• International conference on construction engineering and project management
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• 2024.07a
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• pp.41-48
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• 2024

The construction industry is a significant contributor to carbon emissions, with its life cycle emissions posing significant environmental challenges. Despite its increasing importance, embodied carbon (EC) generated from the construction process is often ignored. Modular construction (MC), characterized by a combination of off-site manufacturing and on-site assembly, has been recognized for its potential to contribute to environmental benefits. However, there is still a lack of systematic explanation of urban high-rise MC. This study aims to identify whether and to what extent high-rise MC can achieve EC reductions and lay the foundation for effective carbon reductuons in the construction industry. To achieve this, the study develops a multi-level EC measurement framework for assessing EC during the construction process, using a real case to quantify the EC and determine carbon reduction performance. The innovation is a more comprehensive understanding of the boundaries of EC, as MC includes the amount of superstructure work and decoration integration. The results show that although the MC will increase EC from the transportation stage due to heavier modules, it achieves a net reduction in total EC by reducing on-site machinery energy consumption and waste rates. In conclusion, this study contributes to a better understanding of the EC emissions associated with high-rise MC, offering a valuable measurement framework for global regions evaluating the EC impacts of high-rise MC in similar contexts.

• International conference on construction engineering and project management
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• 2024.07a
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• pp.815-822
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• 2024

This study aims to facilitate the integration of digital technology into construction supervision by leveraging construction supervision checklists, a fundamental tool for inspections in this field. To achieve this, this research analyzed the tools and practices used in construction supervision, identifying 12 key supervision task types. These task types formed the basis for developing four distinct digital technologies, each tailored to specific inspection tasks based on practical feasibility. A checklist development process followed with the use of predefined criteria. Checklist items from the Ministry of Land, Infrastructure, and Transport of South Korea were analyzed and categorized according to the identified inspection task types. Digital technologies were then integrated for each task type, with corresponding supervision locations documented. This process enhanced the checklist's effectiveness by incorporating methods for digitizing tasks. The findings suggested that approximately 61% of traditional tasks could be potentially replaced by digital technology, highlighting the potential for successful digitization implementation. In addition, surveys among industry professionals provided insights into the level of productivity enhancement achievable through technology adoption compared to traditional practices, offering a basis for predicting productivity improvements across various disciplines. In conclusion, this research supports the effective integration of digital technology into construction supervision through an enhanced checklist. It also sheds light on practitioners' perceptions of technology usage and aids in developing strategies for technology adoption in this domain.

• Korean Journal of Environment and Ecology
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• v.24 no.2
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• pp.186-193
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• 2010

In order to examine the traits of sluice gate water control, halophyte community formation and their inter-relations in Saemangeum, both water level condition and halophyte community formation were analyzed periodically and spatially on the topographic map with Surfer, Saemageum Spatial Analysis System, and related field reports. The traits of water level condition are that average water level in the growing period of halophytes was similar to annual average water level, annual low level and high level appeared in the growing period, and water level was usually maintained within a range of -1.0m~0.5m above mean sea level, but it has changed more frequently year by year. Routine water level control, natural disaster prevention, construction, and civil appeal took major percentages of the reasons for sluice gate's opening and shutting. Since 2007, not only the overall control frequency of sluice gate but also its control frequency for construction and natural disaster prevention have increased outstandingly. Halophyte community had formed at a rate of 1,209ha/year in the 4,315 ha land in 2008, 6.3 times larger than in 2005, and 2,382 ha above around 1.0m was estimated to be artificially vegetated, 89.1 % of the 2,673ha-size sown area. High water level was found to be a more possible determinant than average water level or low water level in halophyte community formation and it was thought to be secondary factors whether tillage was conducted or/and whether surface sealing formed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2285-2291
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• 2013

In this study, daily based groundwater recharge was estimated under unsteady state by using groundwater table fluctuation model developed by Kim et al. (2013). This technique analyzes groundwater variation characteristics by using reaction factor related with groundwater flow and specific yield related with recharge. For the application of this model, measured groundwater level at JD Yongdam 1 and JW Konghang for 5 years were used. This model can estimate daily based groundwater recharge and the computed groundwater levels showed good agreement with measured groundwater levels. At JD Yongdam 1 and JW Konghang, the estimated recharges (rates) were 520.4~904.0mm (32.7~61.8%) and 447.4~633.4mm (24.0~45.1%), respectively. The developed model can be suggested as an efficient and precise method to estimate daily based groundwater recharge by using groundwater level data.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2277-2284
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• 2013

In this study, a groundwater table fluctuation method is suggested to predict groundwater level by means of groundwater table fluctuation due to recharge and discharge under unsteady condition. This model analyzes groundwater variation characteristics by using reaction factor related with groundwater flow and specific yield related with recharge. For the test of this model, measured groundwater level at JD Yongdam 1 and JW Konghang for 5 years (2006-2010) were used. At JD Yongdam 1, the estimated specific yield was 0.023, and the estimated reaction factor was 0.039. At JW Konghang, the estimated specific yield was 0.009 and the estimated reaction factor was 0.028, respectively. This model can estimate recharge and saturated parameters, thus it is expected that this model would be the proper tool for checking the parameter of hydrologic model and percolation features.

