ارائه روش جدید مبتنی بر نمودار برای طراحی برشی ورق‌های فولادی در دماهای بالا

نوع مقاله : مقاله پژوهشی

نویسندگان

1 استادیار، گروه مهندسی عمران، دانشگاه شهید مدنی آذربایجان، تبریز، ایران

2 پژوهشگر پسا دکتری، دانشکده مهندسی عمران، دانشگاه تبریز، تبریز، ایران

3 پژوهشگر پسا دکتری، دانشکده مهندسی عمران، دانشگاه صنعتی شریف، تهران، ایران

چکیده

افزایش استفاده از ورق­‌های جدار نازک، لزوم بررسی عمیق­تر رفتار این اعضا را نشان می­‌دهد. با توجه به هزینه قابل توجه انجام کارهای آزمایشگاهی و از طرفی عدم دسترسی همیشگی به نرم­‌افزارهای شبیه­‌سازی عددی پیشرفته نظیر آباکوس، انسیس و...، نیاز به وجود روش طراحی ساده جهت ارزیابی مقاومت برشی ورق­‌ها احساس می‌­شود. این نیاز در دماهای بالا با توجه به تغییر مد خرابی برشی ورق فولادی در برابر حرارت بیش از پیش خود را نشان می‌­دهد. در این مقاله، روابط طراحی برشی آیین‌­نامه فولاد و پل آمریکا به کمک ضرایب کاهشی آیین­‌نامه اروپا برای استفاده در دماهای بالا اصلاح شده و روابط و نمودارهای طراحی جهت تخمین مقاومت برشی نهایی و دمای متناظر با لحظه خرابی انواع ورق (سخت ­شده و سخت ­نشده) با شرایط مرزی مختلف با در نظرگرفتن تغییر مد خرابی پیشنهاد شده است. مطابق نتایج، نمودارهای پیشنهادی در هر دو دمای محیط و دمای بالا در ورق­های فشرده دارای دقت بیشتری نسبت به ورق‌­های غیرفشرده و لاغر هستند. بدین ترتیب که حداکثر اختلاف بین نتایج نمودارهای پیشنهادی و نتایج شبیه­‌سازی اجزاء محدود مقاله حاضر در دمای محیط در ورق‌های فشرده، غیرفشرده و لاغر به ترتیب به حدود 1/1%، 23% و 28% می­رسد. از طرفی نمودارهای پیشنهادی در دمای 400 و 600 درجه سانتی‌گراد تقریبا با حفظ دقت خود در محدوده ورق­های فشرده، در تخمین مقاومت برشی ورق­‌های غیرفشرده و لاغر منجر به خطایی در حدود 3% تا 11% می­‌شوند. همچنین، حداکثر خطا در مقایسه با نتایج آزمایشگاهی و عددی سایر محققین به ترتیب به حدود 20% و 4% محدود می‌­شود.
 

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Introducing a Novel Diagram-Based Method for Shear Design of Steel Plates at High Temperatures

نویسندگان [English]

  • Abbas Ghadami 1
  • Ghazaleh Pourmoosavi 2
  • Ali Ghamari 3
1 Assistant Professor, Dept. of Civil Engineering, Azarbaijan Shahid Madani University, Tabriz, Iran
2 Post Doc. Researcher, School of Civil Engineering, University of Tabriz, Tabriz, Iran
3 Post Doc. Researcher, Dept. of Civil Engineering, Sharif University of Technology, Tehran, Iran
چکیده [English]

It seems necessary to develop a simplified design approach in order to evaluate the shear strength of web panels under fire condition as the size of furnaces is limited, the cost of experiments aimed at testing the fire resistance of structures is quite high and access to simulation software packages such as ANSYS and ABAQUS is not always guaranteed. In this paper, web panel shear design relationships of AISC360-16 and AASHTO-14 specifications are exploited to be used in fire conditions. To this end, the stress-strain reduction factors provided in EN 1993-1-2 are directly applied. Afterward, the design curves are proposed for the prediction of the ultimate shear strength and limiting temperature of steel plate girders under fire by taking into account the strength degradation caused by high temperatures and the effects due to sectional instability. According to the results, the proposed curves are more accurate in compact plates with plastic shear buckling at both ambient and high temperatures. However, by increasing the web slenderness, the difference is increased. At ambient temperatures, the maximum difference for compact, non-compact, and slender web plates is about 1.1%, 23%, and 28%, respectively. The difference at 400ºC reaches almost 3% and 7% for non-compact and slender web panels, respectively. In addition, at 600ºC, especially for slender plates, proposed curves yield values that are nonconservative for ultimate shear strength, such that the difference is about 11%. Also, the maximum difference for existing experimental and numerical studies is about 20% and 4%, respectively.

