• Steel and Composite Structures
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• v.38 no.6
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• pp.637-656
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• 2021

The component-based method is widely used to analyze the initial stiffness of joint in steel structures. In this study, an analytical component model for determining the column face stiffness of square or rectangular hollow section (SHS/RHS) subjected to tension was established, focusing on endplate connections. Equations for calculating the stiffness of the SHS/RHS column face in bending were derived through regression analysis using numerical results obtained from a finite element model database. Because the presence of bolt holes decreased the bending stiffness of the column face, this effect was calculated using a novel plate-spring-based model through numerical analysis. The developed component model was first applied to predict the bending stiffness of the SHS column face determined through tests. Furthermore, this model was incorporated into the component-based method with other effective components, e.g., bolts under tension, to determine the tensile stiffness of the T-stub connections, which connects the SHS column, and the initial rotational stiffness of the joints. A comparison between the model predictions, test data, and numerical results confirms that the proposed model shows satisfactory accuracy in evaluating the bending stiffness of SHS column faces.

• Geomechanics and Engineering
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• v.6 no.2
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• pp.173-194
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• 2014

Laboratory and field data showed that deep mixed (DM) columns accelerated the rate of consolidation of the soft foundations. Most analyses of consolidation of DM column-improved foundations so far have been based on the elastic theory. In reality, the DM columns may yield due to the stress concentration from the soft soil and its limited strength. The influence of column yielding on the degree of consolidation of the soft foundation improved by DM columns has not been well investigated. A three-dimensional mechanically and hydraulically-coupled numerical method was adopted in this study to investigate the degree of consolidation of the DM column foundation considering column yielding. A unit cell model was used, in which the soil was modeled as a linearly elastic material. For a comparison purpose, the DM column was modeled as an elastic or elastic-plastic material. This study examined the aspects of stress transfer, settlement, and degree of consolidation of the foundations without or with the consideration of the yielding of the DM column. A parametric study was conducted to investigate the influence of the column yielding on the stress concentration ratio, settlement, and average degree of consolidation of the DM column foundation. The stress concentration ratio increased and then decreased to reach a constant value with the increase of the column modulus and time. A simplified method was proposed to calculate the maximum stress concentration ratios under undrained and drained conditions considering the column yielding. The simplified method based on a composite foundation concept could conservatively estimate the consolidation settlement. An increase of the column modulus, area replacement ratio, and/or column permeability increased the rate of consolidation.

• Journal of Ginseng Research
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• v.8 no.1
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• pp.32-37
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• 1984

In order to shorten the extraction time of saponin in ginseng products, election with Extrelut column and phase-separation methods were compared. The results obtained are as follows. 1. Saponin of ginseng products was extracted completely within 3 hours by election method with Extrelut column, and the rate of removing glucose by the column was increased with increasing glucose content in ginseng products. 2. Stirring method was superior to refluxing method for removing sugars from ginseng products, and removing rate was deceased in the order of lactose, sucrose and glucose. 3. Extraction rate of ginsenoside from ginseng extracts by the elution method was nearly same as that of phase-separation method; however, the former was much higher than the latter in the case of ginseng teas. Therefore, the elution by Extrelut column is to be improper for extraction of saponin in ginseng tea which contains much sugar. It was necessary to remove lipophilic compounds for extraction of saponin from ginseng extracts by elution with Extrelut column.

• Structural Engineering and Mechanics
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• v.43 no.2
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• pp.147-161
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• 2012

This paper presents a curvature method for analysis of beam-columns with different materials and arbitrary cross-section shapes and subjected to combined biaxial moments and axial load. Both material and geometric nonlinearities (the p-delta effect in this case) were incorporated. The proposed method considers biaxial curvatures and uniform normal strains of discrete cross-sections of beam-columns as basic unknowns, and seeks for a solution of the column deflection curve that satisfies force equilibrium conditions. A piecewise representation of the beam-column deflection curve is constructed based on the curvatures and angles of rotation of the segmented cross-sections. The resulting bending moments were evaluated based on the deformed column shape and the axial load. The moment curvature relationship and the beam-column deflection calculation are presented in matrix form and the Newton-Raphson method is employed to ensure fast and stable convergence. Comparison with results of analytic solutions and eccentric compression tests of wood beam-columns implies that this method is reliable and effective for beam-columns subjected to eccentric compression load, lateral bracings and complex boundary conditions.

