Maximum inter-story drift demands of steel frames in terms of the intensity measure INp.

In the present work, a new equation to predict the maximum inter-story drift demands of mid-rise steel framed buildings is proposed in terms of a new ground motion intensity measures based on the spectral shape. For this aim, the maxim\um inter-story drift of steel frames with 4, 6, 8 and 10 stories subjected to several narrow-band ground motions is estimated as a function of the spectral acceleration at first mode of vibration Sa(T₁), which is commonly used in earthquake engineering and seismology, and with a new parameter related to the structural response known as I_Np. It is observed that the spectral-shape-based intensity measure I_Np is the parameter best related with the structural response of the selected steel frames under narrow-band motions. For this reason, an equation to compute the maximum inter-story drift demand of mid-rise steel frames as a function of I_Np is proposed. The equation is useful for the rapid seismic assessment. [ABSTRACT FROM AUTHOR]