Çift simetri eksenli I-enkesitli çelik elemanların doğrusal değişen momentler altındaki yanal burulmalı burkulma davranışı

Abstract

Çelik yapılardaki teknik gelişmeler ve daha geniş uygulama alanları nedeniyle yapısal stabilite problemleri üzerine yapılan araştırmaların önemi artmaktadır. Yanal burulmalı burkulma, özellikle kuvvetli eksenlerinde eğilmeye maruz kalmış çift simetri eksenli I-kesitli çelik elemanlar için önemli bir sorundur. Bu elemanlar yatay yer değiştirme ve dönmeye karşı uygun bir şekilde desteklenmezlerse, yük taşıma kapasitelerine ulaşamadan önce yanal burulmalı burkulma riski altındadırlar. Bu çalışmada, farklı uç moment etkisi altındaki çift simetri eksenli I-kesitli çelik elamanların elastik yanal burulmalı burkulma davranışı, önerilen bir yöntem ile birlikte çeşitli tasarım standartları, literatürdeki yaklaşımlar ve sonlu eleman analizleri dikkate alınarak incelenmiştir. Burada önerilen yöntem, doğrusal değişen moment etkisi altında yanal burulmalı burkulma davranışını temsil eden diferansiyel denklemin sonlu farklar yöntemi ile çözümüne dayanır. Kritik moment ve moment düzeltme faktörü açısından bu yaklaşımları karşılaştırmak ve değerlendirebilmek için farklı yatay yönde tutulma uzunlukları ve çeşitli uç moment değerleri dikkate alınmıştır. Analiz sonuçları, yanal burulmalı burkulmanın, eğilme altında bulunan çift simetri eksenli I-kesitli çelik elemanlar için önemli bir konu olduğu ve önerilen yöntem ile tasarım standartları, literatürdeki yaklaşımlar ve sonlu elemanlar sonuçları ile karşılaştırıldığında sonuçların tatmin edici bir şekilde yansıtıldığını göstermektedir.

Keywords

• Yanal burulmalı burkulma,Çift simetri eksenli I-kesitli çelik eleman,Çelik yapı tasarımı,Moment düzeltme katsayısı

Lateral torsional buckling of doubly symmetric I-shaped steel members under linear moment gradient

Abstract

Due to technical developments and wider range of applications in the steel structures, significance of the research on structural stability problems become forward. Lateral torsional buckling is a major problem especially for doubly symmetric I-shaped steel members subjected to flexure about their strong axis. If these members are not appropriately braced against lateral deflection and twisting, they are under the risk of failure by lateral torsional buckling prior to the reach their load carrying capacity. In this study, elastic lateral torsional buckling behavior of doubly symmetric I-shaped steel members under linear moment gradient is investigated considering a proposed method, several design standards and codes, approaches from the literature and finite element analysis. Proposed method herein is based on finite difference solution of lateral torsional buckling differential equation considering linear moment gradient. Different unbraced member lengths and various end moment values are considered in order to compare and evaluate these approaches in terms of critical moment and moment modification factor.  Analysis results show that lateral torsional buckling is a key issue for doubly symmetric I-shaped steel members that are under flexure and it is reflected satisfactorily with the proposed method considering the design codes and standards, approaches from the literature and finite element analysis results.

Keywords

• eral torsional buckling,Doubly symmetric I-shaped steel member,Structural steel design,Moment modification factor

References

1. Xiong G, Kang SB, Yang B, Wang S, Bai J, Nie S, Dai G. “Experimental and numerical studies on lateral torsional buckling of welded Q460GJ structural steel beams”. Engineering Structures, 126, 1-14, 2016.
2. Taras A, Greiner R. “New design curves for lateral-torsional buckling-Proposal based on a consistent derivation”. Journal of Constructional Steel Research, 66(5), 648-663, 2010.
3. Uzun ET. Nonlinear Analysis of Steel Frames Considering Lateral Torsional Buckling. MSc Thesis, Izmir Katip Celebi University, Izmir, Turkey, 2017.
4. Valarinho L, Correia JR, Costa MM, Branco FA, Silvestre N. “Lateral-torsional buckling behaviour of long-span laminated glass beams: Analytical, experimental and numerical study”. Materials and Design, 102, 264-275, 2016.
5. Dou C, Pi YL. “Flexural-torsional buckling resistance design of circular arches with elastic end restraints”. Journal of Structural Engineering, 142(2), 04015104-1-04015104-10, 2015.
6. Taras A, Greiner R. “Torsional and flexural torsional buckling-A study on laterally restrained I sections”. Journal of Structural Steel Research, 64(7), 725-731, 2008.
7. Agüero A, Pallarés FJ, Pallarés L. “Equivalent geometric imperfection definition in steel structures sensitive the lateral torsional buckling due to bending moment”. Engineering Structures, 96, 41-55, 2015.
8. Bradford MA, Pi YL. “A new analytical solution for lateral torsional buckling of arches under axial uniform compression”. Engineering Structures, 41, 14-23, 2012.

