• Asian Journal of Turfgrass Science
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• v.16 no.1
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• pp.31-40
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• 2002

This study was conducted to analyze the correlation of soil physical properties and growth of turfgrass on the ground of Olympic-mainstadium. Soil hardness and turf visual quality were measured at 77 plots (10m x 10m divided each) independently and analyzed correlation later. Physicochemical properties of the topsoil analyzed from three typical levels of the severely, moderately, slightly compacted areas. The ground showed high hardness at the center circle and the goal line, but low at the end line areas. On the contrary, visual quality rate of turfgrass was low at the center circle and the goal line, but high at the end line areas. The correlation was shown a significant negative value on soil hardness between turf visual quality Soil hardness seems to be accelerated by the improper soil texture of sandy loam which contained a large amount of finer particle of silt (10.7%) and clay (11.1%) which values exceeded for USGA (United State Golf Association) recommendation. Deterioration of turf quality resulted initially from improper construction and followed by high soil compaction with continuous uses of the ground without proper maintenance. To perform the international quality of the turf ground, the initial construction procedures should be followed by standard specifications of sport ground.

• Korean Journal of Construction Engineering and Management
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• v.17 no.1
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• pp.56-65
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• 2016

Many cases have mentioned the effect by applying BIM on the media such as at conferences, workshops, reports, ect. These cases reported that costs could be saved directly by prevention the need to re-do and reconstruct caused by using BIM. BIM users mentioned that using BIM has potential value in saving costs. The benefits of the BIM include intangible value that cannot be estimated in costs, such as reducing work time and improving productivity. However, the financial value of using BIM, such as Return on Investment, has not yet been exposed, and BIM users have a negative view of the financial value of BIM in Korea. Therefore, this study has researched the effects of applying BIM on construction estimate services in view of business productivity, not finance. This study compared the traditional and BIM based estimation, and verified the effect of estimating BIM through work sampling. This study investigated a precondition for getting the effects of BIM based estimation. The results show a need for BIM education, 3D Modeling standards, and database on quantity in order to improve product ivity and reduce work time on BIM based estimation

• The Journal of Korean Society for Radiation Therapy
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• v.15 no.1
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• pp.11-18
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• 2003

The concrete is usually used to build a radiation therapy facility and the enough concrete thickness for high energy x-ray beam is about 1 meter. But if the space is not enough to build a radiation therapy facility with concrete, the substitute for concrete is needed, and the Ledite can be a good substitute for concrete. In this study, we compared the Ledite with the concrete. The comparing list are the needed shielding thickness, the period of construction and the cost.

• Journal of the Korea Institute of Building Construction
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• v.11 no.6
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• pp.597-608
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• 2011

It has been often noted as a problem that as there are no objective and clear criteria for the repair cost estimate of persistent defects, when a claim arises in relation to an apartment construction, significantly different amounts of compensation may be given for similar defects based on the experience and tendencies of the construction experts asked to make a judgment. For this reason, this research aims to present defect managers with a more reasonable and objective estimation criteria and a system to determine the repair cost of defects based on an analysis of relevant factors. The research findings show that the historical cost system is applied first, and then a standard of estimation is used to estimate the cost for the items that are not included in the historical cost system. The criteria for the repair cost for each defect is as follows: the repair cost for defects arising from a regulation violation is determined by calculating the reconstruction cost of the parts in question after demolishing them; the repair cost for progressive defects is determined based on a contribution ratio proportional to the age of the building; the repair cost for repetitive defects is calculated by considering an alternative to maximize the intended function of the defective parts; and the repair cost for value depreciation defects is determined based on the ratio of the warranty period to the lapsed years. However, repair cost estimation for dual value depreciation defects should be studied in future research.

• Journal of the Korean Geosynthetics Society
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• v.19 no.1
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• pp.75-82
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• 2020

There have been often cases of collapse for geogrid reinforced soil (GRS) retaining wall. Hence, social interest in the reinforcement and restoration of the collapsed GRS wall is increasing day by day. However, there are only few researches. For this reason, a series of numerical analyses using the Plaxis 2D program was conducted in this study to analyze the suitable reinforcement methods that can be applied on the existing damaged GRS wall caused by overturning of the modular blocks facing and the surface settlement at the backfill as the results from the design failure. The restoration plan used in this study is composed of two cases: (Case 1) soil nailing reinforcement and reinforced concrete (RC) wall facing construction on the existing damaged GRS wall; and (Case 2) removal of the entire damaged GRS wall and then reconstruction. The results on the internal stability of the GRS wall show that Case 1 obtained a greater safety factor than Case 2 for tensile force while Case 2 had a greater safety factor than Case 1 for pullout failures. Case 1 was found to be more stable than Case 2 in terms of the global slope safety by shear strength reduction method and the external deformation behavior by numerical analysis. In this study, the existing damaged GRS wall which was reinforced using Case 1 method shows more stable external behavior.

