Buckling Strength of Cold-Formed Circular Steel Column Subjected to Axial Load

In this study, the global buckling behavior of a cold-formed circular steel column was discussed with a focus on the effects of its mechanical properties and initial imperfections on the behavior. As the first step, the stress–strain curves of the column under tensile and compressive loads as well as its residual stresses were investigated. Subsequently, a finite element analysis was conducted to clarify if the analysis properly simulated the stub column behavior. The analysis results obtained using measured compressive stress–strain curves and residual stresses agreed well with experimental results. Finally, another finite element analysis was performed on the long column buckling to examine the effects of its mechanical properties and initial imperfections. It was shown that the global buckling strength was affected not only by imperfections such as residual stress and out-of-straightness but also by the anisotropic mechanical properties of the material

Innovative Damage Control Systems Using Replaceable Energy Dissipating Steel Fuses for Cold-formed Steel Structures

This paper describes the development of innovative seismic technologies for cold-formed steel structures; a rocking steel shear wall system with replaceable energy dissipating steel fuses for low rise housing units. In this system, the fuses are placed at the base of a folded-steel sheet wall connecting an anchor bolt and the steel sheet wall. It is designed so that most of the earthquake energy can be dissipated by plastic deformation of the fuse elements, while the shear wall remains intact and resists vertical and horizontal forces caused by large earthquakes. As expected in seismic events, the fuses at the base move cyclically into plastic regions when the wall behaves in a rocking manner. As a result, the wall system is expected to show a stable energy absorption behavior. To maximize its energy absorption capability in this research, the shape of the fuse is optimized, such that a butterfly shape is employed to have a greater yielding region. To verify the seismic performance of the proposed system, static shear wall tests and earthquake response analyses were respectively conducted. It was confirmed, with both results, that the developed fuses have high energy absorbing capacity and the rocking shear wall systems using them also have high seismic performance in comparison with conventional shear wall systems. The proposed system contributes to increased sustainability of the building systems through which damaged fuses are replaced after strong earthquakes

Shear Resistance Mechanisms on Steel Sheet Shear Walls with Burring Holes and Cross-Rails

Steel sheet shear walls with burring holes are employed in low and mid-rise buildings in seismically active regions. A configuration with burrs on the inside enables the thinner wall and omitting the machining of equipment holes. The effects of cross-rails which are generally designed to strengthen the bearing capacities of the studs, on 2.73~4.53m height shear walls were clarified by finite element analysis and experiments. Post-buckling behavior depends on tension fields restrained by the cross-rails. The formulas of the allowable strengths and the indexes of ultimate strengths were developed using the mechanisms

Shear Resistance Mechanisms on Steel Sheet Shear Walls with Burring Holes and Cross-Rails

Steel sheet shear walls with burring holes are employed in low and mid-rise buildings in seismically active regions. A configuration with burrs on the inside enables the thinner wall and omitting the machining of equipment holes. The effects of cross-rails which are generally designed to strengthen the bearing capacities of the studs, on 2.73~4.53m height shear walls were clarified by finite element analysis and experiments. Post-buckling behavior depends on tension fields restrained by the cross-rails. The formulas of the allowable strengths and the indexes of ultimate strengths were developed using the mechanisms