• Journal of Ginseng Research
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• v.13 no.2
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• pp.254-259
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• 1989

A radioprotective ginseng protein fraction was obtained from Korean white ginseng powder by the following isolation and purification procedures: Tris-HCI buffer extraction, 70% ammonium sulfate fractionation, CM-rellulosr column chromatography, heat inactivation and Sephadex G-75 column chromatography. This fraction was further purified by Sepharose 4B and Sephadex G-150 column chromatographies. Three fractions obtained were subjected to Native-PAGE and SDS-PAGE using gradient gels and the silver staining method. Molecular weights of the native proteins and their subunits were estimated.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.101-102
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• 2017

This study was carried out as basic study to apply to construction site the HPC method which is being developed. The construction cost of HPC method was analyzed in comparison with conventional method (half slab method). With regard to research method, it was decided that data on construction work carried out by half slab method was analyzed. According to the results of study, in case of being applied to the construction work using a divided column, the number of columns was decreased. So, it was shown that member production cost, and transport and assemblage cost reduced. In case of being applied to construction work using an undivided column, the analysis showed that there was little difference in construction cost. Therefore, the analysis showed that, if HPC construction method was applied to large structure using a large column, the construction cost was reduced to some extent in comparison with conventional half slab method.

• Journal of the Korean Geotechnical Society
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• v.19 no.4
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• pp.133-144
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• 2003

The resonant column testing is a laboratory testing method to determine the shear modulus and material damping factor of soils. The method has been widely used for many applications and its importance has increased. Since the first use of the testing method in 1960's, the low-technology electronic devices fir testing and data acquisition have limited the measurement only to the amplitude of the linear spectrum. The limitations of the testing method are also attributed to the assumption of linear-elastic material in the theory of the resonant column testing and also to the incomplete understanding of the dynamic behaviour of the resonant column testing device. Recently, Joh et al. proposed a theory to overcome the limitations of the resonant column testing by deriving the equation of motion and providing its solution for the resonant column testing device. This study proposed the improved data reduction and analysis method for the resonant column testing, thanks to the advanced data acquisition system and the new theoretical solution for the resonant column testing system. For the verification of the proposed data reduction and analysis method, the numerical simulation of the resonant column testing was performed by the finite element analysis. Also, a series of resonant column testing were performed fir Joomunjin sand, which verified the feasibility of the proposed method and revealed the limitations of the conventional data reduction and analysis method.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.10a
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• pp.291-311
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• 2006

The acceleration of consolidation by stone columns was mostly analysed within the framework of a basic unit cell model (i.e. a cylindrical soil body around a column). A method of converting the axisymmetric unit cell into the equivalent plane-strain model would be required for two-dimensional numerical modelling of multi-column field applications. This paper proposes two practical simplified conversion methods to obtain the equivalent plane-strain model of the unit cell, and investigates their applicability to multi-column reinforced ground. In the first conversion method, the soil permeability is matched according to an analytical equation, whereas in the second method, the column width is matched based on the equivalence of column area. The validity of these methods is tested by comparison with the numerical results of unit-cell simulations and with the field data from an embankment case history. The results show that for the case of linear-elastic material modelling, both methods produce reasonably accurate long-term consolidation settlements, whereas for the case of elasto-plastic material modelling, the second method is preferable as the first one gives erroneously lower long-term settlements, where plastic yielding of stone column are ignored.

• Journal of architectural history
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• v.3 no.1
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• pp.45-55
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• 1994

This study deals with the method of constructing and repairing column, important element of traditional wooden building. Column should have long-lasting strength and resistance to decay and vermin because it is more important in role of structure than in that of ornament. And the rotten or the split part of wooden column should be repaired regularly or irregularly. First of all, this study treats of general character related to the life length and strength of wood. Then it describes the technical method of choosing proper wood for column and that of carpentering, painting, and mending wooden column.

• Analytical Science and Technology
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• v.12 no.3
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• pp.196-202
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• 1999

Brown algae, Sargassum horneri, was used as an adsorbent to remove heavy metal Cd(II) and Pb(II) ions. Sargassum horneri picked in East Coast was formulated into the grain with the size of 40-60 mesh after wind dry. Batch method was used in order to investigate the adsorption rate by measuring the adsorption amounts with shaking time. In the column method, the adsorption amounts were measured by flowing metal solutions into the algae-packed column at the rate of 1 ml/min. Adsorption amounts in both batch method and column method were in the following order : pH 10.5>7.0>3.5. It was found that Pb(II) was more adsorbed on the algae grain than Cd(II). It was also revealed that the adsorption amounts reached the maximum within 5 minutes irrespective of pH condition in the batch method. It was concluded that the batch method was more effective than the column method in terms of recovery rate.