کلیدواژه‌ها [English]

  • Fire
  • Plate slenderness
  • Pteel plate girder
  • Shear Strength
  • Design diagram
[1] Kövesdi, B., Alcaine, J., Dunai, L., Mirambell, E., Braun, B. and Kuhlmann, U., 2014. “Interaction behaviour of steel I-girders; part II: Longitudinally stiffened girders”. Journal of Constructional Steel Research, 103, pp.344-353.
[2] Dwaikat, M.M., 2016. “On the plastic moment-shear interaction curves of steel sections under fire”. Journal of Structural Fire Engineering, 7, pp.97-113.
[3] Knobloch, M., 2014. “Stability of steel structures in fire: State‐of‐the‐art”, recent studies in Switzerland and future trends. Stahlbau, 83(4), pp.257-264.
[4] Wagner, H., 1931. “Flat sheet metal girders with very thin metal web. Part I: general theories and assumptions”.
[5] Basler, K., 1961. “Strength of plate girders in shear”. Journal of the Structural Division, 87(7), pp.151-180.
[6] Höglund, T., 1997. “Shear buckling resistance of steel and aluminium plate girders”. Thin-walled structures, 29(1-4), pp.13-30.
[7] EN 1993-1-5, Eurocode3. 2006. Design of steel structures - Part 1-5: Plated structural elements. European Committee for Standardisation (CEN).
[8] Tan, K.H. and Qian, Z.H., 2008. “Experimental behaviour of a thermally restrained plate girder loaded in shear at elevated temperature”. Journal of Constructional Steel Research, 64(5), pp.596-606.
[9] Vimonsatit, V., Tan, K.H. and Qian, Z.H., 2007. “Testing of plate girder web panel loaded in shear at elevated temperature”. Journal of Structural Engineering, 133(6), pp.815-824.
[10] Vimonsatit, V., Tan, K.H. and Ting, S.K., 2007. “Shear strength of plate girder web panel at elevated temperature”. Journal of Constructional Steel Research, 63(11), pp.1442-1451.
[11] Qian, Z.H. and Tan, K.H., 2009. “Deflection behaviour of plate girders loaded in shear at elevated temperatures”. Journal of Constructional steel research, 65(4), pp.991-1000.
[12] Scandella, C., Knobloch, M. and Fontana, M., 2014. “Numerical analysis on the fire behaviour of steel plate girders”. In Progress on Safety of Structures in Fire: Proceedings of the 8th International Conference on Structures in Fire (Vol. 1, pp. 105-112). Tongji University Press.
[13] Salminen, M. and Heinisuo, M., 2014. “Numerical analysis of thin steel plates loaded in shear at non-uniform elevated temperatures”. Journal of Constructional Steel Research, 97, pp.105-113.
[14] Kodur, V.K.R. and Naser, M.Z., 2014. “Effect of shear on fire response of steel beams”. Journal of Constructional Steel Research, 97, pp.48-58.
[15] Reis, A., Lopes, N. and Real, P.V., 2016. “Shear–bending interaction in steel plate girders subjected to elevated temperatures”. Thin-Walled Structures, 104, pp.34-43.
[16] Quan, G., Huang, S.S. and Burgess, I., 2015. “An analytical approach to modelling shear panels in steel beams at elevated temperatures”. Engineering Structures, 85, pp.73-82.
[17] Kodur, V.K.R. and Naser, M.Z., 2018. “Approach for shear capacity evaluation of fire exposed steel and composite beams”. Journal of Constructional Steel Research, 141, pp.91-103.
[18] Pourmoosavi, GH., Ghasemi, S.M., Azar, B.F. and Talatahari, S., 2020. “Shear design curves of unstiffened plate girder web panels at high temperatures”. Journal of Constructional Steel Research, 164, p.105808.
[19] Pourmoosavi, G.H., Ghasemi, S.M., Azar, B.F. and Talatahari, S., 2020. “Numerical investigation on ultimate shear strength of long steel plate girder web panels at high temperatures”. Journal of Building Engineering, 29, p.101070.
[20] Lee, S.C., Lee, D.S. and Yoo, C.H., 2008. “Ultimate shear strength of long web panels”. Journal of Constructional Steel Research, 64(12), pp.1357-1365.
[21] Tech report, Basler, K., Yen, B.T., Mueller, J.A. and Thurlimann, B., 1960. Web buckling tests on welded plate girders. Part 4: tests on plate girders subjected to combined bending and shear. WRC Bulletin, 64, Reprint No. 165 (60-5), Fritz Engineering Laboratory, Lehigh University.
