بررسی تاثیر میراگر لزجی بر ضریب رفتار سازه های بتن مسلح

نوع مقاله : علمی - پژوهشی

نویسندگان

1 استاد، دانشکده مهندسی، دانشگاه فردوسی مشهد، مشهد، ایران

2 گروه عمران دانشکده مهندسی دانشگاه فردوسی مشهد ایران

3 دانشجوی کارشناسی ارشد گروه عمران دانشکده مهندسی دانشگاه فردوسی مشهد ایران

چکیده

امروزه یافتن راه‌های کاهش نیروی زلزله‌، به علت خسارات ناشی از آن، از مهم‌ترین چالش‌ها در زمینه مهندسی زلزله می‌باشد. در این میان انتخاب میراگر غیرفعال لزجی، به علت کم‌هزینه بودن، تکنولوژی مناسب‌تر و رواج استفاده در کشور ارجحیت دارد. در این پژوهش تاثیر میراگر لزجی بر عملکرد لرزه‌ای قاب خمشی بتنی مورد بررسی قرار گرفتهاست. بدین منظور سه قاب خمشی متوسط بتنی 3، 6 و 10 طبقه با نرم‌افزار Sap2000 و بدون اثر میراگر طراحی می‌شوند. سپس، با نرم‌افزارSiesmo struct وارد کردن میراگر مورد تحلیل قرار می‌گیرد. بدین منظور، این قاب‌ها یک بار بدون میراگر و بار دیگر با میراگر لزجی به روش-های معمول، طراحی و سپس زیر اثر بار‌های استاتیکی افزایشی، تحلیل استاتیکی غیرخطی و درنهایت تحت اثر شتاب‌نگاشت‌های زلزله‌های انتخاب شده، تحلیل دینامیکی تاریخچه زمانی می‌شوند.
بر پایه‌ی این بررسی‌ها، مقداری برای ضریب رفتار ناشی از میراگر افزوده به سازه، پیشنهاد می‌شود و با مقادیر موجود در آیین‌نامه2800 و همچنین در زلزله‌های میدان‌دور و میدان‌نزدیک مقایسه می‌شود. نتایج حاکی از افزایش %20 میرایی، تحت تاثیر میراگرهای لزجی، به سازه می‌باشد. ضریب رفتار به‌دست آمده، برمبنای تحلیل استاتیکی غیرخطی بارافزون و تحلیل دینامیکی تاریخچه‌ی زمانی غیرخطی، به ترتیب، 95/0 و 89/0 پیشنهاد می گردد و یا یکدیگر مقایسه می شود.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Investigation of behavior factor for reinforced concrete structures by Viscous damper

نویسندگان [English]

  • Hashem Shariatmadar 1
  • Azade Rezayi pazhand 2
  • Negar Rahimzade 3
1 Associated professor, Faculty of Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
2 civil engineering . Ferdowsi university of Mashhad
3 M.Sc student of civil engineering . Ferdowsi university of Mashhad.Iran
چکیده [English]

Nowadays, finding ways to reduce earthquake force due to its damages is one of the most important challenges in the field of earthquake engineering. As a result, the selection of passive Viscouz damper is preferable due to its low cost advantage, more appropriate technology and commen use in country. In this research, the effect of Viscouz damper on seismic performance of concrete moment resisting frame has been investigated. For this purpose, three medium concrete moment resisting frames, which have3, 6 and 10-floors, are designed by the Sap2000 software without damper effect. Then, the damper has been analyzed by siesmo struct software. these frames have been designed by common methods, and then have been studied under the acceleration of selected earthquake mappings by using static pushover and dynamic time history analysis, with and without supplemental viscous dampers. Based on these studies, a value is suggested for the behavior factor of the damper added to the structure and compared with the values contained in the 2800 regulations. Also, this factor is investigated in structures equipped with this damper in far field and near field earthquakes. by including viscous damper, damping increases 20% .the suggested values of the behaviour factor for the static pushover and dynamic time history analysis are 6.29 and 6.23 respectively.

