https://doi.org/10.12652/Ksce.2026.46.2.0119

이헌우(Lee, Heon-Woo) ; 김영찬(Kim, Young-Chan) ; 지성원(Ji, Sung-Won) ; 허종완(Hu, Jong-Wan)

This study proposes a three-dimensional yield honeycomb damper capable of stably dissipating energy during earthquake disasters. The honeycomb structure is the most stable structural geometry derived from nature and has attracted interest from many research fields, including structural engineering. Such honeycomb structures have frequently been applied in the form of dampers to resist earthquakes. However, it was recognized that these structures, being composed of planar elements, have the disadvantage of only being able to dissipate loads in the shear direction. Unlike previously proposed planar dampers, the three-dimensional yield honeycomb damper utilizes a three-dimensional honeycomb structure, designed to maintain energy dissipation capabilities even under various deformation conditions. The variables selected were the number of base polygonal faces, the damper length, and the base diameter, and 30 dampers were designed. To verify performance, cyclic loading was applied, and a three-dimensional nonlinear analysis was performed using the ABAQUS program to derive force-displacement hysteresis curves. Using these curves, responses such as maximum load and energy dissipation were derived, and ratio graphs were created to verify the variation in response for each variable, thereby analyzing the performance. Through this, it was confirmed that the most important factor is the slenderness ratio of the columns constituting the honeycomb damper. In addition, the excellent honeycomb structure exhibited behavior in which the load was distributed throughout the structure, and the results of this study are expected to serve as basic data for the design and performance evaluation of yield dampers with honeycomb structures.

https://doi.org/10.12652/Ksce.2026.46.2.0127

이가영(Lee, Gayoung) ; 신주영(Shin, Ju-young) ; 장상범(Jang, Sangbeom) ; 박지연(Park, Jiyeon)

Regional frequency analysis (RFA) improves rainfall quantile estimation by pooling data from hydrologically homogeneous regions, providing higher reliability than at-site analysis in regions with a shortage of observed data. While the generalized extreme value (GEV) distribution is recommended as the preferred candidate distribution in the 2019 Ministry of Environment guidelines, a limited capacity to reproduce tail behavior has been noted due to the increasing intensity and localization of rainfall caused by climate change. This study evaluated the applicability of the four-parameter kappa distribution, which offers greater flexibility in presenting extreme tail behavior, as an alternative to the three-parameter GEV distribution. Among the 26 homogeneous regions, this study focused on Regions #12 (Gyeongbok) and #15 (Northern Gangwon), where all candidate distributions in the current version of the guideline were rejected. In Region #15, the kappa distribution satisfied the goodness-of-fit measures and adequately represented the statistical characteristics. However, parameters of the kappa distribution could not be estimated for some durations in Region #12. Furthermore, for the 50- and 100-year return periods, the kappa distribution yielded rainfall quantiles 20-30 % lower than GEV, suggesting a potential conservative bias in current GEV-based designs. These findings demonstrate that the kappa distribution is a viable alternative for responding to the statistical shifts in extreme precipitation.

https://doi.org/10.12652/Ksce.2026.46.2.0137

정윤환(Jeong, Yoon-Hwan) ; 김병식(Kim, Byung Sik) ; 홍승호(Hong, Seung Ho)

To overcome the limitations of existing disaster prevention policies focused heavily on physical hydrological conditions, this study proposes the introduction of ‘Water Disaster Special Management Areas’ and a spatial prioritization scheme that comprehensively reflects the socio-economic impacts of extreme rainfall events caused by climate change. To this end, the Socio-Economic Impact Index(SEII) was calculated by applying weights derived from a Pearson correlation analysis between various socio-economic baseline indicators, such as population density, the proportion of vulnerable populations, and financial independence, and historical flood damage amounts. A K-means clustering analysis conducted on data from 229 local municipalities nationwide identified 30 municipalities as the ‘Very High’ risk group. Furthermore, a spatial overlay analysis using data from large-scale new development districts (with a land area of 1,000,000 m2 or more) within these municipalities revealed distinct spatial characteristics of vulnerability: the Seoul metropolitan area is predominantly residential-focused, whereas non-metropolitan areas are industrial-focused. Building upon these findings, and in practical connection with the recently enacted ‘Act on Prevention of Inundation Damage in Urban River Basins,’ this study established quantitative criteria to prioritize the application of budget-intensive disaster prevention measures, such as upgrading to a 100-year design frequency and implementing deep stormwater storage tunnels. Ultimately, the results of this study are expected to serve as an objective decision-support tool to efficiently allocate limited national disaster management resources and enhance the effectiveness of disaster prevention policies, moving beyond uniform management based solely on administrative boundaries.

https://doi.org/10.12652/Ksce.2026.46.2.0149

주윤호(Ju, Yunho) ; 김태준(Kim, Taejun) ; 김정화(Kim, Junghwa)

