23935

ارزيابي تاب آوري لرزه اي مدرسه با اسكلت فولادي و بهبود آن از طريق روش هاي بهسازي لرزه اي

كارشناسي ارشد

مهندسي عمران-زلزله

1395-1399

1399/12/24

دكتر مرتضي رئيسي دهكردي

دكتر مهدي اقبالي

عمران

همواره خسارات مالي و تلفات انساني زيادي به دليل وقوع زلزله متوجه سازهها ميشود. وقوع زمين لرزههاي متعدد در كشور، منجر به اهميت توجه به لرزهخيزي و طراحي لرزهاي سازهها در اين منطقه شده است. وقوع حوادث مهمي از جمله زلزله رودبار، بم و سرپل ذهاب نياز به مديريت سوانح در سطوح سازهاي و شهري را با تاكيد بر متغير تابآوري لرزهاي و زمان بازيابي سازه به منظور كاهش خسارات آشكار ساخته است. به بيان ديگر جهت كاهش خسارات سازه ها بايد نوع نگاه در طراحي، به سمت اقدامات پيشگيرانه قبل از وقوع حوادث بزرگ و كاهش زمان بازيابي سازه سوق پيدا نمايد. به منظور ارزيابي تاب آوري لرزه اي ، يك نمونه مدرسه فولادي در شهر زنجان انتخاب و مشخصات آن بررسي گرديد . جهت مقاوم سازي ساختمان مذكور ، سه گزينه مهاربند ضربدري ، مهاربند واگرا و مهاربند شورون در نظر گرفته شد . سپس با استفاده از 44 ركورد حوزه دور FEMA P695 تحليل ديناميكي فزاينده بر روي اين سازه ها انجام پذيرفت و منحني هاي شكنندگي و آسيب پذيري آن ها استخراج گرديد . در نهايت زمان بازيابي و شاخص تاب آوري لرزه اي به دست آمد . نتايج نشان مي دهد كه مقاوم سازي مدارس تاثير قابل توجهي بر روي بهبود تاب آوري لرزه اي داشته است و بين گزينه هاي مقاوم سازي مهاربند ضربدري عملكرد بهتري را دارا مي باشد .

1400/03/20

Evaluation of Seismic Resilience of Steel School and its Improvement through Seismic Retrofit Methods

3/15/2022 12:00:00 AM

Seismic Resilience is a new method in earthquake engineering, which includes technical,organizational, social, economic, and environmental aspects. The goal of the resilience is to minimize casualties and economic and operational losses in order to bring the community or the system damaged to "natural" conditions in the shortest possible time. The Code 2800 considers schools as important buildings and applies a higher safety margin for educational spaces than other buildings. Recent events have shown that these essential facilities arevulnerable to severe accidents as places where thousands of children and young adults and even adults spend their best time of their life in there, So the structural and non-structural damage to these buildings leading to their closure. Regarding the inadequacy and precision of the previous codes, many schools in the country need to improve and increase resilience. Itshould be noted that the techniques used in retrofitting should minimize performance reduction during incidents. In this research, a school(Alghadir) located in Zanjan city in Iran built in 1984 will be investigated for seismic resilience evaluation. For this purpose, after structural modeling in OpenSEES software and with the change of the structural system , (1) existing school (2) school retrofitted with X-braced system, (3) school retrofitted with EBF system, and finally (5) school retrofitted with chevron braced system, the nonlinear analysis of mentioned structures are done. the 44 numbers of far-field earthquake records based on the FEMA-P695 recommendation were used for nonlinear analysis. Records are scale in accordance with the 2800 regulations and the output of the software opensees (maximum inter-story drift ratio) is given. The other step was Incremental Dynamic Analysis (IDA) of different structural types and extracting fragility and vulnerability curves. Finally with considering earthquake hazard level, recovery time and resilience indexes are obtained . The results show that retrofitting with X-braced system is the best option having the highest resiliency and the lowest losses. The results of this study could help stockholders how to make a decision on selection of the best option for retrofitting operations taking into account resiliency parameters, structural deficiency, and disaster risk reduction mitigations.

تاب آوري لرزه اي , تحليل ديناميكي فزاينده , مدرسه با اسكلت فولادي , زمان بازيابي , روش هاي بهسازي لرزه اي