NUMERICAL STUDY OF SHEATHED COLD-FORMED STEEL COLUMNS

Purpose The primary purpose of this research was to expand the knowledge base regarding the behavior of steel columns during exposure to fire. This paper presents the numerical study of the effect of heat on the performance of parking steel column in a seven-story steel building under cyclic loading. Design/methodology/approach In this research, the forces and deformations developed during a fire are estimated by using detailed 3D finite-element models. The analyses are in the form of a coupled thermo-mechanical analysis in two types of loading: concurrent loading (fire and cyclic loading) and non-concurrent loading (first fire and then cyclically), and the analyses have been conducted in both states of the fire loading with cooling and without cooling using the ABAQUS software. Further, it was investigated whether, during the fire loading, the specimen was protected by a 3-cm-thick concrete coating and how much it changes the seismic performance. After verification of the specimen with the experimental test results, the column model was investigated under different loading conditions. Findings The result of analyses indicates that the effect of thermal damage on the performance of steel columns, when cooling is happening late, is more than the state in which cooling occurs immediately after the fire. In this paper, thermal–seismic performance of parking steel columns has been specified and the effect of the fire damage has been investigated for the protected steel by concrete coating and to the non-protected steel, under both cooling and non-cooling states. Originality/value This study led to recommendations based on the findings and suggestions for additional work to support performance-based fire engineering. It is clear that predicting force and deformation on steel column during fire is complex and it is affected by many variables. Here in this paper, those variables are examined and proper results have been achieved.

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Buckling behavior of cold-formed steel columns at both ambient temperature and simulated fire conditions

Fire Research ◽

10.4081/fire.2017.16 ◽

2016 ◽

Author(s):

Hélder D. Craveiro ◽

João Paulo C. Rodrigues ◽

Luís M. Laím

Keyword(s):

Experimental Investigation ◽

Ambient Temperature ◽

Cross Sections ◽

Failure Modes ◽

Steel Columns ◽

Buckling Behavior ◽

Wide Range ◽

Cold Formed Steel ◽

Simulated Fire ◽

Fire Conditions

Cold-formed steel (CFS) profiles with a wide range of cross-section shapes are commonly used in building construction industry. Nowadays several cross-sections can be built using the available standard single sections (C, U, Σ, etc.), namely open built-up and closed built-up cross-sections. This paper reports an extensive experimental investigation on the behavior of single and built-up cold-formed steel columns at both ambient and simulated fire conditions considering the effect of restraint to thermal elongation. The buckling behavior, ultimate loads and failure modes, of different types of CFS columns at both ambient and simulated fire conditions with restraint to thermal elongation, are presented and compared. Regarding the buckling tests at ambient temperature it was observed that the use of built-up cross-sections ensures significantly higher values of buckling loads. Especially for the built-up cross-sections the failure modes were characterized by the interaction of individual buckling modes, namely flexural about the minor axis, distortional and local buckling. Regarding the fire tests, it is clear that the same levels of restraint used in the experimental investigation induce different rates in the generated restraining forces due to thermal elongation of the columns. Another conclusion that can be drawn from the results is that by increasing the level of restraint to thermal elongation the failure of the columns is controlled by the generated restraining forces, whereas for lower levels of restraint the temperature plays a more important role. Hence, higher levels of imposed restraint to thermal elongation will lead to higher values of generated restraining forces and eventually to lower values of critical temperature and time.

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Experiment and Design Method on Cold-Formed Thin-Walled Steel Lipped Channel Columns with Slotted Web Holes Under Axial Compression

The Open Civil Engineering Journal ◽

10.2174/1874149501711010244 ◽

2017 ◽

Vol 11 (1) ◽

pp. 244-257 ◽

Cited By ~ 2

Author(s):

Xingyou Yao

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Ultimate Strength ◽

Test Results ◽

Distortional Buckling ◽

Steel Columns ◽

Cold Formed Steel ◽

Thin Walled ◽

Shell Finite Element ◽

The Web

Background: Cold-formed steel structural sections used in the walls of residential buildings and agricultural facilities are commonly C-shaped sections with web holes. These holes located in the web of sections can alter the elastic stiffness and the ultimate strength of a structural member. The objective of this paper is to study the buckling mode and load-carrying capacity of cold-formed thin-walled steel column with slotted web holes. Methods: Compression tests were conducted on 26 intermediate length columns with and without holes. The tested compressive members included four different kinds of holes. For each specimen, a shell finite element Eigen-buckling analysis and nonlinear analysis were also conducted. The influence of the slotted web hole on local and distortional buckling response had also been studied. The comparison on ultimate strength between test results and calculated results using Chinese cold-formed steel specification GB50018-2002, North American cold-formed steel specification AISI S100-2016, and nonlinear Finite Element method was made. Result: Test results showed that the distortional buckling occurred for intermediate columns with slotted holes and the ultimate strength of columns with holes was less than that of columns without holes. The ultimate strength of columns decreased with the increase in transverse width of hole in the cross-section of member. The Finite element analysis results showed that the web holes could influence on the elastic buckling stress of columns. The shell finite element could be used to model the buckling modes and analysis the ultimate strength of members with slotted web holes. The calculated ultimate strength shows that results predicted with AISI S100-2016 and analyzed using finite element method are close to test results. The calculated results using Chinese code are higher than the test results because Chinese code has no provision to calculate the ultimate strength of members with slotted web holes. Conclusion: The calculated method for cold-formed thin-walled steel columns with slotted web holes are proposed based on effective width method in Chinese code. The results calculated using the proposed method show good agreement with test results and can be used in engineering design for some specific cold-formed steel columns with slotted web holes studied in this paper.

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Investigation of Structural and Material Effects on Crashworthiness of Advanced High Strength Steel Columns

Transportation: Making Tracks for Tomorrow’s Transportation ◽

10.1115/imece2003-55106 ◽

2003 ◽

Author(s):

Faycal Ben-Yahia ◽

James A. Nemes ◽

Farid Hassani

Keyword(s):

Numerical Study ◽

Hsla Steel ◽

High Strength Steels ◽

High Strength ◽

Column Height ◽

Steel Columns ◽

Advanced High Strength Steels ◽

Element Simulation ◽

Formed Channel ◽

Good Agreement

An experimental and numerical study was performed to evaluate the crashworthiness of several advanced high strength steels. The behavior of two Dual Phase (DP) steels and an HSLA steel are compared by examining the crush response of longeron column specimens, experimentally and computationally. The closed section columns, fabricated by spot welding formed channel sections, in both single hat and double hat configurations were exposed to 182 kg and 454 kg axial impacts at different velocities. Final column height and impact force history were recorded and compared with results of finite element simulation of the columns. Good agreement was found between experiments and computations.

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Flexural–torsional failure and DSM design of fixed-ended cold-formed steel columns at elevated temperatures

Thin-Walled Structures ◽

10.1016/j.tws.2021.108362 ◽

2021 ◽

Vol 169 ◽

pp. 108362

Author(s):

Antônio Albuquerque Bicelli ◽

Alexandre Landesmann ◽

Dinar Camotim ◽

Pedro Borges Dinis

Keyword(s):

Elevated Temperatures ◽

Steel Columns ◽

Cold Formed Steel

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