https://doi.org/10.12652/Ksce.2024.44.2.0133

이헌우(Lee, Heon-Woo) ; 노진원(Noh, Jin-Won) ; 김영찬(Kim, Young-Chan) ; 허종완(Hu, Jong-Wan)

The purpose of this study is to propose a new material called polyketone to overcome the limitations of polyurethane, which is currently used as a compression member in the field of earthquake-resistant structures. Although existing polyurethane has excellent elastic properties, it tends to be insufficient to recover the displacement that occurs in the structure. On the other hand, polyketone has excellent strength performance and is attracting attention as an eco-friendly material. In order to evaluate the compression properties of polyketone, which has these advantages, we would like to conduct a comparative experiment with polyurethane that was previously used. The speed dependence of polyketone was identified through simple compression experiments and experimental speed changes under repeated loading conditions, and additional compression behavior was applied to confirm compression behavior characteristics. Polyketone showed compressive strength about 10 times higher than that of polyurethane, and its excellent recovery characteristics were demonstrated by its deformation recovery ability about 14 times higher at relatively small displacements.

https://doi.org/10.12652/Ksce.2024.44.2.0141

유찬호(Yoo, Chan Ho) ; 김지수(Kim, Ji-Su)

In this study, micro CT images were used to confirm the tensile fracture strength according to the pore distribution characteristics of 3D printed concrete. Unlike general specimens, concrete structures printed by 3D printing techniques have the direction of pores (voids) depending on the stacking direction and the presence of filaments contact surfaces. Accordingly, the pore distribution of 3D printed concrete specimens was analyzed through quantitative and qualitative methods, and the tensile strength by direction was analyzed through a finite element technique. It was confirmed that the pores inside the 3D printed specimen had directionality, resulting in their anisotropic behavior. This study aims to analyze the characteristics of 3D concrete printing specimen and correlate them with simulation-based mechanical properties to improve performance of 3D printed material and structure.

https://doi.org/10.12652/Ksce.2024.44.2.0149

장동민(Jang, Dongmin) ; 박성원(Park, Sung Won)

Severe casualties and property damage are occurring due to urban floods caused by extreme rainfall. However, there is a lack of research on preparedness, appropriate estimation of flood damages, assessment of losses, and compensation. Particularly, the flood damage estimation methods used in the USA and Japan show significant differences from the domestic situation, highlighting the need for methods tailored to the Korean context. This study addresses these issues by developing an optimized flood damage estimation technique based on the building characteristics. Utilizing the flood prediction solution developed by the Korea Institute of Science and Technology Information (KISTI), we have established an optimal flood damage estimation technology. We introduced a methodology for flood damage estimation by incorporating vulnerability curves based on the inventory of structures and apply this technique to real-life cases. The results show that our approach yields more realistic outcomes compared to the flood damage estimation methods employed in the USA and Japan. This research can be practically applied to procedures for flood damage in urban basement residences, and it is expected to contribute to establishing appropriate response procedures in cases of public grievances.

https://doi.org/10.12652/Ksce.2024.44.2.0161

유재웅(Yu, Jae-Ung) ; 권윤정(Kwon, Yoon Jeong) ; 박민우(Park, Minwoo) ; 권현한(Kwon, Hyun-Han)

A Copula approach has the advantage of providing structural dependencies for representing multivariate distributions for the hydrometeorological variable marginal distribution involved, however, copulas are inflexible for extending in high dimensions, and satisfy certain assumptions to make the dependency. In addition, since the process of estimating design rainfall under the future climate associated with durations given a return period is mainly analyzed by 24-hour annual maximum rainfalls, the dependency structure contains information only on the daily and sub-daily extreme precipitation. Methods based on bivariate copula do not provide information for other duration's dependencies, which causes the intensity to be reversed. The vine copula has been proposed to process the multivariate analysis as vines consisting of trees with nodes and edges connecting pair-copula construction. In this study, we aimed to downscale under climate change to produce sub-daily extreme precipitation data considering different durations based on vine copula.

