• 한국공간구조학회논문집
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• 제6권3호
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• pp.77-86
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• 2006

본 논문은 횡하중을 받는 냉간성형 ㄷ 형강보의 응력해석에 관해 다루고 있다. 냉간형강 보에 가해지는 각 하중 레벨에서의 응력을 계산하여 국부좌굴과 횡좌굴을 고려하여 구조해석을 실시하였다. 해석모델은 박벽보의 기본이론에 의해 유도되었으며 1차원 보요소 유한요소해석을 통하여 수치해석을 하였다. 수치해석결과는 AISI 규준과 비교되었으며, 본 연구에서 제안된 해석모델이 냉간형강보의 처짐뿐 아니라 응력도 매우 정확히 예측함을 알 수 있었다.

• Steel and Composite Structures
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• 제18권1호
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• pp.71-90
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• 2015

Axial compression tests have been carried out on 18 rectangular concrete-filled cold-formed steel tubular (CFST) columns with the aim of investigating the axial behaviour of rectangular CFST columns under different loading methods (steel loaded-first and full-section loaded methods). The influence of different loading methods on the ultimate strength of the specimens was compared and the development of Poisson's Ratio as it responds to an increasing load was reported and analysed. Then, the relationship between the constraining factor and the strength index, and the relationship between the constraining factor and ductility index of the specimens, were both discussed. Furthermore, the test results of the full-section loaded specimens were compared with five international code predicted values, and an equation was derived to predict the axial carrying capacity for rectangular CFST columns with a steel loaded-first loading method.

• Steel and Composite Structures
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• 제2권6호
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• pp.411-428
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• 2002

Non-linear large-displacement elasto-plastic finite element analyses are used to propose design recommendations for the eaves bracket of a cold-formed steel portal frame. Owing to the thinness of the sheet steel used for the brackets, such a structural design problem is not trivial as the brackets need to be designed against failure through buckling; without availability of the finite element method, expensive laboratory testing would therefore be required. In this paper, the finite element method is firstly used to predict the plastic moment capacity of the eaves bracket. Parametric studies are then used to propose design recommendations for the eaves bracket against two potential buckling modes of failure: (1) buckling of the stiffened free-edge into one-half sine wave, (2) local plate buckling of the exposed triangular bracket area.The results of full-scale laboratory tests on selected geometries of eaves bracket demonstrate that the proposed design recommendations are conservative. The use of the finite element method in this way exploits modern computational techniques for an otherwise difficult structural design problem.

• Steel and Composite Structures
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• 제30권5호
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• pp.457-469
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• 2019

Steel pallet racking industry has globally used from the industrial revolution and has deeply evolved from hot-rolled profile into cold-formed profile to raise the optimization in engineering field. Nowadays, some studies regarding cold-formed steel profile have been performed, but fewer studies in terms of cold-formed pallet racking specifically in connection due to the semi-rigid behavior by lug-hooked into the upright have been conducted. The objective of this study is to review the related literature on steel storage racking connection behavior.

• 소성∙가공
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• 제12권2호
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• pp.83-87
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• 2003

Current state of plastic processes of steel bearing parts is surveyed. According to the advances in plastic forming technologies and their great advantage to mass production, plastic processes are adopted in manufacturing majority of bering parts. The rings are forged or ring rolled and the rolling elements, i.e, balls or rollers are cold formed before fine machining. Bearing's steel retainers are mainly press formed using cold rolled seel strips. Including the general explanation about above processes, some details of forging technology, control of forging temperature and after cooling process, and examples of computer simulation are described.

• Steel and Composite Structures
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• 제27권5호
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• pp.545-554
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• 2018

This study presents a novel method of improving the strength and stiffness of cold-formed steel (CFS) beams. Flexural members are primary members in most of the structures. Hence, there is an urgent need in the CFS industry to look beyond the conventional CFS beam sections and develop novel techniques to address the severe local buckling problems that exist in CFS flexural members. The primary objective of this study was to develop new CFS composite beam sections with improved structural performance and economy. This paper presents an experimental study conducted on different CFS composite beams with simply supported end conditions under four point loading. Material properties and geometric imperfections of the models were measured. The test strengths of the models are compared with the design strengths predicted by using Australian/New Zealand Standard for cold-formed steel structures. Furthermore, to ensure high precision testing, a special testing rig was also developed for testing of long span beams. The description of test models, testing rig features and test results are presented here. For better interpretation of results, a comparison of the test results with a hot rolled section is also presented. The test results have shown that the proposed CFS composite beams are promising both in terms of better structural performance as well as economy.

