• Journal of the Korean GEO-environmental Society
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• v.19 no.11
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• pp.5-14
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• 2018

Worldwide, soil compaction work is one of the most important activities that are carried out on civil engineering works sites. Compaction work, particularly in the area of road construction, is considered to be important, as poor compaction work is closely related with poor construction even after a construction is complete. Currently, the plate bearing test or the sand cone method relative to the unit weight of soil test are commonly used to measure the degree of compaction, but as these require a great deal of time, equipment and manpower, it is difficult to secure economic efficiency. The method that is used to measure the degree of compaction according to the penetration depth achieved by free fall objects through gravity is the Free-Fall Penetration Test (FFPT), which uses a so-called "portable compaction measuring meter (PCMM)." In this study, the degree of compaction was measured and a penetration depth graph was developed after the field test using the portable compaction measuring meter. The coefficient of determination was 0.963 at a drop height of 10 cm, showing the highest level of accuracy. Both horizontal axis and longitudinal axis were developed in a decimal form of graph, and the range of allowable error was ${\pm}1.28mm$ based on the penetration depth. The portable compaction measuring meter makes it possible to measure the degree of compaction simply, quickly and accurately in the field, which will ensure economic efficiency and facilitate the process management.

• Journal of the Korean Geosynthetics Society
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• v.20 no.3
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• pp.1-10
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• 2021

The purpose of this study is to present the possibility a utilization of the tertiary mudstone in Pohang as road subsoil material through pilot experiments on the road embankment structure. This mudstone is an unconsolidated rock that is distributed in the soft rock sedimentary layer, the tertiary layer of the Cenozoic, and causes physical problems such as slaking, swelling, and reduced shear strength and chemical problem like acid drainage. In order to solve various complex problems, an laboratory mixing test was conducted, and the optimal mixing conditions of the tertiary mudstone (90%), composite slag (steel making 70%, blast furnace 30%), and neutralization and coating agent treatment were derived. In order to prove its utilization, a real-scale road embankment structure was constructed and tests were conducted for each section. The pre-processing section is stable due to the design of optimal mixing conditions, while in post-processing section, natural weathering proceeded rapidly, and structural problems were concerned. Since the effect of neutralizing and coating agents was confirmed in temporary-staking section, the neutralizing and coating agents can be applied during the temporary storage period.

• Korean Journal of Construction Engineering and Management
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• v.20 no.1
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• pp.3-13
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• 2019

Recently, quality problems of steel used for construction have been raised as a cause of building collapse and safety accidents. Accordingly, it becomes more important to secure quality through material management, procurement management, and construction management for construction used steels. However, the quality management for construction used steels is confined to technical production and process control. So, it does not provide a solution of various non-conforming steel products issues. Therefore, this study suggests improvements of the construction system to secure quality of the construction used steels. Through expert interviews, we identify the items for system improvement and derive the top priority items by considering utility through a structured Analytic Hierarchy Process (AHP). It also divided the respondents into enterprise and research groups to analyze differences, implications and future improvement issues and suggest a road map. It is expected that the priority items derived in this study could be useful as a basic data for making policy decisions to assure the quality of construction used steel.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.6
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• pp.851-857
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• 2018

In this research, LCA analysis of the manufacturing process of pot bearing for fixed, movable in all directions, movable in one direction was carried out to analyze the environmental load using the LCA methodology. Especially, the water footprint that has been and issue in recent years was analyzed. As a result of LCA, it was analyzed that the contribution of the plate was more than 64.2% in all of the six impact categories in the case of fixed pot bearing base, and more than 94% in the category of resource depletion and photochemical oxidant creation. In the case of all direction pot bearing and one direction pot bearing, the contribution of PTFE was the highest in the global warming and stratospheric ozone depletion, and the contribution by the plate was higher in the other impact categories. The water footprint of each type of pot bearing was analyzed as $22.4m^3\;H_2O\;eq/kg$ for one direction pot bearing, $17.1m^3\;H_2O\;eq/kg$ for fixed pot bearing, and $14.1m^3\;H_2O\;eq/kg$ for all direction pot bearing. As a result of life cycle analysis, the contribution of water use in manufacturing was more than 65% in all three types. The results of this study can be used as basic data for decision making in construction method and material selection of bridges in the future.

• The Korean Journal of Archival Studies
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• no.74
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• pp.119-153
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• 2022

Metaverse combines the real and virtual worlds to create a world where all experiences and activities in the real world are possible even in the virtual world without time and space constraints. Currently, metaverse technology is expanding and converging into the realms of society, economy, and culture. In particular, the MZ generation, the main user base, is engaged in various cultural activities such as games, contents, culture, exhibitions, and performances in the metaverse world. Archives, one of the cultural institutions, should provide a new type of service by fusion of Archival information services with metaverse technology so that the MZ generation can know the value and meaning of archives. This will arouse the interest of the MZ generation, which will naturally increase the awareness of the archives, increase visits and use, and will serve as an opportunity to expand the user base. Therefore, in this study, the concept, type, and characteristics of each service were examined, and the representative metaverse platform for each service was selected and a platform utilization plan suitable for Archival information services such as exhibition, experience, and publicity was proposed. In addition, by using 'Spatial', a blockchain-based social metaverse platform, to directly produce exhibition contents, we want to check the considerations suggested, the production process, and the advantages of the metaverse exhibition.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.2
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• pp.25-32
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• 2023