کلیدواژه‌ها [English]

  • viscous damper
  • Behavior factor
  • Seismic response
  • Nonlinear static analysis
  • Nonlinear time history analysis
[1] FEMA - Federal Emergency Management Agency , NEHRP Guidelines for the Seismic Rehabilitation of Buildings and NEHRP Commentary on the Guidelines for the Seismic Rehabilitation of Buildings Reports No.FEMA-273 and FEMA-274, Washington, D.C.; 1997.
 [2] FEMA 356, 2000, Prestandard and Commentary for the Seismic Rehabilitation of Buildings, prepared by the Building Seismic Safety Council for the Federal Emergency Management Agency, 2000, Washington, D.C.
 [3] NEHRP – National Earthquake Hazard Reduction Program, NEHRP Recommended Provisions for Seismic Regulations for New Buildings and Other Structures, Appendix to Chapter 13, Structures with Damping Systems, Federal Emergency Management Agency, Washington, D.C.; 2003.
 [4] ASCE 7-05, American Society of Civil Engineers , Minimum Design Loads for Buildings and other Structures, ASCE, Reston,Virginia; 2006.
 [5] ASCE 41-06, American Society of Civil Engineers, Seismic Rehabilition of Eristing Buildings, ASCE, Reston, Virginia; 2007.
 [6] Constantinou M. C., Tadjbakhsh I. G., “Optimum Design of A First Story Damping System”, Computers & Struct., Vol. 17, 305-310; 1983.
 [7] Hahn G. D., Sathiavageeswaran K. R., “Effects of Added-Damper Distribution on The Seismic Response of Buildings”, Computers & Struct., Vol. 43, 941-950, 1992.
 [8] S.Soda. “Role of viscouse damping in nonlinear vibration of building exposed to intense ground motion”, Journal of Wind Engineering and Industrial Aerodynamics 59.247-264; 1996.
 [9] Geol, R. K. “Effects of supplemental viscous damping on seismic response of asymmetric-plan systems.” Earthquake Engineering and Structural Dynamics. Vol.27, No.2, PP.125-141; 1998.
 [10] Chang K. C., Soong T. T., Lai M. L., and Oh S.-T., “Seismic Behavior of Steel Frame With Added Viscoelastic Dampers”, Jonrnal of Structural Engineering, Vol. 121, No. 10, 1418–1426; 1995.
 [11] Wu B., Ou J. P., and Soong T. T., “Optimal Placement of Energy Dissipation Devices for ThreeDimensional Structures”, Eng. Struct. Vol. 19, No. 2, 113–125; 1997.
 [12] Agrawal A. K., and Yang J. N., “Optimal Placement of Passive Dampers on Buildings Using Combinatorial Optimization”, J. Intell. Mater. Syst. Struct., Vol. 10, No. 12, 997–1014; 1999.
 [13] Yang J. N., Lin S., Kim J.-H., and Agrawal A. K., “Optimal Design of Passive Energy Dissipation Systems Based on H∞ and H2 Performances ” ,  Earthquake Eng . Struct. Dyn. Vol. 31, No. 4, 921–936; 2002. 
 [14] Min K. W., Kim J., and Lee S. H., “Vibration Tests of 5-Storey Steel Frame With Viscoelastic Dampers”, Eng. Struct, Vol. 26, No. 6, 831–839; 2004.
 [15] Kim J., Choi H., “Displacement-Based Design of Supplemental Dampers for Seismic Retrofit of a Framed Structure”, J. Struct. Eng., Vol. 132, No. 6, 873–883; 2006.
 [16] Hwang, Tsai, Wang, Huang. “Experimental study of RC building structures with supplemental viscous dampers and lightly reinforced walls”, Engineering Structures 28 .1816-1824; 2006.
 [17] Occhiuzzi. “Additional viscous dampers for civil structures: Analysis of design methods based on effective evaluation of modal damping ratios”. Engineering Structures 31. 10931101; 2009.
 [18] Zimmer, M., Characterization of Visco-Elastic Materials for Use in Seismic Energy Dissipation Systems, Master of Science Thesis, Department of Civil, Structural and Environmental Engineering, University at Bu_alo, State University of New York, Bu_alo, N.Y. (2000).
 [19] ATC, Structural Response Modification Factors: ATC-19, Applied Technology Council, Redwood City, California, pp. 5-32; .5991
 [20] Fukumoto, Y. and Lu, G. “Stability and ductility of steel structure under cyclic loading”, CRC press, Inc, PP. 99-.(1991 221
 [21] A. S. Whittaker, V. V. Bertero, C. L. Thompson, and L. J. Alonso, "Seismic testing of steel plate   energy dissipation devices," Earthquake Spectra, vol. 7, no. 4, pp. 563-604, 1991..