https://doi.org/10.12652/Ksce.2024.44.2.0173

김종천(Kim, JongChun) ; 황석환(Hwang, Seokhwan) ; 정종호(Jeong, Jongho)

In recent, there has been a trend toward primarily utilizing data-driven models employing artificial intelligence technologies, such as machine learning, for flood prediction. These data-driven models offer the advantage of utilizing pre-training results, significantly reducing the required simulation time. However, it remains that a considerable amount of flood data is necessary for the pre-training in data-driven models, while the available observed data for application is often insufficient. As an alternative, validated simulation results from physically-based models are being employed as pre-training data alongside observed data. In this context, we developed a flood mapping accelerator to generate flood maps for pre-training. The proposed accelerator automates the entire process of flood mapping, i.e., estimating flood discharge using HEC-1, calculating water surface levels using HEC-RAS, simulating channel overflow and generating flood maps using RAS Mapper. With the accelerator, users can easily prepare a database for pre-training of data-driven models from hundreds to tens of thousands of rainfall scenarios. It includes various convenient menus containing a Graphic User Interface(GUI), and its practical applicability has been validated across 26 test-beds.

https://doi.org/10.12652/Ksce.2024.44.2.0183

김한임(Kim, Hanim)

An environmentally-friendly nanocoating method that effectively adds flame retardant(FR) and gas shielding properties to combustible polymeric construction materials such as flexible polyurethane (PU) foam was studied. Naturally-driven two-dimensional(2D) nanomaterials such as graphene oxide (GO) can exhibit liquid crystalline (LC) properties in aqueous solutions, enabling uniform coatings on the various substrates including 3D-porous foams. LC phase-assisted coating serves as 3D-scaffold, facilitating the introduction of small molecules having antioxidant capabilities such as dopamine which is to form uniformly stacked FR coating. Additionally, the structural characteristics of the 2D-materials can effectively hinder the migration of toxic gases and flammable substances in the gas phase generated during combustion. This LC phase flame retardant coating technology could be a new approach to provide environmentally friendly and effective flame retardant and gas barrier properties to various types of polymeric materials.

https://doi.org/10.12652/Ksce.2024.44.2.0191

노유진(Noh, Yujin) ; 박종전(Park, Jongjeon) ; 오경석(Oh, Kyuoung Seok) ; 장서용(Jang, Seo-Yong) ; 고준영(Ko, Junyoung)

In this study, three-dimensional finite element analysis was used to analyze the behavior of existing and reinforcing piles according to the pile support conditions for vertical extension remodeling. Cap support conditions (group pile, piled raft foundation) and pile tip conditions (rock, soil embedment) were considered as factors influencing existing and reinforcing piles behavior. For the quantitative analysis of existing and reinforcing piles, the displacement, load distribution ratio, and axial force by depth according to the analysis stage were analyzed. As a result of the analysis, it was confirmed that the largest settlement occurred in the reinforcing pile due to the pre-loading method. In particular, a large amount of settlement occurred in group piles regardless of the embedment conditions. In the piled raft foundation, it was confirmed that the displacement and load distribution ratio of existing piles and reinforcing piles were reduced due to the influence of the raft. The axial force by depth showed a difference between group pile and piled raft foundation, which appears to be a major factor affecting displacement and load distribution ratio. Based on the numerical analysis results, it was confirmed that cap support conditions and pile tip embedment conditions should be considered in the design of pile foundations for vertical extension remodeling.

https://doi.org/10.12652/Ksce.2024.44.2.0203

하용수(Ha, Yong-Soo) ; 김윤태(Kim, Yun-Tae) ; 오명학(Oh, Myounghak)

