تحلیل دینامیکی دودکش های فولادی با احتساب مولفه های دورانی زمین لرزه

نوع مقاله : علمی - پژوهشی

نویسندگان

1 استادیار بخش مهندسی عمران، دانشکده فنی و مهندسی، دانشگاه زنجان

2 دانشجوی دکتری مهندسی عمران، دانشکده فنی و مهندسی، دانشگاه زنجان

چکیده

در این تحقیق اثر مولفه‌های دورانی ناشی از زمین‌لرزه بر رفتار دینامیکی خطی دودکش‌های فولادی مورد تحلیل و بررسی قرار گرفته است. بدین منظور در این مطالعه ابتدا مولفه‌های دورانی ناشی از چهار زمین‌لرزه با استفاده از مولفه‌های انتقالی و در نظر گرفتن سرعت امواج وابسته به فرکانس به دست آمده است. در ادامه برای بررسی اثرات این مولفه‌ها بر پاسخ دینامیکی دودکش‌های فولادی، شش مدل دودکش فولادی با ارتفاع‌های مختلف تحت بارگذاری مولفه‌های چهار زلزله متفاوت در حالات اعمال مولفه‌های دورانی و انتقالی بصورت همزمان و اثر تنها مولفه ‌های انتقالی تحت تحلیل و بررسی قرار گرفته است. نتایج عددی تحلیل‌های لرزه‌ای حاکی از آن است که مقادیر بیشینه تغییرمکان‌ها، تنش‌ها و برش پایه دچار تغییرات بسزایی شده و محل رخداد ماکزیمم پاسخ ها دچار تغییر شده است. همچنین نتایج نشان از تاثیر مولفه ‌های دورانی بر پاسخ سازه‌ها با افزایش ارتفاع، و نزدیکی فرکانس غالب مولفه دورانی و فرکانس غالب سازه دارد به طوریکه در برخی موارد اعمال مولفه های دورانی باعث کاهش میزان پاسخ ها شده و در مواردی با نزدیک تر شدن فرکانس این مولفه ها و فرکانس غالب سازه و نیز افزایش ارتفاع سازه مقدار پاسخ ها بصورت قابل توجهی افزایش می‌یابد. این نتایج نشانگر اهمیت احتساب مولفه های دورانی زمین‌لرزه در آنالیز و طراحی این نوع از سازه ها می باشند.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Dynamic analysis of steel chimney considering rotational components of earthquake

نویسندگان [English]

  • Amir Javad moradloo 1
  • Hoseyn Bayat 1
  • Ehsan Teymoori 2
1 Department of Civil engineering, University of zanjan
2 Department of Civil engineering, University of Zanajn
چکیده [English]

The present study deals with dynamic analysis of steel chimney taking rotational components of earthquake into account. The translational components of the earthquake have been used in order to obtain the rotational components of the earthquake, based on the intersecting isotropic elastic wave propagation. For this purpose, a transitional component of ground motion using frequency discrete Fourier transformed to discrete frequency and G value for each frequency determined. Then, the incident angle of the wave was calculated for each frequency then, fourier spectrums of rocking and torsion components of ground motion were calculated. Finally, the inverse of Fourier conversion were calculated to evaluate time history of rocking and torsion components of ground motion .In order to verify the proposed methodology, the rotational components of San Fernando Earthquake were determined based on the proposed model and compared to Li and Liang's results. In Li's model, the incident angle and apparent wave velocity was supposed to be constant while in the present study the incident angle and apparent wave velocity were variable based on each frequency Then, the rotational components of San Fernando, Tabas and Taft were calculated based on the proposed model and the results were used in dynamic analysis of the steel chimneys. Finally, dynamic analyses of three model of steel chimney are presented to evaluate the effects of combined translational and rotational components on the seismic response of the chimney. The deduced results show that the maximum values of displacement, stresses and shear force and also, the distribution of them have changed significantly. On the other hand, the magnitudes of these responses for different earthquakes with respect to the frequency content of rotational components of the earthquake are different. The results indicate that the effects of earthquake rotational components on the dynamic response of steel chimneys are very significant.

کلیدواژه‌ها [English]

