https://doi.org/10.12652/Ksce.2023.43.6.0689

양다현(Yang, Dahyeon) ; 이민진(Lee, Min-Jin) ; 안효준(An, Hyojoon) ; 정현진(Jung Hyun-Jin) ; 이종한(Lee, Jong-Han)

Domestic bridges with a service life of more than 30 years are expected to account for approximately 54% of all bridges within the next 10 years. As bridges rapidly deteriorate, it is necessary to establish an appropriate maintenance plan. Recent domestic and international research have focused on the integration of BIM to digitize bridge maintenance information and then enhance accessibility and usability of the information. Accordingly, this study developed a BIM-FEM interoperability algorithm for bridge decks to convert maintenance information into data and efficiently manage the history of maintenance. After creating an initial crack BIM based on an exterior damage map, bridge specification and damage information were linked to a numerical analysis that performs damage analysis considering damage scenarios and design loads. The spread of cracks obtained from the analysis results were updated into the BIM. Based on the damage spread information on the BIM, an automated technology was also developed to assess both the current and future condition ratings of the bridge deck. This approach can enable an efficient maintenance of the deck using the history data from bridge inspection and diagnosis as well as future information on cracks and defects. The expected early detection and prevention would ultimately improve the lifespan and safety of bridges.

https://doi.org/10.12652/Ksce.2023.43.6.0699

정길영(Chung, Gil-Young) ; 김기배(Kim, Gi-Bae) ; 박현성(Park, Hyun-Sung) ; 박형규(Park, Hyung-Kui) ; 전영선(Choun, Young-Sun) ; 장수혁(Chang, Soo-Hyuk)

Nuclear power plants (NPPs) consider possible external events, including natural hazards, during the design phase to ensure safe operation. However, in recent years, due to the increasing probability of natural hazards exceeding the design, a careful review of extreme natural hazards and unforeseen external events during the design phase has become necessary. In this study, the objective was to screen potential extreme natural hazards at NPP sites in Korea. Initially, we investigated and analyzed the characteristics of NPP sites and the events caused by external hazards. Furthermore, we analyzed existing literature and research data to establish screening procedures and criteria that suit the actual conditions of domestic NPPs. Based on these criteria and data, we conducted qualitative screening for each NPP site and identified potential extreme natural hazards through quantitative screening and walkdown. As a result of the screening, in addition to internal flooding caused by heavy rain, wind pressure and extreme air pressure caused by extreme winds were screened as potential extreme natural hazards common to all sites. Additionally, at the Kori site, storm surge was selected as the most significant potential extreme natural hazard.

https://doi.org/10.12652/Ksce.2023.43.6.0709

이상문(Lee, Sang-Moon) ; 정우영(Jung, Woo-Young)

In general, most of the electrical equipment responsible for control within power plants is housed in self-standing cabinets. These cabinets are typically fixed to a slab using post-installed anchors. Although the fixation method of using post-installed anchors provides stability, there is a risk of conductor failure due to external forces, including moments. However, the performance assessment of current anchors is only evaluated through uniaxial material tests. Therefore, the primary purpose of this study is to compare the static performance of post-installed anchors, considering on-site installation conditions, with their performance in material tests and to analyze the behavioral characteristics of the anchors. While conducting experiments using actual cabinets would be ideal, practical and spatial constraints make this approach difficult. As an alternative, experiments were conducted using a test specimen consisting of a steel column and a support. As a result, the pull-out performance of anchors reflecting on-site installation conditions was measured to be about 10% higher than that observed in material tests. The trends in load reduction and the point of maximum performance for the anchors also differed. To verify the reliability of the experimental study, a 3D FEM analysis was performed, which will provide predictive information on the loads transferred to the post-installed anchors for structural performance evaluations of electrical cabinets using shaking table test in the future.

https://doi.org/10.12652/Ksce.2023.43.6.0721

지희원(Jee, Hee Won) ; 김현주(Kim, Hyeonju) ; 서승범(Seo, Seung Beom)

