• Proceeding of KASS Symposium
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• 2008.05a
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• pp.49-52
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• 2008

Structural Wood is developed by purpose to make efficient use of wood resources. The biggest advantage of structural wood is stable as strength is high than wood product that is used by structure in existing. Order manufacture according to design details is available. It Is used to main structure elements to large spatial structure. Structure wood kind utilizes Glulam, prefabricated wood I-joists and laminated veneer lumber(LVL) and so on. Structural Design and construction of Open-air Stage Roof Structure is described in the presented paper. Architectural roof materials is used to PVF/PFLT membrane. Column and diagonal members is used to steel members(SS400), and Cantilever beam is used to Glulam assembled with different Grade laminations(10S-28B).

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.5
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• pp.567-578
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• 2007

Statement of problem: The endodontically treated tooth is generally restored with post and core, owing to the brittle and the loss of large amount of tooth structure. As periodontal treatment was developed, there are many cases that periodontally involved teeth used in prosthetic treatment. Purpose: The purpose of this study was to analyze the stress distribution in the dentin and post structures by the various post materials and the amount of remaining alveolar bone height. Material and method: The 3-dimensional finite element models of mandible 1st premolars were divided into six types according to the various amount of remaining alveolar bone and post type. All types were modeled using equal length, diameter and shape of the post. Three types of post and core materials were used: prefabricated titaniumpost and amalgam core, prefabricated stainless steel post and amalgam core, and cast gold post and core. 300 Newton force was applied to functional cusp of mandible 1st premolar. Results: The results were as follows: First, there was no apparent difference in the pattern of stress distribution according to the alveolar bone condition concentrate on the post middle area. Second, there was difference in pattern of stress distribution according to the core materials, gold post and core generated same than amalgam core. Third, there was no apparent difference in the pattern of stress distribution within the dentin according to the post and core materials. But a cast gold post and core generated the lowest maximum stress value, a stainless steel post generated the highest maximum stress value. Fourth, in the reduced alveolar bone model, maximum stress value is 1.5 times than that of the normal alveolar bone model. Conclusion: Within the limitations of this study, to provide minimal stress to the root with alveolar bone reduced, the post length may be as long as apical seal was not destroyed. To prevent fracture of tooth, it is rational to use gold alloy which material was good for stress distribution for post materials.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.6
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• pp.131-138
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• 2014

The steel structure fabrication plant certification program was enacted as a part of the construction technology management act, article 24-3, to improve the quality of steel construction after the decay falling accident of Seongsu Bridge in 1994. However, the national certification program for structural precast concrete that is a prefabricated construction products produced by casting concrete in plant is not implemented yet. So, to introduce the proper certification system for precast concrete, the quality certification programs of North America, Europe and Japan are surveyed. In North America, the organizations that manage the plant certification programs are PCI, NPCA, CPCI and so on. Sales of precast concrete elements in Europe are governed by the construction products regulation 305/2011. Therefore, CE marking is mandatory from July 2013 for all construction products including precast concrete. In Japan, precast concrete products used in civil engineering are certificated by JIS mark, product certification system and plants for manufacturing precast concrete building elements are audited by Japan Prefabricated Construction Suppliers and Manufacturers Association. Based on these survey studies, in this paper is described an adaptation of precast concrete plant certification to comport with the certification system in Korea.

• Computers and Concrete
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• v.17 no.1
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• pp.1-27
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• 2016

Final construction project cost is significantly determined by construction rate. The Industrialized Building System (IBS) was promoted to enhance the importance of prefabrication technology rather than conventional methods in construction. Ensuring the stability of a building constructed by using IBS is a challenging issue. Accordingly, the connections in a prefabricated building have a basic, natural, and essential role in providing the best continuity among the members of the building. Deficiencies of conventional precast connections were observed when precast buildings experience a large induced load, such as earthquakes and other disasters. Thus, researchers aim to determine the behavior of precast concrete structure with a specific type of connection. To clarify this problem, this study investigates the capacity behavior of precast concrete panel connections for industrial buildings with a new type of precast wall-to-wall connection (i.e., U-shaped steel channel connection). This capacity behavior is compared with the capacity behavior of precast concrete panel connections for industrial buildings that used a common approach (i.e., loop connection), which is subjected to monotonic loading as in-plane and out-of-plane loading by developing a finite element model. The principal stress distribution, deformation of concrete panels and welded wire mesh (BRC) reinforcements, plastic strain trend in the concrete panels and connections, and crack propagations are investigated for the aforementioned connection. Pushover analysis revealed that loop connections have significant defects in terms of strength for in-plane and out-of-plane loads at three translational degrees of freedom compared with the U-shaped steel channel connection.

