Journal of Asian Architecture and Building Engineering ISSN: (Print) (Online) Journal homepage: https://www.tandfonline.com/loi/tabe20 Development of a risk assessment model against disasters in high-rise buildings and results of a building simulation analysis Tae-Young Kim , Gi-Sung Han , Boo-Sung Kang & Kyung-Hoon Lee To cite this article: Tae-Young Kim , Gi-Sung Han , Boo-Sung Kang & Kyung-Hoon Lee (2021): Development of a risk assessment model against disasters in high-rise buildings and results of a building simulation analysis, Journal of Asian Architecture and Building Engineering, DOI: 10.1080/13467581.2020.1869016 To link to this article: https://doi.org/10.1080/13467581.2020.1869016 © 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group on behalf of the Architectural Institute of Japan, Architectural Institute of Korea and Architectural Society of China. Published online: 27 Jan 2021. Submit your article to this journal Article views: 246 View related articles View Crossmark data Full Terms & Conditions of access and use can be found at https://www.tandfonline.com/action/journalInformation?journalCode=tabe20 JOURNAL OF ASIAN ARCHITECTURE AND BUILDING ENGINEERING https://doi.org/10.1080/13467581.2020.1869016 ARCHITECTURAL PLANNING AND DESIGN Development of a risk assessment model against disasters in high-rise buildings and results of a building simulation analysis Tae-Young Kim a , Gi-Sung Han b , Boo-Sung Kang c and Kyung-Hoon Lee a a Department of Architecture, Korea University, Seoul, Republic of Korea; bProgram in Unban Regeneration, Korea University, Seoul, Republic of Korea; cDepartment of Architectural Design, Seoul National University of Science and Technology, Seoul, Republic of Korea ABSTRACT ARTICLE HISTORY This study developed a method to assess a building’s risk against disaster, tentatively named the Korean Integrated Disaster Evaluation Simulator (K-IDES). Based on previous studies analyzing FEMA’s risk management series in the US, the FEMA IRVS was selected as a case study for developing a framework for the K-IDES. Through the comparative analysis of domes­ tic building design guides, codes, and special legislation related to disasters, a risk assessment methodology for quantitative results was developed. The assessment method consists of a classification system, a calculation for the quantification of risk, and a simulation in which the developed checklist for the K-IDES is applied to similar types of high-rise buildings to validate its accuracy. The final goal was to systemize an integrated risk management strategy for a building against disasters, checking for vulnerable areas from the conceptual stage of the design, and to utilize the risk management strategy after construction. Received 3 July 2020 Accepted 22 December 2020 1. Introduction 1.1. Purpose and background As of 2018, Korea ranks 11th in the world in the density of high-rise buildings (buildings more than 150 m in height), with approximately 400 such buildings (under construction or completed, based on The Council on Tall Buildings and Urban Habitat) (CTBUH). The con­ centration of multifunction buildings in urban areas and the continuous increase in the number of highdensity and functionally complex high-rise buildings in older cities can become a threat in a disaster, specifi­ cally if buildings and property incur physical damage (Lee 2009, 2012). The 9/11 terrorist attack in New York City is a good example. In addition to the collapse of the World Trade Center (WTC), the damage also spread to the surrounding high-rise buildings, which ampli­ fied the consequences of the explosion. The facade and structure were further damaged by collapsing debris, and fire caused more loss and destruction (FEMA 2007b). To reduce risk and loss in the case of a disaster, studies have been conducted domestically to improve buildings’ performance against disasters by strength­ ening standards for material, equipment, and evacua­ tion against fire, as well as reinforcing structural standards after seismic occurrences (Su, Yoon, and Ju 2012; KOSIS). However, most of these studies have focussed on partial improvements, where the build­ ings need to be evacuated in the event of an individual disaster. Studies on evaluation criteria, evaluation CONTACT Kyung-Hoon Lee kh92lee@korea.ac.kr KEYWORDS risk management method of US Federal Emergency Management Agency; risk assessment method against disaster in high-rise building; building design guidelines against disaster methods, and design guides for reinforcing buildings against various catastrophic disaster risks are insuffi­ cient (Kang et al. 2010; Kang, Park, and Lee 2011; Choi et al. 2012; Kang and Lee 2014; Kang et al. 2018, 2019). This study aims to construct a disaster risk assessment model (tentatively named the Korean Integrated Disaster Evaluation Simulator or K-IDES) for Korean high-rise buildings to fill this research gap (Kim and Lee 2018a, 2018b). Preliminary studies have been conducted on the risk management series of US Federal Emergency Management Agency (FEMA) to guide risk manage­ ment and quantitative risk analysis, with the goal of building a risk assessment system against various disasters (Kim and Lee 2018a, 2018b). Scenarios