• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.10-11
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• 2013

Green Frame is a column-beam system formed by composite precast concrete column and beam connected with steel buried in both members. During the installation of Green columns, the columns of Green Frame, covering 3 floors per each piece and beams, the eccentricity can be observed due to the construction error and the weight of beam itself. Such eccentricity may have a little influence on a single frame, yet, it can develop critical issues to the installation of subsequent beams or beams on the upper floors in the context of a building as a whole that has multiple frames. These issues lead to delay in frame installation, decrease of productivity and increase of cost, etc. Therefore, this study presents a steel-joint connection method in order to solve the issues. The steel-joint connection method exists on slope plane and reinforcing plate in steel frame buried in composite PC members. Through this method, the issues can be resolved without requiring additional equipment or manpower.

• Steel and Composite Structures
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• v.2 no.3
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• pp.161-170
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• 2002

The problem of the elastic buckling of a cylindrical liquid-storage tank subject to horizontal earthquake loading is considered. An equivalent static loading is used to represent the dynamic effect. A theoretical solution based on the nonlinear Fl$\ddot{u}$gge shell equations is developed, and numerical results are found using the new differential quadrature method. A second solution is obtained using the finite element package ADINA. A major motivation of the study was to show that the new method can serve to verify finite element solutions for cylindrical shell buckling problems. For this purpose the paper concludes with a comparison of buckling results for a number of cases covering a wide range in tank geometry.

• Fire Science and Engineering
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• v.26 no.6
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• pp.72-77
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• 2012

When the concrete and steel combined composite beam is exposed to high temperature, concrete could delay temperature rising of steel by covering or increase heat capacity of structural member. For becoming of structural reinforcing by unification between materials, fire resistance rate of composite beam would be higher than simple steel beam. The temperature rising of exposed steel of composite beam is directly related with section shape and exposure length of steel. In this study, fire resistant tests were carried out for composite beams and steel beam with same thickness of spray-type fire resistant materials in standard fire, and after that, temperature histories were analysed and compared with shape factor. The correlation between steel temperature and shape factor was showed very high. This result suggests that if it can be predict the comparative advantage of member by factor which cause the performance enhancement, it could be conclude that an Standard Accreditation method can be adjust to members without indivisual certifiicate of accreditation.

• Journal of Korean Association for Spatial Structures
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• v.17 no.2
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• pp.33-41
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• 2017

Composite Floor system infilled with PCM(Phase Change Material) between upper and lower steel plates was developed to apply the steel frame. When steel frames were applied this system, it can absolutely reduce the duration of construction due to dry construction method. However to apply this system as a structural floor member without fire resistance covering, it must have 2 hours fire resistance performance. Because PCM consisted of three quarters of section with thermal insulation performance, fire resistance performance of this floor system was expected to easily have 2 hours fire resistance performance. This paper was to investigate behavior characteristics of PCM infilled floor system at elevated temperature using FEM analysis to develop the fire resistance performance of it.

• Composites Research
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• v.18 no.4
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• pp.66-74
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• 2005

This paper reports new repair and strengthening mathod using improved material. This mathod have two type according to covering thickness of reinforcement. One type is near surface mounted FRP rod. Anther type is overay. Fiber Reinforced Plastic (FRP) materials has become very popular in recent years. FRP material used to rehabilitate many types of structures with superior characteristics such as high strength and stiffness and corrosion resistance. This strengthening mathod were used FRP rod which have better bond and shear strangth than current FRP rod. Development of FRP rod due to 3-D winding system. In addition, Ductile hybrid FRP has a certain plastic deformation and an elongation greater than 3% at maximum load is usually required for steel reinforcement in concrete structures. Moerover this mathod can be effective repair of base concrete by sprayed polymer mortar.

• Composites Research
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• v.28 no.5
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• pp.249-253
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• 2015

This paper reports a study on a method for achieving lightweight thermoplastic laminate composites referred to as tow spreading technology. Thickness of an unspread 12 K carbon fiber tow is reduced by increasing the tow width from 7 mm to 20 mm. The polypropylene (PP) film was used to stabilize and impregnate the spread tow, covering it into a partially consolidated prepreg: 12 K carbon fiber spread tow/PP. Laminates were fabricated from the spread tow prepreg and control laminate composites were produced from unspread tow prepreg consisting of 12 K carbon fiber and PP. The void content, tensile and flexural properties of the composite laminates were investigated. Consequently, the spread tow laminate composite exhibited lower void content and improved mechanical properties.