• International Journal of Highway Engineering
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• v.9 no.2 s.32
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• pp.27-37
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• 2007

This research was conducted to determine the optimum lifting positions on precast concrete slabs for precast concrete pavement construction, based on the analysis of concrete stress distribution under various lifting conditions. To analyze stresses in concrete slabs, the finite element method was implemented and a numerical model of the precast slab that was going to be used in the experimental construction was developed. Changes in the stress distribution due to the lifting angle were investigated because slab lifting is not always performed in the perpendicular direction to the slab surface. In addition, the effect of the lifting level, the distance between the neutral axis of the slab and the lifting point, on the stress distribution was investigated since the lifting point is not always at the neutral axis of the slab. To consider the actual steel design of the precast slab, the effect of the reinforcement near the lifting point was also investigated. From this study, the optimum lifting positions of the precast slabs were determined according to the lifting angle and level, and the results were compared with the lifting positions used in the PCI standards.

• Korean Journal of Construction Engineering and Management
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• v.7 no.2 s.30
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• pp.138-147
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• 2006

The objective of this research is to explore a more precise forecasting method by applying Case-based Reasoning (CBR). The newly suggested method in this study enables project managers to forecast monthly expenditures with less time and effort by retrieving and referring only projects of a similar nature, while filtering out irrelevant cases included in database. For the purpose of accurate forecasting, 1) the choice of the numbers of referring projects and 2) the better selection among three levels ? which include a 20-work package level, a 7-major work package level, and a total sum level analysis, were investigated in detail. It is concluded that selecting similar projects at $12{\sim}19%$ out of the whole database will produce a more precise forecasting. The new forecasting model, which suggests the predicted values based on previous projects, is more than just a forecasting methodology; it provides a bridge that enables current data collection techniques to be used within the context of the accumulated information. This will eventually help all the participants in the construction industry to build up the knowledge derived from invaluable experience.

• Journal of Environmental Health Sciences
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• v.32 no.2 s.89
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• pp.118-125
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• 2006

The road traffic noise has been increasing broader effects on urban areas as well as rural areas because of rapidly increasing traffic volume and newly-constructed roads. 10 sites in building development areas were selected and the noise levels were measured by the apartment floors and by the various block plans of apartment complex. The results showed that the highest traffic noise level was obtained at the 5 and 7 floors on the apartment floors. On the basis of 7 floor with the highest level, the correction coefficient obtained from noise reduction by each floor and measurement point was -5.54 dB(A)(1st floors), -0.96 dB(A)(3rd floors), -0.38 dB(A)(5th floors), 0.00 dB(A)(7th floors), -1.98 dB(A)(l0th floors), -3.10 dB(A)(13th floors), -3.45 dB(A)(15th floors). The level of road traffic noise in the arrangement construction of right angle was about 3.0 dB(A) at N-4 point and 2.1 dB(A) at N-6 point lower than that of a plan figure, respectively. The results suggested that application of correction coefficient obtained by the apartment floor and by the arrangement construction can be improved in road traffic noise.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.3
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• pp.115-125
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• 1992

The variation of flow pattern caused by the topographical change of Kwangyang bay, is analyzed using the numerical tidal model for the depth-integrated two- dimensional long wave equation. The results of study are as follows. Due to pier construction, the area of water surface is deceased and the water inflow into the Kwangyang bay is reduced. For this result, at the outer bay of Myo island, the tidal range is slightly increased. And at the inner bay, water level is dropped generally, and especially at the time of low water tide, the phenomena of water level drop obviously appears. According to the variation pattern, flow velocities is lower than those of non-construction condition over the Kwangyang bay. But at the channel(from Kwangyang east stream) flowing into the east Kwangyang bay, for the contraction of channel profile, flow velocity is increased. The study based on the 100 year frequency design flood discharge from Sueocheon(river) and Dongcheon(river) which are flowing into the bay and Seomjin River flowing along the boundary of the bay is also performed. During the spring tide condition, the results showed the rise of water level about 1.2 m at Seomjin River Estuary and 0.3 m at inner bay is occurred.

• Ecology and Resilient Infrastructure
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• v.3 no.2
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• pp.110-116
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• 2016

The rapid expansion of buildings and paved roads increases the risk of flood disaster in an urban area. One of the solutions can be the use of permeable pavements. This study evaluated the permeability of permeable blocks used for the roadway pavement. Joint fillers and mat sands of the investigated blocks met the corresponding standards. The flexural strength of the blocks was 5.29 MPa to meet these standards. Based on interior permeability test results after pollution, the four products evaluated were categorized into the following three levels: One for the $1^{st}$ level, one for the $2^{nd}$ level and two for the $3^{rd}$ level. From the field permeability test and pervious concrete infiltration test results nine months after their construction, all the products except one passed the quality standards of 0.1 mm/s.