• International journal of steel structures
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• v.18 no.5
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• pp.1723-1740
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• 2018

This paper presents a Finite Element (FE) study on Lean Duplex Stainless Steel stub column with built-up sections subjected to pure axial compression with column web spacing varied at different position across the column flanges. The thicknesses of the steel sections were from 2 to 7 mm to encompass a range of section slenderness. The aim is to study and compare the strength and deformation capacities as well as the failure modes of the built-up stub columns. The FE results have been compared with the un-factored design strengths predicted through EN1993-1-4 (2006) + A1 (2015) and ASCE8-02 standards, Continuous Strength Method (CSM) and Direct Strength Method (DSM). The results showed that the design rules generally under predict the bearing capacities of the specimens. It's been observed that the CSM method offers improved mean resistance and reduced scatter for both classes of cross-sections (i.e. slender and stocky sections) compared to the EN1993-1-4 (2006) + A1 (2015) and ASCE 8-02 design rules which are known to be conservative for stocky cross-sections.

• Journal of the Korean GEO-environmental Society
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• v.7 no.1
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• pp.5-18
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• 2006

Stone column or granular compaction pile have been used in widely during the several decades as a technique to reinforce soft cohesive soils and increase bearing capacity, accelerate consolidation settlement of the foundation soil. The bearing capacity of the granular compaction pile is governed mainly by the lateral confining pressure mobilized in the native soft soil to restrain bulging collapse of the granular pile. Therefore, the technique becomes unfeasible in soft, compressible clayey soils that do not provide sufficient lateral confinement. This paper presents the main results of numerical study of granular compaction pile which is partly mixed with lean concrete. 3D finite element analyses are performed with composite reinforced foundations by both granular compaction pile and partly mixed granular compaction pile with lean-mixed concrete. Finally, a regression formula for calculating settlement reduction coefficients is proposed in this study by using numerical analysis results and applicability of the proposed method is identified by a series of parametric study about settlement reduction coefficients.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.336-342
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• 2005

Stone column or granular compaction pile have been used in widely during the several decades as a technique to reinforce soft cohesive soils and increase bearing capacity, accelerate consolidation settlement of the foundation soil. The bearing capacity of the granular compaction pile is governed mainly by the lateral confining pressure mobilized in the native soft soil to restrain bulging collapse of the granular pile. Therefore, the technique becomes unfeasible in soft, compressible clayey soils that do not provide sufficient lateral confinement. This paper presents the main results of numerical study of granular compaction pile which is partly mixed with lean concrete. 3D finite element analyses are performed with composite reinforced foundations by both granular compaction pile and partly mixed granular compaction pile with lean-mixed concrete.

• Structural Engineering and Mechanics
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• v.11 no.1
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• pp.1-16
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• 2001

This paper discusses the elastic stability of unbraced frames under non-proportional loading based on the concept of storey-based buckling. Unlike the case of proportional loading, in which the load pattern is predefined, load patterns for non-proportional loading are unknown, and there may be various load patterns that will correspond to different critical buckling loads of the frame. The problem of determining elastic critical loads of unbraced frames under non-proportional loading is expressed as the minimization and maximization problem with subject to stability constraints and is solved by a linear programming method. The minimum and maximum loads represent the lower and upper bounds of critical loads for unbraced frames and provide realistic estimation of stability capacities of the frame under extreme load cases. The proposed approach of evaluating the stability of unbraced frames under non-proportional loading has taken into account the variability of magnitudes and patterns of loads, therefore, it is recommended for the design practice.

• Korean Chemical Engineering Research
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• v.54 no.5
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• pp.648-652
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• 2016

The study of $CO_2$ absorption in a packed column by 1,1,3,3-tetramethylguanidine (TMG) dissolved in ethylene glycol is presented. Absorption column of inner diameter 1 in and 0.6 m length was filled with Protruded-packing $0.16in{\times}0.16in$. We investigated the effect of operating conditions on overall mass transfer coefficients as well as on $CO_2$ removal efficiency. The loading values reached at about $1.0mol_{CO2}/mol_{TMG}$. In case of absorbent with lean $CO_2$ loading, the overall mass transfer coefficient was proportional to the concentration of TMG. However, in the range of more than ${\alpha}=0.5molCO_2/molTMG$, the overall mass transfer coefficients decreased with the concentration of TMG. It is due to the increasing of mass transfer resistance in liquid phase as increasing of viscosity at higher loading values.

• Steel and Composite Structures
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• v.43 no.3
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• pp.327-340
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• 2022

A vast amount of experimental and analytical research has been conducted related to the seismic behavior and performance of concrete filled steel tubular (CFT) columns. This research has resulted in a wealth of information on the component behavior. However, analytical and experimental data for structural systems with CFT columns is limited, and the well-known behavior of steel or concrete structures is assumed valid for designing these systems. This paper presents the development of an analytical model for nonlinear analysis of composite moment resisting frame (CFT-MRF) systems with CFT columns and steel wide-flange (WF) beams under seismic loading. The model integrates component models for steel WF beams, CFT columns, connections between CFT columns and WF beams, and CFT panel zones. These component models account for nonlinear behavior due to steel yielding and local buckling in the beams and columns, concrete cracking and crushing in the columns, and yielding of panel zones and connections. Component tests were used to validate the component models. The model for a CFT-MRF considers second order geometric effects from the gravity load bearing system using a lean-on column. The experimental results from the testing of a four-story CFT-MRF test structure are used as a benchmark to validate the modeling procedure. An analytical model of the test structure was created using the modeling procedure and imposed-displacement analyses were used to reproduce the tests with the analytical model of the test structure. Good agreement was found at the global and local level. The model reproduced reasonably well the story shear-story drift response as well as the column, beam and connection moment-rotation response, but overpredicted the inelastic deformation of the panel zone.

• Korean Journal of Heritage: History & Science
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• v.43 no.2
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• pp.40-59
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• 2010

Anssolim is the unique technique which standing columns lean in a inward direction of buildings in traditional architecture, which has not been thoroughly investigated to this day. With a dearth of previous studies, the anssolim technique can only be examined through detailed three-dimensional surveys. The main halls of Korean palaces can be seen as buildings that were built with the regulations of the day in mind, making them excellent research subjects when studying the anssolim technique. The findings can be summarized as follows. 1. In the main halls that were studied, anssolim was applied most to main space (eokan) columns, then lessened for peripheral columns. 2. The largest second-floor cheoma columns were placed inward in the eokan, then became smaller as with the peripheral columns. In the case of the eokan, the columns were arranged according to the size of the anssolim. 3. The second-floor cheoma column anssolim in the middle-floor main hall were generally a third or a quarter of the size of those on the first floor. As on the first floor, the largest anssolim were applied to the eokan columns, then became gradually smaller towards the periphery columns. 4. In the palace main halls, the largest anssolim were used for the eokan columns, and became smaller with the peripheral columns. This unique structure can be seen to be a Korean technique that deviates from the Chinese "Yingzaofashi(營造法式)" techniques. Although this study is limited in that it only studies the main hall of Korean palaces, it is significant in that it shed new light on the technological implications of the anssolim technique, and can be used as important data for research into the history of technology. Although this type of data is difficult to extrapolate, it has been made as accurate as possible by minimizing the margin of error in the data for the palaces that were actually studied.