INELASTIC DESIGN OF INFILLED FRAMES

This paper describes a new method of analysis and design for steel fra mes with concrete or masonry infilling walls subjected to in-plane for ces. The method is based on data generated from previous experiments a s well as results from a series of nonlinear finite-element (NLFE) ana lyses. The method accounts for elastic and plastic behavior of infille d frames considering the limited ductility of infill materials. The pr oposed method predicts the strength and stiffness of infilled frames a s well as the infill diagonal cracking load. The method also allows fo r the major practical imperfections, such as lack of fit and shrinkage of the infill. Variations, such as infill aspect ratio and beams havi ng different strength and stiffness from the columns, are accounted fo r and it is concluded that the behavior of frames with pin or semirigi d joints can also be predicted. The method is further developed to mod el multistory infilled frames as braced frames, replacing the infills by equivalent diagonal struts.