عملکرد لرزه‌ای سازه‌های نامتقارن جرمی جداسازی شده فولادی با سیستم‌های مهاربندی شورون، ضربدری و زیپر

نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه مهندسی عمران، دانشکده فنی مهندسی دانشگاه خوارزمی، تهران، ایران

2 گروه عمران، دانشکده فنی و مهندسی دانشگاه خوارزمی تهران ایران

چکیده

از روش‌های موثر مقابله با اثرات زمین‌لرزه بر سازه استفاده از سیستم جداساز لرزه‌‏ای است. در این مقاله عملکرد سازه‌های نامتقارن جداسازی شده فولادی با سیستم‌های ‏مهاربندی مختلف تحت اثر مولفه‌های افقی و قائم بررسی شده است. بدین منظور 3 نوع سیستم مهاربندی شورون، ضربدری و زیپر در سازه‌های 5 و 10 طبقه با ایجاد ‏نامتقارنی 10% و 20% درصدی ناشی از خروج از مرکزیت جرمی تحت اثر مولفه‌های قائم و افقی ‏زلزله مطالعه گردید. تحلیل تاریخچه زمانی ‏غیر‌خطی با 7 شتاب‌نگاشت منتخب حوزه نزدیک انجام شده ‌است. ابتدا سازه متقارن در دو حالت پایه ثابت و جداسازی شده تحلیل شد و سپس اثر نامتقارنی در دو حالت خروج از ‏مرکزیت جرمی 10% و 20% در سازه‌های مورد نظر مورد مقایسه قرار گرفت. متوسط مقدار نیروی برشی، دریفت و دوران طبقات و انرژی ورودی به سازه، پارامترهای مورد بررسی در این مقاله هستند. با افزایش خروج از مرکزیت جرمی سازه میزان جذب انرژی ورودی سازه توسط جداساز کاهش و برش پایه افزایش یافته است. در میان سیستم‌های مهاربندی متخلف، انرژی جذب شده توسط سیستم جداساز در سازه با مهاربند زیپر 53% افزایش یافته و میزان برش پایه 80% کاهش داشته است. بر اساس نتایج تحلیل، جداسازی از پایه در سازه با مهاربند ضربدری در حالت متقارن و نامتقارن جرمی، سبب کاهش بیش از 70% دوران طبقات نسبت به سایر سیستم‌های مهاربندی شده است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Seismic performance of asymmetric isolated steel structures with different bracing systems

نویسنده [English]

  • Seyedmohammadreza Hsseini 1
1 Faculty of Engineering, Kharazmi University, Tehran, Iran
چکیده [English]

In this paper, the seismic performance of asymmetric isolated structures with different bracing systems under near-fault strong ground motions is investigated. Non-linear dynamic analyses are performed under the simultaneous application of horizontal and vertical components of seismic acceleration. For this purpose, three types of chevron, cross and zipper bracing systems in 5 and 10-story structures with 0%, 10% and 20% mass eccentricity have been studied. Non-linear time history analysis is performed by seven selected accelerograms. First, the symmetrical structure was analyzed in fixed and isolated base states. Then, the asymmetric effect on two eccentricity cases 10% and 20% in the target structures, was compared. The parameters studied in this paper are the average shear force, drift and rotation of floors, and input energy to the structure. With an increasing eccentricity of the structure, the energy absorption by the isolator is reduced and the base shear is increased. Among the different bracing systems, the energy absorbed by the isolation system in the structure with zipper bracing increased by 53% and the base shear rate decreased by 80%. Based on the analysis results, base-isolation in the structure with cross-bracing in symmetrical and asymmetric has caused a reduction of more than 70% of the floor rotation compared to other bracing systems.

کلیدواژه‌ها [English]

  • Seismic isolator
  • Asymmetric structures
  • Cross brace
  • Chevron brace
  • Zipper brace
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