeling parameters were varied deterministically as sources of uncertainties for two single-story SCBFs under 16 different short and long duration earthquakes. Tornado diagram analysis was used to rank the effect of such parameters, and the analysis results were also used to develop two sets of fragility curves under short and long duration earthquakes to understand the effect of duration on SCBFs.