تخمین مدل تقاضای لرزه‌ای برای سطوح خرابی متوسط و زلزله های نزدیک گسل پالسگونه

نوع مقاله : پژوهشی اصیل (کامل)

نویسندگان
کامران نوبخت وکیلی 1
کوثر یزدان نجاد 2
آزاد یزدانی 3
1 مربی گروه مهندسی عمران دانشگاه کردستان
2 پژوهشگر پسادکتری، گروه مهندسی عمران، دانشگاه کردستان
3 گروه عمران دانشگاه کردستان
10.22034/23.1.11
چکیده
تخمینمدل تقاضای لرزه‌ای که معیار شدت حرکت زمینرا به معیار خرابی سازه‌ها مرتبط می­سازد،یکی از مهم‌ترین مؤلفه‌ها در طراحی سازه­ها بر مبنای عملکرد می­باشد. در مدل تقاضای لرزه ای ارتباط بین پاسخ سازه و یک پارامتر لرزه ای که بیانگر ماهیت تصادفی زلزله می‌باشد، در قالب یک ساختار ریاضی بیان می‌شود. لذا انتخاب مناسب شاخص شدت زلزله به عنوان پارامتر لرزه‌ای و تشخیص درست نحوه ارتباط آن با خسارت سازه می‌تواند نقش مهمی در کاهش خطاها در ارزیابی‌های لرزه‌ای داشته باشد. در بسیاری از مطالعات، شتاب طیفی مود اول (Sa(t1)) یا حداکثر شتاب زمین (PGA) به عنوان شاخص شدت مناسب معرفی شده‌، در حالیکه عدم کفایت این شاخص‌ها در برخی موارد مشاهده شده است. از طرفی انتخاب روشی مناسب برای سنجش کفایت شاخص‌های شدت با توجه به عدم قطعیت‌های موجود و همچنین بررسی کفایت مدل‌های تک‌خطی برای تقاضا از اهمیت ویژه‌ای برخوردار بوده و باید مورد توجه قرار گیرد. در این مطالعه، میزان مناسب بودن شاخص­های شدت مختلف با استفاده از مفاهیم تئوری اطلاعات و آنتروپیمورد ارزیابی قرار گرفته و از شتاب طیفی مود اول به عنوان شاخص مبنا استفاده شده است. برای این منظور، چندین سازه قاب خمشی بتنی با تعداد طبقات و ارتفاع متفاوت در نظر گرفته شده و تحلیل دینامیکی تاریخچه زمانی با مجموعه ای از رکوردهای پالس‌دار زلزله توسط نرم افزار IDARC انجام شده است. برای پاسخ سازه از شاخص خسارت پارک-انگ که کاربرد بسیاری به ویژه در سازه های بتنی دارد، استفاده شده است. با توجه به اینکه احتمال رفتار متفاوت شاخص های شدت در سطوح مختلف خسارت وجود دارد، بحث مدل های تقاضای چند خطی مطرح شده و عملکرد چندین مدل چندخطی با آزمون های آماری مورد سنجش قرار گرفته است. نتایج نشان می‌دهد که شاخص­های شدت بر پایه سرعت، از کفایت لازم برای سطوح خرابی کم و متوسط، تحت رکوردهای پالس­­دار برخوردار هستند. در این سطوح استفاده از شاخص‌های شدت شتاب طیفی مود اول یا شاخص‌های بر مبنای شتاب مانند حداکثر شتاب زمین می‌تواند باعث ایجاد خطا شود. همچنین مطالعات انجام شده در این مقاله نشان داده که استفاده از مدل تک خطی برای تمام سطوح خسارت مناسب نبوده و استفاده از یک مدل سه خطی با توجه به سطوح خسارت می تواند باعث کاهش خطا در ارزیابی های لرزه‌ای گردد.

کلیدواژه‌ها

موضوعات

عنوان مقاله English

Estimation of the Seismic Demand Model in Moderate Damage Level for Pulse-like Records

نویسندگان English

K. Nobakht Vakili 1
K. Yazdannejad 2
K. Yazdani 3
1 Instructor, Civil Engineering Group, University of Kurdistan
2 Postdoctoral researcher, Civil Engineering Group, University of Kurdistan
3 Professor, Civil Engineering Group, University of Kurdistan
چکیده English

