مقاوم سازی لرزه ای توزیع ستون RC برای ساختمان مدرسه موجود Optimal seismic retrofitted RC column distribution for an existing school building

1. Introduction Many engineers established seismic design criteria for structures to reduce the damage caused by seismic activities. Considering worldwide population densities and social infrastructure systems, the most damaging earthquakes have frequently occurred in California in the western United States. Following the severe destruction or collapse of several hospital buildings during the San Fernando earthquake in 1971, California passed a bill [1] specifying that hospital buildings must remain functional after earthquakes. The follow-up bill in 1994, which was called “SB 1953” [2], stated that all key facilities of the society, including hospitals at the secondary healthcare facility level or higher and school buildings, must be evaluated for seismic performance and retrofitted accordingly. The seismic retrofitting of general buildings has been significantly improved. Starting from FEMA 273 [3], the Vision 2000 seismic retrofitting standard (SEAOC 1995, [4]) established guidelines for the seismic retrofitting of existing buildings and the performance-based design concept. ASCE41-06 [5] is being widely used today based on this and through FEMA 356 [6]. Buildings in the United States have been retrofitted according to the current seismic design and retrofitting criteria although technological evolution may require additional standards. While design techniques for seismic retrofitting have been improved, the actual construction site performance significantly varies depending on proficiency. Seismic performance may also differ. Therefore, overcoming these shortcomings is necessary to develop retrofitting techniques that would lead to increased work efficiency and produce standardized retrofitting materials to enable unskilled workers to perform fast and effective work. During an earthquake, the RC columns of a structure are generally subjected to lateral loads (shear loads) together with axial loads. Column failures may be caused by the lack of shear strength, bending strength, or ductility [7]. Studies on seismic retrofitting materials currently focus on these factors. The RC column seismic retrofitting material developed by Seo, Kim, and Kwon [8] is particularly considered excellent in terms of shear strength, ductility, and work efficiency. Therefore, the present study uses an optimization process to identify the most efficient locations to apply seismic retrofitting to RC columns in school buildings using the RC column seismic retrofitting material developed by Seo et al. [8].