As the frequency of extreme rainfall events increase due to climate change, climate change adaptation measures have been proposed by the central and local governments. In order to reduce flood damage in urban areas, various flood response policies, such as low impact development techniques and enhancement of the capacity of rainwater drainage networks, have been proposed. When these policies are established, regional characteristics and policy-effectiveness from the cost-benefit perspective must be considered for the flood mitigation measures. In this study, capacity enhancement of rainwater pipe networks and low impact development techniques including green roof and permeable pavement techniques are selected. And the flood reduction effect of the target watershed, Gwanak campus of Seoul National University, was analyzed using SWMM model which is an urban runoff simulation model. In addition, along with the quantified urban flooding reduction outputs, construction and operation costs for various policy scenarios were calculated so that cost-benefit analyses were conducted to analyze the effectiveness of the applied policy scenarios. As a result of cost-benefit analysis, a policy that adopts both permeable pavement and rainwater pipe expansion was selected as the best cost-effective scenario for flood mitigation. The research methodology, proposed in this study, is expected to be utilized for decision-making in the planning stage for flood mitigation measures for each region.

https://doi.org/10.12652/Ksce.2023.43.6.0735

류지원(Ryu, Jiwon) ; 지운(Ji, Un) ; 김상혁(Kim, Sanghyeok) ; 장은경(Jang, Eun-kyung)

In recent times, the sharp increase in extreme flood damages due to climate change has posed a challenge to effectively address flood-related issues solely relying on conventional flood management infrastructure. In response to this problem, this study aims to consider the effectiveness of nature-based flood management approaches, specifically levee retreat and relocation. To achieve this, we utilized a 1D numerical model, HEC-RAS, to analyze the flood reduction effects concerning floodwater levels, flow velocities, and time-dependent responses to a 100-year frequency flood event. The analysis results revealed that the effect of creating a flood buffer zone of the nature-based solution extends from upstream to downstream, reducing flood water levels by up to 30 cm. The selection of the flow roughness coefficient in consideration of the nature-based flood buffer space creation characteristics should be based on precise criteria and scientific evidence because it is sensitive to the flood control effect analysis results. Notably, floodwater levels increased in some expanded floodplain sections, and the reduction in flow velocities varied depending on the ratio of the expanded cross-sectional area. In conclusion, levee retreat and floodplain expansion are viable nature-based alternatives for effective flood management. However, a comprehensive design approach is essential considering flood control effects, flow velocity reduction, and the timing of peak water levels. This study offers insights into addressing the challenges of climate-induced extreme flooding and advancing flood management strategies.

https://doi.org/10.12652/Ksce.2023.43.6.0749

황승용(Hwang, Seung-Yong)

A depth-integrated model with an approximate Riemann solver for flux computation of the shallow water equations was applied to hydraulic jump experiments. Due to the hydraulic jump, different flow regimes occur simultaneously in a single channel. Therefore, the Weisbach resistance coefficient, which reflects flow conditions rather than the Manning roughness coefficient that is independent of depth or flow, has been employed for flow resistance. Simulation results were in good agreement with experimental results, and it was confirmed that Manning coefficients converted from Weisbach coefficients were appropriately set in the supercritical and subcritical flow reaches, respectively. Limitations of the shallow water equations that rely on hydrostatic assumptions have been revealed in comparison with hydraulic jump experiments, highlighting the need for the introduction of a non-hydrostatic shallow-water flow model.

https://doi.org/10.12652/Ksce.2023.43.6.0763

이승연(Lee, Seungyeon) ; 이상은(Lee, Sangeun)

The water availability in a river is related to the return flow of residential water. However it is still difficult to determine the exact return flow. In this study, the residential water-cycle system is defined as a process consisting of water inflow, water transfer and water outflow. The study area is Hampyeong-gun, Jeollanam-do, and is set as a single inflow to a single outflow through the water-cycle system after classification of complete and incomplete measurement points. The time-series prediction models(ARIMA model and TFM) are established with daily inflow and outflow data for 6 years. Inflow and outflow are predicted by dividing into training and test periods. As a result, both models show the feasibility of short-term prediction by deriving stable residuals and securing statistical significance, implementing the preliminary form of the water-cycle system. As a further study, it is suggested to predict the actual return flow of the target basin and efficient water operation by adding input factors and selecting the optimal model.

https://doi.org/10.12652/Ksce.2023.43.6.0775

이현지(Lee, Hyeonji) ; 신영섭(Shin, Youngsub) ; 강동호(Kang, Dongho) ; 김병식(Kim, Byungsik)

