بررسی عملکرد لرزه‌ای کوله پل‌های نامنظم در ارتفاع بر اثر اعمال زلزله در راستاهای مختلف

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانش‌آموخته کارشناسی ارشد، دانشکده فنی و مهندسی، دانشگاه بین‌المللی امام خمینی (ره)، قزوین، ایران

2 استادیار، گروه عمران، دانشکده فنی و مهندسی، دانشگاه بین‌المللی امام خمینی (ره)، قزوین

چکیده

ارزیابی پل­های بزرگراهی، به منظور سنجش عملکرد لرزه­ای برای برنامه­ریزی یک سیستم حمل­و­نقلی، قبل و پس از وقوع زلزله اهمیت زیادی دارد. سازه­های نامنظم، به­دلیل رفتار لرزه­ای پیچیده­تر اعضا، همواره در کانون توجه پژوهشگران و طراحان بوده­اند. در این مطالعه، مدل سه­بعدی کوله­های زینی در مجموعه­ای از پل­های نامنظم در ارتفاع با استفاده از نرم­افزار اجزای محدود OpenSees تشکیل شده است. با توجه به اینکه نامنظمی در ارتفاع پایه­ها منجر به تفاوت در سختی آن­ها می­شود، توزیع نیروی زلزله بر هر پایه نامتوازن خواهد بود. از سوی دیگر، میزان نیرویی که متوجه کوله­ها می­شود، به مقاومت و سختی پایه­های میانی نیز بستگی دارد. علاوه بر نقش نامنظمی، تأثیر دو رویکرد مجزا برای مدل‏سازی شرایط تکیه­گاهی پایه­های میانی، اعم از تکیه­گاه گیردار و انعطاف­پذیر (اندرکنش خاک­و­سازه) در تحلیل ملاحظه شده است. همچنین، لازم است برای پل­های دارای پیچیدگی­های رفتاری که تحت اثر تحریکات زلزله به­وسیله دو مؤلفه افقی متعامد هستند، تعداد کافی شتابنگاشت با زوایای مختلف به سازه اعمال شود تا بیشترین تقاضای اعضای آن به‏دست آید. بنابراین، هر یک از مدل­ها به ازای یک مجموعه شتابنگاشت که هر کدام در هفت زاویه گوناگون دوران داده شده­اند، تحت تحلیل دینامیک افزاینده قرار گرفته است. تحلیلدو سطح ظرفیتی مختلف مشخص کرد که نوع و میزان نامنظمی پل، اندرکنش خاک و سازه و زاویه اعمال تحریکات زلزله (سوئگی) سه عامل مهمی هستند که هر یک می­توانند در به‏دست آوردن پاسخ شکنندگی اعضای تشکیل دهنده کوله نقش چشمگیری ایفا کنند. بدون استثنا، در تمامی مدل­ها، فرض تکیه­گاه گیردار برای پایه­های میانی باعث ایجاد پاسخ محافظه­کارانه­ در اعضای کوله در مقایسه با حالت اندرکنش خاک­و­سازه می­شود. در حالی که تأثیر زاویه اعمال شتابنگاشت بر بحرانی شدن شکنندگی هر یک از اعضای کوله می­تواند از یک مدل به مدل دیگر و به ازای حالت­های ظرفیتی مختلف، متغیر باشد.

کلیدواژه‌ها


عنوان مقاله [English]

Seismic Performance Assessment of Abutment in Bridges with Altitudinal Irregularity Subjected to Ground Motion Directionality Effects

نویسندگان [English]

  • soheil soltanieh 1
  • Mohammad Mahdi Memarpour 2
  • Fouad Kilanehei 2
1 Graduated MSc. of Earthquake Engineering, Imam Khomeini International University, Qazvin, Iran
2 Assistant Professor, Department of Civil Engineering, Faculty of Engineering & Technology, Imam Khomeini International University, Qazvin, Iran
چکیده [English]

