In this paper, an optimization framework is developed for performance-based seismic design of composite moment frames consisting of concrete filled steel box columns and I-shaped steel beams. Material cost of the structure and seismic damage under severe earthquake ground motions are minimized as objective functions. Two design examples are presented to demonstrate the applicability and efficie...

A comprehensive computational model to simulate the nonlinear seismic response of composite frames with rectangular concrete-filled steel tube (RCFT) beam-columns and steel girders and braces is presented in this work. A three-dimensional fiber-based distributed plasticity mixed finite element formulation is introduced. The finite element formulation of RCFT beam-columns was derived with separa...

The assessment of response of composite seismic force resisting systems requires accurate nonlinear formulations for the composite members. In this work, reporting the first phase of a NEES project, a three-dimensional distributed plasticity formulation is presented for both circular and rectangular composite concrete-filled steel tubes (CFTs) that includes new constitutive models for the concr...