• Steel and Composite Structures
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• 제16권6호
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• pp.657-679
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• 2014

This paper describes a series of compression tests performed on cold-formed steel channel sections with perforations in the web (thermal studs) fabricated from a galvanized steel plate whose thickness ranged from 1.0 mm to 1.6 mm and nominal yield stress was 295 MPa. The structural behavior and performance of thermal studs undergoing local, distortional, or flexural-torsional buckling were investigated experimentally and analytically. The compression tests indicate that the slits in the web had significant negative effects on the buckling and ultimate strength of thin-walled channel section columns. The compressive strength of perforated thermal studs was estimated using equivalent solid channel sections of reduced thickness instead of the studs. The direct strength method, a newly developed and adopted alternative to the effective width method for designing cold-formed steel sections in the AISI Standard S100 (2004) and AS/NZS 4600 (Standard Australia 2005), was calibrated to the test results for its application to cold-formed channel sections with slits in the web. The results verify that the DSM can predict the ultimate strength of channel section columns with slits in the web by substituting equivalent solid sections of reduced thickness for them.

• Steel and Composite Structures
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• 제34권2호
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• pp.171-188
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• 2020

The past research on cold-formed steel (CFS) flexural members have proved that rectangular hollow flanged sections perform better than conventional I-sections due to their higher torsional rigidity over the later ones. However, CFS members are vulnerable to local buckling, substantially due to their thin-walled features. The use of packing, such as firmly connected timber planks, to the flanges of conventional CFS lipped I-sections can drastically improve their flexural performance as well as structural efficiency. Whilst several CFS composites have been developed so far, only limited packing materials have been tried. This paper presents a series of tests carried out on different rectangular hollow compression flanged sections with innovative packing materials. Four-point flexural tests were carried out to assess the flexural capacity, failure modes and deformed shapes of the CFS composite beam specimens. The geometric imperfections were measured and reported. The North American Specifications and Indian Standard for cold-formed steel structures were used to compare the design strengths of the experimental specimen. The test results indicate clearly that CFS rectangular 'compression' flanged composite beams perform significantly better than the conventional rectangular hollow flanged CFS sections.

• Steel and Composite Structures
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• 제31권5호
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• pp.453-467
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• 2019

Portal frame structures, made up of cold-formed steel trusses, are increasingly being used for lightweight building construction. A novel pin-jointed moment connector, called the Howick Rivet Connector (HRC), was developed and tested previously in T-joints and truss assemblage to determine its reliable strength, stiffness and moment resisting capacity. This paper presents an experimental study on the HRC, in moment resisting cold-formed steel trusses. The connection method is devised where intersecting truss members are confined by a gusset connected by HRCs to create a rigid moment connection. In total, three large scale experiments were conducted to determine the elastic capacity and cyclic behaviour of the gusseted truss moment connection comprising HRC connectors. Theoretical failure loads were also calculated and compared against the experimental failure loads. Results show that the HRCs work effectively at carrying high shear loads between the members of the truss, enabling rigid behaviour to be developed and giving elastic behaviour without tilting up to a defined yield point. An extended gusset connection has been proposed to maximize the moment carrying capacity in a truss knee connection using the HRCs, in which they are aligned around the perimeter of the gusset to maximize the moment capacity and to increase the stability of the truss knee joint.

• Steel and Composite Structures
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• 제43권3호
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• pp.403-417
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• 2022

Recently, there has been an increasing demand for buildings that allow rapid assembly of construction elements, have ample open space areas and are flexible in their final intended use. Accordingly, researchers have developed new competitive structures in terms of cost and efficiency, such as cold-formed steel and timber composite floors, to satisfy these requirements. Cold-formed steel and timber composite floors are light floors with relatively high stiffness, which allow for longer spans. As a result, they inherently have lower fundamental natural frequency and lower damping. Therefore, they are likely to undergo unwanted vibrations under the action of human activities such as walking. It is also quite expensive and complex to implement vibration control measures on problematic floors. In this study, a finite element model of a composite floor reported in the literature was developed and validated against four-point bending test results. The validated FE model was then utilised to examine the vibration behaviour of the investigated composite floor. Predictions obtained from the numerical model were compared against predictions from analytical formulas reported in the literature. Finally, the influence of various parameters on the vibration behaviour of the composite floor was studied and discussed.