• Structural Engineering and Mechanics
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• v.74 no.1
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• pp.91-104
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• 2020

A mathematical analysis has been carried out for understanding the traversal attributes of torsional waves in a Voigt-type viscoelastic porous layer bounded with corrugated surfaces resting over a heterogeneous transversely isotropic gravitating semi-infinite medium. Both the media are assumed to be under the effect of initial stresses acting along horizontal directions. In the presumed geometry, continuous and periodic type of corrugation has been considered. The condensed form of dispersion relation has been obtained analytically with the aid of the Whittaker's function and suitable boundary conditions. The influence of viscoelasticity, porosity, initial stresses, heterogeneity, gravity, undulation and position parameters on the phase and damped velocities has been illustrated graphically. In addition, relative examination investigating the impact of corrugated and planar bounded surfaces on the dispersion and damping characteristics is one of the important highlights of this study.

• Journal of the Korean Geographical Society
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• v.51 no.3
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• pp.441-454
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• 2016

This study deals with the contemporary rural housing with special reference to the roof types/materials and the outer wall materials in Ulleungdo Mountains. The most frequent roof type of rural housing is the hip-and-gable roof type(42.1%); and the next, the gable roof type(25.8%). For the roof materials, the precoated steel plate(69.1%), the asphalt shingle(11.8%), and the cement(10.7%) are the most frequent but the roofing tile and the artificial slate are not used. And for the outer wall materials, the cement(27.5%), the siding(21.3%), the corrugated galvanized iron(16.8%), and the lumber sheet(6.7%) are the most frequent. It is the hip-and-gable roof housing type with the precoated steel plate(roof materials)(41%), or the hip-and-gable roof housing type with the precoated steel plate(roof materials) and the cement(outer wall material) (18.0%) that is the most frequent type of rural housing in Ulleungdo Mountains. For the roof/wall materials, the ratio of the corrugated galvanized iron is high probably due to the relatively low cost of transport, and the ratio of the roofing tile, the artificial slate, the red brick, and the building stone is very low probably due to the relatively high cost of transport.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.2A
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• pp.281-288
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• 2008

The Prestressed Concrete (hereinafter PSC) box girder bridges with corrugated steel webs have been drawing an attention as a new structure type of PSC bridge fully utilizing the feature of concrete and steel. However, the previous study focused on the shear buckling of the corrugated steel web and development of connection between concrete flange and steel web. Therefore, it needs to perform a study on the torsional behavior and develop the rational torsional analysis model for PSC box girder with corrugated steel web. In this study, torsional analysis model is developed using Rausch's equation based on space truss model, equilibrium equation considering softening effect of reinforced concrete element and compatibility equation. Validation studies are performed on developed model through the comparison with the experimental results of loading test for PSC box girder with corrugated steel webs. Parametric studies are also performed to investigate the effect of prestressing force and concrete strength in torsional behavior of PSC box girder with corrugated steel web. The modified correction factor is also derived for the torsional coefficient of PSC box girder with corrugated steel web through the parametric study using the proposed anlaytical model.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.2
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• pp.31-38
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• 2008

A column test was performed far a new-type column with a quasi static test. An internally confined hollow reinforced concrete column with a corrugated steel tube (ICH RC-CT column) was tested to evaluate its seismic performance. And also, a general solid RC column was tested fur the comparison. The test was performed as planned drift levels. The lateral displacements and the lateral loads of column specimens were measured during tests. From the test results, the ICH RC-CT column showed smaller energy absorbing capacity than a solid RC column but showed the almost equal energy ductility and equivalent viscous damping ratio to those of the solid RC column.

• Steel and Composite Structures
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• v.43 no.6
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• pp.809-819
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• 2022

This paper proposes a method to predict the deflection of prestressed concrete (PC) beams with corrugated steel web (CSW) under constant load concerning time-dependent variation in concrete material. Over time, the top and bottom concrete slabs subjected to asymmetric compression experience shrinkage and creep deformations. Here, the classical Euler-Bernoulli beam theory assumption that the plane sections remain plane is not valid due to shear deformation of CSW. Therefore, this study presents a method based on the first-order shear deformation to find the long-term deflection of the composite beams under bending by considering time effects. Two experimental prestressed beams of this type were monitored under their self-weight over time, and the theoretical results were compared with those data. Additionally, 3D analytical models of the experimental beams were used according to material properties, and the results were compared with two previous cases. There was good consistency between the analytical and numerical results with low error, which increased by wave radius. It is concluded that the proposed method could reliably be used for design purposes.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2004.04a
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• pp.192-210
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• 2004

