• Journal of Korean Society of Steel Construction
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• v.19 no.6
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• pp.655-661
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• 2007

A new steel connection method using wedges known as Self-Locking Connector has been developed. In this study, experimental investigation was conducted to verify the seismic performance of steel beam-to-column joints with Self-Locking Connectors. Cyclic-loading tests were performed on two beam-to-column joints with Self-Locking Connectors. The two beam-to-column joint specimens were of the cantilever-type and had the same details. Test results showed that beam-to-column joints with Self-Locking Connectors were able to developa total rotation capacity of 0.06 radian, which is greater than the 0.04 radian required for Special Moment Frames. Moreover, their energy absorption capacity was much greater than that of conventional joints.

• Steel and Composite Structures
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• v.25 no.5
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• pp.603-615
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• 2017

This experimental research presents the seismic performance of steel reinforced high-strength concrete (SRHC) short columns. Eleven SRHC column specimens were tested under simulated earthquake loading conditions, including six short column specimens and five normal column specimens. The parameters studied included the axial load level, stirrup details and shear span ratio. The failure modes, critical region length, energy dissipation capacity and deformation capacity, stiffness and strength degradation and shear displacement of SRHC short columns were analyzed in detail. The effects of the parameters on seismic performance were discussed. The test results showed that SRHC short columns exhibited shear-flexure failure characteristics. The critical region length of SRHC short columns could be taken as the whole column height, regardless of axial load level. In comparison to SRHC normal columns, SRHC short columns had weaker energy dissipation capacity and deformation capacity, and experienced faster stiffness degradation and strength degradation. The decrease in energy dissipation and deformation capacity due to the decreasing shear span ratio was more serious when the axial load level was higher. However, SRHC short columns confined by multiple stirrups might possess good seismic behavior with enough deformation capacity (ultimate drift ratio ${\geq}2.5%$), even though a relative large axial load ratio (= 0.38) and relative small structural steel ratio (= 3.58%) were used, and were suitable to be used in tall buildings in earthquake regions.

• Structural Monitoring and Maintenance
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• v.9 no.1
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• pp.81-105
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• 2022

The use of concrete filled steel tube (CFST) column is widely accepted due to its property of high axial load carrying capacity, more ductility and more resistant to earthquake specially using in bridges and high-rise buildings. The initial imperfection (δ) that produces during casting or fixing causes the reduction in load carrying capacity, this is the reason, experimental capacity is always less then theoretical one. In this research, the effect of δ on load carrying capacity and behavior of concrete filled steel tube (CFST) column have been investigated by numerically simulation of large number of models with different δ and other geometric parameters that include length (L), width (B), steel tube thickness (t), f'_c and f_y. Finite element analysis software ANSYS v18 is used to develop model of SCFST column to evaluate strength capacity, buckling and failure pattern of member which is applied during experimental study under cyclic axial loading. After validation of results, 42 models with different parameters are evaluated to develop empirical equation predicting axial load carrying capacity for different value of δ. Results indicate that empirical equation shows the 0 to 9% error for finite element analysis Forty-two models in comparison with ANSYS results, respectively. Empirical equation can be used for predicting the axial capacity of early estimating the axial capacity of SCFT column including 𝛿.

• Steel and Composite Structures
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• v.17 no.1
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• pp.83-103
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• 2014

The objective of this research is to study the ultimate moment capacity of the connections between steel I-beams and concrete-filled steel tube columns using different stiffener configurations. The main parameters considered are column cross section shape, square or circular, and filling the column with concrete. This analytical study includes finite element models using ANSYS program taking geometric and material nonlinearities into consideration. These models are verified against the experimental results obtained from previous researches and current design guides. The results show that using proper stiffener configuration affects the stress distribution through the connection and increases the ultimate moment capacity of the connections. Also, circular column is advantageous than the square column for all stiffener configurations and dimensions.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04b
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• pp.475-480
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• 1998

The composite framed structures, consisting of RC columns and steel beams more popular in korea because of their efficiency and quality. However the force transfer mechanisms between the column and beam may by very complicated since the materials of columns and beams are different. This study develops "the column penetration joint" which the web of steel beam doesn't penetrate and which could improve the strength, deformation, and energy dissipation capacities compared to existing composite joints. It is the concrete-filled square tube joint with the exterior diaphragms and the cruciform stiffening plates. This study evaluated the strength of RC column penetration to steel beam connection by analyzing the results of partial experiments, and reviewed the applicability the strength formula through the comparison of tested results of joint experiment.

• Computers and Concrete
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• v.5 no.6
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• pp.525-544
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• 2008

In this research, the self-centering effect in precast and prestressed reinforced concrete structures was investigated experimentally. The reinforced concrete beams and columns were precast and connected by post-tensioning tendons passing through the center of the beams as well as the panel zone of the connections. Three beam-to-interior-column connections were constructed to investigate parameters such as beam to column interfaces (steel on steel or plastic on plastic), energy dissipating devices (unbonded buckling restrained steel bars or steel angles) and the spacing of hoops in the panel zone. In addition to the self-centering effect, the shear strength in the panel zone of interior column connections was experimentally and theoretically evaluated, since the panel zone designed by current code provisions may not be conservative enough to resist the panel shear increased by the post-tensioning force.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.733-740
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• 2006

Inverted V (or chevron) braced steel frames have been seen as being highly prone to soft story response once the compression brace buckles under earthquake loading. To salvage chevron braced frames. the concept of the zipper column was proposed many years ago such that the zipper column can redistribute the inelastic demand over the height of the building. However. rational design method for the zipper column has not been established yet. In this paper, a new dynamic design method for the zipper column was proposed by combining the refined physical braced model and modal pushover analysis. Inelastic dynamic analysis conducted on 6 story building model showed that the proposed method was more superior to the existing static design method and was very effective in improving seismic performance of chevron braced steel frames.

• Journal of the Korea institute for structural maintenance and inspection
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• v.4 no.3
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• pp.205-210
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• 2000

The objective of this study is to investigate the structural behavior of steel beam-high strength concrete column joints subjected to reversed cyclic loadings. The variables of the experimental study is amount of steel plates at the beam-to-column joint panel zone. Three specimens were prepared and tested under constant uniaxial load($0.2f_{ck}A_g$) to reinforced high strength concrete column, and the reversed cyclic loads were applied to end of steel beams, The failure modes, hysteresis loop, stiffness degradations and energy dissipation capacities were analyzed and compared for test variables.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2019.05a
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• pp.23-24
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• 2019

In this study, analysis of steel fiber orientation and distribution inside fiber reinforced concrete was performed using micro-CT scanning technology. Samples were extracted from the column according to its height and distance from the mold. Samples were scanned in order to attain the image of steel fibers then region of interest were obtained by binarization process. By calculating the principle moment of inertia of each fiber, direction vector, scale, center postion, volume, and surface area were gained in order to analyze the orientation and distribution. Most of the fibers inside the column tended to be perpendicular to the main axis of the column. Moreover, most of the fibers appeared at the bottom of the column and at the position where it is farthest from the mold.

• Journal of Korean Society of Steel Construction
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• v.20 no.3
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• pp.437-444
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• 2008

The use of imported structural steel tubes has been increased in domestic construction field because of its low price, but the mechanical properties of those steel tube are not verified exactly. This study includes coupon test and stub - column compression test on the structural steel tube. The compression test of stub - column was performed to characterize and quantify the material characteristic and strength of column compatibility, in which we compared the experiment formula and the abstract formula by the application of the LRFD standard formula and multiple column curve.