نگرش محاسباتی بر تغییرات جابجایی نسبی در تخمین تقاضای لرزه‌ای اسکلت های قاب محیطی خمشی میان مرتبه

نوع مقاله: علمی - پژوهشی

نویسندگان

1 دانشجوی دکتری مهندسی سازه، دانشکده فنی و مهندسی، دانشگاه خوارزمی، تهران، ایران

2 استادیار، دانشکده فنی و مهندسی، دانشگاه خوارزمی، تهران، ایران

3 دانشیار، دانشکده فنی و مهندسی، دانشگاه خوارزمی، تهران، ایران

چکیده

امروزه جهت دستیابی به پاسخ‌های لرزه‌ای سازه‌ها استفاده از روش‌های تحلیل دینامیکی و استاتیکی غیر خطی رواج یافته است. روش‌های دینامیکی غیر خطی با وجود دقت مناسب در برآورد تقاضای لرزه‌ای، نیاز به محاسبات گسترده و پیچیده داشته و حساس به ماهیت رکوردهای زلزله نیز می‌باشند. روش‌های استاتیکی غیر خطی نیز پاسخ‌های لرزه‌ای سازه‌ها را با یک دامنه خطا برآورد می‌نمایند. کاربرد مدل تحلیلی محیط پیوسته، یک روش محاسباتی جایگزین در تخمین نیاز لرزه‌ای سازه‌ها است. چنانچه رفتار لرزه‌ای سازه با اندرکنش دو کنسول معادل خمشی و برشی مدل سازی شود، می‌‌توان یک روند تحلیلی را بر اساس روابط فرم بسته تدوین نمود. در این تحقیق؛ مدل‌های مطالعاتی با دو سیستم قاب خمشی محیطی ترکیبی و دسته شده، بصورت سازه‌های 10 طبقه بوده که در پلان و ارتفاع، منظم می‌باشند. بازه تغییرات پاسخ‌های لرزه‌ای سازه‌های مطالعاتی توسط مدل فرم بسته ترکیبی دو کنسول خمشی- برشی محاسبه می‌‌شود. سپس این نتایج با پاسخ‌های بدست آمده از آنالیز‌های خطی و غیر خطی تاریخچه پاسخ تحت رکوردهای سه مولفه‌ای زلزله با ماهیت نیرومند جهت داری شکست، مقایسه گردیده است. درباره ویژگی‌های رکوردهای حوزه نزدیک می‌توان به باند فرکانس‌های پایین پر انرژی، وجود حرکت پالس گونه با پریود بلند، روند سریع آزاد شدن انرژی جنبشی ارتعاشات نیرومند زمین، اشاره نمود. نتایج این پژوهش بیانگر تخمین دست بالا و با دقت نسبی برای پارامترهای نیاز لرزه‌ای سازه‌های مطالعاتی است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Computational Notification of Relative Displacement Variations in Estimation of Seismic Demand of Mid-Rise Moment Frame Skeletons

نویسندگان [English]

  • Saman Khalili 1
  • Afshin Meshkat-Dini 2
  • J. Keyvani Ghamsari 3
1 PhD Student, Kharazmi University, Tehran, Iran
2 Assistant Professor, Kharazmi University, Tehran, Iran
3 Associate Professor, Department of Civil Engineering, Kharazmi University, Tehran, Iran
چکیده [English]

Dynamic time history analysis methods are commonly used to determine the seismic responses of structures. Despite their ability to somewhat precisely estimate seismic demand, nonlinear dynamic methods require extensively complex computations and are sensitive to the nature of earthquake records. Nonlinear static analysis methods also estimate the seismic responses of structures within an error range. The continuum analytical model is an alternative computation method for estimation of the seismic demand of structures. If the seismic behaviour of a structure is modeled based on the interaction between the equivalent flexural and shear cantilevers, it is possible to develop an analytical procedure based on the closed-form equations. In this study, the studied models were prepared using a hybrid and a bundled moment framed tube skeletons as 10-story structures which are symmetric and regular with plan and height. The variations range of seismic responses of the studied structures was calculated using the closed-form model of flexural and shear combined cantilever. Then, these results are compared with the response parameters obtained from linear and nonlinear time history analyses subjected the three components earthquake records contain strong forward directivity effects. Some of the characteristics of near-field records are powerful low-frequency band, pulse-like motions with long periods, rapid release of kinetic vibration energy in a short period, and ratio of peak velocity to peak acceleration. This research results denote the presence of an overestimation on the seismic demand parameters with relative precision.

کلیدواژه‌ها [English]

  • " Nonlinear Dynamic Response "
  • " Drift Demand "
  • " Bundled Tube "
  • " Hybrid Framed Tube "
  • " Three Component Record "

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