Ports often suffer pavement damage due to soft ground and heavy equipment operations, leading to issues such as differential settlement and cracks. In this study, we developed port concrete blocks and applied them to a port in two configurations to figure out settlement characteristics. Falling weight deflectometer (FWD) tests on asphalt pavement and block pavements were conducted to figure out deflection and bearing capacity. The block pavement with the cement treated base showed improved bearing capacity with the port operation since lower settlements were detected than asphalt pavement. In the cement treated base, the relative deflection ratio to asphalt concrete pavement was less than 1, indicating enhanced bearing capacity. LiDAR measurements identified multiple settlements in the crushed-stone base due to surface loads after construction. Both relative deflection ratio and LiDAR measurements suggested that block pavement can be widely applied to various port sites with its applicability and bearing capacity of cement-treated base.

https://doi.org/10.12652/Ksce.2024.44.2.0215

박재현(Park, Jaehyon) ; 김경국(Kim, Kyeongkuk) ; 김경석(Kim, Kyeongseok)

The government is encouraging the expansion of renewable energy facilities through national renewable energy policy. However, the installation of renewable energy generation facilities has led to local resident complaints due to landscape degradation, electromagnetic wave emission, real estate devaluation, and environmental pollution. This creates conflicts between power project developers and residents, making the progress of projects more difficult. This study applies non-cooperative game theory to analyze eight cases of renewable energy projects where conflicts between developers and residents were resolved through resident’s investment participation. By accepting investments from local stakeholders, residents achieved returns ranging from a maximum of 25 % to a minimum of 4.1 %. It was found through game theory analysis that a dominant strategy involves residents agreeing to the development of the project and the developers sharing a portion of the profits with the residents. The analysis results show that the point where dominant strategy meet forms a Nash equilibrium, and at the same time becomes the Pareto optimal point, benefiting both power generation operators and residents.

https://doi.org/10.12652/Ksce.2024.44.2.0223

이동준(Lee, Dong-Jun) ; 현진오(Hyun, Jin-Oh) ; 민성규(Min, Sung Gyu) ; 임지용(Lim, Ji-Yong) ; 신민철(Shin, Min Cheol) ; 권석현(Kwon, Suk Hyun)

The Ministry of Land, Infrastructure and Transport presented the “Construction Industry BIM Enforcement Guidelines Constructors Edition” to reflect the design BIM data in the construction stage. The enforcement guidelines were prepared with the aim of providing guidelines for detailed common implementation plans such as minimum BIM business methods and procedures necessary for ordering, designing, and construction stages for the full-scale BIM application in all fields of the construction industry. In this study, interference and design errors were examined based on the enforcement guidelines, and the application effects were grasped for various sites where equipment placement and operation plans were established. As a result, intuitive examination was possible by comparing the digital field 3D model and the planned model in one space, and the optimum equipment arrangement and operation plan were derived through simulation examination according to the execution stage.

https://doi.org/10.12652/Ksce.2024.44.2.0231

김석환(Kim, Seokhwan) ; 김태건(Kim, Taegeon) ; 김홍조(Kim, Hongjo)

Marine debris entering through rivers negatively impacts the environment and poses a direct threat to human health. While barriers to prevent the outflow of floating debris are being installed, attention to their maintenance, especially the scheduling of garbage collection, is insufficient. Currently, maintenance relies on a sequential collection method based on the experience and know-how of field workers, with little systematic research to support it. In response, this study proposes a new feedback-based collection method based on YOLOv7, Monte Carlo simulation for trash collection analysis. The proposed method conducts collection based on the amount of trash detected by remote sensors such as CCTV, and the expected costs are statistically and economically compared using Monte Carlo Simulation (MCS). The results showed that the new collection strategy offers a cost advantage of about 63 % over the existing strategy.

https://doi.org/10.12652/Ksce.2024.44.2.0237

조은세상(Jo, Eun Se Sang) ; 장준봉(Jang, Junbong)