This study investigates how structural characteristics of highway tunnels affect traffic performance deterioration and proposes a differentiated correction framework for volume?delay functions (VDFs) based on tunnel typology. Using nationwide data from 204 highway tunnels in South Korea, a three-year dataset of 5-minute vehicle detection system (VDS) observations was constructed by matching each tunnel section with an adjacent general road section under identical traffic conditions. Traffic performance was quantified using the speed ratio, defined as the ratio of average tunnel speed to that of the corresponding general section, thereby isolating structural effects from demand and temporal variations. To account for structural heterogeneity, cluster analysis was conducted using key geometric and design variables. Three structurally distinct tunnel clusters were identified, and statistical tests confirmed significant inter-cluster differences, particularly in tunnel length, curvature radius, and longitudinal gradient. Cluster-specific univariate and multivariate nonlinear regression analyses reveal that the effect of tunnel length on speed reduction is not universal. A statistically significant nonlinear length effect was observed only in one structurally constrained cluster, where speed ratio decreased with increasing tunnel length following a quadratic relationship. In contrast, structural variables failed to explain speed ratio variations in the remaining clusters, suggesting the dominance of non-structural factors. These findings demonstrate that traffic performance degradation mechanisms in tunnels are heterogeneous and depend on structural typology rather than individual geometric variables alone. Accordingly, applying uniform VDF correction factors may introduce systematic bias. This study provides empirical support for a selective, type-based VDF correction strategy and enhances the realism of macroscopic traffic assignment and tunnel performance evaluation.

https://doi.org/10.12652/Ksce.2026.46.2.0165

백종은(Baek, Jongeun) ; 최준성(Choi, JunSeoung) ; 정예지(Jung, YeJi) ; 김현수(Kim, HyunSoo)

Stone Mastic Asphalt (SMA) provides superior durability and rutting resistance through its skeletal structure, which is characterized by stone-on-stone contact. This study aims to enhance the construction quality of SMA pavements by evaluating a mix design that prioritizes aggregate interlocking and assessing the field applicability of pneumatic tire rollers for compaction. To quantitatively evaluate interlocking, the Voids in Coarse Aggregate (VCA) criterion was applied. Initial assessments of a standard 13 mm SMA mixture revealed insufficient coarse aggregate content. Increasing the coarse aggregate content by 2 percentage points (from 72.7 % to 74.7 %) satisfied the VCA criteria and optimized the stone-on-stone contact. For field application during highway SMA overlays, tire rollers were employed for secondary compaction. To prevent the “pick-up” phenomenon?where the mixture adheres to the tires?anti-adhesion procedures, such as coating tires with vegetable oil and preheating, were implemented. Performance evaluations of the test sections indicated that using tire rollers increased the compaction degree by 0.4 %p, improved interlayer bond strength by 8.5 %, and reduced surface deflection by 16.7 % compared to conventional methods. These results demonstrate that the application of tire rollers significantly contributes to improved compaction efficiency and enhanced initial pavement performance.

https://doi.org/10.12652/Ksce.2026.46.2.0173

김창윤(Kim, Changyoon) ; 최지원(Choi, Jiwon) ; 문수영(Moon, Soo-Young)

The government of Korea is endeavoring to improve the environment of deteriorated school facilities to ensure students' healthy learning rights. As part of these efforts, there have been initiatives to utilize domestic timber as a primary construction material. Eco-friendly timber is being applied to building exterior walls to improve the thermal insulation performance of aging buildings and to enhance the learning environment for students and school staff. However, budget and cost constraints have posed significant challenges to its practical implementation. This study conducted a case study on the development of an industrialized timber exterior panel system to establish a solid rationale for eco-friendly timber construction materials. First, performance targets and economic feasibility analysis criteria for the panel system were derived. Based on these, a quantitative analysis of environmental and economic values was performed using Life Cycle Assessment (Life Cycle Analysis) and Benefit-Cost analysis. The results demonstrated economic feasibility with a Benefit-Cost ratio of 1.378, confirming through the case study that the proposed technology serves as an efficient alternative for school remodeling. Future research is required to further refine evaluation criteria and quantify the health-promoting benefits of timber to integrate them into economic assessments, thereby comprehensively identifying the potential value of eco-friendly timber schools.

https://doi.org/10.12652/Ksce.2026.46.2.0181

임광균(Lim, Kwang-kyun) ; 윤경철(Yun, Gyeong-Cheol)

As urban railway lines originally centered in Seoul have been extended across the metropolitan area, the authority and responsibility of local governments for railway operations have expanded. However, many local governments lack sufficient organizational capacity and manpower for railway operation and therefore outsource operations to experienced railway operators. In this process, continuous debates have arisen regarding the appropriateness of staffing levels, actual manpower input, and cost settlements for outsourced sections. This study empirically examines the appropriateness of staffing levels under the delegation agreement between Seoul Metro and Incheon Transit Corporation for the Bucheon section of Seoul Metropolitan Subway Line 7. To achieve this, the staffing levels specified in the operation agreements were compared with unit staffing levels derived from operational performance in the directly operated section, while differences across operational fields and previously suggested staffing standards were also examined. The analysis shows that both Seoul Metro and Incheon Transit Corporation exhibit tendencies toward overestimation in agreement-based staffing levels compared to performance-based benchmarks. When recalculated based on unit staffing levels, the appropriate staffing levels are estimated at approximately 70 personnel for Seoul Metro and 161 personnel for Incheon Transit Corporation. Across operational fields?including rolling stock and control, station services, train operation, and technical maintenance?the agreement-based unit staffing levels were generally higher than those observed in the directly operated section. The results of this study are expected to serve as fundamental data for establishing more rational staffing standards for delegated urban railway operations and for improving inter-agency operation agreements and cost settlement systems in the Seoul metropolitan railway network.