such as explosions, fire, earthquakes, and typhoons – all likely to occur in Korea – have been studied (KOSIS). The risk assessment method of the K-IDES was established by comparing and analyzing the evaluation methods derived from a case study on the FEMA and through the application of suitable parts to domestic building codes, guidelines, and legislation related to disaster management (Kim and Lee 2018a, 2018b). Based on previous studies, we derived criteria, evaluation items, and evaluation methods for assessing the risk of high-rise buildings against disasters and analyzed simulation results for an actual urban high-rise building in Korea by using the proposed method. The results suggest future research directions for improving the accuracy and utilization of evaluation models. Department of Architecture, Korea University, Anamro 145, Seongbuk-ku, Seoul, Korea, 02841 © 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group on behalf of the Architectural Institute of Japan, Architectural Institute of Korea and Architectural Society of China. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. 2 T.-Y. KIM ET AL. 1.2. Scope and method 1.2.1. Analysis of precedent research The concept of disaster risk assessment in buildings was established through the analysis of the contents of the design guide, risk assessment method, and refer­ ence manual for risk prevention of buildings against terrorism developed by the FEMA of the US Department of Homeland Security (FEMA 2005a, 2005b, 2007a, 2007b, 2009, 2011; FEM 2011). The spe­ cific method of evaluating risk against disaster in the development of the K-IDES was applied to evaluation criteria, evaluation quantification, and the analysis of the evaluation results based on FEMA’s integrated rapid visual screening (IRVS) for integrated risk assess­ ment against various disasters (Kim and Lee 2018a). 1.2.2. Analysis of domestic building guides and evaluation criteria related to disasters To develop evaluation criteria and evaluation items for domestic buildings, the High-Rise Building Design Guidelines of the Seoul Metropolitan Government; the Anti-Terrorism Building Design Guidelines in MultiPurpose Facilities of the Ministry of Land, Infrastructure, and Transportation; the Special Act on Management of Disasters in Super High-Rise Buildings and Complex Buildings With Underground Connections, and the Preliminary Disaster Impact Assessment Consultation Guidelines of the Ministry of Public Safety and Security were analyzed, classified by item, and compared by content (Ministry of Government Legislation 2015; Ministry of Public Safety and Security 2014; Seoul Metropolitan Government 2009; Ministry of Land, Infrastructure and Transportation 2010, 2017). The results were then used to develop detailed evaluation criteria for the K-IDES (Kim and Lee 2018a). 1.2.3. Development of checklist for the K-IDES’ risk assessment The first step was to check the classification system of the risk assessment field in the IRVS evaluation system and to review the differences in building codes and Figure 1. The framework of the study. design guidelines regarding high-rise buildings’ pro­ tection against disaster between the two countries. The second step of assessment of the items’ category classification system was centered on the planning element of buildings, and details of each item reflect­ ing domestic codes and design guidelines were pre­ pared. Finally, the criteria that could be selected for each item was divided into five attribute options (Kim and Lee 2018b). 1.2.4. Establishment of a method to quantify the weight and risk by items Risk quantification uses expert interviews to deter­ mine the assessment rate of environmental threats and a building’s physical vulnerability to disaster (Kang, Park, and Lee 2011; Choi et al. 2012; Kang and Lee 2014). The risk score is computed using the risk calculation method devised by FEMA (2011). The value chosen for each item is based on the isometric scale of five intervals and uses a uniform scale for each item, but they are differentiated by applying weighted values to the important items (Kang, Park, and Lee 2011; Choi et al. 2012; Kang and Lee 2014; Kim and Lee 2018b). The selection of weighted items and the determination of weights were based on prioritizing important items through group interviews with experts, and the weights of the selected items were determined using the frequency of item selec­ tion by the experts (Kim and Lee 2018b; Kang et al. 2018, 2019). 1.2.5. Simulation test and results analysis through the K-IDES and IRVS To verify the evaluation model, nine high-rise buildings with completion dates of less than 10 years and a height of 100 m or more were selected from three cities: Seoul, Incheon, and Busan. Environmental indi­ cators were simulated using FEMA IRVS and the K-IDES. Through the comparative analysis of their assessed risk results, the limitations of the IRVS were examined. By analyzing the risks by disaster through the K-IDES, the exposure of high-rise buildings in Korea to disaster and JOURNAL OF ASIAN ARCHITECTURE AND BUILDING ENGINEERING major risk areas for reflecting design guidelines to prepare for disaster was identified. This study confirms the evaluation method and eva­ luation items of the K-IDES based on two existing stu­ dies and presents the results of a simulation analysis on domestic buildings using the K-IDES, which was devel­ oped as part of a disaster risk assessment program. 