ارزیابی پاسخ لرزه ای سد بتنی دو قوسی تحت تحریک غیر یکنواخت تکیه گاهی با استفاده از روش ارتعاش تصادفی

تاری نژاد, رضا; نوری ناورود, حامد; صبح خیز, رامتین; ایثاری, محسن; محجوب, حامد

doi:10.22065/jsce.2018.114662.1435

ارزیابی پاسخ لرزه ای سد بتنی دو قوسی تحت تحریک غیر یکنواخت تکیه گاهی با استفاده از روش ارتعاش تصادفی

نوع مقاله : علمی - پژوهشی

نویسندگان

¹ دانشکده مهندسی عمران

² دانشکده مهندسی عمران دانشگاه تبریز

10.22065/jsce.2018.114662.1435

چکیده

اهمیت اثرات تحریک غیریکنواخت در پاسخ لرزه ای سازه ها به خوبی شناخته شده است. برای بررسی اثرات جابجایی‌های غیر یکنواخت روی پاسخ لرزه‌ای یک سد اطلاعات جابجایی زمین‌لرزه مورد نیاز خواهد بود. چنین اطلاعاتی در طول یک زمین‌لرزه در ساختگاه یک سد به ندرت به ثبت رسیده است و عموما تعداد داده‌های ثبت شده نیز به کفایت انجام تحلیل غیر یکنواخت را نمی‌نماید. در پژوهش حاضر، با استفاده از طیف کانای-تاجیمی در روش ارتعاش تصادفی، شتابهای غیر یکنواخت با اعمال اثرات عبور موج ، اثرات ناپیوستگی ناشی از تفرق امواج و با اعمال مدل طیف ارتباطی، روی ساختگاه مورد بررسی تولید شد. در ادامه مدل سه بعدی از سد کارون 4 به عنوان بلندترین سد بتنی دو قوسی در ایران تهیه شد. مدل آماده شده، تحت شتابهای یکنواخت و غیریکنواخت تولید شده در دو حالت مخزن خالی و پر بررسی و رفتارهای لرزه ای آن مورد ارزیابی قرار گرفت. نتایج به دست آمده نشان می دهد که، تحلیل های غیر یکنواخت منجر به تفاوت در رفتار لرزه ای سازه در مقایسه با تحلیل یکنواخت می شود. چنانکه که دیده شد، تحریکهای غیر یکنواخت باعث افزایش تنشها و جابجایی های بدنه سد می شوند. علاوه براین ، وجود مخزن نیز منجر به افزایش تنش در بدنه سد شده است.

کلیدواژه‌ها

موضوعات

سازه های هیدرولیکی

عنوان مقاله [English]

Evaluation of seismic responses of an arch dam under non-uniform ground motion using random vibration

نویسندگان [English]

Reza Tarinejad ¹
Hamed NouriNavroud ¹
Ramtin Sobhkhiz ¹
Mohsen Isari ¹
Hamed Mahjoub ²

¹ Faculty of Civil engineering

² Faculty of Civil Engineering

چکیده [English]

To investigate the seismic responses of dams due to ground non uniform displacements, the records of earthquake displacements are required. Such data is seldom recorded during a specific earthquake and in the most cases the recorded data in not sufficient for non-uniform analysis of a dam. In this study non uniform accelerations are generated using Kanai-Tajimi spectrum with considering wave passage, incoherent effects and coherence spectrum model. A 3-d finite element model of dam-foundation of Karun 4 arch dam as the highest dam in Iran is modeled. The model is analyzed under uniform and non-uniform generated accelerations and its responses are investigated. The results show that, non-uniform excitation leads to differences in seismic response than uniform excitation on dam. It is indicated that considering non-uniform excitation in seismic analysis increases the stresses and displacements on the dam body.
To investigate the seismic responses of dams due to ground non uniform displacements, the records of earthquake displacements are required. Such data is seldom recorded during a specific earthquake and in the most cases the recorded data in not sufficient for non-uniform analysis of a dam. In this study non uniform accelerations are generated using Kanai-Tajimi spectrum with considering wave passage, incoherent effects and coherence spectrum model. A 3-d finite element model of dam-foundation of Karun 4 arch dam as the highest dam in Iran is modeled. The model is analyzed under uniform and non-uniform generated accelerations and its responses are investigated. The results show that, non-uniform excitation leads to differences in seismic response than uniform excitation on dam. It is indicated that considering non-uniform excitation in seismic analysis increases the stresses and displacements on the dam body.

