• Korean Journal of Construction Engineering and Management
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• v.19 no.5
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• pp.70-80
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• 2018

Recently, the construction industry has lively utilized system forms to improve the work productivity and safety of form work, and the beam table form is one of them. However, the beam table form is used limitedly for the construction of buildings where the same beam size is applied to every floor. To make it possible to apply the beam table form to a building where different beam sizes are designed according to the uses of floors, it was analyzed that among the components of the beam table form, the beam bracket, should be able to flexible adjust the size of the beam form only with simple operation. Therefore, the purpose of this study is to propose the conceptual design of "an adjustable beam bracket for beam table form" that allows the adjustment of beam form size with simple operation and has excellent applicability to construction sites as well. In case this study's conceptual design of adjustable beam bracket for beam table form is fabricated into a real thing, it is expected that the beam table form will be applicable to even buildings where different beam sizes are designed according to the uses of floors, thereby contributing to the improvement in the work productivity and safety of form work.

• Nuclear Engineering and Technology
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• v.53 no.9
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• pp.3068-3084
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• 2021

Investigations of large commercial aircraft impact effect on nuclear power plant (NPP) buildings have been drawing extensive attentions, particularly after the 9/11 event, and this paper aims to experimentally assess the damage and vibrations of NPP buildings subjected to aircraft crash. In present Part I, two shots of reduce-scaled model test of aircraft impacting on NPP building were carried out. Firstly, the 1:15 aircraft model (weighs 135 kg) and RC NPP model (weighs about 70 t) are designed and prepared. Then, based on the large rocket sled loading test platform, the aircraft models were accelerated to impact perpendicularly on the two sides of NPP model, i.e., containment and auxiliary buildings, with a velocity of about 170 m/s. The strain-time histories of rebars within the impact area and acceleration-time histories of each floor of NPP model are derived from the pre-arranged twenty-one strain gauges and twenty tri-axial accelerometers, and the whole impact processes were recorded by three high-speed cameras. The local penetration and perforation failure modes occurred respectively in the collision scenarios of containment and auxiliary buildings, and some suggestions for the NPP design are given. The maximum acceleration in the 1:15 scaled tests is 1785.73 g, and thus the corresponding maximum resultant acceleration in a prototype impact might be about 119 g, which poses a potential threat to the nuclear equipment. Furthermore, it was found that the nonlinear decrease of vibrations along the height was well reflected by the variations of both the maximum resultant vibrations and Cumulative Absolute Velocity (CAV). The present experimental work on the damage and dynamic responses of NPP structure under aircraft impact is firstly presented, which could provide a benchmark basis for further safety assessments of prototype NPP structure as well as inner systems and components against aircraft crash.

• Economic and Environmental Geology
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• v.52 no.1
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• pp.91-106
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• 2019

The Donghachong tomb from Royal Tombs at Neungsanri is composed of 15 sides including the floor, and the most highly proportion of rock, two-mica granite, are used on the 7 sides (46.6%). Also, augen gneiss consist with another 3 sides (20.0%), and each of the remaining 3 sides (6.7%) are made up of granodiorite, gneissous granite and leucocratic granite, all of which were used to comprise the tabural stone. Meanwhile, the two floors of the burial chamber and the front chamber, are made up of brick-shaped amphibole schist (13.3%). These rocks are occurred in the Buyeo area and their provenance sites are located at the side of Guemgang river. The Memorial Stone for Liu Renyuen in Tang China is a typical augen gneiss showing distinct schistosity and augen texture. This rock has the same petrographic characteristics with the rocks used to build the Donghachong tomb, Sanjikri dolmens and Setapri pagoda in Buyeo. This augen gneiss is distributed from the Jeungsanri in Buyeo to Dukjiri in Gongju as a large scaled rock body, and where currently are the quarries to produce stone aggregates, garden and landscape rocks. Thus, it is highly probable that the site around Buyeo was the source area of augen gneisses since the Bronze Age. However, while augen gneiss is easier to form into shapes it should have disadvantages when it comes to painting on the tomb wall because of their petrographic characteristics of low strength and dark color. Therefore, it is very intriguing to investigate which transportation method the people of Baekje chose with consideration of the distance and terrain, efficiency and convenience.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.3
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• pp.1-8
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• 2019

