مطالعه تحلیلی میراگرهای فلزی آکاردئـونی در مقـاوم‌سازی لــرزه‌ای پل‌ها

نوع مقاله : Articles

نویسندگان

1 پژوهشگاه بین‌المللی زلزله‌شناسی و مهندسی زلزله

2 دانشگاه آزاد اسلامی واحد تهران جنوب

چکیده

پل‌ها به‌عنــوان یک عضـو اصلی سیستم‌هـای ارتباطـی زمینـی، جـزو سازه‌هـای با اهمیت بالا محسوب می‌شوند. با نگاهـی به زلزلـه‌های گذشته و اثرات مخرب آن بر سازه پل‌ها، اهمیت مقاوم‌سازی پل‌ها بیش از پیش احساس می‌شود. در این گزارش یک پل بتنی موجـود به‌عنوان نمونـه توسط نرم‌افـزار SAP2000 مـدل می‌شود و مـدل پـــل تحت چهار رکــورد زلزلـه طبس، کـوبه، نورثـریج و ال‌سنترو با چهار PGA مختلف مورد تحلیل دینامیکی غیرخطی تاریخچه زمانی قرار می‌گیرد و سپس با اضافه کردن میراگر آکاردئونی فلزی به سازه پل نتایج حاصل از تحلیل در دو حالت قبل و بعد از نصب میراگر با هم مقایســه می‌شود که نتیجـه آن کاهش پاسخ‌هـای لرزه‌ای سازه پل پس از نصب میـراگر و همچنین جذب و اتلاف انرژی قابل قبول توسط میراگرها و افزایش اتلاف انرژی در اعضا و سازه کلی پل می‌باشد، این مطلب نشان‌دهنده‌ی مؤثر بودن میراگرهای فلزی آکاردئونی به‌عنوان گزینه ای مناسب در مقاوم سـازی لـرزه ای پل ها می باشد.

کلیدواژه‌ها


عنوان مقاله [English]

Analytical Study of Steel Accordion Metal Dampers in Seismic Retrofitting of Bridges

نویسندگان [English]

  • Fariborz Nateghi-Alahi 1
  • Mehrtash Motamedi 2
  • Pejman Sekhavati 2
1 International Institute of Earthquake Engineering and Seismology
2 Islamic Azad University, Tehran South Branch
چکیده [English]

Experiencing earthquakes with different magnitude scales every few years, Iran is one of the most seismically active countries in the world. Therefore, it is very important to do research studies in terms of seismology before construction of bridges. Without considering seismic parameters, it would not be possible to design earthquake resistant bridges. Earth`s natural structure in different areas varies in relation with factors including kinetic energy at faults, global plate movements, velocity and maximum acceleration of plate displacements as well as the frequency and oscillation time.As mentioned before, demolition of an important structure like bridges,which is one of the basic elements in communication system among different areas leads to both heavy losses of life, and economic, social, hygienic and political losses. While a close and exact searching look at real seismic conditions of design site makes engineers able not only to prevent heavy costs of design and construction of bridges and to decrease earthquake losses significantly, but also to hold the communication system in service for the purpose of providing passages for firefighters to make all losses minimum.Studying occurred earthquakes such as Northridge and Kobe, which caused a lot of losses to different structures especially bridges contribute to feel the need of considering and studying available bridges in Iran under earthquake.Accordingto the increasing growth of studies in field of vulnerability assessment and earthquake-resistant construction, this need was felt that a damper tested in building structures would be used as an option to make bridges earthquake-resistant.In this article, analytical studies have been done on an available concrete bridge, which is common in Iran based on structure types and its elements arrangement.This bridge was modeled in SAP 2000, and the model was run based on four earthquake records including Tabas,Kobe, Northridge and El Centro applying four different PGAs and nonlinear dynamic time-history analysis were carried out, then the steel accordion damper was installed in order to compare analysis results of model before and after the damper installation.The result showed a decrease in seismic response of bridge structure after damper installation and acceptable amount of energy absorption and losses by dampers, which contribute to energy-loss increment in different elements of the main structure. These results lead to the conclusion that steel accordion dampers are a suitable solution in earthquake-resistant design of bridges.

کلیدواژه‌ها [English]

  • Earthquake Resistant
  • Energy Losses
  • Seismic Response
  • Steel Accordion Damper
  • Nonlinear Dynamic Time-History Analysis
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  2. Motamedi, M. and Nateghi, A.F. (2004) Using accordion thin-walled tube as a Hysteretic metallic damper. 13th World Conference on Earthquake Engineering, Vancouver, Canada, Paper No. 2264.
  3. Motamedi, M. (2005) Experimental Study of Application of Metallic Damper in Seismic Retrofitting of Steel Building Frames. Ph.D. Thesis, Islamic Azad University, Science & Research Branch, Tehran, Iran (in Persian).
  4. Sekhavati, P. (2007) Analysis Study of Using Yielding Metal Dampers in Seismic Retrofitting of Bridges. M.Sc. Thesis, Islamic Azad University, South Branch, Tehran, Iran (in Persian).
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