2. Review of precedent research 2.1. Analysis of IRVS risk assessment The IRVS, developed by the FEMA, refers to a quantifiable risk assessment of critical vulnerability in various types’ buildings against a terrorist attack or natural disasters. Risk scoring involves calculating the individual risk for each disaster and integrating these individual risks. This risk quantification is accomplished by assessing each of the following-tiered categories: consequence, threat, and vulnerability (FEMA 2011; FEM 2011). The consequence is the assessment of the degree of damage to a building (property) and the loss of the building’s operating system due to a disaster. The threat is the assessment of the degree of hazard for a natural disaster, social disaster, potential events, signs, and behavioral threat factors that lead to loss of assets, injury of individuals, or damage to organiza­ tions (FEMA 2011; FEM 2011). Lastly, vulnerability is the assessment of the vulnerable factors of the building that can cause damage to assets in the event of a disaster. Vulnerability is further divided into eight subcategories: site, architecture, envelope, structure, MEP, fire, security, and cybersecurity. Vulnerability assessment consists of evaluating the application level of a design guide to protect a building from disaster (FEMA 2005a, 2011). Risk scores by the disaster are calculated by multiplying the evaluated values of consequence, threat, and vulnerability to sum up the value by assessing each item in these categories. Disaster areas for buildings’ risk assessment and calcu­ lation formulas for the risk scoring in the IRVS are described in Table 1. 2.2. Limitations of IRVS application on domestic buildings First, as the IRVS model is designed to cover all types of buildings, it is difficult to derive differential results when evaluating buildings with similar uses or charac­ teristics. The error rate is especially high in the case of fire, security, and cybersecurity subcategories, as the evaluation items consist of qualitative analysis of build­ ings’ contents, and thus, a lot depends on the evalua­ tor’s subjective choices (FEMA 2011). Furthermore, the response options of most evaluation items are limited to two, unlike other items that allow five or more selections, and thus, these evaluations reduce the sen­ sitivity and accuracy of risk assessment (FEMA 2011). Regardless of the ratio of the number of evaluation items in consequences, threat, and vulnerability, the sum of the maximum values can be 10, and in the case of an explosion, there are 3 evaluation items each in consequences and threat, which leads to their weight being 25 times that of the 79 evaluation items in vulnerability. Therefore, the impact of the risk assess­ ment factors on buildings’ planning is insignificant, making it difficult to find a link between disaster risk and planning elements. Second, the error in the IRVS model is due to a change in the beta value of the individual risk calculation formula, which is caused by displace­ ments in values below 0.9 and above 0.9. If the alpha value is above 0.9, the beta value is fixed at 3.0, but when the alpha value is close to 0.9, the beta value is closer to 5. When the beta value is close to 5, it changes from 5 to 3, and the risk score rapidly increases. For example, when Ci = 8.9, Ti = 9, Vi = 10 and Ci = 9, Ti = 9, Vi = 10, the beta value changes from 0.89 to 0.9 at a difference of 0.1 and the risk score dramatically rises from 3.82 to 9.32. There is no evi­ dence of a sharp increase in the risk score due to the differences in displacement in these beta values, and this can be interpreted as an error. The functional relationship between the beta value and the alpha value that determines the beta value required to calculate the risk score is described in Figure 2. Table 1. IRVS composition and risk assessment method against disasters. Manmade hazards Categories Blast CBR Consequence 3* 3* Threats 3* 3* Vulnerability 79* 63* Individual formula ffiffiffiffiffiffiffifficalculation ffiffiffiffiffiffiffiffi pffiffiffiffiffiffirisk Ri ¼ Bi Ci � Ti � Vi Natural hazards Fire 3* 3* 48* Seismic 3* 3* 69* 3 Wind 3* 3* 71* Total sum Remark Flood Max Min 3* 10 0 * number of questions 3* 10 0 51* 10 0 Integrated risk calculation sffiffiffiffiffiffiffiffiffiffiffiffi formula n2 n1 P n1 R ¼/ Ri i¼1 Required values to analyze individual disaster scenarios Required values to calculate integrated disaster scenarios Ri Risk score of the ith disaster scenario R Aggregated risk Ci Consequence rating of the ith disaster scenario Ri Risk score of the ith disaster scenario Ti Threat rating of the ith disaster scenario n2 Total number of disaster scenarios Vi Vulnerability rating of the ith disaster scenario n1 Power value 10 αi Alpha value, αi = Min (Ci, Ti, Vi)/Max (Ci, Ti, Vi) / Scaling factor 1/12 βi Beta value, βi value depends on value, If αi≤0.1, βi=4.0, If αi, ≥0.9, βi = 3.0, If 0.1< αi
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