Evaluation of highway bridges is a matter of importance in terms of seismic performance analysis for pre-and post-earthquake planning of a transportation system. Irregular structures have always been in the spotlight of researchers and engineers. In this study, a three-dimensional model of seat-type abutments is generated in a set of irregular bridges with unequal height of piers using OpenSess finite element software. Since altitudinal irregularity leads to different stiffness of individual piers, the distribution of seismic forces will be dissimilar for each pier. On the other hand, the proportion of seismic forces absorbed by the abutments is dependent on strength and stiffness of central piers. In addition to irregularity effects, the influence of two distinct approaches of pier support modeling such as fixed-base and flexible-base (soil-structure-interaction) is taken into account in the analyses. In addition, in order to obtain maximum demand on bridge members with complex behavior, subjected to the ground motion by orthogonal components, nonlinear time-history analysis using multiple earthquake records should be applied in different directions. Therefore, incremental dynamic analysis is performed on each bridge model for a set of seismic records each rotated in seven various directions. By processing the outcomes obtained from analysis of two levels of damage states, it is determined that the irregularity ratio and configuration, soil-structure-interaction, and incident angle of seismic motions are three important factors in evaluation of fragility characteristics of abutment constitutive members. With no exceptions in the investigated models, the fixed-base assumption of central piers produces conservative response of the abutment components in comparison to soil-structure-interaction consideration. However, the effects of ground motion directionality on the fragility characteristics of individual members of abutment vary for different damage states from one model to another.

کلیدواژه‌ها [English]