The estimation of seismic demand that connects the ground motion intensity measure and the damage measure of structures is one of the most important components in the performance-based design. In the seismic demand model, the relationship between the structural response and a seismic parameter that expresses the random nature of earthquake is expressed in the mathematical form. Therefore, proper choice of earthquake intensity measure as a seismic parameter and identifying how it is related to structural damage can play an important role in reducing errors in seismic assessments. In many studies, the first mode spectral acceleration (Sa (t1)) or maximum ground acceleration (PGA) has been introduced as an appropriate intensity measure. However, some recent studies indicate that these IMs are insufficient in some circumstances. On the other hand, choosing a suitable method for measuring the sufficiency of intensity measures due to the existing uncertainties and also examining the performance of single-line demand model is of particular importance and should be considered. In this study, the suitability of different intensity measures of ground motion is quantified by using information theory and relative entropy concepts and Sa (t1) is used as the base IM. For this purpose, several concrete moment frame structures with different number of floors and heights have been considered and time history dynamic analysis has been performed using pulse-like earthquake records by IDARC software. The Park-Ang damage index, which has many applications, especially in concrete structures, has been used for structural response. Given that there is a possibility of different behavior of intensity measures at different damage levels, the discussion of multilinear demand models is proposed and the performance of several multilinear models has been evaluated by statistical tests. The results show that velocity-based intensity measures are sufficient for moderate damage level under pulse liked records. At these damage levels, the use of first mode spectral acceleration or acceleration-based intensity measures such as maximum ground acceleration can cause errors. Also, studies conducted in this paper have shown that the use of single-linear model is not suitable for all damage levels and the use of a three linear model with respect to damage levels can reduce errors in seismic assessments.

