شناسایی پارامترهای سازه‌ای تراز جداساز پایه بر اساس روش زیرفضا

نوع مقاله : مقاله پژوهشی

نویسندگان

1 استادیار گروه عمران دانشکده مهندسی دانشگاه کردستان

2 گروه مهندسی عمران، دانشکده مهندسی، دانشگاه کردستان

چکیده

یکی از روش‌های متداول در کنترل پاسخ لرزه‌ای سازه‌ها استفاده از جداساز لرزه‌ای می‌باشد. جداسازها با افزایش زمان تناوب سازه، برش پایه و همچنین جابه‌جایی نسبی طبقات را کاهش می‌دهند. به ‌طور معمول، در اثر عوامل محیطی شدید مانند زلزله و باد تغییر شکل زیادی در تراز جداساز اتفاق می‌افتد که این امر می‌تواند منجر به وقوع آسیب در جداسازها شود؛ که در اثر آن احتمال ایجاد جابه‌جایی ماندگار در تراز جداساز و همچنین برخورد سازه با ساختمان‌های مجاور وجود دارد. از این رو برای جلوگیری از وقوع خسارت‌ در ساختمان‌های مجهز به جداساز تحت اثر تحریکات شدید زمین، شناسایی آسیب در تراز جداساز از اهمیت زیادی برخوردار است. در این پژوهش، با فرض رفتار خطی سازه اصلی یک روش پیشنهادی بر مبنای زیرفضا برای شناسایی سختی تراز جداساز با تعداد حسگرهای محدود ارائه می‌گردد. برای این منظور با استفاده از تکنیک فشرده‌سازی، سازه مجهز به جداساز با تعداد درجات آزادی زیاد به یک سازه دو درجه آزاد تبدیل می‌گردد؛ به ‌طوری که سختی مرتبط با اولین درجه آزادی در سیستم کاهش یافته متناظر با سختی تراز جداساز در سازه اولیه باشد. سپس با استفاده از پارامترهای مارکوف شناسایی شده سیستم، سختی سازه کاهش یافته شناسایی می‌گردد. به ‌منظور ارزیابی و مقایسه عملکرد روش پیشنهادی از مثال‌های عددی استفاده می‌شود. نتایج به ‌دست‌ آمده نشان می‌دهد که حتی با وجود اغتشاش در پاسخ‌های اندازه‌گیری شده، روش پیشنهادی مقدار آسیب در تراز جداساز را با دقت قابل قبولی شناسایی می‌نماید.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Subspace based identification of structural parameters of the base isolation level

نویسندگان [English]

  • Kaveh Karami 1
  • Pejman Fatehi 2
  • Asra Hoseini 2
1 Assistant Professor of Structural Engineering. Department of Civil Engineering, University of Kurdistan
2 Department of Civil Engineering, University of Kurdistan, Sanandaj, Iran
چکیده [English]

One of the common methods in controlling the seismic response of structures is the use of seismic isolators. Base isolations reduce the base shear as well as the relative displacement of the floors by increasing the period of the structure. Typically, extreme deformation of the base isolation level occurs due to severe environmental factors, which can lead to damage to the base isolations; As a result, there is a possibility of permanent deformation in the base isolation and also the collision of the structure with adjacent buildings. Therefore, to prevent damage to buildings equipped with base isolations due to severe ground motions, it is important to identify damage at the base isolations. In this study, assuming the linear behavior of the main structure, a proposed subspace-based method for identifying the stiffness of the base isolation with a limited number of sensors is presented. For this purpose, using the compression technique, the structure equipped with a separator with a large number of degrees of freedom (DOFs) is transformed into a two DOF structure; So that the stiffness associated with the first DOF in the reduced system corresponds to the stiffness of the Base isolation level in the original structure. Then, using the identified Markov parameters of the system, the reduced structural stiffness is identified. Numerical examples are used to evaluate and compare the performance of the proposed method. The results show that even in the presence of noises in the measured responses, the proposed method detects the amount of damage at the base isolation level with acceptable accuracy.

کلیدواژه‌ها [English]

  • Base Isolation
  • damage identification
  • subspace technique
  • Passive control
  • Structural health monitoring
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