Pavement management systems (PMS) provide procedures to quantify road serviceability based on pavement conditions such as cracks and plastic deformation and suggest proper maintenance methods. The deterioration of the road pavement is relevant to the time although the quantifications on road serviceability in PMS present road surface conditions at the evaluation. More systematic evaluation on road serviceability may need time-dependent factors of road environments and that can improve PMS. Rainfall, temperature and vehicle loads can be environmental factors for road serviceability evaluation. As no data are avablie that can link between road conditions and environmental road factors, we conducted experiments to suggest economical devices and methods to obtain relevant data. We used temperature sensors and accelerometers with Arduino to measure road surface temperature and dynamic loads and provide data to improve pavement serviceability evaluation.

https://doi.org/10.12652/Ksce.2024.44.2.0245

권영우(Kwon, Youngwoo) ; 최열(Choi, Yeol)

Since 2020, quantitative easing and easy money policies have been implemented for the purpose of economic stimulus. As a result, real estate prices have skyrocketed. In this study, the relationship between sales and rental prices by housing type during the period of soaring real estate prices in Busan was analyzed spatio-temporally. Based on the actual transaction price data, housing type, transaction type, and monthly data of district units were constructed. Among the spatio-temporal analysis models, the SpVAR, which is used to understand the temporal and spatial effects of variables, and the GSTAR, which is used to understand the effects of each region on those variables, were used. As a result, the sales price of apartment had positive effect on the sale price of apartment, row house, and detached house in the surrounding area, including the target area. On the other hand, it was confirmed that demand was converted to apartment rental due to an increase in apartment sales prices, and the sale price fell again over time. The spatio-temporal spillover effect of apartments was positive, but the positive effect of row house and detached house were concentrated in the original downtown area.

https://doi.org/10.12652/Ksce.2024.44.2.0257

김희재(Kim, Hee Jae) ; 김시곤(Kim, Si Gon)

Today, high-speed rail is gradually increasing in importance as an eco-friendly means of transportation responsible for the movement of people between regions. In the past, problems of inefficiency continued due to monopolistic operation of the railway industry, and with the introduction of a public enterprise competition system, KTX and SRT operating organizations are making efforts to expand service quantity and improve quality. However, the high-speed rail service quality evaluation was limited to modifying and supplementing indicators from the operator's perspective suitable for past quality evaluations, and the evaluation target or method was not specific. Therefore, in this study, we developed a hierarchical model to measure high-speed rail customer service quality based on the model of Brady and Cronin(2001) and applied the analytical hierarchical decision-making method(AHP) to derive the priorities of Korea's high-speed rail competitiveness factors. Based on the results, it is believed that introducing reasonable and standardized service quality indicators will contribute to establishing a marketing strategy to improve the customer service competitiveness of high-speed rail operators.

https://doi.org/10.12652/Ksce.2024.44.2.0263

이기림(Lee, Kirim) ; 성지훈(Seong, Jihoon) ; 정세정(Jung, Sejung) ; 신현길(Shin, Hyeongil) ; 김도훈(Kim, Dohoon) ; 이원희(Lee Wonhee)

As unmanned aerial vehicles(UAVs) and sensors have been developed in a variety of ways, it has become possible to update information on the ground faster than existing aerial photography or remote sensing. However, acquisition and input of ground control points(GCPs) UAV photogrammetry takes a lot of time, and geometric distortion occurs if measurement and input of GCPs are incorrect. In this study, RGB-based orthophotos were generated to reduce GCPs measurment and input time, and comparison and evaluation were performed by applying feature point algorithms to target orthophotos from various sensors. Four feature point extraction algorithms were applied to the two study sites, and as a result, speeded up robust features(SURF) was the best in terms of the ratio of matching pairs to feature points. When compared overall, the accelerated-KAZE(AKAZE) method extracted the most feature points and matching pairs, and the binary robust invariant scalable keypoints(BRISK) method extracted the fewest feature points and matching pairs. Through these results, it was confirmed that the AKAZE method is superior when performing geometric correction of the objective orthophoto for each sensor.