Evaluation of Extreme Wind Fragility of Balcony Window Systems in Apartments

강풍에 대한 아파트 발코니 창호 시스템의 취약도 평가

In this paper, the wind fragility is estimated for balcony window systems of the apartment in the multi-story residential building. The wind fragility is defined as the probability of failure of a system over the entire range of wind speeds to which the system could be exposed. In this study, eight prototypes of balcony window systems were selected to estimate their wind fragility using a Monte Carlo simulation, which is the most commonly applied method to develop the wind fragility. All estimated fragility curves were represented by log-normal cumulative distribution parameters; the mean and standard deviation values. With the aim of determining the crucial factors affecting wind fragility, five factors were considered herein: the exposure categories(B, C, and D according to ASCE 7-10), building height, building roof type, unit plan area of the apartment, and increasing internal pressure. The results show that wind fragility is worsened as the exposure category changes from B to D and the building changes from low-rise to high-rise. In terms of roof type, a gable roof is more vulnerable than a flat roof. A gable roof takes a heavier wind load on the wall than a flat roof, because ASCE 7-10 provision specifies lower pressure coefficients for roof angles of less than $10^{\circ}$, such as in flat roof. As unit area of the plan increases, the wind fragility is worsened because of the increasing number of windows. In addition, the probability of window failure is also increased proportionally. In future research, the estimated wind fragility will be validated using post-disaster survey data.