• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.05a
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• pp.139-142
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• 2003

Traditionally, the thickness of fire protection materials of structural elements such as beam and column have been decided by fire test using the predominant steel section of $H-300{\times}300{\times}10{\times}15$ for column and $H-400{\times}200{\times}8{\times}13$ for beam in Korea. But this way of determination of fire protection thickness yields very unduly results. Because the temperature-increment rate of structural steel elements depends mainly on magnitude of their cross-areas. In general, the thicker size of cross-areas for structural elements, the lower temperature shows up. It had already proved that the fire protection thickness only depends on the size of cross-areas and the fire protection method for three-fide or four-side exposed conditions in European countries, the United State of America and so on. To demonstrate there would be differences among various cross-areas for structural elements, we conducted several fire tests with full-scale specimens of beams and columns. For the determination of critical temperature for steel section when the fire resistant performance is needed to be decided, we conducted with a loaded fire test for beam and column, respectively. The small column in 1.0 meter length and beam in 1.5 meter length were used in order to deprive the rational fire protection thickness of structural elements such as beam and column, respectively. After test, we could obtain there were significant temperature lass between higher cross-areas and lower cross-areas. The critical temperature of steel as a criterion is used 538$^{\circ}C$ for column and 593$^{\circ}C$ for beam which is from ASTM E 119 because we don't make provisions as critical temperature by elements. We could consider that the best way of determination of fire protection thickness is using the following multi-regression equation which was deprived from several fire tests using the concept of section factor, FR(column) = 0.17 +5191.49t A/Hp + 40.77t, FR(beam) = 0.25 +6899.31t A/Hp + 32.60t(where, FR means fire resistant time, t means thickness, A means cross-area and Hp means heated parameter).

• Steel and Composite Structures
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• v.13 no.5
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• pp.409-421
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• 2012

Recently, as the height of building is getting higher, the applications of CFST column for high-rise buildings have been increased. In structural system of high-rise building, The RC core and exterior concrete-filled tubular (CFST) column-beam pinned connection is one of the structural systems that support lateral load. If this structural system is used, due to the minimal CFST column thickness compared to that of the CFST column width, the local moment occurred by the eccentric distance between the column flange surface from shear bolts joints degrades the shear strength of the CFST column-beam pinned connections. This study performed a finite element analysis to investigate the shear strength under eccentric moment of the CFST column-beam pinned connections. The column's width and thickness were used as variables for the analysis. To guarantee the reliability of the finite element analysis, an actual-size specimens were fabricated and tested. The yield line theory was used to formulate an shear strength formula for the CFT column-beam pinned connection. the shear strength formula was suggested through comparison on the results of FEM analysis, test and yield lime theory, the shear strength formula was suggested.

• Steel and Composite Structures
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• v.20 no.4
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• pp.851-867
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• 2016

Cruciform sections are an appropriate option for columns of orthogonal moment resisting frames for equal bending strength and stiffness about two main axes and the implementation is easier for continuity plates. These columns consist of two I-shaped sections, so that one of them is cut out in middle and two generated T-shaped sections be welded into I-shaped profile. Furthermore, in steel moment frames, unbalance moment at the beam-column connection leads to shear deformation in panel zone. Most of the obtained relations for panel zone strength derived from experimental and analytical results are on I-shaped columns with almost thin flanges. In this paper, a parametric study has been carried out using Finite Element Method (FEM) with effective parameters at the panel zone behavior. These parameters consist of column flange thickness, column web thickness, and thickness of continuity plates. Additionally, a mathematical model has been suggested to determine strength of cruciform column panel zone and has been shown its accuracy and efficiency.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.118-119
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• 2014

A fire in a steel framed building can decrease a structural stability and cause deformation. And the fire continues the building can be demolished. Therefore, every country requires fire resistance performance of structural elements. In case of column, fire protective thickness derived from a specific fire test using an horizontal furnace is allowed to apply any kinds of sections and lengths of column. However, the lengths and sections of the column in steel framed buildings are various. In this paper, to know the differences of fire performance of steel column according to variance of lengths, a maximum allowable stress, steel surface temperature history, deflection are calculated and the thickness of fire protective material for longer column(4700 mm) need to enforce about 10% more than shorter column (3500 mm).

• Structural Engineering and Mechanics
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• v.55 no.5
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• pp.931-951
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• 2015

To improve the durability and service life of reinforced concrete column such as bridge piers, an advanced composite column made of Ultra High Performance Cementitious Composites (UHPCC) permanent form is proposed. Based on elasticity plasticity theory, axial compression behavior of the composite column was studied theoretically. The first circumferential cracking load and ultimate limit loading capacity are derived for the composite column. Short composite column compression tests and numerical simulations using FEM method were carried out to justify the theoretical formula. The effects of UHPCC tube thickness on the axial compression behavior were studied. Using the established theoretical model and numerical simulation, the large dimension composite columns are calculated and analyzed with different UHPCC tube thickness. These studies may provide a reference for advanced composite column design and application.