• Proceedings of the KSRS Conference
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• v.1
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• pp.316-319
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• 2006

Monthly-mean aerosol parameters derived from the 1998-2004 SeaWiFS observations over East Asian waters are analyzed. SeaWiFS GAC Level 1 data covering the Northeast Asian area are collected and processed by the standard atmospheric correction algorithm released by the SeaWiFS Project to produce daily aerosol optical thickness (AOT) and ${{\AA}}ngstr{\ddot{o}}m$ exponent imageries. Monthly mean AOT and ${{\AA}}ngstr{\ddot{o}}m$ exponent values are extracted from the daily composite images for six study areas chosen from the surrounding waters of Japan. A slight increasing trend of ${{\AA}}ngstr{\ddot{o}}m$ exponent is found and interpreted as about 4-5% increase in submicron fraction of aerosol optical thickness at 550nm. Two cloud screening methods, including the standard cloud masking method of SeaWiFS and the one based on the local variance method, are applied to the SeaWiFS data processing, in an attempt to inspect the influence to the observed statistical uptrend which probably induced by different cloud mask algorithms. The variability comes from the different cloud masking algorithms are discussed.

• Steel and Composite Structures
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• v.49 no.2
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• pp.181-196
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• 2023

Marine structures including offshore wind turbines (OWTs) always work under cyclic loads, which arouses much attention on the fatigue design. The tripod substructure is one of the typical foundation forms for fixed OWTs. The three-planar tubular Y-joint (3Y joint) is one of the important components in fatigue design as it is most likely to have cracks. With the existence of the multiplanar interaction effect, calculating the hot spot stress (HSS) of 3Y joints is complicated. To assist with fatigue design, the distributions of stress concentration factor (SCF) and multiplanar interaction factor (MIF) along weld toe curves induced by the out-of-plane bending moment are explored in this study. An FE analysis method was first developed and verified against experimental results. This method was applied to build a numerical database including 1920 FE models covering common ranges of geometric parameters. A parametric study has been carried out to reveal the distribution patterns of SCF and MIF. After multidimensional nonlinear fittings, SCF and MIF distribution formulas have been proposed. Accuracy and reliability checking prove that the proposed formulas are suitable for calculating the HSS of 3Y joints.

• Journal of the Korean Ceramic Society
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• v.52 no.3
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• pp.173-179
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• 2015

We report the facile synthesis of graphene-$CdLa_2S_4$ composite through a facile solvothermal method at low temperature. The as-prepared products were characterized by X-ray diffraction (XRD) and by Scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analysis and BET analysis, revealing the uniform covering of the graphene nanosheet with $CdLa_2S_4$ nanocrystals. The as-prepared samples show a higher efficiency for the photocatalytic degradation of typical MB dye compared with P25 and $CdLa_2S_4$ bulk nanoparticles. The enhancement of visible-light-responsive photocatalytic properties by decolorization of Rh.B dye may be attributed to the following causes. Firstly, graphene nanosheet is capable of accepting, transporting and storing electrons, and thus retarding or hindering the recombination of the electrons with the holes remaining on the excited $CdLa_2S_4$ nanoparticles. Secondly, graphene nanosheet can increase the adsorption of pollutants. The final cause is that their extended light absorption range. This work not only offers a simple way to synthesize graphene-based composites via a one-step process at low temperature but also a path to obtain efficient functional materials for environmental purification and other applications.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.4
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• pp.99-106
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• 2011

This study performed research for improvement on basic concept of PBD applying suitable design method before and after LB-DECK composition. According to study, in this case, before composition, it can reduce minuteness cracks by increasing bending tensile strength utilizing polymer concrete, can expect sensuous effect, improve durability as to low permeability, and was evaluated that can reduce covering depth according as it. Also, because LB-DECK baseplate that apply the empirical design method composite is superior load resistance ability than general baseplate, safety is increased, it is expected to secure constructibility and economic performance at the same time because reinforcement arrangement method and reinforcement amount are fixed even if span effective span is increased at ultimate strength design method application.