• Journal of the Korea Society for Simulation
• /
• v.27 no.2
• /
• pp.83-90
• /
• 2018

This paper describes the method of hull shape optimization to improve the resistance performance of planing hulls when a reference hull shape and its principal dimensions are given. First, the planing hull of precedent research is adopted as the reference hull and an optimization problem is formulated by defining hull shape parameters. The search space of this research is discretized for computing cost and DPSO(Discrete binary version of Particle Swarm Optimization) method is used to solve the optimization problem. As the result of optimization, the decrease of resistance is confirmed from the comparison between the reference hull's and the modified hull's planing performance from computational results.

• Journal of Korean Society of Steel Construction
• /
• v.12 no.4 s.47
• /
• pp.429-436
• /
• 2000

The composite system, which is consisted of the steel girder and reinforced concrete column has some advantages in the structural efficiency and the construction productivity by complementing the shortcomings between the two materials. This research is aimed at the development of the composite beam-column connection system by which the steel beam can be connected to the R/C column with smooth stress transfer. And, to ensure safety of this system, the tests of moment and shear resisting performance have been carried out for actual size specimen. From the test, the connection system has been preyed to take good resistance and stress transfer between steel girder and reinforced concrete column.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.20 no.4
• /
• pp.426-434
• /
• 2014

The research developed twin keel yacht for everyone which is able to stand erectly on mud flat without list and intended to commercialize the development product for popularization of west coast's marine leisure industry. Yacht's linear was utilized by "Blue Water21" has superior performance among the existing sailing yachts and twin keel model has been tested by calculation of mono keel's extent and its center of gravity. The result was that only 4 % of difference have been identified between mono keel and twin keel's hydrodynamic resistance which was smaller difference than predicted.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.25 no.2
• /
• pp.58-65
• /
• 2021

As increasing social needs of pavement maintenance, pattern frame method has been constructed in Korea. The pattern frame not only increases the skid resistance of pavements but also improve the scenery. However, construction of the pattern frame currently relies on imported materials. In this paper, we localize the materials used in pattern frame and conduct performance verification on them. The important performance indicators are the adhesion strength of undercoating materials and the skid resistance of finished pattern frames. The adhesion strength was targeted at 1.4MPa, and the localization alternative material met the target performance with 2.35MPa, the skid resistance performance was targeted at 40BPN, and the localization alternative material met the target performance with 75BPN. In the case of localized materials, approximately 40% cost reduction (per 1m²)compared to imported materials was confirmed.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.9 no.1
• /
• pp.217-223
• /
• 2005

This study is on the evaluation of three kinds of surface protectors for protecting reinforced concrete against corrosion of reinforcing steel by chloride attack and carbonation. In this study, the test has been carried out on the performance of specimens applied with surface protectors for anti-corrosion and anti-carbonation. The result showed that specimens applied with the three kinds of surface protectors, were excellent in resistance to the corrosion of reinforcing steel and carbonation. Especially the specimen applied with finish coating in conjunction with hydrophobic primer showed great reduction in the corrosion of reinforcing steel and carbonation.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.21 no.2
• /
• pp.1-12
• /
• 2017

In this study, It was purpose to provide preliminary data for extension of the applicability of deep corrugated steel plate composite members by steel grade and shear reinforcement method. From the result of flexural test on deep corrugated plates composite members using GR40 and SS590, positive moment capacity was increased about 28% by SS590 steel. But to change steel grade was proved to have insignificant effects for increasement of negative moment capacity. In the moment test result of same overlapping length, Increasement rate of positive and negative moment capacity was not significantly improved by increasing the number of bolt. It was estimated to be due to the characteristics of bolt connection such as distance between centers of bolts, edge distance of bolt. In the test result on the spacing of shear reinforcement, positive moment capacity was increased and deformation of negative moment was reduced as the distance decrease. In the test result on the shape of shear reinforcement, positive and negative moment resistance was increased about 2% ~ 7% by U shaped shear reinforcement. In conclusion It was estimated that moment capacity of deep corrugated steel plate composite members are depend on steel grade of deep corrugated steel plate, spacing of shear reinforcement and reinforcing bar.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.19 no.6
• /
• pp.37-45
• /
• 2015

In this experimental study, effect of milled glass fibers was investigated on corrosion resistance of PSC grout mortar. In order to check whether the mortar mixture with milled glass fibers satisfy the required properties as a PSC grout, time of flow, bleeding and compressive strength measured. The corrosion resistance were investigated through chloride ion migration test, mortar absorption test and surface resistivity measurement. It is confirmed that all proportions with milled glass fibers have better corrosion resistance than that with only OPC binder. Time of flow was reduced but the bleeding was increased to unacceptable level by using milled glass fibers. Consequently, the mix proportion with milled glass fibers for a PSC grout should be modified to have lower water/binder ratio.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.1
• /
• pp.111-118
• /
• 2016

The scaling of concrete caused by the combined effects of frost and deicing salt is one of the principle causes of damage to transportation infrastructure in cold-climate regions. In this study, to evaluate the factors affecting scaling resistance of concrete, the relationship between the properties of concrete, such as the mechanical properties and pore structure, and scaling resistance was examined experimentally. The test results showed that the scaling resistance was strongly dependent on the absorption properties of concrete, but not on the compressive strength. Furthermore, it is believed that both the spacing factor and specific surface of the air voids was not a good parameter for evaluating the scaling resistance of concrete. SGC concrete was less durable than OPC and SFC concrete with respect to the scaling resistance in the scope of the present study.

• Proceedings of the Korean Institute of Industrial Safety Conference
• /
• 2003.05a
• /
• pp.309-314
• /
• 2003

우리나라 전기설비에 관한 기본법규인 “전기설비기술기준”에서는 보호용 접지에 관해 접지공사의 종류, 접지저항, 접지선의 굵기 등을 규정하고 있다. 이에 따라 접지설계를 할 때, 특히 접지저항에 대해서는 전기설비기술기준의 해석에 있는 제21조를 근거로 접지공사 종류별로 규정된 접지저항을 유지하도록 규정하고 있는 경우가 많다.(중략)

• Proceedings of the Korea Concrete Institute Conference
• /
• 2009.05a
• /
• pp.13-14
• /
• 2009

Segmented composite is known that resists at static and impact load well. In this study, segmented composite was evaluated by static and impact load test. Additionally, finite element analysis method was employed and optimal mix of mortar was developed. Therefore, impact resistance shows aspect that is influenced by interaction of interface and layout of segmented blocks.