Steel elevator pit was developed for the purpose of minimizing the excavation, simplifying the construction of the frame and economical efficiency by improving the problems that occurred in the existing reinforced concrete. It is common to apply conventional RC method through excavation to underground structures such as underground floor collector well and elevator pit. In recent years, the use of steel collector well and steel elevator pits to reduce construction costs by minimizing the materials of steel and concrete has been continuously increasing. The steel elevator pit is an underground structure and then the performance of the welding part and the structure system is important. Specimen with only steel plate and concrete without studs could support the load more than 3 times than the specimen with deck only. Therefore, even if there is no stud, the deck (steel plate) rib is formed and the effect of restraining the steel plate and the concrete during the bending action can be expected. However, since sudden fracture in the elevator pit may occur, stud bolt arrangement is necessary for the composite effect of steel plate and concrete. It is expected that the bending strength can be expected to increase by about 15% or more depending with and without stud bolts.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.12
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• pp.340-352
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• 2018

This study presents a method to find the extant central halls with the plan most similar to the remains and to find out and compare the architectural style of extant buildings for the restoration. In the Joseon dynasty, there existed both remains and the extant hall. In particular, the $3{\times}2Kan$ hall is the minimum size that functions as the hall, so the number of comparison articles is small. The subjects are three remains and 29 Extant Halls. The absolute size of the comparison articles are the Area, Ratio of front/side, and the relative sizes are the Ratio of front Eokan/Hyeopkan and Ratio of the front Eokan/the side row. The Daeungjeon remain in Bugjijangsa is similar in absolute size and relative sizes to Oeosa daeungjeon. The Bubdang remain in Seonchalsaji is similar to Sangwonsa daeungjeon in the Area and Ratio of front/side, and similar to Daejeogsa geungnakjeon in the Ratio of front/side and Ratio of front Eokan/Hyeopkan. The Bubdang remain in Seungseonsaji is similar to Seodongsa daeungjeon in the Area, Ratio of front Eokan/Hyeopkan and Ratio of the front Eokan /the side row. Consequently, this method has high value as a way to expand by other comparison articles.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.2
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• pp.1-10
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• 2021

In this study, a circular pipe can be installed by suction pressure for construction on soft ground with a low-water level. A series of laboratory-scale model tests were conducted in sandy ground to comprehend the suction pressure of the circular pipe in low-water levels. For repeated tests on saturated sandy soil, a container was mounted with three vibration generators on the floor. A repetitive vibration was applied using the vibration system for ground compaction. In the model tests, different diameters and thicknesses on saturated sandy soil with a water depth were considered. The result showed that the suction pressure increased with increasing penetration depth of the circular pipe. Moreover, the suction pressure required to penetrate the pipe decreased with increasing diameter. In the low-water level, the total suction pressure measured at the top lid increased because additional suction pressure is required to lift the water column. On the other hand, this led to a decrease in suction pressure to penetrate the circular pipe because the weight of the water column is applied as a dead load. Therefore, it is necessary to consider the water level to design the required suction pressure accurately.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.12
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• pp.888-895
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• 2020

In the construction industry, off-site construction (OSC) is drawing attention as a production method due to changes in working hours and the supply and demand of manpower. In 1991, there was a policy of spreading and expanding the use of precast concrete (PC) apartment homes, but they have not been actively used so far since they were discontinued due to quality problems. In this study, policy tasks were analyzed to motivate the application of OSC-based PCs in the apartment housing sector, and policy directions were derived by conducting focus group interviews (FGI). Nine policies are suggested regarding the following topics: PC apartment supply quantity provision, priority application of public housing, priority supply of public housing, preferential floor area ratio, funding, tax support, improvement of business area structure, improvement of delivery method, factory certification system, and training of experts. The results of the FGIs are as follows. First, in order to revitalize PC apartment homes, leading efforts from the public sector are required. Second, rather than reorganizing the business sector or introducing a new delivery method, a policy direction that induces the strengthening of cooperation is desirable. Third, PC activation should be promoted on an institutional basis for securing appropriate construction costs and quality.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.1
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• pp.77-84
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• 2022