• Land and Housing Review
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• v.2 no.4
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• pp.397-406
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• 2011

This research aims to develop various infill-systems for practically applying to long-life housing with 100-year durability and flexibility as a strategy for realizing sustainable residential environment. Especially, the developed infill-systems & technologies were concentrated to the mock-up house applied with the standard model of long-life housing, and their in-situ applicability by a phase, experts' consultation, and questionnaire survey were also evaluated. This research was executed to divide by 3 phases. In the First phase infill-systems for a housing unit of $84m^2$ exclusive use area as well as a support of whole structure and infill-systems including dry wall, and windows were constructed, and their in-situ applicability were evaluated. In the Second phase vertical integration of upper and lower housing units of $50m^2$ and $40m^2$ exclusive use area was investigated the first in domestic for 3 housing units of $50m^2$ exclusive use area. In addition, various infill-systems including the horizontal expansion of $50m^2$ and $10m^2$ exclusive use areas were also constructed and evaluated on their in-situ applicability. In the third phase diverse performance tests and field investigation for in-situ verifying of dry Ondol, developed this research, were executed to improve their practicability. Inner dry walls were taken apart, moved and re-constructed for verifying their practicability to investigate 3R-Reduce, Reuse and Recycle-realization too.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.3
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• pp.97-103
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• 2011

In this research, a small-scaled laboratory test and FEM analysis have been carried out to evaluate the feasibility of field construction with couple of recycled materials, such as in-situ soil, water-treatment sludge, and crumb rubbers. A static loading, which simulates the real traffic load, was adopted in lab test. The test was carried out, according to simulated field construction stages, such as excavation, bedding materials and pipe installation, placing and curing of controlled low strength materials, and simulated traffic loading. Couple of measuring instruments were adopted. The maximum vertical and horizontal deformations were 0.83% and 1.09%, during placing the CLSM. The measured vertical and horizontal deformations with curing time were 0.603mm and 0.676mm, respectively. The reduction effect of vertical and lateral earth pressure was relatively big. Also, FEM analysis was carried out to get the deformation, earth pressure and strain of PVC with different Controlled Low Strength Materials(CLSM) materials.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.4
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• pp.221-232
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• 2021

Most of measurement sensors used for maintenance are continuously exposed to various environmental factors such as transportation and rainfall, so the possibility of breakage increases gradually. The maintenance measurement sensor of domestic subway tunnel shows an average of 14.2% to 14.8% of loss rate after about 5 to 6 years from installation, and it shows a sensor loss rate of about 13.9% in case of foreign countries. As a result, it can be seen that an average of 15% of maintenance measurement sensors at home and abroad cannot send measuring values after 5~6 years. In order to continuously collect accurate data, measurement data must be recovered by performing repair or replacement of the sensor, but some lost measurement sensors are buried after installation. So, there are many difficulties in repairing sensors, including cost and time. Therefore, in this paper, we propose lost measurement sensor data estimation technology based on data trend analysis using adjacent sensors.

• Korean Journal of Construction Engineering and Management
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• v.20 no.1
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• pp.22-31
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• 2019

The application of BIM that can manage and integrate information generated during the entire life cycle of buildings in domestic and overseas construction projects is becoming active. When BIM is utilized in the construction phase, it can shorten the construction period, reduce the occurrence of reworks and improve collaboration capability. However, there are limitations in applying BIM to the construction phase due to the insufficient definition level of domestic BIM guidelines and inadequate design standards. In this regard, this study developed BIM model requirements checklist for the application of BIM in the construction phase. To develop the checklists, 21 domestic and overseas BIM guidelines, three public construction projects and four private construction projects to which construction BIM was applied, were analyzed. Based on the guidelines and cases, a total of 62 construction BIM model requirements (31 model objects and 31 attribute rules) and proposed construction BIM model requirement checklists by dividing the 61 requirements according to the requirement and purpose for utilization were identified. It is expected that the practical applications of the checklists proposed in this study will improve the level of BIM model in construction phase. In addition, this study has its significance as a basic research that can be used in the development of standardized guidelines for BIM model in construction phase from academic aspects.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.313-320
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• 2018

The purposes of this study were to verify the status of Barrier Free Design Certification in the center for the elderly. To achieve these purposes, the architectural characteristics of the center for elderly and the status of Barrier Free Design Certification was analyzed. The results of this study were as follows. (1) The functional composition of centers for the elderly are similar regardless of the location, but the area and shape of the plot are very different according to the location. (2) According to an analysis on the status of Barrier Free Design Certification in centers for elderly, the sanitation and intermediate facilities are necessarily considerable adjustment. (3) For the accessability and conveniences of Barrier Free Design Certification in a small building, such as centers for the elderly, they are necessary to simplify the self-assessment documents, minimize the period for judging, and reducing the fees for certification.