In terms of flood management, it is necessary to analyze quantitative rainfall and runoff from a spatial and temporal perspective and to analyze runoff for heavy rainfall events that are concentrated within a short period of time. The simulation and analysis results of rainfall-runoff models vary depending on the type and input data. In particular, rainfall data is an important factor, so calculating areal mean rainfall is very important. In this study, the areal mean rainfall of the Samcheok Osipcheon(Riv.) watersheds located in the mountainous terrain was calculated using the Arithmetic Mean Method, Thiessen’s Weighting Method, and the Isohyetal Method, and the rainfall-runoff results were compared by applying the distributional model S-RAT and the lumped model HEC-HMS. The results of the temporal transferability study showed that the combination of the distributional model and the Isohyetal Method had the best statistical performance with MAE of 64.62 ㎥/s, RMSE of 82.47 ㎥/s, and R2 and NSE of 0.9383 and 0.8547, respectively. It is considered that this study was properly analyzed because the peak flood volume occurrence time of the observed and simulated flows is within 1 hour. Therefore, the results of this study can be used for frequency analysis in the future, which can be used to improve the accuracy of simulating peak flood volume and peak flood occurrence time in mountainous watersheds with steep slopes.

https://doi.org/10.12652/Ksce.2023.43.6.0785

권기범(Kwon, Kibeom) ; 강민규(Kang, Minkyu) ; 황병현(Hwang, Byeonghyun) ; 최항석(Choi, Hangseok)

Risk management is essential for preventing accidents arising from uncertainties in TBM tunnel projects, especially concerning managing the risk of TBM tunnel collapse, which can cause extensive damage from the tunnel face to the ground surface. In addition, prioritizing risks is necessary to allocate resources efficiently within time and cost constraints. Therefore, this study aimed to establish a TBM risk database through case studies of TBM accidents and determine a risk priority for TBM tunnel collapse using the Bayes theorem. The database consisted of 87 cases, dealing with three accidents and five geological sources. Applying the Bayes theorem to the database, it was found that fault zones and weak ground significantly increased the probability of tunnel collapse, while the other sources showed low correlations with collapse. Therefore, the risk priority for TBM tunnel collapse, considering geological sources, is as follows: 1) Fault zone, 2) Weak ground, 3) Mixed ground, 4) High in-situ stress, and 5) Expansive ground. In practice, the derived risk priority can serve as a valuable reference for risk management, enhancing the safety and efficiency of TBM construction. It provides guidance for developing appropriate countermeasure plans and allocating resources effectively to mitigate the risk of TBM tunnel collapse.

https://doi.org/10.12652/Ksce.2023.43.6.0793

김황배(Kim, Hwang Bae)

This study classifies the types of urban railway stations that reflect the location characteristics of urban railway stations, the structure and form of station taxes, and the number of users, and the level of inconvenience in the transfer movement line for users by station type, the number and connectivity of transfer information, and the level of transfer convenience facilities. The number of installations, conflicts between users, and transfer information signs were analyzed. As a result of data analysis, it was found that the factors that cause the most inconvenience to urban rail users when transferring are the length and curvature of the transfer line, pedestrian density and number of passengers in the transfer passage, presence or absence of transportation convenience facilities, and the size and height of transfer information letters. These transfer inconveniences were objectified, quantified, and presented as evaluation indicators that can measure the transfer convenience of urban railway stations. Additionally, an evaluation scale was developed to measure the service level for each evaluation indicator. The evaluation scale for each indicator presented six levels by applying linear interpolation based on the maximum and minimum values of data derived through field surveys. However, it is judged that a comprehensive evaluation of transfer convenience that combines the importance and weight of each convenience evaluation indicator should be established through future research.

https://doi.org/10.12652/Ksce.2023.43.6.0801

문준부(Mun, Junbu) ; 이강욱(Lee, Kangwook) ; 윤성민(Yun, Sungmin)

Road construction projects have a long duration so cost overruns and schedule delays are occurred. However, performance assessment system that can manage and prepare for this in advance is insufficient. In addition, road construction are affected by many factors during under construction. Therefore it is necessary to conduct performance assessment considering the characteristics of roads and prepare for similar projects in the future. The purpose of this study is to provide a framework to evaluate construction phase performance and present a performance management plan using road construction information. Also, This study conducted time adjustment between the start and the finish of the project and developed performance metrics based on absolute and relative indicator. This study analyzed the cost, schedule, and changes of the road project construction process, showing the possibility of advancement of performance assessment and how to use it when planning new road construction projects.

