چكيده به لاتين
Resilience is a new approach in earthquake engineering, which includes technical, organizational, social, economic, and environmental aspect. 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 are vulnerable 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. It should be noted that the techniques used in retrofitting should minimize performance reduction during incidents.
In this research, a high school located in Zanjan city in Iran built in 1981will be investigated for seismic resilience evaluation. For this purpose, after structural modeling in opensees software, first considering the uncertainty of steel materials and earthquake loading, and with the change of the structural system , (1) as-built school without masonry infill walls, (2) as-built school with masonry infill walls, (3) school retrofitted with X-braced system, (4) school retrofitted with EBF system, and finally (5) school retrofitted with chevron braced system, the nonlinear analysis of mentioned structures are done. the 22 number 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 as input to the Rt software. The other step was Incremental Dynamic Analysis (IDA) of different structural types and extracting fragility and vulnerability curves with considering materials uncertainty. Damage is given as input to the Rt software. Finally with considering earthquake hazard level uncertainty, recovery time uncertainty, initial losses uncertainty, resilience index uncertainty For reliability analysis, the First Order Reliability Method (FORM) and Sampling method were applied in Rt software. The results show that retrofitting with X-braced system is the best option having the highest resiliency and the lowest losses. Moreover, considering the effect of infill walls, it can be concluded that the damage to the structure would be decreased. 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.
Keywords: Resiliency, Reliability Analysis, Opensees, Rt, infill .