Application methods of chemicals were investigated tn minimize strength reduction of corrugated boards under the high humidity environment encountered in the cold chain system. Starch insolubilizers were introduced in the starch solution preparation of the Stain hall method and their insolubilization effect of starch binder were estimated. The performance of water repellent agents(WRA) and moisture proof agents(MPA) were evaluated in terms of water and moisture resistance. And effects of the combination of the chemicals and the coating method were also examined. Addition of the polyamine polyamide insolubilizer to the main part in the Stain hall process improved the binding force and water resistance of starch, which contributed to minimize the strength reduction of paper under the high humidity environment. AZC and Glyoxal type insolubilizers could not be used in the experiment due to an excessively increased viscosity of starch solution and the poor stability. Conventional WRA treatment to the base paper enhanced water and moisture resistance very slightly even though water repellency of the paper reached R10 by the treatment. MPA showed excellent performance than WRA not only in water and moisture resistance but in water repellency. Double coating on paper with MPA was more effective than the single coating at the same coating weight. A newly developed MPA showed excellent performance and runnability only by a single coating instead of a double coating.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.2
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• pp.60-69
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• 2004

Application methods of chemicals were investigated to minimize strength reduction of corrugated boards under the high humidity environment encountered in the cold chain system. Starch insolubilizers were introduced in the starch solution preparation of the Stein hall method and their insolubilization effect of starch binder were estimated. The performance of water repellent agents(WRA) and moisture proof agents(MPA) were evaluated in terms of water and moisture resistance. And effects of the combination of the chemicals and the coating method were also examined. Addition of the polyamine polyamide insolubilizer to the main part in the Stein hall process improved the binding force and water resistance of starch, which contributed to minimize the strength reduction of paper under the high humidity environment. AZC and Glyoxal type insolubilizers could not be used in the experiment due to an excessively increased viscosity of starch solution and the poor stability. Conventional WRA treatment to the base paper enhanced water and moisture resistance very slightly even though water repellency of the paper reached R10 by the treatment. MPA showed excellent performance than WRA not only in water and moisture resistance but in water repellency. Double coating on paper with MPA was more effective than the single coating at the same coating weight. A newly developed MPA showed excellent performance and runnability only by a single coating instead of a double coating.

• Journal of the Korean GEO-environmental Society
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• v.7 no.6
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• pp.75-88
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• 2006

This paper evaluates the feasibility of use of high-strength steel for soil-metal corrugated steel structures. Two specifications, the AASHTO(2004) and the CHBDC(2000), were compared and the scientific background of equations for the buckling stability in those specifications were investigated to figure out the governing factors for buckling strength of structures. Numerous finite element analyses for round-pipe type of soil-metal corrugated steel structures were carried out with considering the elastic-plastic relationship of a material and the geometrical non-linearity, as well as the various design variables, such as span length, depths of soil cover, section properties, tensile strength and backfill conditions. Buckling strength equation of the CHBDC(2000) is still valid and conservative for both normal and high-strength steel soil-metal corrugated steel structures, and the buckling strength increases with the use of hight-strengths steel.

• Journal of the Korean Society of Safety
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• v.31 no.6
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• pp.25-31
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• 2016

This paper has analyzed the structure, applicable regulations and the resistance characteristics of insulation ring type of CSST (Corrugated Stainless Steel Tubing for Gas). With the flammability test conducted in accordance with KS C IEC 60811-1-1, the evaluation of insulation resistance, temperature characteristics, and reliability has been conducted. An insulation ring type CSST consists of protective coating, tube, nut, insulation ring, packing, socket, and ball valve. Connecting an insulation ring type CSST to gas tubings for gas appliance is not permitted, moreover, the product shall be installed inside a sleeve pipe in case of buried installation such as the ceiling. Damages on protective coating and tube were detected when fire was applied to the test sample with a portable torch for 60 seconds. The insulation resistance of a normal product was $49.59M{\Omega}$, while that of the product completed the flammability test reduced to $9.21M{\Omega}$. The mean insulation resistance within the confidence Interval of 95% using the mini tap program 17 was $49.59M{\Omega}$ and the mean insulation resistance within the confidence interval reduced to $9.21M{\Omega}$. In the normal distribution analysis of 95% confidence interval, the value-P of the normal product was stable at 0.075 and AD(Anderson-Darling) statistic value was turned out to be 0.063, which is very normal, and the standard deviation was analyzed as 0.2586. The value P of the product completed the flammability test resulted in 0.005, the AD was 1.355 and the standard deviation reduced to 0.07908.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.4 no.2
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• pp.33-38
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• 1998

In point of flexographic printing on generally corrugated fiberboard cartons, the precision of film master and the adequate compression rate are very important factor in bar-code printing. Also, the complete system including scanner is essential for the purpose of enhancing the reading rate. The film master had good precision when the film was prepared by means of printing/developing machine after transformation of input bar-code number through transceiver, and the BWR 100 showed better compression rate than BWR 200. Also considering the bar-code reading, the complete system targeting the reading rate above 99.8% could be configured by Omni-Directional Scanner type accomplishing the reading rate above 99.5%.