An investigating into the effect of various modeling parameters on the behavior of special steel moment frames

In this paper, the effect of various modeling parameters such as beam – column connections, soil and shallow foundation types are studied to assess the seismic response of steel moment frames. For this purpose, five-story special steel moment frames with two different soil types (II and IV) have been considered. The footing and strip shallow foundations have been designed for these buildings, with safety factor of three. Prequalified bolted flang plate connections are used in these buildings. The finite element models are developed using OpenSees software considering soil – foundation – structure interaction. The seismic performance of SMFs are evaluated using nonlinear time history analyses, through seven far–fault ground motions. Nonlinear behavior of soil is modeled by nonlinear Winkler springs. The numerical results show that in the models that considered beam-column connections, SFSI and soil type IV, the maximum inter-story drift is more, compare to models without connections and with fixed based conditions. The maximum base shear of structures in the mentioned models is reduced. In models, that structures rested on soil type II, maximum values of these two parameters are diminished. The effect of foundation type in models resting on the soil type IV is more than models with soil type II. Generally, connections, foundation type and soil-foundation-structure interactions have a great influence on the nonlinear responses of steel moment frames.