Effect of Ground Motion Duration and Response Spectral Shape on Seismic Performance of Steel Moment Resisting Frame Buildings

This study aims to assess sensitivity of typical steel moment resisting frame (MRF) buildings constructed in New Zealand by implementing hazard consistent incremental dynamic analysis (H-IDA). H-IDA is a recently developed framework, which is performed using multiple sets of ground motions each of which represent key ground motion characteristics consistent with different levels of seismic hazard. Unlike the current trend of seismic design and analysis of structures, which explicitly consider only amplitude measure of the ground motion, such as spectral acceleration at the fundamental period of the structure (Sa(T1)), this study takes into account the effect of ground motion duration as well as response spectral shape on the performance of structures. In order to quantify the effect of duration of ground motion on a structure, significant duration (Ds) is used while SaRatio is implemented to quantify the response spectral shape. A typical office building plan developed for consistent case study between different QuakeCoRE projects is adopted to model 4 and 12 storey steel MRF buildings in OpenSees. Rotational spring is incorporated in the model to capture nonlinear behaviour of the steel MRF, which employs a bilinear hysteretic response based on the Modified Ibarra, Median and Krawinkler (IMK) Deterioration Model. Empirical equations developed by Lignos and Krawinkler (2010) are used to compute deterioration parameters for rotational behaviour of the hinges. The results of IDA analyses of these two building models are used to investigate sensitivities of typical mid-rise and low-rise steel buildings towards ground motion duration and spectral shape