Ho-Jeong Kim

Fragility Assessment for Cladding of Industrial Buildings Subjected to Extreme Wind

This paper presents a fragility assessment for the cladding in steel-framed constructions built in extreme wind speed regions. A fragility assessment methodology is developed to assess the performance of sandwich wall/roof panels and openings subjected to wind-induced building pressures. The majority of industrial buildings in Korea are of steel-framed construction. A review of the performance of industrial buildings after recent typhoons Maemi, Kompasu and Bolaven has shown that most of wind damage originated in the building envelope. The goal of this study is to develop a fragility model for building cladding, using available resistance test data, developed wind load statistics, and a recent building code. Six baseline structures considering different roof shapes, building sizes and geographic locations were investigated using a fully probabilistic Monte Carlo simulation engine. The fragilities of each baseline building considering four different levels of damage were developed as a function of a 3-second gust wind speed. The fragility assessment methodology described in this paper can be used to measure the performances of industrial buildings in extreme wind speed regions, as well as to provide information for risk and loss assessments.

Evaluation of Extreme Wind Fragility for Balcony Windows Installed in Mid/Low-Rise Apartments

2002년부터 2011년까지 자연재해로 인한 피해액은 2011년 화폐기준으로 약 21조 2천억 원에 이른다(NEMA, 2011). 이 중 태풍, 돌풍과 같이 강풍 동반 재해는 전체 피해액의 약 64% 정도에 이르는 심각한 피해를 야기하고 있다. 2012년 통계청의 자료를 살펴보면 아파트는 전국 17,733,831 주택가구수 중 약 47%의 높은 비중을 차지하고 있는 대표적 인 주거문화임을 알 수 있다. 아파트는 2005년 개정된 건축법 시행령(MOLIT, 2005) 적용여부에 따라 분류될 수 있다. 2005년 이전의 아파트는 발코니의 용도변경이 건축법적으로 허용되지 않았기 때문에 통상 창호 설치 업체에 의하여 발코 니 창호가 설치되었다. 이 당시 아파트에 적용된 발코니 창호 는 일반적으로 창호유리에 대한 안전성이 검토되고 설치되었 으나 Fig. 1에 보이는 것과 같이 태풍 등으로 인한 강풍에는 매우 취약한 것으로 파악된다(Kim, 2007). Abstract

Quantitative Wind Risk Assessment for Low and Mid-Rise Apartment Buildings Based on a Probabilistic Model

This study develops a risk assessment model and evaluates wind risk to predict typhoon-induced damage. A wind risk assessment model was developed using the convolution of a wind hazard model and a wind fragility model, and both models were developed using the Monte Carlo simulation based on probability theory. Wind risk was quantitatively evaluated using the window system and part of the exterior materials installed in low and mid-rise apartments. Wind risk was compared according to regional (namely Busan, Daegu, Daejeon, and Seoul), geomorphological (namely topographic factor and exposure category), and morphological factors of buildings (height, roof tilt angle, and number of housing units) in order to evaluate relative influence. By employing the risk assessment model this study compared 432 wind risks and found that the most influential factor was exposure category, followed by the topographic coefficient, building height, target site of assessment, roof tilt angle, and number of housing units (in that order). The wind risk assessment model in this study could be used as basic data for the estimation of damage driven by wind and for the establishment of damage reduction measures, combined with the economic value of apartment buildings′ exterior materials and interior contents.

Fragility Assessment of Vinyl Greenhouses and Livestock Sheds Subjected to Volcanic Ash Fall Hazards

In this study, fragility functions are developed to estimate expected volcanic ash damage to vinyl greenhouses and livestock sheds among common agricultural facilities in South Korea. The fragility functions are derived through the FOSM (first-order second-moment) analytical approach based on the thickness distribution of volcanic ash observed in the 1980 eruption of Mt. Saint Helens in the USA and on agricultural facility codes and specifications in South Korea. In this study, the volcanic ash fragility functions evaluated represent the conditional probability of failure of vinyl greenhouses and livestock sheds over the full range of volcanic ash loads. For the evaluation, 4 types (i.e., automated, single span, tree crop, and double span types) of multi-hazard resisting vinyl greenhouses and 3 types (i.e., standard, coastal, and mountain types) of livestock sheds conventionally utilized in South Korea are considered. All volcanic ash fragility functions estimated in this study are fitted using parameters of the lognormal CDF (cumulative distribution function), and the obtained parameters are compiled into a database for use in the future. The volcanic ash fragility functions developed in this study are intended to be used to evaluate potential risks and losses from volcanic eruptions around the Korean Peninsula.