• Journal of architectural history
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• v.21 no.3
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• pp.7-28
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• 2012

This study is intended to Mindori structure which is general private houses' structural type among traditional types and is a basic study to confirm structural characteristics of Hwatong connection which is general connection type of column-beam-cross beam. It is aimed to analyze how main member, column, such as size, figure, thickness of Sungetuk and Dugeup affect on structure. Following conclusions are drawn. 1. According to connection conditions, models with big coefficient of friction show stable hysteretic behavior until the angle rotation of member reaches 1/60 and models with small coefficient of friction show dramatical increase in load after the angle rotation of member reaches 1/24. After the angle rotation of member reaches 1/30, separation distance of members is identified physically and cracks are not observed. 2. Specimens with big coefficient of friction show similar inner force regardless of column size(except column size 150mm) and models with small coefficient of friction show increasing inner force as the column size increases. Specimens with same sectional area have similar inner force even though the column figures are different. The thickness of Sungetuk and Dugeup doesn't affect inner force greatly, however, when the thickness of Sungetuk is thin, it could lead to failure of structure as it breaks. 3. The bigger the size of column and the coefficient of friction are, the smaller Bending stiffness depreciation ratio is. 4. Energy Dissipation Efficiency differs from the coefficient of friction. When the coefficient of friction is big, square column shows bigger than round one and it is bigger when the thickness of Sungetuk and Dugeup is thicker. When the coefficient of friction is small, round column shows bigger than square one.

• Structural Engineering and Mechanics
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• v.89 no.2
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• pp.155-170
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• 2024

Several types of column-beam connections are used in the design of steel structures. This situation causes different cross-section effects and, therefore, different displacements and deformations. In other words, connection elements such as welds, bolts, continuity plates, end plates, and stiffness plates used in steel column-beam connections directly affect the section effects. This matter reveals the necessity of knowing the steel column-beam connection behaviours. In this article, behaviours of bolted column-beam connection with end plate widely used in steel structures are investigated comparatively the effects of the stiffness plates added to the beam body, the change in the end plate thickness and bolt diameter. The results obtained reveal that the moment and force carrying capacity of the said connection increases with the increase in the end plate thickness and bolt diameter. In contrast, it causes the other elements to deform and lose their capacity. This matter shows that optimum dimensions are very important in steel column-beam connections. In addition, it has been seen that adding a stiffness plate to the beam body part positively contributes to the connection's moment-carrying capacity.

• Steel and Composite Structures
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• v.32 no.4
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• pp.497-507
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• 2019

Exposed column base connections are used in low- to mid-rise steel moment resisting frames. This paper is to investigate the effect of the base plate thickness on the exposed column base connection strength, stiffness, and energy dissipation. Five specimens with different base plate thickness were numerically modelled using ABAQUS software. The numerical model is able to reproduce the key characteristics of the experimental response. Based on the numerical analysis, the critical base plate thickness to identify the base plate and anchor rod yield mechanism is proposed. For the connection with base plate yield mechanism, the resisting moment is carried by the flexural bending of the base plate. Yield lines in the base plate on the tension side and compression side are illustrated, respectively. This type of connection exhibits a relatively large energy dissipation. For the connection with anchor rod yield mechanism, the moment is resisted through a combination of bearing stresses of concrete foundation on the compression side and tensile forces in the anchor rods on the tension side. This type of connection exhibits self-centering behavior and shows higher initial stiffness and bending strength. In addition, the methods to predict the moment resistance of the connection with different yield mechanisms are presented. And the evaluated moment resistances agree well with the values obtained from the FEM model.

• Steel and Composite Structures
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• v.29 no.6
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• pp.717-734
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• 2018

This paper presents the flexural performance of steel beam-to-column joints composed of hollow structural section beams and columns. A finite element (FE) model was developed incorporating geometrical and material nonlinearities to evaluate the behaviour of joints subjected to bending moments. The numerical outcomes were validated with experimental results and compared with EN1993-1-8. The demountability of the structure was discussed based on the tested specimen. A parametric analysis was carried out to investigate the effects of steel yield strength, end-plate thickness, beam thickness, column wall thickness, bolt diameter, number of bolts and location. Consequently, an analytical model was derived based on the component method to predict the moment-rotation relationships for the sub-assemblies with extended end-plates. The accuracy of the proposed model was calibrated by the experimental and numerical results. It is found that the FE model is fairly reliable to predict the initial stiffness and moment capacity of the joints, while EN1993-1-8 overestimates the initial stiffness extensively. The beam-to-column joints are shown to be demountable and reusable with a moment up to 53% of the ultimate moment capacity. The end-plate thickness and column wall thickness have a significant influence on the joint behaviour, and the layout of double bolt-rows in tension is recommended for joints with extended end-plates. The derived analytical model is capable of predicting the moment-rotation relationship of the structure.

• Steel and Composite Structures
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• v.45 no.1
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• pp.101-118
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• 2022

The seismic performance of the reinforced concrete (RC) special-shaped column to steel beam connections with steel jacket used in the RC column to steel beam fabricated frame structures was investigated in this study. The three full-scale specimens were subjected to cyclic loading. The failure mode, ultimate bearing capacity, shear strength capacity, stiffness degradation, energy dissipation capacity, and strain distribution of the specimens were studied by varying the steel jacket thickness parameters. Test results indicate that the RC special-shaped column to steel beam connection with steel jacket is reliable and has excellent seismic performance. The hysteresis curve is full and has excellent energy dissipation capacity. The thickness of the steel jacket is an important parameter affecting the seismic performance of the proposed connections, and the shear strength capacity, ductility, and initial stiffness of the specimens improve with the increase in the thickness of the steel jacket. The calculation formula for the shear strength capacity of RC special-shaped column to steel beam connections with steel jacket is proposed on the basis of the experimental results and numerical simulation analysis. The theoretical values of the formula are in good agreement with the experimental values.