  • Bridge abutment
  • Irregular bridges
  • Ground motion directionality
  • Soil-structure-interaction
  • Incremental Dynamic Analysis
AASHTO. 2012. “Bridge design specifications”. Association of State Highway and Transportation Officials- LRFD, Washington, DC.
Abbasi, M., Zakeri, B. and Amiri, G. G. 2015. “Probabilistic seismic assessment of multiframe concrete box-girder bridges with unequal-height piers”. J. Perform. Constr. Facilities, 30(2): 04015016.
American Petroleum Institute. 2007. “Recommended practice for planning, designing, and constructing fixed offshore platforms”. API Recommended Practice 2A-WSD, 21st Edition.
Aviram, A., Mackie, K. R. and Stojadinovic, B. 2008. “Effect of abutment modeling on the seismic response of bridge structures”. Earthq. Eng. Eng. Vib., 7(4): 395-402.
Baker, J. W. 2005. “Vector-valued ground motion intensity measures for probabilistic seismic demand analysis”. Pacific Earthquake Engineering Research Center, College of Engineering, University of California, Berkeley.
Baker, J. W. 2015. “Efficient analytical fragility function fitting using dynamic structural analysis”. Earthq. Spectra, 31(1): 579-599.
Baker, J. W., Eeri, M., Cornell, C. A. and Eeri, M. 2006. “Which spectral acceleration are you using?”. Earthq. Spectra, 22(2): 293-312.
Banerjee, S. and Shinozuka, M. 2011. “Effect of ground motion directionality on fragility characteristics of a highway bridge”. Adv. Civ. Eng., 2011: 1-12.
Boulanger, R. W., Curras, C. J., Kutter, B. L., Wilson, D. W. and Abghari, A. 1999. “Seismic soil-pile-structure interaction experiments and analyses”. J. Geotech. Geoenviron. Eng., 125(9): 750-759.
Caltrans, S. D. C. 2013. “Caltrans Seismic Design Criteria Version 1.7”. California Department of Transportation, Sacramento, California.
Choi, E. 2002. “Seismic analysis and retrofit of mid-America bridges”. Doctoral Dissertation, Georgia Institute of Technology.
CSI, Bridge. 2015. “Integrated finite element analysis and design of structures: Basic analysis reference manual”. Computers and Structures, Inc., Berkeley, California, USA.
FEMA, P695. 2009. “Quantification of building seismic performance factors”. Federal Emergency Management Agency.
Goel, R. K. and Chopra, A. K. 2008. “Role of shear keys in seismic behavior of bridges crossing fault-rupture zones”. J. Bridge Eng., 13(4).
Jara, J. M., Reynoso, J. R., Olmos, B. A. and Jara, M. 2015. “Expected seismic performance of irregular medium-span simply supported bridges on soft and hard soils”. Eng. Struct., 98: 174-185.
Jeremić, B., Kunnath, S. and Xiong, F. 2004. “Influence of soil–foundation–structure interaction on seismic response of the I-880 viaduct”. Eng. Struct., 26(3): 391-402.
Kappos, A. J., Manolis, G. D. and Moschonas, I. F. 2002. “Seismic assessment and design of R/C bridges with irregular configuration, including SSI effects”. Eng. Struct., 24(10): 1337-1348.
Kaviani, P., Zareian, F. and Taciroglu, E. 2012. “Seismic behavior of reinforced concrete bridges with skew-angled seat-type abutments”. Eng. Struct., 45: 137-150.
Kotsoglou, A. and Pantazopoulou, S. 2007. “Bridge–embankment interaction under transverse ground excitation”. Earthq. Eng. Struct. Dyn., 36(12): 1719-1740.
Mander, J., Priestley, M. and Park, R. 1988. “Theoretical stress-strain model for confined concrete”. J. Struct. Eng., 114(8): 1804-1826.
Martin, G. R. and Yan, L. 1995. “Modeling passive earth pressure for bridge abutments”. Earthquake-Induced Movements and Seismic Remediation of Existing Foundations and Abutments, ASCE, San Diego, pp. 1-16. ASCE.
McKenna, F., Fenves, G. and Scott, M. 2010. “Open system for earthquake engineering simulation (OpenSees)”. Pacific Earthquake Engineering Research Center (PEER), University of California, Berkeley, CA.
Megally, S. H., Silva, P. F. and Seible, F. 2002. “Seismic response of sacrificial shear keys in bridge abutments”. Final Report Submitted to Caltrans under Contract No. 59A0051, Department of Structural Engineering, University of California, San Diego.
Muthukumar, S. 2003. “A contact element approach with hysteresis damping for the analysis and design of pounding in bridges”. Doctoral Dissertation, Georgia Institute of Technology.
Mylonakis, G. 2000. “Seismic soil-structure interaction: Beneficial or detrimental?”. J. Earthq. Eng., 4(3): 277.
Nielson, B. G. 2005. “Analytical fragility curves for highway bridges in moderate seismic zones”. Doctoral Dissertation, Georgia Institute of Technology.
PEER. 2015. “NGA-West2 final products”. Pacific Earthquake Engineering Research Center, University of California, Berkeley, CA.
Ramanathan, K. N. 2012. “Next generation seismic fragility curves for California bridges incorporating the evolution in seismic design philosophy”. Doctoral Dissertation, Georgia Institute of Technology.  
Restrepo, J. C. O. 2006. “Displacement-based design of continuous concrete bridges under transverse seismic excitation”. Università degli Studi di Pavia.  
Shamsabadi, A. 2007. “Three-dimensional nonlinear seismic soil-abutment-foundation-structure interaction analysis of skewed bridges”. University of Southern California.
Shamsabadi, A. and Yan, L. 2008. “Closed-form force-displacement backbone curves for bridge abutment-backfill systems”. Proceedings of the Geotechnical Earthquake Engineering and Soil Dynamics IV Congress, ASCE, pp. 1-10.
Tehrani, P. and Mitchell, D. 2013. “Incremental dynamic analysis (IDA) applied to seismic risk assessment of bridges”. PP. 561-596. In: Tesfamariam, S. and Goda, ‎K. (Eds.), Handbook of Seismic Risk Analysis and Management of Civil Infrastucure Systems.
Tonias, D. E. 1994. “Bridge Engineering: Design, Rehabilitation and Maintenance Modern Highwy Bridges”.
Torbol, M. and Shinozuka, M. 2014. “The directionality effect in the seismic risk assessment of highway networks”. Struct. Infrastruct. Eng., 10(2): 175-188.
Vamvatsikos, D. and Cornell, C. A. 2002. “Incremental dynamic analysis”. Earthq. Eng. Struct. Dyn. 31(3): 491-514.
Vamvatsikos, D. and Cornell, C. A. 2004. “Applied incremental dynamic analysis”. Earthq. Spectra, 20(2): 523-553.
Wang, Z., Padgett, J. E., Dueñas-Osorio, L., Eeri, M. and Eeri, M. 2013. “Influence of vertical ground motions on the seismic fragility modeling of a bridge-soil-foundation system”. Earthq. Spectra, 29(3): 937-962.