• Proceedings of the Korea Concrete Institute Conference
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• 1993.10a
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• pp.284-289
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• 1993

To analyze the effects of compressive strength of concrete and longitudinal steel ratio on buckling behavior of columns, 36tied reinforced concrete columns with hinged ends were tested. The 100mm square cross section was used and the amount of eccentricity was 10mm. The compressive strengths of column specimens with slenderness ratios of 15, 30 and 50 were 202, 513 and 752 kg/$\textrm{cm}^2$. The longitudinal steel ratio of columns with bending about a section diagonal and about a principal axis were 2.85%(4-D10). The ratio of ultimate load capacity to that of short column with the same eccentricity was much decreased at high slenderness ratio with increasing the compressive strength of concrete. And the lateral displacement of column at the ultimate load was decreased as the strength was increased. These are due to that at high slenderness ratio, the load capacity and behavior of column are affected by flexural rigidity. And, it was also found that for the same quantity of confining steel and level of axis load, there is little difference between the flexural strength for bending about a section diagonal and for bending about principal axis.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.514-519
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• 2004

The paper discusses the general behavior of fire-damaged slender reinforced concrete columns on the basis of results obtained from parametric studies. Effects of slenderness ratio, concrete strength, cover thickness, reinforcement ratios, exposed time to fire, and eccentricity on the ultimate capacity of fire-damaged column are theoretically observed. With the increase of slenderness ratio, similar tendency of relative strength reduction was observed between fire-damaged columns and columns at room temperature.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.33-37
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• 1995

A side-cut grinding generates a machining error by the decrease of the quill rigidity. In this paper, The effect on the grinding force, machining error and surface roughness due to the change of the quill rigidity is investigated experimentally. The slenderness ratio of the quill is a significant factor to analyse the change of the grinding force and machining error.

• Journal of Korean Society of Steel Construction
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• v.13 no.3
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• pp.245-254
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• 2001

This paper presents the basic data for the strength behavior of longitudinally profiled plates(LP plate). The effects of loading conditions, thickness and slenderness ratio of plates are examined by using FEM analysis. The analysis results shown that the strength behavior of LP plate is varied with the loading conditions. The major causes of the reduction in strength are the distribution of deflection and the slenderness ratio of plate. Based on the results, this paper presents some discussions about the strength evaluation of LP plate with considering the equivalent thickness.

• Steel and Composite Structures
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• v.47 no.3
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• pp.437-450
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• 2023

A half open cross section built-up column, namely cold-formed thin-walled steel built-up column with 12-limbsection (CTSBC-12) is put forward. To deeply reveal the mechanical behaviors of CTSBC-12 under axial compression and put forward its calculation formula of axial bearing capacity, based on the previous axial compression experimental research, the finite element analysis (FEA) is conducted on 9 CTSBC-12 specimens, and then the variable parameter analysis is carried out. The results show the FEA is in good agreement with the experimental research, the ultimate bearing capacity error is within 10%. When the slenderness ratio is more than 96.54, the ultimate bearing capacity of CTSBC-12 decreases rapidly, and the failure mode changes from local buckling to global buckling. With the local buckling failure mode unchanged, the ultimate bearing capacity decreases gradually as the ratio of web height to thickness increases. Three methods are used for calculating the ultimate bearing capacity, the direct strength method of AISI S100-2007 gives result of ultimate axial load which is closest to the test and FEA results. But for simplicity and practicality, a simplified axial bearing capacity formula is proposed, which has better calculation accuracy with the slenderness ratio changing from 30 to 100.