https://doi.org/10.12652/Ksce.2023.43.6.0811

백준우(Baik, Joonwoo) ; 정세환(Chung, Sehwan) ; 지석호(Chi, Seokho)

Understanding the local conditions is a crucial factor in enhancing the success potential of overseas construction projects. This can be achieved through the analysis of news articles of the target market using topic modeling techniques. In this study, the authors aimed to analyze news articles using two topic modeling methods, namely Latent Dirichlet Allocation (LDA) and BERTopic, in order to determine the optimal approach for market condition analysis. To evaluate the alignment between the generated topics and the actual themes of the news documents, the research collected 6,273 BBC news articles, created ground truth data for individual news article topics, and finally compared this ground truth with the results of the topic modeling. The F1 score for LDA was 0.011, while BERTopic achieved a score of 0.244. These results indicate that BERTopic more accurately reflected the actual topics of news articles, making it more effective for understanding the overseas construction market.

https://doi.org/10.12652/Ksce.2023.43.6.0821

문준부(Mun, Junbu) ; 이주희(Lee, Juhui) ; 백승원(Baek, Seungwon) ; 이강욱(Lee, Kangwook) ; 윤성민(Yun, Sungmin)

Various studies has tried to unveil causes of cost overrun and schedule delay in the road construction project. However, these causes need standardization due to difference by guidelines, relevant research, and facilities. Therefore, this study identifies and elaborate standard road construction cost and schedule variation factors that can be used in the planning and execution of the project. variation factors have been derived and grouped through literature review and modified and supplemented through expert interview. In addition, the connection with the relevant guidance factors is confirmed and the usability is reviewed by applying actual road construction cases. The factors suggested in this study comprehensively include factors of related guidelines and previous research, more clearly distinguish, support decision making.

https://doi.org/10.12652/Ksce.2023.43.6.0831

박현철(Park, Hyunchul) ; 박선아(Park, Seona) ; 이진수(Lee, Jinsoo) ; 편무욱(Pyeon, Muwook)

The purpose of this study is to quickly collect and analyze information generated in real-time at disaster sites to propose an integrated plan for an on-site support system that can support accurate disaster site situation identification and decision-making, and to review field applicability through prototype simulation. Accordingly, information collection, sharing, and convergence technologies that can be used at disaster sites were reviewed, and a plan for integrating a smart disaster site support system that can create an efficient flow of information resources and information necessary for the entire stage of disaster management was presented. In order to examine the possibility of operating the system with a prototype manufactured based on the integration plan, simulations were conducted based on the storm and flood disaster scenario, and it was confirmed that various functions in the system were implemented normally and displayed on the GIS situation board. Through this study, it is expected that efficient and active disaster response will be possible in a rapidly changing disaster environment.

https://doi.org/10.12652/Ksce.2023.43.6.0841

강동욱(Kang, Donguk) ; 조민건(Cho, Mingeon) ; 차기춘(Cha, Gichun) ; 박승희(Park, Seunghee)

Construction projects have risks due to various factors such as construction delays and construction accidents. Based on these construction risks, the method of calculating the construction period of the construction project is mainly made by subjective judgment that relies on supervisor experience. In addition, unreasonable shortening construction to meet construction project schedules delayed by construction delays and construction disasters causes negative consequences such as poor construction, and economic losses are caused by the absence of infrastructure due to delayed schedules. Data-based scientific approaches and statistical analysis are needed to solve the risks of such construction projects. Data collected in actual construction projects is stored in unstructured text, so to apply data-based risks, data pre-processing involves a lot of manpower and cost, so basic data through a data classification model using text mining is required. Therefore, in this study, a document-based data generation classification model for risk management was developed through a data classification model based on SVM (Support Vector Machine) by collecting construction project documents and utilizing text mining. Through quantitative analysis through future research results, it is expected that risk management will be possible by being used as efficient and objective basic data for construction project process management.

https://doi.org/10.12652/Ksce.2023.43.6.0851

김정수(Kim, Jeongsoo) ; 문현석(Moon, Hyounseok) ; 박상미(Park, Sangmi)

