SIMPLE FIRE DESIGN OF COLD-FORMED STEEL C-SECTION BEAMS WITH LATERAL-TORSIONAL BUCKLING

ce/papers ◽  
2017 ◽  
Vol 1 (4) ◽  
pp. 573-590
Author(s):  
Luís Laím ◽  
João Paulo C. Rodrigues
Keyword(s):  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Cold Formed Steel ◽  
Fire Design

scholarly journals GEM – A SOFTWARE FOR STABILITY VERIFICATION OF NON-UNIFORM MEMBERS, Adaptation of the general method procedure to fire design

2016 ◽  
Author(s):  
João Ferreira ◽  
Paulo Vila Real ◽  
Carlos Couto ◽  
Paulo Cachim
Keyword(s):  
Computer Program ◽  
Elevated Temperatures ◽  
Numerical Results ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Tapered Beam ◽  
Eurocode 3 ◽  
The Stability ◽  
Fire Design ◽  
General Method

<span lang="EN-GB">There is currently no specific rules in Part 1-2 of Eurocode 3 for the stability verification of non-uniform members under fire conditions. For normal temperature, Part 1-1 of the same code provides a General Method to check the stability against lateral and lateral-torsional buckling for these type of members, though it requires some extensive calculations. It is here demonstrated in this paper how both problems can be addressed, by exposing a procedure that accounts for the modifications of the method at elevated temperatures, and by showing its implementation within a computer program. It is also shown how the program can be used to assess the study of the method itself, by applying it to a case of a web-tapered beam-column and comparing it to numerical results.</span>

The effects of residual stresses and strains on lateral-torsional buckling behavior of cold-formed steel channel and built-up I-sections beams

2019 ◽  
Vol 10 (2) ◽  
pp. 230-243
Author(s):  
Mohammad Zaman Kabir ◽  
Mehdi Parvizi
Keyword(s):  
Residual Stresses ◽  
Major Effect ◽  
Buckling Analysis ◽  
Roll Forming ◽  
Lateral Torsional Buckling ◽  
Forming Process ◽  
Torsional Buckling ◽  
Content Type ◽  
Cold Formed Steel ◽  
Residual Stresses And Strains

Purpose The purpose of this paper is to focus on the influences of residual stresses which were induced during roll-forming sections on lateral-torsional buckling of thin-walled cold-formed steel channel and built-up I-sections beams. Built-up I section is made up of two back-to-back cold-formed channel beams. In this direction, at the primary stage, the roll-forming process of a channel section was simulated in ABAQUS environment and the accuracy of the result was verified with those existing experiments. Residual stresses and strains in both longitudinal and circumferential transverse directions were extracted and considered in the lateral-torsional buckling analysis under uniform end moments. The contribution of the current research is devoted to the numerical simulation of the rolling process in ABAQUS software enabling to restore the remaining stresses and strains for the buckling analysis in the identical software. The results showed that the residual stresses decrease considerably the lateral-torsional buckling strength as they have a major impact on short-span beams for channel sections and larger span for built-up I sections. The obtained moment capacity from the buckling analysis was compared to the predictions by American Iron and Steel Institute design code and it is found to be conservative. Design/methodology/approach This paper has explained a numerical study on the roll-forming process of a channel section and member moment capacities related to the lateral-torsional buckling of the rolled form channel and built-up I-sections beams under uniform bending about its major axis. It has also investigated the effects of residual stresses and strains on the behaviour of this buckling mode. Findings The residuals decrease the moment capacities of the channel beams and have major effect on shorter spans and also increase the local buckling strength of compression flange. But the residuals have major effect on larger spans for built-up I sections. It could be seen that the ratio of moment (with residuals and without residuals) for singly symmetric sections is more pronounced than doubly symmetric sections. So it is recommended to use doubly symmetric section of cold-formed section beams. Originality/value The incorporation of residual stresses and strains in the process of numerical simulation of rolled forming of cold-formed steel sections under end moments is the main contribution of the current work. The effect of residual stresses and strains on the lateral-torsional buckling is, for the first time, addressed in the paper.

scholarly journals Experimental Investigation for Non and Partially Composite Cold-Formed Steel Floor Beams

2019 ◽  
Vol 5 (6) ◽  
pp. 1407-1423
Author(s):  
Tuka Mohammed Qasim ◽  
Salah Rohaima Al-Zaidee
Keyword(s):  
Carrying Capacity ◽  
Single Channel ◽  
Composite Model ◽  
Load Carrying Capacity ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Buckling Modes ◽  
The Third ◽  
Load Carrying ◽  
Cold Formed Steel

In this study, six full-scaled models of RC floors supported by cold-form steel sections have been tested. Each model consists of RC 75mm thick slab supported on two parallel cold-formed steel beams with a span of 3m and spacing of 500mm. The slab has an overhang part of 250mm on each side. In the first and fourth models, the slab has been casted directly on the top flanges with no shear connector to simulate the effectiveness of friction in resisting of the lateral-torsional buckling. Shear studs have been drilled in the second and fifth models to ensure the composite action. Finally, the flanges have been embedded for the third and sixth models. A single channel beam is used in the first, second, and third models while a built-up beam is used in the fourth, fifth, and sixth models. Each model has been loaded up to failure under a pure bending with two-line loads located at the third points. Data for loads, deformations, and strains have been gathered. Except the fourth and the sixth models that failed in local buckling modes, all other models failed in global lateral-torsional buckling modes. For the single beam models; the load carrying capacity of the non-composite model is 82.9% less than the capacity of the composite models with shear studs and embedded flange. For the built-up models; the load carrying capacity of the non-composite model is 44.2 % less than the loads of the composite model with shear stud and 48.7% less than the model with the embedded flange.

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