9. Wu L, Mohareb M. “Finite-element formulation for the lateral torsional buckling of plane frames”. Journal of Engineering Mechanics, 139(4), 512-524, 2013.
10. Zhang X, Rasmussen KJR, Zhang H. “Experimental investigation of locally and distortionally buckled portal frames”. Journal of Constructional Steel Research, 122, 571-583, 2016.
11. Wang Y, Yang L, Gao B, Shi Y, Yuan H. “Experimental study of lateral-torsional buckling behavior of stainless steel welded I-section beams”. International Journal of Steel Structures, 14(2), 411-420, 2014.
12. Lim NH, Park NH, Kank YJ, Sung IH. “Elastic buckling of I-beams under linear moment gradient”. Solids and Structures, 40, 5635-5647, 2003.
13. White DW, Kim YD. “Unified flexural resistance equations for stability design of steel I-section members: Moment gradient tests”. Journal of Structural Engineering, 134, 1471-1486, 2008.
14. Salvadory MG. “Lateral buckling of I-beams”. ASCE Transaction, 120, 1165-1177, 1955.
15. Moon J, Lim NH, Lee HE. “Moment gradient correction factor and inelastic flexural-torsional buckling of I-girder with corrugated steel webs”. Thin-Walled Structures, 62, 18-27, 2013.
16. Kirby PA, Nethercot DA. Design for Structural Stability. 1st ed. New York, USA, Halsted Press, 1979.
17. Serna MA, Lopez A, Puente I, Yong DJ. “Equivalent uniform moment factors for lateral-torsional buckling of steel members.” Journal of Constructional Steel Research, 62, 566-580, 2005.
18. Wong E, Driver RG. “Critical evaluation of equivalent moment factor procedures for laterally unsupported beams.” AISC Engineering Journal, 47, 1-20, 2010.
19. Galambos TV, Surovek AE. Structural Stability of Steel: Concepts and Applications for Structural Engineers. 1st ed. USA, Wiley, 2008.
20. Ziemian RD. Guide to Stability Design Criteria for Metal Structures. 6th ed. USA, Wiley, 2010.
21. European Committee for Standardization. “Design of steel structures-Part 1-1: General Rules and Rules for Buildings, EN1993-1-1”. Brussel, Belgium, 1992.
22. British Standards Institution. “Structural use of steelwork in building, BS5950-1”. London, UK, 2000.
23. Standards Association of Australia. “Steel structures. Standards Australia, AS4100”. Sydney, Australia, 1998.
24. American Institute of Steel Construction. “Specification for Structural Steel Buildings, ANSI/AISC360-10”. Chicago-Illinois, USA, 2010.
25. Ministry of Environment and Urbanization. “Turkish Steel Design Code, TSDC”. Ankara, Turkey, 2016.
26. Turkish Standard Institution. “Calculation Rules According to Plastic Theory of Steel Structures, TS4561”. Ankara, Turkey, 1985.
27. Secer M, Uzun E.T. “Nonlinear analysis of steel frames accounting lateral torsional buckling”. 21st International Scientific Conference: Mechanika 2016, Lithuania, 12-13 May 2016.
28. Timoshenko SP, Gere JM. Theory of Elastic Stability. 2nd ed. Tokyo, McGraw Hill-Kogakusha Ltd, 1961.
29. MATLAB Version R2013a, The MathWorks Inc., Natick, MA, USA, 2013.
30. Turkish Standard Institution. “Eurocode 3: Design of steel structures-Part 1-1: General Rules and Rules for Buildings TS EN 1993-1-1”. Ankara, Turkey, 2005.
31. ANSYS H. Version 15.0, Ansys. Inc., Canonsburg, PA USA, 2013.