Advanced Inelastic Analysis of Spatial Structures

Publisher Summary This chapter presents the nonlinear inelastic models that can be used for analyzing space frame structures within the context of advanced inelastic analysis. In this approach, each steel-framing member is modeled as a one beam-column element. Plastic hinges are allowed to form at the element ends and within the element length. To allow for the gradual plastification effect, a two-surface model is adopted. The initial yield surface bounds the region of elastic sectional behavior, while the plastic strength surface defines the state of full plastification of the section. It is assumed that there is a smooth transition from the initial yield surface, as the force state moves to the plastic strength surface. A major part of the bending and torsional resistance in a building structure is provided by core walls. The core walls are modeled by thin-walled frame elements. The centerline of the core-wall is located on the shear center axis. Any significant twisting action should be analyzed to include both warping and torsional effects. Beam-to-column and beam-to-core-wall connections are modeled as rotational spring elements, having the moment-rotation relationship described by the four-parameter power model. The advanced analysis program is applied to investigate the collapse of a roof truss system and perform nonlinear inelastic analysis of a core-braced frame with semirigid connections.