scholarly journals PARAMETRIC STUDY ON THE LATERAL TORSIONAL BUCKLING OF STAINLESS STEEL I BEAMS WITH CLASS 4 CROSS-SECTIONS IN CASE OF FIRE

2016 ◽  
Author(s):  
Nuno Lopes ◽  
Pedro Gamelas ◽  
Paulo Vila Real
Keyword(s):  
Stainless Steel ◽  
Cross Sections ◽  
Elevated Temperatures ◽  
Numerical Study ◽  
Design Guidelines ◽  
Steel Grade ◽  
Steel Beams ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Steel Members

For predicting the behaviour of beams with thin-walled I sections, named Class 4 in Eurocode 3 (EC3), it is necessary to account for the occurrence of both local and lateral torsional buckling (LTB). These instability phenomena, which are intensified at elevated temperatures, should be accurately considered in design rules. The fire design guidelines for stainless steel members, given in Part 1-2 of EC3, propose the use of the same formulae developed for carbon steel (CS) elements. However, these two materials have different constitutive laws, leading to believe that the use of those formulae should be validated. This work presents a parametric numerical study on the behaviour of stainless steel beams with Class 4 I sections at elevated temperatures. The influences of several parameters such as stainless steel grade, loading type and cross section slenderness are evaluated, and comparisons between the obtained numerical results and EC3 rules are presented.

Lateral Torsional-Buckling of Class 4 Steel Plate Beams at Elevated Temperature: Experimental and Numerical Comparison

2015 ◽  
Vol 6 (3) ◽  
pp. 223-236 ◽  
Author(s):  
Martin Prachar ◽  
Michal Jandera ◽  
Frantisek Wald ◽  
Bin Zhao
Keyword(s):  
Elevated Temperature ◽  
Cross Sections ◽  
Elevated Temperatures ◽  
Numerical Comparison ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Ongoing Research ◽  
Steel Members ◽  
Set Up ◽  
Hot Rolled

This paper presents ongoing research in behaviour of laterally unrestrained beams (I or H section) of Class 4 cross-sections at elevated temperatures, which is based on the RFCS project FIDESC4 - Fire Design of Steel Members with Welded or Hot-rolled Class 4 Cross-sections. Despite the current EC3 contains a number of simple rules for design of slender Class 4 cross-sections at elevated temperature, based on recent numerical simulations they were found to be over-conservative. Therefore, new well representing design models, which simulate the actual behaviour of the structures exposed to fire, are crucial. These design rules should be based on extensive numerical simulation validated on experimental data. Within this task, several tests were carried out to study lateral torsional buckling of Class 4 beams in fire. The design of the test set-up and description of the experiment is given, as well as verification of numerical model.

scholarly journals Lateral torsional buckling capacity of corroded steel beams: A parametric study

2021 ◽  
Vol 1201 (1) ◽  
pp. 012038
Author(s):  
G Kullashi ◽  
S C Siriwardane ◽  
M A Atteya
Keyword(s):  
Cross Sections ◽  
Parametric Study ◽  
Analytical Framework ◽  
Reduction Factor ◽  
Steel Beams ◽  
Uniform Corrosion ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Moment Capacity ◽  
The Moment

Abstract Thickness reduction due to uniform corrosion increases the tendency of lateral torsional buckling (LTB) of open cross-sections and it reduces the moment capacity of the beam. The effect of the various corrosion cases on the LTB moment capacity (M b,rd) of the I-beams are investigated in this paper. An analytical framework for patch corroded I-beams is introduced to provide a guideline for simulating the nonlinear lateral torsional buckling behaviour of patch corroded simple beams. Hence the effect of different corrosion scenarios to reduce the buckling reduction factor (η LT) is investigated by conducting a parametric study. Twelve different beam lengths were considered to obtain different non-dimensional slenderness ratios (λ LT) in this parametric study. The degraded buckling curves were obtained for each corrosion scenarios.

Lateral-torsional buckling of steel beams with slender cross-sections in case of fire

2015 ◽  
Vol 4 (1) ◽  
pp. 52
Author(s):  
Carlos Couto ◽  
Paulo Vila Real ◽  
Nuno Lopes ◽  
Bin Zhao
Keyword(s):  
Cross Sections ◽  
Steel Beams ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling

Fire behaviour and resistance of cold-formed steel beams with sigma cross-sections

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Flávio Arrais ◽  
Nuno Lopes ◽  
Paulo Vila Real
Keyword(s):  
Numerical Analysis ◽  
Cross Section ◽  
Cross Sections ◽  
Failure Modes ◽  
Elevated Temperatures ◽  
Numerical Results ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Content Type ◽  
Finite Element Software

PurposeSigma cross-section profiles are often chosen for their lightness and ability to support large spans, offering a favourable bending resistance. However, they are more susceptible to local, distortional and lateral-torsional buckling, as possible failure modes when compared to common I-sections and hollow cross-sections. However, the instability phenomena associated to these members are not completely understood in fire situation. Therefore, the purpose of this study is to analyse the behaviour of beams composed of cold-formed sigma sections at elevated temperatures.Design/methodology/approachThis study presents a numerical analysis, using advanced methods by applying the finite element software SAFIR. A numerical analysis of the behaviour of simply supported cold-formed sigma beams in the case of fire is presented considering different cross-section slenderness values, elevated temperatures, steel grades and bending moment diagrams. Comparisons are made between the obtained numerically ultimate bending capacities and the design bending resistances from Eurocode 3 Part 1–2 rules and its respective French National Annex (FN Annex).FindingsThe current design expressions revealed to be over conservative when compared with the obtained numerical results. It was possible to observe that the FN Annex is less conservative than the general prescriptions, the first having a better agreement with the numerical results.Originality/valueFollowing the previous comparisons, new fire design formulae are analysed. This new methodology, which introduces minimum changes in the existing formulae, provides at the same time safety and accuracy when compared to the numerical results, considering the occurrence of local, distortional and lateral-torsional buckling phenomena in these members at elevated temperatures.

Experimental and Numerical Study on Lateral-Torsional Buckling Behavior of High Performance Steel Beams

2018 ◽  
Vol 18 (07) ◽  
pp. 1850090 ◽  
Author(s):  
Y. L. Xu ◽  
Y. J. Shi ◽  
Y. R. Wu ◽  
H. Y. Ban
Keyword(s):  
High Performance ◽  
Numerical Study ◽  
High Strength ◽  
Element Model ◽  
Steel Beams ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Buckling Behavior ◽  
Eurocode 3 ◽  
High Performance Steel

A new type of high performance steel (HPS), designated WGJ steel, with high strength as well as improved fire and corrosion resistance, was recently developed by Wuhan Iron and Steel (Group) Company. This paper investigated the lateral-torsional buckling behavior of beams fabricated of WGJ steel through experimental and numerical analysis. Welded I-section beams were tested under concentrated loads, which indicated that lateral-torsional buckling was the dominant failure mode. A finite element model was established and validated by the experimental results. Parametric analyses were conducted to further understand the effect of steel strength on the lateral-torsional buckling capacity of steel beams. The numerical results were compared with design values obtained from the clauses in Eurocode 3 and GB50017. It is found that the design equations in GB50017 give less safe margins for the overall stability design of welded I-section beams fabricated of WGJ high performance steel, whereas Eurocode 3 appears to be more conservative in all conditions.

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