Assessment of seismic behaviour of SMRFs with RBS connections by means of mixed‐based state‐space approach

SUMMARY With an intention to implement a reliable numerical implementation of the mixed-based state-space strategy for steel structural systems, the paper presents a thorough seismic analysis of steel moment resisting frames (SMRFs) with reduced beam section (RBS) connections. Firstly, a model of beam-column element inclusive of material and geometric nonlinearities is effi ciently utilized derived from appropriate force interpolation functions. Moreover, with the present formulation, non-prismatic properties of RBS region can be considered without the necessity of heavy discretization of elements. Contribution of panel zone is taken into account by considering a nonlinear rotational spring as well. In addition, the extension of Wen-Bouc model to capture material inelasticity is applied that is apparently superior to other constitutive behaviour when it leads to both a smooth hysteretic model and rather precisely well-mannered state-space depiction capable of conveying several hysteretic features. The state-space approach is then employed where nodal forces balance and constitutive equations are solved simultaneously. Secondly, three-dimensional fi nite element analysis is surveyed to validate proposed macroelement model. Finally, a set of nonlinear static and transient analyses of four- and eight-storey frames with and without RBS connections are fulfi lled. Then, structural demand parameters used to assess the global and local response of designated frames. Copyright © 2008 John Wiley & Sons, Ltd.