• International conference on construction engineering and project management
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• 2020.12a
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• pp.157-166
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• 2020

Automated rebar fabrication, which requires effective information exchange between model designers and fabricators, has brought the integration and interoperability of data from different sources to the notice of both academics and industry practitioners. Industry Foundation Classes (IFC) was one of the most commonly used data formats to represent the semantic information of prefabricated components in buildings, whereas the data format utilized by rebar fabrication machine is BundesVereinigung der Bausoftware (BVBS), which is a numerical data structure exchanging reinforcement information through ASCII encoded files. Seamless transformation between IFC and BVBS empowers the automated rebar fabrication and improve the construction productivity. In order to improve data interoperability between IFC and BVBS, this study presents an IFC extension based on the attributes required by automated rebar fabrication machines with the help of Information Delivery Manual (IDM) and Model View Definition (MVD). IDM is applied to describe and display the information needed for the design, construction and operation of projects, whereas MVD is a subset of IFC schema used to describe the automated rebar fabrication workflow. Firstly, with a rich pool of vocabularies practitioners, OmniClass is used in information exchange between IFC and BVBS, providing a hierarchy classification structure for reinforcing elements. Then, using International Framework for Dictionaries (IFD), the usage of each attribute is defined in a more consistent manner to assist the data mapping process. Besides, in order to address missing information within automated fabrication process, a schematic data mapping diagram has been made to deliver IFC information from BIM models to BVBS format for better data interoperability among different software agents. A case study based on the data mapping will be presented to demonstrate the proposed IFC extension and how it could assist/facilitate the information management.

• Journal of Korean Society of Steel Construction
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• v.27 no.5
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• pp.471-481
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• 2015

Modular building is a prefabricated construction system for building where factory-produced pre-engineered modular units are delivered to site and assembled as substantial elements of a building. There are two basic kinds of modular structures. One is a load-bearing wall structure designed to transfer the load through longitudinal walls. The other is a frame structure composed of columns and beams. For frame structure, square hollow section is often used as a column member and channel as a beam member in modular unit. Lower and upper modules are fasten with bolts via a pre-installed access hole in the SHS column. However, the access holes can weaken the panel zone that would affect the behavior of beam to column connection. The 5 specimens of beam to column connections with parameters of access hole, column thickness and diaphragm were made and this paper describes the test results.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.3
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• pp.288-299
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• 2003

Statement of problem: Many kinds of post and core systems are in the market, but there are no clear selection criteria for them. Purpose: The purpose of this study was to compare the flexural strength and modulus of elasticity of core materials, and measure the bending strength of post systems made of a variety of materials. Material and Methods: The flexural strength and elastic modulus of thirteen kinds core buildup materials were measured on beams of specimens of $2.0{\times}2.0{\times}24{\pm}0.1mm$. Ten specimens per group were fabricated and loaded on an lnstron testing machine at a crosshead speed of 0.25mm/min. A test span of 20 mm was used. The failure loads were recorded and flexural strength calculated with the measured dimensions. The elastic modulus was calculated from the slopes of the linear portions of the stress-stram graphs. Also nine kinds commercially available prefabricated posts made of various materials with similar nominal diameters, approximately 1.25mm, were loaded in a three-point bend test until plastic deformation or failure occurred. Ten posts per group were tested and the obtained data were anaylzed with analysis of variance and compared with the Tukey multiple comparison tests. Results: Clearfil Photo Core and Luxacore had flexural strengths approaching amalgam, but its modulus of elasticity was only about 15% of that of amalgam. The strengths of the glass ionomer and resin modified glass ionomer were very low. The heat pressed glass ceramic core had a high elastic modulus but a relatively low flexural strength approximating that of the lower strength composite resin core materials. The stainless steel, zirconia and carbon fiber post exhibited high bending strengths. The glass fiber posts displayed strengths that were approximately half of the higher strength posts. Conclusion: When moderate amounts of coronal tooth structure are to be replaced by a post and core on an anterior tooth, a prefabricated post and high strength, high elastic modulus core may be suitable. CLINICAL IMPLICATIONS In this study several newly introduced post and core systems demonstrated satisfactory physical properties. However when the higher stress situation exists with only a minimal ferrule extension remaining a cast post and core or zirconia post and pressed core are desirable.

