• Current Research on Agriculture and Life Sciences
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• v.24
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• pp.37-42
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• 2006

The purpose of this study was a biota research and analysis for Close-to-nature stream restoration planning of Shinchun. The summary of this study is as follows; 1) The vascular plants in research area recorded of 45 species and insect fauna recorded of 34 species of 8 orders. As a result of table of community classification, the communities were two group; Quercus variabilis community(I), Pinus densiflora-Quercus variabilis-Quercus dentata community(II). 2) As a result of analysis on correlation of tree species, the level of significance in positive correlation between Quercus dentata and Corylus heterophyll aindicated 1% and between Pinus densiflora and Lespedeza bicolor also indicated 1%. 3) As a result of DBH analysis, it is expected that Quercus variabilis and Quercus dentata will dominateover other species in competition and its succession continuously maintains from now on in community I. In community II, it is assumed that there is a high possibility of changing into community of Quercus such as Quercus mongolica, Quercus dentata, and Quercus variabilis. 4) As a result of analysis on insect fauna, insect fauna consists of 94% of whole species as 32 species, 23 families, 8 orders. And 7 species, 7 families 4 orders was found in highly urbanized area, the vicinity of Sang-Dong bridge. 5) As mentioned above, Based on A biota fundamental research, Close-to-nature stream restoration planning were full of suggestions: i) Designating ecosystem preservation area, ii) Making Close-to-nature stream revetments, iii) Making pool-and-riffle, vi) Making decks for observation and walks for nature experience, v) Creating wetland biotope. Through these methods, it is necessary to promote bio-diversity and lead people to the space for eco-learning.

• Magazine of the Korea Concrete Institute
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• v.9 no.4
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• pp.197-205
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• 1997

The shrinkage of polymer concrete overlays to cement concrete causes interface shear, normal and axial stresses in the overlays. These can lead to deterioration of the polymer concrete overlays due to affection of adhesion polymer concrete and cement concrete. The shrinkage stress in the polymer concrete cause it to shorten and the shorting is measured: With the modulus of elasticity of the polymer concrete and strain known the stresses can be calculated. The purpose of this study is to provide the basic data of application of polymer concrete overlays such as bridge decks, highway and airport pavement repair and overlay materials. From the test results. It has been found that depending on the type polymer. overlay thickness, time after curing and temperature. the shrinkage stresses are eliminated by relaxation in time ranging from a few hours to a few days.

• Journal of Korean Society of Steel Construction
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• v.14 no.1
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• pp.23-29
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• 2002

Many of the bridge systems, including the girders and cross-beams, and concrete decks behave as the special orthotropic plates. Such systems with boundary conditions other than Navier or Levy solution types, or with irregular cross sections, analytical solution is very difficult to obtain. Numerical method for eigenvalue problems are also very much involved in seeking such a solution. A method of calculating the natural frequency corresponding to the first mode of vibration of beam and tower structures with irregular cross-sections was developed and reported by Kim in 1974. Recently, this method was extended to two dimensional problems including composite laminates, and has been applied to composite plates with shear deformation effects. In this paper, application of this method to the specially orthotropic laminated plates with various boundary condition is accomplished and the result of analysis is presented.

• Journal of Korean Society of Steel Construction
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• v.28 no.4
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• pp.243-251
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• 2016

Longitudinally structural cracks are sometimes observed in the pavement on steel plate deck bridges because traffic truck loadings can cause large local deformations of the thin deck plate stiffened by longitudinal and transverse beams. In this study, an improved finite strip method using flat-shell strip, prism, and link elements is presented to investigate local deformations of steel decks with pavements in which flexural and torsional stiffness effects of thin floor beams are rigorously taken into account. A simplified deck model extracted from steel plate-girder bridges is analyzed using the developed FSM and the commercial FE program, ABAQUS and also, their numerical results are compared and discussed.

• Korean Journal of Computational Design and Engineering
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• v.19 no.4
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• pp.347-355
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• 2014

IFC converters and viewers, applicable in the construction field, are being actively developed while, in the civil engineering field, IFC schemata are being developed. To prove the IFC schema grammatically, the existing ISO 10303 30s' pre-processors and post-processors may be used. However, to visually prove the IFC model, the existing commercial 3D modeling software should be converted into the IFC schema of civil engineering field, and a viewer is needed to view it. Thus, this study developed a IFC converter and viewer prototype system to apply BIM in the road field. To express the road line, LandXML was analyzed, and IFC suitable for expressing shapes in the road field was designed. Also, an IFC suitable for bridges with focus on representative bridge structures such as abuts, piers and decks was designed. Further, a converter was developed using AutoCAD's Civil3D and Revit's 3rdp party tools, and software was also developed designed to combine each converted IFC model into one IFC. In addition, a viewer designed to view IFC in the road field was developed to prove the converted IFC. Eight major verification and examination items were selected and used in testing the converted model, and it was confirmed that the viewer normally viewed the IFC schema in the road field. The proposed IFC converter is expected to be used as a visual IFC verification tool in the road field.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.985-988
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• 2008