A Comparative Study on Residential Satisfaction in Relation to Spatial Characteristics of the Residential-Commercial Area in Urban Seoul Focused on the Analysis of Seorae Village of Banpo 4-dong and the Garosu-gil area of Sinsa-dong

This study compares residential satisfaction in terms of local urban spatial characteristics between Seorae Village of Banpo 4-dong, and the Garosu-gil area of Sinsa-dong, both of which display distinct local identities and instances of mixed use. The results can be summarized as follows: First, residential satisfaction was higher in Seorae Village, Banpo 4-dong, than in the Garosu-gil area, Sinsa-dong, across all statistically significant criteria which were related to urban space characteristics such as the effective utilization of shared external space through block-unit development, independent territoriality of commercial and residential areas, qualitative completeness of green and street spaces. Second, the most influential factors affecting residential satisfaction were amenity, neighborhood, and safety in descending order, with amenity and safety showing a high degree of correlation. The amenity factor was significantly affected by the quality of transition areas situated between individual housing and urban space, and the neighborhood factor was closely related to community awareness. Third, while the commercialization of residential areas was largely regarded in a positive light, satisfaction regarding the street space in residential and commercial areas showed low correlation to overall residential satisfaction. Securing parking space and green space, and resolving the noise issue were identified as areas in need of improvement associated with the commercialization of residential areas, and they were major causes for residents in Sinsa-dong near the Garosu-gil area to relocate.

Assessment of Extreme Wind Risk for Window Systems in Apartment Buildings Based on Probabilistic Model

In this study, a coupled probabilistic framework is developed to assess wind risk on apartment buildings by using the convolution of wind hazard and fragility functions. In this framework, typhoon induced extreme wind is estimated by applying the developed Monte Carlo simulation model to the climatological data of typhoons affecting Korean peninsular from 1951 to 2013. The Monte Carlo simulation technique is also used to assess wind fragility function for 4 different damage states by comparing the probability distributions of the window systems resistance performance and wind load. Wind hazard and fragility functions are modeled by the Weibull and lognormal probability distributions based on simulated wind speeds and failure probabilities. The modeled functions are convoluted to obtain the wind risk for the different damage levels. The developed probabilistic framework clearly shows that wind risk are influenced by various important characteristics of terrain and apartment building such as location of building, exposure category, topographic condition, roof angle, height of building, etc. The risk model presented in this paper can be used as tools to predict economic loss estimation and to establish wind risk mitigation plan for the existing building inventory.

Fragility Assessment of Agricultural Facilities Subjected to Volcanic Ash Fall Hazards

Abstract This paper presents findings from the assessment of the volcanic ash fragility for multi-hazard resisting vinyl greenhouse and livestock shed among the agricultural facilities. The volcanic ash fragility was evaluated by using a combination of the FOSM (first-order second-moment) method, available statistics of volcanic load, facility specifications, and building code. In this study, the evaluated volcanic ash fragilities represent the conditional probability of failure of the agricultural facilities over the full range of volcanic ash loads. For the evaluation, 6 types(ie., 2 single span, 2 tree crop, and 2 double span types) of multi-hazard resisting vinyl greenhouses and 3 types(ie., standard, coast, and mountain types) of livestock sheds are considered. All volcanic ash fragilities estimated in this study were fitted by using parameters of the GEV(generalized extreme value) distribution function, and the obtained parameters were complied into a database to be used in future. The volcanic ash fragilities obtained in this study are planning to be used to evaluate risk by volcanic ash when Mt. Baekdu erupts.

A Study on the 19th-Century Depiction of Parallel Projection in Donggwoldo

Abstract Donggwoldo, or ″Painting of Eastern Palaces,″ is a late Joseon documentary painting of Changdeokgung Palace, its rear garden Huwon, and Changgyeonggung Palace. It falls under the category of 19th century map paintings. In Donggwoldo, a contemplative mode of depiction based on parallel projection is used to create a multi-perspective spatial structure; however, the focus is less on achieving a unified mode of depiction and more on adhering to the tradition of Joseon paintings that used artistic techniques selectively to fulfill specific purposes. In contrast to their actual layout, the buildings of the palaces followed a strict order of arrangement and positioning based on the traditional principles of architectural composition. While various sections of the palace are accurately partitioned and clearly reflect hierarchy, they are also individually magnified or scaled down to restructure the buildings into near-ideal forms of palatial architecture. This conceptual interference makes Donggwoldo transcend its practical function of documentation, and suggests that the aim was less on creating an accurate depiction of the actual palaces, but rather on effectively reflecting the architectural ideology behind their creation.

Wind Fragility Development for Roof Sheathing System of Light-Frame Wood Structure

This paper presents a fragility assessment for roof sheathing in light-frame wood constructions built in high wind regions. A fragility methodology is developed to assess the performance of roof sheathing subjected to wind-induced building pressures. The goal of this study is to develop a fragility model for roof sheathing system using available resistance test data, recently developed wind load statistics and building code. A typical baseline building considering different geographic locations is investigated using a Mote Carlo simulation method. Fragilities of the baseline building considering three different levels of damages are developed as a function of 3 second gust wind speed. The fragility methodology described in this paper can be used to estimate physical vulnerability and financial loss of light-frame wood construction in high wind regions.