Cyclic analysis of PR steel frames with composite reinforced concrete infill walls

This paper presents a formulation for the modeling and the simulation of composite reinforced concrete infilled steel frames (S-RCW) with partially-restrained connections suitable for analyzing three-dimensional structures subjected to static or transient dynamic (seismic) loading conditions. The analysis formulation allows for second-order geometric nonlinearity as well as for material nonlinearity. This structural system can provide a reliable and economic lateral resistance system for low- to moderate-rise buildings in seismic areas. The four main components of the S-RCW formulation, presented in this paper, include: (a) a fully nonlinear steel beam-column element, complete with shear deformability; (b) a fully nonlinear reinforced concrete panel element, which allows for the formation of multiple crack patterns; (c) a steel-concrete interface element, which takes into account the slippage and contact phenomena at the frame-infill interface; and (d) a partially restrained beam-to-column connection element, using a component-based model. This formulation may be used for corroboration with experiments, for design based upon use of linear or nonlinear analysis, and for assessment of seismic demand.