Maglev is a system that a train runs levitated above a rail. Therefore it is very important to maintain a constant levitation gap for achieving serviceability and ride comfort. This study is a cooperation research subject of the 3-1 subject, performance improvement of maglev track structures, of the Center for Urban Maglev Program in Korea, started in 2006. The aim of this study is development of rapid constructions of bridge superstructure for maglev. At present, precast deck is widely used because of its superiority to cast-in-place concrete on quality and the term of works. The research group suggested basic systems of maglev guideway with PSC-U type and trapezoidal open steel box type girder, and precast deck, cooperating with Korea Railroad Research Institute, the managing institute of the 3-1 subject. In this study, full-scale structure was fabricated for structural safety evaluation of precast decks and rail, and a static performance test of those structures was performed.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.57-60
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• 2008

Maglev is a system that a train runs levitated above a rail. Therefore it is very important to maintain a constant levitation gap for achieving serviceability and ride comfort. This study is a cooperation research subject of the 3-1 subject, performance improvement of maglev track structures, of the Center for Urban Maglev Program in Korea, started in 2006. The aim of this study is development of rapid constructions of bridge superstructure for maglev. At present, precast deck is widely used because of its superiority to cast-in-place concrete on quality and the term of works. The research group suggested basic systems of maglev guideway with PSC-U type and trapezoidal open steel box type girder, and precast deck, cooperating with Korea Railroad Research Institute, the managing institute of the 3-1 subject. In this study, a mock-up consisted of girders, decks and rail was fabricated and test was performed for constructability, serviceability and maintenance evaluation of PSC U-type girder, precast deck, and new guide rail system.

• Journal of Korean Society of Steel Construction
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• v.15 no.6 s.67
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• pp.611-620
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• 2003

Shear studs with a diameter of 19mm or 22mm are typically used in steel-concrete composite bridge. For the simplification of details in steel bridges, the convenience of removing concrete slab, and the efficient distribution of shear pockets for precast decks, large studs can be an excellent alternative. Through push-out tests on large stud shear connectors that transcend the limitation of current design codes, static behavior was investigated and comparisons with design equations performed. The shear stiffness of the connectors in elastic range and trilinear load-slip curves were proposed after shear tests on 25mm, 27mm, and 30mm studs. The ultimate slip capacity and ultimate strength of large studs were also evaluated, with the test results revealing conservative values for the design shear strength in Eurocode-4. For 30mm stud shear connectors, the welding quality and bearing capacity of concrete slab should be improved.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5A
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• pp.503-510
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• 2009

Latex modified concrete (LMC) is a successful polymer-portland cement concretes, which have been developed and used for many years, in overlaying bridge decks and resurfacing industrial floors. The excellent bond strength to substrate, easy application and high resistance to impact, abrasion, wear, aggressive chemicals and freeze-thaw deterioration have made this material used widely. The objective of this study was to determine experimentally the load-deflection response and ultimate strength of reinforced RC beams. The cracking patterns and the mode of failure were observed. Because of excellent bond strength and repairing effects, the RC beams repaired by LMC at compression or tension zone showed over 100% recovery from damaged structures. The RC beams overlaid by LMC showed significant improvement at load carrying capacity as overlay thickness increases. However, the beams repaired of tension zone without shear stirrups almost showed no strengthen effect, and indicated an interfacial failures. The interfacial behavior was estimated by numerical method adopting the concept of shear flow.

• Journal of Korean Society of Steel Construction
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• v.22 no.2
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• pp.173-183
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• 2010

In this study, noncomposite and composite eco-arch structures with I-beams and precast concrete(PC) decks were investigated. Four finite-element models(a steel-girder model, a steel-girder-and-several-PC-panels model, a three-steel-girder model, and a three-steel-girder-and-several-PC-panels model) using a general finite-element program, ABAQUS, were reviewed to predict the strength of the noncomposite and composite arch structures. Based on the results of the finite- element analysis, the behaviors of the four models were investigated, and deflection and strain gauges for the experimental specimen consisting of three steel girders and several PC panels were set up to obtain the ultimate strength. The ultimate strength of the specimen was estimated to be 1,961kN. The ultimate strength was much larger than the 1,380-kN load calculated using AASHTO LRFD Bridge Design Specifications(2007). The noncomposite and composite arch bridges were found to have enough strength for safety.