Assessment on Economic Effect of Seismic Retrofit to RC School Building Considering Expected Damage

In 2016 and 2017, earthquakes in Korea caused major seismic damage to school buildings, it is necessary securing seismic performance to reduce damages. Minimum quantity of retrofit satisfying target performance is lowest in retrofit cost but might be higher repair cost than high quantity of retrofit scheme. This study aimed to assess economic effect of seismic retrofit in reinforced concrete (RC) school buildings considering expected cost that sum of retrofit cost and repair cost. Prototype of three-stories RC moment-resisting frame with partial masonry infills was selected for the school building, four retrofit schemes were selected according to the number of exterior steel braces. The expected damage was derived through damage of structural and non-structural components, and the expected cost of each retrofit scheme is normalized and compared by seismic damage of as-built building. The results show that retrofit scheme with 6 retrofit places satisfies target performance and is the minimum quantity of retrofit, but the repair cost is increased due to damage, the expected cost is higher than the 8 or 12 retrofit places.