In recent years, typical steel construction in regions of high seismic risk has shifted from moment-resisting frames to concentrically braced... Show moreIn recent years, typical steel construction in regions of high seismic risk has shifted from moment-resisting frames to concentrically braced frames. As a result of the increased popularity of braced frames, the poor performance of some conventionally braced frames in past earthquakes, and the limited experimental data available on the inelastic response and the failure characteristics of braced-frame systems, a series of experimental and analytical investigations were initiated. Steel concentrically braced frames are common lateral force resisting systems in both new construction and existing buildings. However, the seismic behavior of braced frames designed prior to the adoption of capacity design principles in the 1980s is generally not well understood despite their widespread presence. These older braced frames, termed non-seismic concentrically braced frames (NCBFs) are the subject of a research project titled “NEESR: Collaborative Developments for Seismic Rehabilitation of Vulnerable Braced Frames” that seeks to evaluate NCBFs and determine retrofit strategies. In this project two tests were conducted. First Test examined a full scale two story NCBF in the inverted V configuration subjected to quasistatic cyclic load and this specimen contained a bottom story beam that is considered weak in capacity design. Second Test examined a post-earthquake repair scenario using the damaged NCBF-INV-1 frame in which the bottom story braces and gusset plates were removed and replaced with seismically compact braces with connection designed for in plane buckling. In this work, finite element models developed in Abaqus were validated using data collected from these tests. The outcomes of this research will be a greater understanding of seismic performance of NCBFs, the development of rehabilitation strategies for vulnerable NCBFs, and a robust technique for modeling NCBFs. M.S. in Civil Engineering, May 2014 Show less