The mandatory use of BIM(Building Information Model) in larger Korean public construction projects necessitates participants to have a comprehensive understanding of the relevant procedures and technologies, especially during the bidding stage. However, most small and medium-sized construction and engineering companies possess limited BIM proficiency and understanding. This hampers their ability to recognize bidding requirements and make informed decisions. To address this challenge, our study introduces a method to gauge the complexity of BIM requirements in bidding documents. This is achieved by integrating a morphological analyzer, which encompasses BIM bidding terminology, with a deep learning model. We investigated the effects of the parameters in our proposed deep learning model and examined its predictive validity. The results revealed an F1-score of 0.83 for the test data, indicating that the model's predictions align closely with the actual BIM performance challenges.

https://doi.org/10.12652/Ksce.2023.43.6.0865

황철승(Hwang, Cheol Seung) ; 김시곤(Kim, Si Gon)

Domestic urban railway are operated by urban railway operating public enterprises, which are owned by the 6 major metropolitan local governments and private operating companies, which are established under the Private Investment Act. Among urban railway operating companies, several public enterprises that operate urban railways with many experience, performance, human resources, and public nature are making efforts to promote overseas business. Therefore, this study examines the outlook for railway and urban railway overseas business, and provides implications for the overseas business approach of domestic urban railway operating public enterprises through data research and comparative analysis on the overseas business approaches and overseas business characteristics of domestic and foreign urban railway operating public enterprises. The results were derived and suggestions for the direction of overseas business were presented. I expect that suggestions will serve as a reference for domestic urban railway operators to promote overseas projects with preparation, implementation plan and direction.

https://doi.org/10.12652/Ksce.2023.43.6.0873

신창수(Shin, Chang Soo) ; 김성수(Kim, Sung Su)

The evolution of civil engineering technology, exemplified by recent milestones like the completion of the Gangnam Global Business Center (GBC), has fostered the construction of expansive civil and architectural structures both above and below the earth's surface. This surge in construction necessitates a commensurate advancement in research and technology pertaining to safety protocols applicable to these vast edifices. Such protocols encompass a spectrum of concerns, ranging from the preemptive mitigation of accidents to the effective management of exigencies such as fires. As the trajectory of construction endeavors continues unabated, encompassing both subterranean and elevated domains, a concomitant imperative emerges to refine the methodologies underpinning precise indoor positioning. To address this need, an innovative web-based simulator has been devised to emulate indoor positioning scenarios for rigorous testing. This research further entails the development of an indoor positioning data Application Programming Interface (API) fortified by Geographic Information System (GIS) spatial operation techniques. This API is anchored in the construction of intricate test data, centered on the spatial layout of building 13 at the Electronics and Telecommunications Research Institute (ETRI). Consequently, the study renders feasible the expeditious provisioning of diverse signal-based and image-based spatial information, pivotal for enhancing the navigational acumen of mobile devices. Path delineation, cellular signal mapping, landmark identification, and ancillary navigational aids are among the manifold datasets promptly furnished by the indoor positioning data API. In summation, this study engenders a crucial leap towards the fortification of safety protocols and navigational precision within the expansive confines of modern architectural wonders.

https://doi.org/10.12652/Ksce.2023.43.6.0883

이한나(Lee, Hanna) ; 윤공현(Yun, Konghyun) ; 김기홍(Kim, Gihong)

As human activities in Korea are spread throughout the mountains, forest fires often affect residential areas, infrastructure, and other facilities. Hence, it is necessary to detect fire-damaged areas quickly to enable support and recovery. Remote sensing is the most efficient tool for this purpose. Fire damage detection experiments were conducted on the east coast of Korea. Because this area comprises a mixture of forest and artificial land cover, data with low resolution are not suitable. We used Sentinel-2 multispectral instrument (MSI) data, which provide adequate temporal and spatial resolution, and the k-nearest neighbor (kNN) algorithm in this study. Six bands of Sentinel-2 MSI and two indices of normalized difference vegetation index (NDVI) and normalized burn ratio (NBR) were used as features for kNN classification. The kNN classifier was trained using 2,000 randomly selected samples in the fire-damaged and undamaged areas. Outliers were removed and a forest type map was used to improve classification performance. Numerous experiments for various neighbors for kNN and feature combinations have been conducted using bi-temporal and uni-temporal approaches. The bi-temporal classification performed better than the uni-temporal classification. However, the uni-temporal classification was able to detect severely damaged areas.