[22] Basler, K., 1961. “Strength of plate girders in shear”. Journal of the Structural Division, 87(7), pp.151-180.
[23] Yoo, C.H. and Lee, S.C., 2006. “Mechanics of web panel postbuckling behavior in shear”. Journal of structural engineering, 132(10), pp.1580-1589.
[24] Daley, A.J., Brad Davis, D. and White, D.W., 2017. “Shear strength of unstiffened steel I-section members”. Journal of Structural Engineering, 143(3), p.04016190.
[25] Lee, S.C. and Yoo, C.H., 1998. “Strength of plate girder web panels under pure shear”. Journal of Structural Engineering, 124(2), pp.184-194.
[26] Lee, S.C., Yoo, C.H. and Yoon, D.Y., 2002. “Behavior of intermediate transverse stiffeners attached on web panels”. Journal of Structural Engineering, 128(3), pp.337-345.
[27] Lee, S.C., Yoo, C.H. and Yoon, D.Y., 2003. “New design rule for intermediate transverse stiffeners attached on web panels”. Journal of Structural Engineering, 129(12), pp.1607-1614.
[28] Garlock, M.E.M. and Glassman, J.D., 2014. “Elevated temperature evaluation of an existing steel web shear buckling analytical model”. Journal of Constructional Steel Research, 101, pp.395-406.
[29] Lee, S.C., Davidson, J.S. and Yoo, C.H., 1996. “Shear buckling coefficients of plate girder web panels”. Computers & structures, 59(5), pp.789-795.
[30] AASHTO, 2014. Bridge Design Specifications, American Association of State Highway and Transportation Officials, Washington, DC.
[31] ANSI/AISC 360-16, 2016. Specification for Structural Steel Buildings. American. Inst. Steel Constr.
[32]  Höglund, T., 1971. “Behaviour and strength of the web of thin plate I-girders”. Bulletin, (93).
[33]  Gheitasi, A. and Alinia, M.M., 2010. “Slenderness classification of unstiffened metal plates under shear loading”. Thin-Walled Structures, 48(7), pp.508-518.
[34] Ghadami, A. and Broujerdian, V., 2019. “Shear behavior of steel plate girders considering variations in geometrical properties”. Journal of Constructional Steel Research, 153, pp.567-577.
[35] Broujerdian, V., Mahyar, P. and Ghadami, A., 2015. “Effect of curvature and aspect ratio on shear resistance of unstiffened plates”. Journal of Constructional Steel Research, 112, pp.263-270.
[36] EN 1993-1-2, Eurocode3. 2005. Design of steel structures - Part 1-2: General rules - Structural fire design. European Committee for Standardisation (CEN).
[37] Ghadami, A. and Broujerdian, V., 2019. “Flexure–shear interaction in hybrid steel I-girders at ambient and elevated temperatures”. Advances in Structural Engineering, 22(6), pp.1501-1516.
[38] Abaqus 6.14., 2016. ABAQUS analysis user's manual, ABAQUS Inc.
[39] Broujerdian, V., Ghamari, A. and Ghadami, A., 2016. “An investigation into crack and its growth on the seismic behavior of steel shear walls”. Thin-Walled Structures, 101, pp.205-212.
[40] Amani, M., Alinia, M.M. and Fadakar, M., 2013. “Imperfection sensitivity of slender/stocky metal plates”. Thin-Walled Structures, 73, pp.207-215.
[41] Hossain, M.R., Ashraf, M. and Albermani, F., 2011. “Numerical modelling of yielding shear panel device for passive energy dissipation”. Thin-Walled Structures, 49(8), pp.1032-1044.
[42] Lee, S.C. and Yoo, C.H., 1999. “Experimental study on ultimate shear strength of web panels”. Journal of structural engineering, 125(8), pp.838-846.
[43] Reis, A., Lopes, N., Real, E. and Real, P.V., 2016. “Numerical modelling of steel plate girders at normal and elevated temperatures”. Fire safety journal, 86, pp.1-15.
[44] Alinia, M.M., Hosseinzadeh, S.A.A. and Habashi, H.R., 2007. “Numerical modelling for buckling analysis of cracked shear panels”. Thin-Walled Structures, 45(12), pp.1058-1067.
[45] Amani, M., Edlund, B.L.O. and Alinia, M.M., 2011. “Buckling and postbuckling behavior of unstiffened slender curved plates under uniform shear”. Thin-walled structures, 49(8), pp.1017-10