A submarine power cable is a transmission cable for carrying electric power below the surface of the water. Recently, submarine cables transfer power from offshore renewable energy schemes to shore, e.g. wind, wave and tidal systems, and these cables are either buried in the seabed or lie on the ocean floor, depending on their location. Since these power cables are used in the extreme environments, they are made to withstand in harsh conditions and temperatures, and strong currents. However, undersea conditions are severe enough to cause all sorts of damage to offshore cables, these conditions result in cable faults that disrupt power transmission. In this paper, we explore the design criteria for such cables and the procedures and challenges of installation, and cable transfer splicing system. The specification of submarine cable designed with 3 circuits of 154kV which is composed of the existing single circuit and new double circuits, and power capacity of 100MVA per cable line. The determination of new submarine cable burial depth and cable arrangement method with both existing and new cables are studied. We have calculated the permission values of cable power capacity for underground route, the values show the over 100MW per cable line.

• Journal of Platform Technology
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• v.10 no.2
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• pp.10-19
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• 2022

Moving assistant devices for people who are difficult to move are becoming electric-powered and automated. These moving assistant devices are not suitable for moving stairs at which the height between floor surfaces is different because these devices are designed and manufactured for flatland moving. An electric-powered and automated moving assistant device should change direction or stop when it approaches stairs in a movement direction. If the user or automatic control system does not change direction or stop in time, a moving assistant device can roll over or collide with stairs. In this paper, we propose a stairs detection method by using oblique distance measured by one sensor tilted to flatland. The method proposed in this paper can detect upward or downward stairs by using a difference between a predicted and measured oblique distance in considering a tilted angle of a sensor for measuring an oblique distance and installation height of the sensor on a moving object. Before the device enters a stairs region, if our proposed method provides information about detected stairs to a device's controller, the controller can do adequate action to avoid the accident.

• Journal of The Korea Institute of Healthcare Architecture
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• v.28 no.3
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• pp.47-54
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• 2022

Purpose: This study presents the analysis on space usage of delivery departments in regional public hospitals. The results intention is to achieve improvement of the delivery environment for the mothers and newborns regarding exposure prevention and efficient infection control. The purpose of this study is to provide fundamental data for architectural plans and guidelines for the delivery department. Method: The investigation and analysis were based on research papers, legal systems, public medical statistical data, and the architectural floor plan drawing. For research, 20 regional public hospitals with an operating delivery room were excluded. Regarding data accessibility, 15 regional public hospitals were selected. Results: To overcome the increased vulnerability of the delivery department, the research results of basic data is provided for the establishment to address urgent needs and rapid response. Thus, the research results are as follows: Firstly, the delivery department needs to respond promptly according to the type of patients. For example, in a case of emergency surgery, a connected circulation plan with the related departments is needed. Secondly, for the environment of the delivery area, alleviating anxiety is imperative for pregnant patients and guardians, labor, childbirth, and recovery. Therefore, these needs must be addressed for treatment space and circulation. Lastly, the delivery department is classified into three areas for analysis: access area, treatment area, and support area. In most of the delivery departments of the 15 selected hospitals, there is no space for the access and support area except for the labor and delivery rooms in the treatment area. For the access area, a waiting area, changing room for pregnant women and guardians, and a storage space for contaminated linens are required for infection prevention, safety, and efficiency. For the treatment area, childbirth processes and circulation should have space reserved for labor, delivery, recovery, examination, and treatment. In preparation for an emergency during childbirth, emergency response measures and supporting space needs to be established. For the support area, circulation and rooms are to be designed for medical staff support, activity space, storage and transportation of equipment, and urgent medical treatment. Implications: Along with the low fertility rate and the decrease of medical institutions that operate delivery departments, for the purpose of establishing a public medical service system and a healthy medical environment for mothers and newborns, the researched information demonstrates basic data on space plan of delivery departments in regional public hospitals.