کلیدواژه‌ها English

Seismic demand model
earthquake intensity measure
relative entropy
damage levels
[1] Baker JW and Cornell CA. Uncertainty specification and propagation for loss estimation using FOSM methods. PEER Technical Report, Berkeley, California, 2003.
[2] Luco N and Cornell CA. Structure-specific scalar intensity measures for near-source and ordinary earthquake ground motions. Earthquake Spectra 2007; 23(2): 357–392.
[3] Yazdani A, Nicknam A, Yousefi Dadras E and Eftekhari SN. Entropy-based sensitivity analysis of global seismic demand of concrete structures. Engineering Structures 2017; 146: 118-126.
[4] Jalayer F, Beck JL and Zareian F. Analyzing the sufficiency of alternative scalar and vector intensity measures of ground shaking based on information theory. Journal of Engineering Mechanics 2012; 138(3), 307–316.
[5] Shome N, Cornell CA, Bazzurro P and Carballo JE. Earthquakes, Records and Nonlinear Responses. Earthquake Spectra 1998; 14(3): 469 – 500.
[6] Gardoni P, Mosalam KH-M and Kiureghian A-D. Probabilistic seismic demand models and fragility estimates for R.C. bridges. Journal of Earthquake Engineering 2003; 7(1): 79-106.
[7] Jalayer F. Direct probabilistic seismic analysis: Implementing nonlinear dynamic assessments. Ph.D Thesis, Department of civil and environmental engineering, Stanford University, 2003.
[8] Cabanas L, Benito B and Herraiz M. An approach to the measurement of the potential structural damage of earthquake ground motions. Earthquake Engineering and Structural Dynamics 1997; 26(1): 79–92.
[9] Cordova P, Deierlein G, Mehanny S and Cornell CA. Development of a two parameter seismic intensity measure and probabilistic assessment procedure. Proceedings of the Second U.S.-Japan workshop on performance-based earthquake engineering for reinforced concrete building structures, Sapporo, Japan, 187-206, 2000.
[10] Kohrangi M, Bazzurro P, Vamvatsikos D. Vector and Scalar IMs in Structural Response Estimation, Part I: Hazard Analysis. Earthquake Spectra 2016; 32(3): 1507-1524.
[11] Adam C, Kampenhuber D, Ibarra LF and Tsantaki S. Optimal Spectral Acceleration-based Intensity Measure for Seismic Collapse Assessment of P-Delta Vulnerable Frame Structures. Journal of Earthquake Engineering 2017; 21(7): 1-7.
[12] Elenas A. Correlation between seismic acceleration parameters and overall structural damage indices of buildings. Soil Dynamics and Earthquake Engineering 2000; 20: 93-100.
[13] Baker JW and Cornell CA. Vector-valued intensity measures incorporating spectral shape for prediction of structural response. Journal of Earthquake Engineering 2008; 12(4): 534–554.
[14] Bradley BA. The seismic demand hazard and importance of the conditioning intensity measure. Earthquake Engineering and Structural Dynamics 2012; 41(11): 1417–1437.
[15] Ebrahimian H, Jalayer F, Lucchini A, Mollaioli F and Manfredi G. Preliminary ranking of alternative scalar and vector intensity measures of ground shaking. Bulletin of Earthquake Engineering 2015; 13(10): 2805-2840.
[16] Bradley BA. Correlation of Arias intensity with amplitude, duration and cumulative intensity measures. Soil Dynamics and Earthquake Engineering 2105; 78: 89–98.
[17] Liu T.T, Lu D.G, Yu X.H. Development of a compound intensity measure using partial least-squares regression and its statistical evaluation based on probabilistic seismic demand analysis. Soil Dynamics and Earthquake Engineering, 2019; 125,105725
[18] Kohrangi M, Bazzurro P, Vamvatsikos D and Spillatura A. Conditional Spectrum based ground motion record selection using average spectral acceleration. Earthquake Engineering and Structural Dynamics 2017; 46(10): 1667-1685.
[19] Cover TM and Thomas JA. Elements of information theory. Second Edition, John Wiley & Sons, Inc., Hoboken, New Jersey, 2006.
[20] Alavi B and Krawinkler H. Behavior of moment-resisting frame structures subjected to near-fault ground motions. Earthquake Engineering and Structural Dynamics 2004;33(6): 687-706.
loading with information entropy-based analysis. Engineering Structures 2018; 165: 359-367.
[21] Harte H and Vere-Jones D. The entropy score and its uses in earthquake forecasting. pure and applied geophysics 2005; 162(6): 1229–1253.
[22] Marsh C. Introduction to continuous entropy. Department of Computer Science, Princeton University, 2013.
[23] Kostinakis KG, FontaraI-K and Athanatopoulou AM. Scalar structure-specific ground motion intensity measures for assessing the seismic performance of structures: A review. Journal of Earthquake Engineering 2018; 22(4): 630-665.
[24] Jeong S-H and Elnashai AS. New three-dimensional damage index for RC buildings with planar irregularities. Journal of Structural Engineering 2006; 132(9): 1482-1490.
[25] Park YJ, Reinhorn A and Kunnath SK. Inelastic damage analysis of reinforced concrete wall frame structures. Report NCEER 87 0008, NCEER/SUNY/Buffalo, 1998.
[26] Iranian National Building Codes, Part 6- Design Loads for Buildings, Building and Housing Research Center, Iran, 2013 (In Persian).
[27] Iranian National Building Codes, Part 9- design and construction of R.C. buildings, Building and Housing Research Center, Iran, 2013 (In Persian).
[28] Standard No. 2800-5, Iranian Code of Practice for Seismic Resistant Design of Buildings, 4rd Revision, Building and Housing Research Center, Iran, 2014 (In Persian).
[29] Kunnath SK, Reinhorn AM and Lobo RF. IDARC Version 7: A program for the inelastic damage analysis of RC structures. Technical Report, National Center for Earthquake Engineering Research, State University of New York, Buffalo, NY, 2010.
[30] Kent DC and Park R. Flexural members with confined concrete. Journal of the Structural Division ASCE 1971; 97(7): 1969-1990.
[31] Reinhorn AM, Roh H, Sivaselvan M, Kunnath SK, Valles RE, Madan A, Li C, Lobo R, and Spillatura A. IDARC2D Version 7.0: A program for the inelastic damage analysis of structures. Technical Report Mceer-09-0006, University at Buffalo, 2009.
[32] Ibarra LF, Medina RA and Krawinkler H. Hysteretic models that incorporate strength and stiffness deterioration. Earthquake Engineering and Structural Dynamics 2005; 34: 1489-1511.
[33] Abdollahzadeh M and Gerami M. Demand and capacity of steel moment frame structures in near field area. Tarbiat modares journal 2014; 14(4): 115-125 [in persian].
[34] Siahpolo N, Gerami M and Vahdani R. The effect of near field and far field earthquakes on the reduction coefficient of resistance and inelastic to elastic deformation ratio with ductility demand approach. Tarbiat modares journal 2018; 17(1): 115-127 [in persian].
[35] Yazdani A, Nicknam A, Eftekhari SN and Yousefi DadrasE. Sensitivity of near-fault PSHA results to Input Variables Based on Information Theory. Bulletin of the Seismological Society of American 2016; 106: 1858-1866.
مهندسی عمران مدرس
دوره 23، شماره 1
فروردین و اردیبهشت 1402
صفحه 163-178