  • seismic analysis
  • Steel chimney
  • Rotational components
  • earthquake
  • Finite element method
[1] Rajkumar,  V. and Vishwanath, B.Patil. (2013). “Analysis of Self-Supporting Chimney”. International Journal of Innovative Technology and Exploring Engineering (IJITEE), 3(5), Page (85-91).
[2] Rohini Padmavathi, V. and Siva Konda Reddy, B. and Srikanth. (2012). “Study of wind load effects on tall RC chimneys”.  Int. J. of Advanced Engineering Technology, 3(2), Page (92-97).
[3] Reddy,  K. R. C. and Jaiswal, O. R. and Godbole, P. N. (2011). “Wind and Earthquake Analysis of Tall RC Chimneys”. Int. J. of ISSN 0974-5904, 4(6), Page (508-511).
[4] Kirtikanta S, Pradip S, Robin D. (2013). ”Analysis of self-supported steel chimney with the effects of manhole and geometrical Properties”. Int. J. of Scientific and Engineering Research, 4(5), Page (250-253).
[5] Reddy, B T K. S M. Hussain, S M A M. (2014). ” Analysis of Self Supported Steel Chimney with Effect of Manhole”. Int.  J. of Scientific and Engineering, 4(5).
[6] Sagar S, Basvaraj G. (2015). ”Performance based seismic evaluation of industrial chimney by static and dynamic analysis “. Int. R. J. of Engineering and Technology, 2(4), Page (1670-1674).
[7] Rakshit B D, Ranjit A, Sanjith J, Chetan G. (2015). ”Analysis of Contilever Steel Chimney as per Indian Satandard”.  J. of Engineering Search and Applications”, 5(5), Page (151-162).
 [8] Rekadi Rama, S V. Reddy, V P. (2016).  “Computerized Virtual Study on Self-Supporting and Guyed Steel Chimney”. Int. J. of Engineering and Technology, 3(5), Page(778-791).
[9] Deshpande, H. John, R. (2015). “Correlation of Geometry and Dynamic Response of Self Supported Short Circular Steel Stacks”. Int. J. of Engineering Technology Science and Research IJETS R, 2(Special Issue), Page (133-144).
[10] Devil, B. Singh, S, S. (2016). ”Analysis of self supporting Steel Stacks with Variable Geometrical Configuration under the seismic loading for different shapes”. Int. J. of Engineering Research and General Science, 4(4), Page (229-233).
[11] Santhi, K. Sridhar, P. (2017). “Analysis of Self Supported Steel Chimney”. Int. J. for Research in Applied Science & Engineering Technology (IJRASET), 5(3), Page (651-656).
[12] Kumar, M, A. Raju, P, M. Babu, N, V. Roopesh, K. (2017). ”A parametric study on lateral load resistance of steel chimneys”. Int. J. of Civil Engineering and Technology, 8(7), Page (858-875).
[13] Kalpesh, D. Shrirang, T. Abhijeet,  O. (2018). ” analysis of self support steel chimney with the effects of geometrical Parameters”. Int. J. of Engineering Research and Application, 8(5), Page (4-9).
[14] Newmark, N M. (1969). ”Torsion in symmetrical buildings”. In: 4th World Conf. on Earthquake Engineering, 2. Santiago, Chile, Page (19- 32).
[15] Ghafory-Ashtiany, M. Singh, M P. (1986). “Structural response for six correlated earthquake components”. Int.  J. of Earthquake Engineering and Structural Dynamic, 14(1), Page (103-119).
[16] Trifunac, M D. (1982). “A note on rotational components of earthquake motions on ground surface for incident body waves”. Int. J. of Soil Dynamics and Earthquake Engineering, 1(1), Page (11-19).
[17] Lee, V W. Trifunac, M D. (1985). “Torsional accelerograms”. Int. J. of Soil Dynamics and Earthquake Engineering, 4(3), Page (132-139).
[18] Lee, V W. Trifunac, M D. (1987). “Rocking strong earthquake accelerations”. Int. J. of Soil Dynamic and Earthquake Engineering, 6(2), Page (75-89).
[19] Castellani, A. Boffi, G. (1986). “Rotational components of the surface ground motion during an earthquake”. Int. J. of Earthquake Engineering and Structural Dynamic, 14(5), Page (751-767).
[20] Castellani, A. Boffi, G. (1989).  “On the rotational components of seismic motion”. Int. J. of Earthquake Engineering and Structural Dynamic, 18(6), Page (785-797).
[21] Nouri, GR. Ghayamghamian, MR.  Hashemifard, M. (2010). “A comparison among different methods in the evaluation of torsional ground motion”. Int, J. of Iran Geophysics, 4(2), Page (32-44).
[22] Hong-Nan, L. Sun, L. Wang, SY. (2004). ” Improved approach for obtaining rotational components of seismic motion”. Int. J. of Nuclear Engineering and Design, 232(2), Page (131-137).
[23] Lee, V W. Liang, L. (2008) “Rotational components of strong motion earthquakes”. In: 14th World Conf. on Earthquake Engineering, Beijing, China.
[24] Kalani Sarokolayi, L. Navayi Neya, B. Tavakoli, H R. (2012). “Rotational Components Generation of Earthquake Ground Motion Using Translational Components”. In: 15th World Conference on Earthquake Engineering, Lisbon.
[25] Kalani Sarakolayi, L. Navayi Neya, B. Vaseghi Amiri, J. Tavakoli, H R. (2013). “Seismic Analysis of Evaluated water Storage Tanks Subjected to Six Correlated Ground Motion Component”.  Int. J. of Iranica Journal of Energy & Environment, 4(3), Page (199-207).
[26] Ghazvini, T. Tavakoli, H. Navayineya, B. Kalani Sarakolayi, L. (2013). “Seismic analysis of above ground storage steel tanks subjected to six correlated earthquake components”. Int. J. of Latin American Journal of Solids and Structures, 10(6), Page (1155-1176).
[27] Sandeep, C. Desai, Raviji, S. Gupta, D. (2010) '' Practical Engineering Approach For Generating The torsional Earthquake Excitation From Translational component”.  Int.  J. of Advanced Structural Engineering, 4(1), Page (1-10).
[28] ANSYS Inc.: ANSYS Documentation Version 12.1
 [29] Bathe, K. J. (1996). “Finite element procedures”, In Engineering Analysis”. 2th Edn. Prentice Hall: University of Michigan, Page (768-769).
[30] Devi, B. Singh, S, S. (2016).” Analysis of Self supporting Steel Stacks with Variable Geometrical  Configuration under the seismic loading for different shapes”. Int. J. of Engineering Research and General Science, 4(4), Page (229-233(.