نسبت تغییرمکان غیرالاستیک سازه‌های دارای حرکت گهواره‌ای در زلزله‌های حوزه دور و نزدیک به گسل پالس‌گونه

نوع مقاله : علمی - پژوهشی

نویسندگان

1 دانشگاه علوم و تحقیقات

2 پژوهشگاه زلزله

چکیده

سازه های دارای حرکت گهواره‌ ای مرکزگرا توانایی کاهش آسیب ماندگار و تمرکز خسارت در میراگرهای تعویض پذیر را دارند. این مقاله به تعیین نسبت تغییرمکان غیرالاستیک سیستم های برگشت پذیر دارای حرکت گهواره‌ای در معرض زلزله های حوزه دور از گسل و نزدیک به گسل پالس مانند می پردازد. نسبت تغییرمکان غیرالاستیک، یعنی نسبت حداکثر تغییرمکان غیرالاستیک به حداکثر تغییرمکان الاستیک سیستم، با انجام تحلیل های دینامیکی غیرخطی تاریخچه زمانی بدست می آید. همچنین تاثیر پارامترهای لرزه ای و مدل سازی بر پاسخ تغییرمکان غیرالاستیک سازه برگشت پذیر دارای حرکت گهواره‌ای ارزیابی می شود. نتایج مطالعه نشان می دهد، تاثیر پارامترهای دوره تناوب پالس زلزله، دوره تناوب غالب رکوردها، و پارامترهای مدلسازی (ضریب اصلاح پاسخ، سختی پس از تسلیم و نسبت انرژی اتلافی) بر نسبت تغییرمکان غیرالاستیک قابل ملاحظه است، اما پارامترهای دیگر نظیر فاصله سایت تا مرکز گسلش، بزرگای زلزله و نوع سایت تاثیر کمتری بر نتایج تحلیل دارد. در انتها با استفاده از رگراسیون دو مرحله ای نتایج مطالعه آماری، روابطی جدید برای برآورد طیف های با مقاومت ثابت مقیاس نشده (سازگار با آیین نامه) و مقیاس شده برای سیستم های مرکزگرا دارای حرکت گهواره‌ای در معرض زلزله های دور و نزدیک گسل پالس‌گونه ارائه شده است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Inelastic displacement ratio for rocking buildings subjected to far-field and near-field pulse-like ground motions

نویسندگان [English]

  • Navid Rahgozar 1
  • Abdolreza sarvghad moghadam 2
1 IAU
2 دانشیار/پزوهشگاه زلزله
چکیده [English]

Self centering rocking buildings are capable of reducing permanent damage and concentrating damage to replaceable energy dissipation devices. This paper aims to calculate inelastic displacement ratio for self centering rocking buildings under far field and near field pulse like ground motions. In this paper, the inelastic displacement ratio, i.e. the ratio of the maximum inelastic displacement to the maximum displacement of the elastic system, for self centering rocking systems are determined using nonlinear dynamic time history analysis. The effects of seismic and modeling parameters on the inelastic displacement demands of self centering rocking buildings are also evaluated. Findings show that the effect of the pulse period of ground motions, predominant period of ground motions, and modelling parameters (i.e. response modification factor, hardening ratio, and energy dissipation ratio) on the inelastic displacement ratio are considerable, while influences of the other parameters such as distance to the fault site, ground motion magnitude, and the soil site are less on the analysis results. Finally, using a two-stage regression on the statistical results, new equations are proposed for estimation of the scaled and unscaled (code base) constant strength spectra of self centering rocking buildings under far field and near field pulse like ground motions.

کلیدواژه‌ها [English]

  • self-centering rocking system
  • inelastic displacement ratio
  • far-field ground motions
  • near-field ground motions
  • Nonlinear dynamic analysis
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