بررسی عملکرد ساختمان های مرکب بتنی- فولادی با جداساز لرزه ای میان طبقه ای در حوزه نزدیک گسل

نوع مقاله : علمی - پژوهشی

نویسندگان

1 دانشگاه شهید بهشتی، دانشکده مهندسی عمران، آب و محیط زیست، گروه سازه و زلزله

2 دانشگاه شهید بهشتی، ، دانشکده مهندسی عمران، آب و محیط زیست

3 استادیار، دانشکده مهندسی عمران، آب و محیط زیست، دانشگاه شهید بهشتی، تهران، ایران

چکیده

یکی از راهکارهای مؤثر کاهش خسارات در حوزه نزدیک گسل ها استفاده از جداساز لرزه ای می باشد که می تواند در تراز روی پی یا در تراز روی طبقات استفاده شود. مزیت اصلی سیستم جداسازی لرزه ای، افزایش زمان تناوب اصلی سازه به منظور انتقال آن زمان تناوب سازه با پایه گیردار و زمان تناوب غالب زلزله به زمان تناوب های بالاتر می باشند. از دیگر مزیت های جداسازی لرزه ای استهلاک انرژی ورودی به سازه می‌باشد که منجر به کاهش شتاب منتقل شده به سازه فوقانی می شود. در این مقاله به بررسی عملکرد سازه های مرکب بتنی- فولادی با و بدون سیستم جداساز لرزه ای در تراز طبقه تحت زلزله های حوزه نزدیک پرداخته می شود. بدین منظور سه ساختمان 4، 7 و 10 طبقه با و بدون جداگر لرزه ای از نوع لاستیکی با هسته سربی (LRB) با میرایی و دوره تناوب مختلف مدلسازی شده است. بررسی نتایج تحلیلها نشان می دهد که با افزایش ارتفاع سازه (مقایسه نتایج ساختمان 10 طبقه با 4 و 7 طبقه) تغییرات برش پایه در مدلهای با جداگر متفاوت کمتر می شود. بعبارت دیگر نقش جداگر با افزایش ارتفاع کمرنگ می شود. همچنین مطالعه تغییرات میرایی و دوره تناوب جداگر نشان می دهد که نیروی برشی طبقات با افزایش زمان تناوب جداگرها در سازه های جداسازی شده کاهش یافته و با افزایش درصد میرایی جداگر افزایش جزئی می یابد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Investigation of Combined Steel-Concrete Structures with Inter-Story Seismic Isolator in Near-Fault Field

نویسندگان [English]

  • Ali Asghar Mortazavi 1
  • Pouria Maleki 2
  • Hamid Saffari 3
1 Shahid Beheshti University, Faculty of Civil, Water and Environmental Engineering, Department of Structure & Earthquake
2 Shahid Beheshti University, Faculty of Civil, Water and Environmental Engineering
3 Assistant Professor, Faculty of Civil & Environmental Engineering, Shahid Beheshti University, Tehran, Iran
چکیده [English]

Seismic isolation systems represent one of the most effective solutions to reduce near-fault damages; the systems can be used at either foundation or story levels. The main advantage of seismic isolation system is that it increases fundamental period of structure to longer periods. Among other advantages of seismic isolators, one can refer to the dissipation of input energy into the structure which lowers the transmitted acceleration to the above structure. In the present research, performance of combined concrete-steel structures with or without seismic isolation systems at story level, are investigated under near-field earthquakes. For this purpose, three structures of 4, 7, and 10 stories with/without seismic Lead Rubber Bearing (LRB) isolation systems with different damping ratios and periods were modelled. The analysis results indicate that, the isolation systems of longer period and smaller damping ratio were associated with lower relative displacement, acceleration and base shear, improving the structure performance. Results of analysis show that, with increasing the structure height (compare the results of the 10 story building with those of the 4 and 7 story counterparts), variations in base shear is reduced in the models with different isolation systems; i.e. the taller the structure, the more faded the role of the isolator. Furthermore, a study of the variations of damping ratio and period of isolator makes it obvious that, with increasing the period of isolators, shear force of the stories in the isolated structures decreases, while it slightly increases with increasing the damping percentage of the isolator.

کلیدواژه‌ها [English]

  • Base isolation
  • Steel-concrete composite structures
  • Dynamic analysis
  • Structural dynamics
  • Near fault earthquake
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