Seismic response of composite frames - I. Response criteria and input motion

To facilitate the evaluation of the seismic response of a class of composite frames through the application of nonlinear dynamic analysis techniques, response criteria which reflect the acceptable limits of structural response are defined. These reponse criteria relate to the behaviour of the frames at local (member) and global (storey) levels. To ensure that the identified frame behaviour is sufficiently general in nature, the response analyses are performed using a diverse range of earthquake loads. To this end, six recorded accelerograms are selected on the basis of their peak ground acceleration-to-velocity (a/v) ratios. Each record is scaled to possess a spectrum intensity equal to that of the Eurocode 8 design spectrum, preserving the important velocity characteristics of the ground motion, while remaining compatible with provisions of the design code. In a companion paper, these response criteria and earthquake loads are applied in the evaluation of behaviour factors for moment-resisting composite frames.