• Journal of KIBIM
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• v.9 no.3
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• pp.30-40
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• 2019

Extraction of fabrication documents is very important because it provides information related to tasks of fabrication and construction. Therefore, in the case of a prefabricated member such as a steel structure, it is necessary to improve the productivity of fabrication documents through 3D BIM. However, research and evidence data on direct comparison analysis of 3D BIM-based documents extraction versus 2D CAD-based documents extraction are hard to find. Thus, this study focuses on productivity analysis of 3D BIM based fabrication documents extraction. In this study, the productivity data of fabrication documents extraction for module construction of EPC project was analyzed. For the productivity analysis, a case study on the fabrication documents of Module A (1,965 sheets) and Module B (1,216 sheets) was conducted. Fabrication documents for each module include general arrangement drawing, assembly drawing, single part drawing and single plate drawing. Comparison of 2D CAD based fabrication documents extraction and 3D BIM based fabrication documents extraction, the productivity for the entire work was improved from 17 hours to 16 hours for Module A and 12 hours to 7 hours for Module B. Especially, the productivity of the assembly drawings, which occupies a large part of the fabrication documents, was improved by about 48.75% from the total time required from 281 hours to 144 hours.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.133-144
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• 2009

Incheon Bridge, 18.4 km long sea-crossing bridge, will be opened to the traffic in October 2009 and this will be the new landmark of the gearing up north-east Asia as well as the largest & longest bridge of Korea. Incheon Bridge is the integrated set of several special featured bridges including a magnificent cable-stayed girder bridge which has a main span of 800 m width to cross the navigation channel in and out of the Port of Incheon. Incheon Bridge is making an epoch of long-span bridge designs thanks to the fully application of the AASHTO LRFD (load & resistance factor design) to both the superstructures and the substructures. A state-of-the-art of the geotechnologies which were applied to the Incheon Bridge construction project is introduced. The most Large-diameter drilled shafts were penetrated into the bedrock to support the colossal superstructures. The bearing capacity and deformational characteristics of the foundations were verified through the world's largest static pile load test. 8 full-scale pilot piles were tested in both offshore site and onshore area prior to the commencement of constructions. Compressible load beyond 30,000 tonf pressed a single 3 m diameter foundation pile by means of bi-directional loading method including the Osterberg cell techniques. Detailed site investigation to characterize the subsurface properties had been carried out. Geotextile tubes, tied sheet pile walls, and trestles were utilized to overcome the very large tidal difference between ebb and flow at the foreshore site. 44 circular-cell type dolphins surround the piers near the navigation channel to protect the bridge against the collision with aberrant vessels. Each dolphin structure consists of the flat sheet piled wall and infilled aggregates to absorb the collision impact. Geo-centrifugal tests were performed to evaluate the behavior of the dolphin in the seabed and to verify the numerical model for the design. Rip-rap embankments on the seabed are expected to prevent the scouring of the foundation. Prefabricated vertical drains, sand compaction piles, deep cement mixings, horizontal natural-fiber drains, and other subsidiary methods were used to improve the soft ground for the site of abutments, toll plazas, and access roads. Light-weight backfill using EPS blocks helps to reduce the earth pressure behind the abutment on the soft ground. Some kinds of reinforced earth like as MSE using geosynthetics were utilized for the ring wall of the abutment. Soil steel bridges made of corrugated steel plates and engineered backfills were constructed for the open-cut tunnel and the culvert. Diverse experiences of advanced designs and constructions from the Incheon Bridge project have been propagated by relevant engineers and it is strongly expected that significant achievements in geotechnical engineering through this project will contribute to the national development of the longspan bridge technologies remarkably.

• Land and Housing Review
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• v.12 no.4
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• pp.103-117
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• 2021

With the current rapid changes in population and technology, the long-lastig housing certification system is a means of prolonging the physical and functional lifespan of a building. The certification requires differentiation between the structure and infill elements to allow for variability and ease of repairs. This works well with prefabricated houses so this study investigated the possibility of applying the long-lastig housing certification requirements to apartment construction using off-site construction (OSC) methods focused on the installation of bathrooms (plumbing and toilet) that differ from the traditional wet method. This study examined three different sized floor plans at 22 m², 46 m², and a combined one resulting in 69 m². The larger 69 m² plan utilized a removeable non-load bearing wall to increase flexibility in the layout of the floorplan. The apartments are constructed of steel reinforced concrete composite columns on a 9 m × 10.5 m grid with integrated slabs. The exterior and interior infill walls are all non-load bearing with some containing plumbing. This separation of the structure and infill walls can help meet some of the criteria in the long-lastig housing certification, particularly with the ease of repairs. Technologies that facilitate the replacement of infill elements that contain plumbing and other building services can benefit the nation by reducing carbon emissions and therefore tax incentives should be introduced to increase the adoption of the proposed construction methods.