• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.107-107
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• 2020

본 연구의 목적은 실제 규모의 초고층 건물을 고려하여 강우-유출 과정을 해석하고, 초고층 건물이 강우-유출 과정에 미치는 영향을 파악하는 것이다. 초고층 건물을 고려하기 위해 건물의 지붕과 벽면을 각각 독립적인 소유역이라 가정하여 분석을 수행하였다. 특히, 건물의 벽면 소유역에는 바람의 영향을 받아 비스듬하게 내리는 강우를 입력자료로 적용하였다. 각 소유역에서 발생하는 유출은 shot noise process 기반 강우 유출-모형으로 모의되었다. Shot noise process 기반 강우-유출 모형을 이용하여 초고층 건물의 벽면과 지붕에서 발생하는 유출을 독립적으로 모의할 수 있었다. 실험실 환경에서 건물 모형이 존재할 때의 강우-유출 과정을 관측하였으며, shot noise process 모형으로 모의한 유출수문곡선과 관측 유출수문곡선이 유사한 특성을 보이는 것을 알 수 있었다. 서울시 강남구에 위치한 실제 규모의 초고층 건물을 고려하여 유출수문곡선을 유도해본 결과, 첨두유출량이 기존 유출수문곡선과 최소 6.5%에서 최대 67.5%까지 차이나는 것으로 확인되었다. 본 연구의 결과는 초고층 건물이 다수 존재하는 도시유역의 강우-유출 해석 결과의 정확성을 향상시킬 수 있을 것으로 판단된다.

• Structural Engineering and Mechanics
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• v.87 no.4
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• pp.347-361
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• 2023

This research aims to assess the behavior of reinforced concrete (RC) residential buildings when moment-resisting frames (MRFs) are used as the lateral resisting system. This investigation was conducted using MIDAS Gen v.19.0. Buildings with various plan footprints (Square, Rectangular, Circular, Triangular, and Plus-Shaped), and different heights (15 m, 30 m, 45 m, and 60 m) are investigated. The defined load cases, the equivalent static lateral load pattern, and the response spectrum function were defined as stated by the American Standard (ASCE 7-16), the 1997 Uniform Building Code (UBC97), the Egyptian Code for Loads (ECP-201), and the European Standard (EC8). Extensive comparisons of the results obtained by the different codes (including the story displacement, the story drift, and the base shear) were undertaken; to assess the response of moment-resisting multi-story framed buildings under lateral loads. The results revealed that, for all study cases under consideration, both ECP-201 and EC8 gave smaller base shear, displacement, and drift by one third to one fourth, around one fourth, around one fifth, respectively for both the ELF and RSA methods if compared to ASCE 7-16 and UBC97.

• Computers and Concrete
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• v.32 no.5
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• pp.527-541
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• 2023

This paper emphasizes the use of CFT columns in frame structures subjected to strong horizontal forces and shows that the efficiency of using CFT columns is increased when the plastic design approach is adopted. Because the plastic design approach is based on redistribution of the force of the internal member, a double node for the rotational degrees of freedom, where the adjacent two rotational degrees of freedom can be connected by a non-dimensional spring element, is designed and implemented into the formulation. In addition, an accompanying criterion is considered in order to make it possible to describe the continuous moment redistribution in members connected to a nodal point up to a complete plastic state. The efficiency of CFT columns is reviewed in comparison with RC columns in terms of the cost and the resistance capacity, as defined by a P-M interaction diagram. Three representative frame structures are considered and the obtained results show that the most efficient and economical design can be expected when the use of CFT columns is considered on the basis of the plastic design, especially when a frame structure is subjected to significant horizontal forces, as in a high-rise building.

• International Journal of High-Rise Buildings
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• v.13 no.1
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• pp.85-95
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• 2024

A composite member made of concrete-filled steel tubes (CFT columns) has been recognized for its fire resistance due to the thermal mass effect of concrete inside the steel tube, as shown in various studies. In this study, the fire resistance performance of reinforced CFT columns under constant axial load was evaluated using finite element analysis with ABAQUS. For this purpose, the variables including cross-section size, steel tube thickness, and concrete cover thickness were set, and the temperature distribution in the column cross-section exposed to a standard fire was investigated using heat transfer analysis. Ultimately, a P-M interaction curve was obtained by evaluating the overall residual strength of columns, and the fire resistance time was determined by evaluating axial displacement-time responses due to the reduction in load capacity during fire through stress analysis.

• International conference on construction engineering and project management
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• 2024.07a
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• pp.1121-1128
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• 2024

Prominent general contractors (GCs) in Japan have historically maintained dedicated research and development (R&D) institutes that conduct comprehensive studies on structural engineering, construction techniques, and environmental management technologies. These research endeavors have evolved over time, reflecting the prevailing conditions and trends in the construction industry during each era. We examined changes in R&D activities over the past decade by analyzing R&D descriptions and statistical data contained in securities reports issued by 14 leading GCs using natural language processing. Our analysis revealed that over the course of the decade, R&D activities transformed significantly due to market dynamics and macro-environmental factors. For instance, during the 2000s, a surge in demand for high-rise condominium buildings led to an increased presence of related terminology in the 2009 fiscal year (FY) securities reports. However, this trend had declined by FY 2019. Notably, in FY 2019, there was an observable increase in R&D efforts concerning wood and cross-laminated timber applications. This can be attributed to the enforcement of laws and standardization measures that facilitated the proliferation of wood-based construction techniques in the 2010s. Throughout the 2010s, the primary concern of the Japanese construction industry was optimizing production processes to meet escalating domestic construction demands. A comparative analysis between 2009 and 2019 indicates a shift in focus, with fewer references to product innovation and a more pronounced emphasis on process innovation.