In this study, a double wall system is introduced, which was invented to simplify the complicated manufacturing process of the existing precast concrete (PC) double wall systems and to remove defects such as laitance that may occur during the production of concrete panels. An experimental study was conducted to investigate the tensile resisting capacity of the steel tube which is embedded in the precast concrete panel to keep the spacing between PC panels and to prevent damage of the PC panels during transportation and casting concrete onsite. The experiment was planned to determine the detail of effective steel tube connection considering the steel plate treatment method according to the formation of the opening, the presence of embedded concrete, and the reinforcement welding for additional dowel action as key variables. As a result, the ultimate tensile strength increased by 20-30% compared to the control specimen (ST) except for the steel tube specimen (ST_CP) which has steel plates bent inward at the end part of the steel tube. Since the specimen (ST_CON) filled with concrete inside the control specimen has no additional process and cost for the steel tube connections compared to the control specimen during the production of the developed double wall system, it is determined to be the appropriate detail of steel tube connection.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3D
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• pp.355-362
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• 2008

Fast track completion of urgent typhoon damage recovery construction project is becoming crucial for the prevention of the secondary damage from the next year typhoon, prompt psychological stabilization of flood sufferers, the early recovery of damaged infrastructure condition and so forth. As the recovery learning process has been continued for last consecutive typhoons and experts suggested, the keys in attaining the goals of the project (preventative, sustainable, cleaner and fast tracking development) are found to be the early contracting and improved competencies in project management especially during the design phase. It can be presumed that the former is attainable through administrative supports in the form of government guidelines, but the latter necessitates more research efforts. In this regards, this study aims to find a way how to lift up the current level of project management capability facing ever changing project mangement environment of urgent typhoon recovery project. By comparing the current level of application of government guidelines in flooded districts and analyzing the time required for each phase from design contracting to construction starting, several reformative ideas are illustrated in association with the necessity of adopting CM method in the deign phase. It is highly expected that CM application in the design phase can be an effective alternative in overcoming current limits in improving the quality of the project and prevent the delay due to the lack of expertise and professional workers in the owner side.

• Land and Housing Review
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• v.15 no.2
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• pp.125-137
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• 2024

A conventional Design for Safety (DfS), introduced to eliminate potential hazards in the design phase proactively, has encountered persistent challenges, such as perfunctory risk assessments and hazard identifications based on 2D drawings and inefficient workflow processes. This study proposes a BIM-based approach to Design for Safety (DfS) to address the limitations of conventional methods, aiming to enhance efficiency and achieve practical safety management benefits. The proposed workflow process for BIM-based DfS has been refined and validated for on-site applicability through various case studies, including risk assessments during the design phase and field applications for safety management activities during the construction phase. Specifically, the critical process of risk assessment within the DfS methodology has also been transitioned to a BIM-based approach. This BIM-based risk assessment process has been evaluated through case studies, encompassing safety reviews for structural design, construction equipment operation, and construction methodology with sequence in design projects. Additionally, the proposed BIM-based DfS has demonstrated exceptional on-site applicability and efficiency, as validated by the application of a BIM deliverable embedded in DfS information for CDE-based daily activity briefing, VR-based safety training, AR-based mitigation measures inspections, and other safety management activities in the construction phase.

• Asian Journal of Turfgrass Science
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• v.17 no.1
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• pp.1-12
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• 2003

Research was Initiated to investigate germination characteristics of cool-season grasses (CSG). Several turfgrasses were tested in different experiments. Experiments I and III were conducted under a room temperature condition of 16$^{\circ}C$ to 23 $^{\circ}C$ and under a constant light condition at 25 $^{\circ}C$, respectively. An alternative environment condition that is a requirement for a CSG germination test by International Seed Testing Association (ISTA) was applied in the Experiment II, consisting of 8-hr light at 25 $^{\circ}C$ and 16-hr dark at 15 $^{\circ}C$. In each experiment, data such as early germinating vigor, germination speed and germination rate were evaluated. Six turfgrass entries were comprised of two varieties each from Kentucky bluegrass (KB, Poa pratensis L.), perennial ryegrass (PR, Lolium perenne L.), and tall fescue (TF, Festuca arundinacea Schreb.), respectively. Significant differences were observed in early germinating vigor, germination speed and germination rate. Early germinating vigor as measured by days to 70% seed germination was variable according to environment conditions, turfgrasses and varieties. It was less than 6 days in PR and 6 to 9 days in TF. However, KB resulted in 11 to 13 days under an alternative condition and 11 to 28 days under a room temperature condition. The germination speed was fastest in PR of 7 to 10 days and slowest in KB of 14 to 21 days. However, intermediate speed of 10 to 14 days was associated with TF. There were considerable variations in germination rate among turfgrasses according to different conditions. Generally, PR and TF germinated well, regardless of environment conditions. However, a great difference was observed among KB varieties, when compared with others. Under a room temperature condition, total germination rate was 71.0% in Midnight and 77.7% in Award. And it increased under an alternative condition, which was 81.7% and 91.7% in Award and Midnight, respectively. However, the poorest rate was found under a constant temperature condition, resulting in 18.0% in Award and 15.3% in Midnight. These results suggest that an intensive germination test required by ISTA be needed prior to the decision of seeding rate, including early germinating vigor and germination speed as well as total germination rate. KB is very sensitive to environment conditions and thus its variety selection should be based on a careful expertise.