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The steel-concrete composite column is a new composite member that can achieve constructability and economy by fi lling the empty space in the steel H-fl ange with concrete. Even before this study was conducted, it had been proven in another study on the axial capacity of a steel-concrete composite column that the steel-concrete composite column with a non-compact section has excellent structural strength. Further studies on fl exural-compressive capacity are necessary, though, due to the structural characteristics of the column. As such, this study on the fl exural strength of a steel-concrete composite column with a non-compact section that is under a constant axial force was conducted for the strong-axis and weak-axis directions, and the results were compared with the evaluations of various design code provisions. Based on the results of the experiment, the axial force-bending moment capacity of the column met the criteria of various countries for both axis directions. Specifi cally, the AISC-LRFD provisions evaluate the load-carrying capacity of the composite column too conservatively. Therefore, the AIJ and EC4 code provisions are considered desirable for use in evaluating the capacity of the axial force-bending moment of steel-concrete composite columns with non-compact steel section.

A buckling-restrained brace (BRB) is a system with excellent earthquake-proof performance, but it does not dissipate energies caused by the load from weak earthquakes or winds. A hybrid BRB (H-BRB), which improved the performance of the BRB, is a type of composite damper system consisting of a BRB and a viscoelastic damper. To explain the wind-induced vibration control performance of H-BRB, a 40-story steel building was designed and used as an analysis model in this study, on the basis of the damping ratio from a structural performance test, using normal steel braces, BRB and H-BRB. In addition, to evaluate the optimal location of H-BRB, a time-history analysis of four models was conducted in the study. For such time-history analysis, wind-load data in a 10-year recurrence interval, which were calculated from the wind tunnel test, were used. The result of the time-history analysis showed that H-BRB is effective in improving both the lateral stiffness and serviceability of a building using the existing BRB. It also confirmed that it is most effective to position H-BRBs mainly on the lower stories.

Generally the analysis of steel moment resisting frames has been performed without considering the accurate connection behaviors. However, a number of beam-column connections of the steel moment resisting systems raised sudden fracture resulted in enormous economical loss in recent earthquakes. In this study, the analytical modeling of Korean beam-column connections in steel moment resisting frames was proposed based on the experimental studies of other researchers. The adopted computer program for inelastic analysis was DRAIN-2DX, and the standard element type was set to the Element Type 10 in DRAIN-2DX for panel zones and beam-connections. The inelastic analysis results of the example structure with connection modeling were compared to those of the structures without connection modeling.