• Journal of the Korea Institute of Building Construction
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• v.20 no.3
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• pp.269-278
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• 2020

In this study, we analyzed the safety accidents that occurred in the apartment construction site and the correlations between the victims according to the type of work accidents through multiple correspondence analysis. There is a lack of disaster-related studies on apartment construction sites, the third most frequent building type in Korea, and most of them have used survey techniques. Therefore, the exploratory data analysis was conducted in industrial accident cause data, and derived the correlation analysis between each disaster victim through multiple correspondence analysis. The results of the study are summarized in two as follows. First, as the number of heights increased due to the high rise and complexity of apartments, the fall rate and mortality rate were high. In addition, deaths are mostly caused by very few experienced workers or those with more than 10 years of experience, resulting from safety training, lack of experience, and insensitivity to safety. Second, multi-correspondence analysis showed that most safety accidents can be prevented by wearing safety equipment, and following proper work process and its safety action. The key factors derived from this study can be used for safety education, supervision, and management in apartment construction sites.

• Journal of the Korea Institute of Building Construction
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• v.22 no.4
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• pp.391-402
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• 2022

With the number of social overhead capital(SOC) projects that introduce private capital on the rise, overseas construction global companies today need to establish and advance their overseas order strategies. In this context, the purpose of this study is to develop the public private partnership(PPP) capacity evaluation model for developing countries and use it for domestic overseas construction companies to establish strategies for overseas expansion. The PPP competency evaluation model analyzes the importance of PPP competency evaluation items and infrastructure environment competency evaluation items through a review of previous studies and an interview survey with overseas construction experts. Through the above analysis results and expert surveys, problems that may occur when overseas construction companies enter the PPP market were derived, and improvement measures were proposed. Countries with a high probability of overseas construction companies entering the PPP market were determined to be those that have a mature PPP system, low risk in construction, and a good entry environment with a high infrastructure market size and growth rate. In addition, a lack of PPP investment experience, the absence of information on the infrastructure environment, and a shortage of PPP experts were identified as problems when entering the overseas construction PPP market. As an improvement measure, it was suggested to enter in cooperation with domestic and foreign companies. In addition, a plan was proposed to develop a curriculum to secure experts in areas such as PPP finance and contracts and to provide PPP information for each country. These findings are expected to contribute to overseas construction companies proposing strategies for entering the overseas construction market and using them for overseas expansion strategies and policy establishment.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.4
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• pp.498-505
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• 2020

Aggregate occupies about 70-85% of the concrete volume and is an important factor in reducing the drying shrinkage of concrete. However, when constructing high-rise buildings, it acts as a problem due to the high load of natural aggregates. If the load becomes large during the construction of a high-rise building, creep may occur and the ground may be eroded. Material costs increase and there are financial problems. In order to reduce the load on concrete, we are working to reduce the weight of aggregates. However, artificial lightweight aggregates affect the interface between the aggregate and the paste due to its higher absorption rate and lower adhesion strength than natural aggregates, affecting the overall strength of concrete. Therefore, in this study, in order to grasp the interface between natural aggregate and lightweight aggregate by type, we adopted a method of measuring electrical resistance using an EIS measuring device, which is a non-destructive test, and lightweight bone. The change in the state of the interface was tested on the outside of the material through a blast furnace slag coating. As a result of the experiment, it was confirmed that the electric resistance was about 90% lower than that in the air-dried state through the electrolyte immersion, and the electric resistance differs depending on the type of aggregate and the presence or absence of coating. As a result of the experiment, the difference in compressive strength depending on the type of aggregate and the presence or absence of coating was shown, and the difference in impedance value and phase angle for each type of lightweight aggregate was shown.

• Journal of the Korea Institute of Building Construction
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• v.10 no.5
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• pp.113-119
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• 2010

Fire resistance and field tests for high-strength concrete(HSC) of 80MPa were carried out to evaluate whether or not it shows the same material properties even in the field condition of being mass-produced and supplied. As a result, it was found that fire resistant HSCs containing composite fiber(NY, PP) of 0.075% have great resistance to fire and spalling. In the field test, before the pumping air contents, slump flow, U-box, L-flow, compressive strength, gap of hydration temperature of interior and exterior of specimen and placing ratio per hour satisfied the required properties of HSC. However, after the pumping of HSC, as slump flow and L-flow were slightly less than required criterion, they need to be improved. In terms of hydration temperature of HSC, it was found to satisfy the related criterion. Packing ability as well as placing ratio per hour of HSC, which was about $44m^3$, show outstanding results. If slump flow of developed ternary HSC is improved after the pumping it can be useful for the construction of high-rise buildings.

• Land and Housing Review
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• v.3 no.4
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• pp.415-421
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• 2012

In case of Korean housing complex, there became more mixed arrangement of buildings with different number of layers for a variety of urban skyline, recently. For example, around 33% of the construction sites of 'A' public corporation have gaps of more than 4 layers between high-rise buildings and low-rise ones in the same site, according to the survey. Generally, construction duration of the housing complex is estimated based on the layers of the highest building. Due to this baseline, whole construction duration could be extended so that the project cost could be increased. Therefore, framework duration of higher-rise buildings should be reduced to secure the feasibility of the project. On the other hands, these shortenings could adversely harm the feasibility in some cases because there are a wide range of combinations of the buildings with different number of layers in designing housing complex. Therefore, this study shows the results of analysis on effects of framework time shortening on the cost in housing complex project. Moreover, this could set the baseline of checking possibilities in condensing the construction duration of projects with buildings of different layers by supplying comprehensive database.