• Steel and Composite Structures
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• v.45 no.1
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• pp.23-38
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• 2022

This paper presents experimental and analytical studies of eccentrically loaded concrete-filled double steel (CFDST) and concrete-filled double skin tube (DCFST) columns having outer stainless steel tube. Eighteen CFDST and DCFST column specimens were manufactured and tested to examine the strength and load-deflection responses. In the study, the main parameters were concrete strength, load eccentricity, cross section and slenderness. The strengths, load-deflection diagrams and failure patterns of the columns were observed. In addition, the tested CFDST and DCFST columns were analyzed to attain the capacity and load versus lateral deflection responses. The obtained theoretical results were compared with the test results. A parametric study was also performed to research the effects of the ratio of eccentricity (e/H_o) slenderness ratio (L/r), H_o/t_o ratio, H_i/t_i ratio and the concrete compressive strength on the behavior of columns. In this work, the obtained results indicated that the ductility and capacity of columns were affected by cross section, concrete strength, steel strength, loading eccentricity and slenderness.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.4
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• pp.321-328
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• 2021

This paper derives numerically new buckling Knockdown factors for the lightweight design of the composite propellant tanks for space launch vehicles. A nonlinear finite element analysis code, ABAQUS, is used for the present postbuckling analysis of composite cylinders under compressive loads. Various thickness ratios (R/t) and slenderness ratios (L/R) are considered and Single Perturbation Load Approach is applied to represent the geometric initial imperfection of the composite cylinder. For the composite cylinder with thickness ratio of 500 and slenderness ratio of 2.04, the buckling Knockdown factor derived in this work is higher by 84.38% than NASA's previous buckling design criteria. Therefore, it is investigated that a lightweight design is possible when the present Knockdown factors are used for the design of composite propellant tanks. In addition, it is shown that global buckling loads and buckling Knockdown factors decrease as the thickness ratio or slenderness ratio of composite cylinders increases.

• Steel and Composite Structures
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• v.7 no.3
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• pp.185-200
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• 2007

Tubular construction is widely used in a range of civil and structural engineering applications. To date, the principal product range has comprised square, rectangular and circular hollow sections. However, hot-rolled structural steel elliptical hollow sections have been recently introduced and offer further choice to engineers and architects. Currently though, a lack of fundamental structural performance data and verified structural design guidance is inhibiting uptake. Of fundamental importance to structural metallic design is the concept of cross-section classification. This paper proposes slenderness parameters and a system of cross-section classification limits for elliptical hollow sections, developed on the basis of laboratory tests and numerical simulations. Four classes of cross-sections, namely Class 1 to 4 have been defined with limiting slenderness values. For the special case of elliptical hollow sections with an aspect ratio of unity, consistency with the slenderness limits for circular hollow sections in Eurocode 3 has been achieved. The proposed system of cross-section classification underpins the development of further design guidance for elliptical hollow sections.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1997.10a
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• pp.254-261
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• 1997

In desingin plate bridges, the width-thickness ratio of flanges and webs are proportioned in such that the premature local buckling of flanges and webs prior to achievement of the full strength of plate-girders must be prevented. It is the common practive in most design codes that the flange local buckling strength and the web bend buckling strength are separately computed. In most practical plate girders, however, the flange buckles simultaneously when web bend-buckling occurs, vice versa. The primary purpose of the present study is to investigate the phenomenon, which may be called flange-web interactive buckling. Using the eight-node shell element available in the commercial multi-purpose program ABAQUS, the phenomenon was quantitatively investigated. Also presented are the effects of various factors such as the ratio of flange slenderness ratio to the web slenderness ratio, the ratio of flange width to the web depth, and the longitudinal stiffeners. A series of comparative studies with various design codes show that the present study provides more accurate and effective design basis in proportioning the flanges and webs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.19-26
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• 2019

To construct buildings on limited land, the size of the building is important. The development process needs to be minimized because determining the size of a structurally safe building at the planning stage incurs considerable time and cost. This study proposes the Limit Slenderness Ratio Approximation Equation. This study examined an outrigger structure system among several systems proposed for controlling the lateral displacement in tall buildings. This study compared the Limit Slenderness Ratio Approximation Equation with the approximate equation by changing the variables of the building model, and examined the size of the building using the approximate Equation. As an analysis program, the MAIDAS architectural structural analysis program was used to conduct model-specific analysis. The appropriate scale of the building to minimize the error between the approximate value calculated by the Limit Slenderness Ratio Approximation Equation and the analysis result of the structural analysis program is as follows. As the number of outrigger installation increases, the error can be reduced; the ratio of the cores is reasonable, from 20% to 30%, and the arrangement of the column is suitable only for the outer column without an internal column.