روش سه مرحله ای انتخاب شتابنگاشت های زلزله برای تحلیل دینامیکی سازه ها

نوع مقاله : مقاله پژوهشی

نویسندگان

1 داتشکده عمران، دانشگاه صنعتی اصفهان، اصفهان، ایران

2 کارشناس ارشد مهندسی زلزله، اصفهان، ایران

3 کارشناس ارشد مهندسی سازه، اصفهان، ایران

چکیده

تحلیل دینامیکی خطی و غیر خطی سازه ها با استفاده از شتابنگاشت های زلزله، روشی مرسوم در تحقیقات مهندسی زلزله و نیز در طراحی سازه های مهم می باشد. امروزه آیین نامه های زلزله لازم می دارند که شتابنگاشت ها اولا"سازگار بوده و ثانیا" به مقیاس در آیند. برای سازگاری شتابنگاشت ها معیارهایی همچون مشابهت ساز و کار کانونی و بزرگا، فاصله های مشابه از مرکز زلزله و بالاخره یکسان بودن نوع خاک محل ثبت زلزله عنوان شده است. در این مقاله یک روند غربالگری سه مرحله ای ارائه شده که در طی آن تعداد رکورد های منتخب به سرعت کاهش داده می شود. رکورد های نهایی از نظر معیارهای ارائه شده مناسب ترین شتابنگاشت ها برای سازه مورد نظر می باشند. استفاده از این روش نسبت به روشهای موجود به کاهش بیشتر پراکندگی پاسخ های تحلیل غیرخطی سازه منجر خواهد شد و با کاهش پراکندگی، میزان اعتماد به ایمنی سازه طراحی شده بیشتر خواهد بود.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

A 3-stage Method for Selection of Ground Motion for Dynamic Time History Analysis

نویسندگان [English]

  • F. Behnamfar 1
  • M. Nooraei 2
  • M. Talebi 3
1 Department of Civil Engineering, Isfahan University of Technology, Esfahan, Iran
2 Senior Earthquake Engineer, Consultant Engineers, Esfahan, Iran
3 Senior Structural Engineer, Consultant Engineers, Chaloos, Iran
چکیده [English]

Results of any dynamic analysis are clearly influenced by the type of the selected acceleration records as the use of inappropriate records can lead to a misunderstanding of the real behavior of structures against earthquakes.
For compatibility of accelerograms various criteria including similarity of focal mechanism and magnitude, the same distance from the epicenter, and finally the same soil type of recording stations has been mentioned. Even with respect to these criteria, referencing to databases of earthquakes results in finding several hundreds and sometimes several thousands of apparently suitable accelerograms. Additional measures should be considered to minimize the number of appropriate records.
In this paper a three-step screening process is presented during which the number of selected records is quickly reduced from a few thousands to a few number. The finally selected records are the most appropriate for the studied structure regarding the chosen requirements.
In the first stage, called the coarse sieve, ground motion parameters and geological parameters are used to select the records. In the second stage, known as the intermediate sieve, a suit of earthquake records that are more similar in terms of spectral parameters are extracted and in the third and last stage, known as the fine sieve, the final records are selected with studying the spectral shapes of the records. It is shown that the proposed selection method results in a much less scatter in the nonlinear structural responses among the selected earthquakes resulting in an enhanced confidence in the safety of the designed structure.

کلیدواژه‌ها [English]

  • ground motion selection
  • Nonlinear Time History Analysis
  • scatter
  • screening process
  • structures
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