کلیدواژه‌ها [English]

Non-uniform excitation
Arch Concrete Dam
Kanai-Tajimi Spectrum
Dynamic Response
Site Effect

مراجع

[1] Harichandran RS, Vanmarcke EH. (1986) Stochastic variation of earthquake ground motion in space and time. Journal of the Engineering Mechanics Division. 112:154–74.

[2] Zerva, A. (2009) Spatially variation of seismic ground motions: Modeling and engineering applications, CRC Press, Boca Raton, FL.

[3] Luco, J.E., and Wong, H. L. (1986) Response of a rigid foundation to a spatially random ground motion. Earthquake Engineering and Structural Dynamics, Vol.14, 891-908.

[4] Abrahamson NA. (1993) Spatial variation of multiple support inputs. In: Proceedings of the 1^st US Seminar on Seismic Evaluation and Retrofit of Steel Bridges, San Francisco, CA.

[5] Der Kiureghian A, Neuenhofer A. (1992) Response spectrum method for multiple- support seismic excitation. Earthquake Engineering and Structural Dynamics. 21:712–40.

[6] Der Kiureghian, A. (1996) A coherency model for spatially varying ground motions, Earthquake Engineering and Structural Dynamics 25, 99–111.

[7] Harichandran, R. S., Hawwari, A., and Sweidan, B. N. (1996) Response of long-span bridges to spatially varying ground motion. J. Struct. Eng., 10.1061/(ASCE)0733-9445(1996)122:5(476), 476–484.

[8] Bi, K. and Hao, H. (2011) Influence of irregular topography and random soil properties on coherency loss of spatial seismic ground motions, Earthquake Engineering and Structural Dynamics 40,1045–1061.

[9] Bi, K. and Hao, H. (2012) Modelling and simulation of spatially varying earthquake ground motions at sites with vary conditions,” Probabilistic Engineering Mechanics 29, 92–104.

[10] He, C., Wang, J., Zhang, C and Jin., F. (2014) Simulation of broadband seismic ground motions at dam canyons by using a deterministic numerical approach, Soil Dynamics and Earthquake Engineering, 0267-7261.

[11] Lin, J., Li, J., Zhang, W. and Williams, F. W. (1997) Random seismic responses of multi‐support structures in evolutionary inhomogeneous random fields, Earthquake engineering & structural dynamics 26(1), 135-145.

[12] Konakli, K., and Der Kiureghian, A. (2012). Simulation of spatially varying ground motions including inherence, wave-passage and differential site-response effects. Earthquake Eng. Struct. Dyn., 41(3), 495–513.

[13] Alves, S.W. (2005) Nonlinear analysis of Pacoima Dam with spatially non-uniform ground motion, PhD Dissertation, California Institute of Technology, Pasadena, California.

[14] Tarinejad, R, Fatehi R and Harichandarn, R.S. (2013) Response of an arch dam to non-uniform excitation generated by a seismic wave scattering model, Soil Dynamics and Earthquake Engineering, Volume 52, Pages 40-54.

[15] Wu, Y., Gao, Y, Zhang, N, Li, D. (2016) Simulation of Spatially Varying Ground Motions in V-shaped Symmetric Canyons. Journal of Earthquake Engineering, 00:1–19.

[16] Liu, G., Feng, X., Jijian., L. and Haitao., Z. (2017) Simulation of Spatially Variable Seismic Underground Motions in U-shaped Canyons, Journal of Earthquake Engineering, DOI: 10.1080/13632469.2017.1326427.

[17] Tarinejad, R., Isari, M., TaghaviGhalesari, A. (2017) A new boundary element solution to evaluate the geometric effects of the canyon site on the displacement response spectrum, Earthquake Engineering and Engineering Vibration, In press.

[18] Tarinejad, R., Mahjoob, H., Roshanravan, A. (2015) Development of a Neural-Autoregressive Model for Time History Analysis of an Arch Dam-Reservoir System, 10th International Congress on Civil Engineering, 5-7, University of Tabriz, Tabriz, Iran.