• Aerospace Engineering and Technology
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• v.6 no.2
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• pp.188-196
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• 2007

A composite case was designed to satisfy the required condition of KSLV-I kick motor system. we performed the structure and combustion tests to insure the reliability of the case before the production of the flight model. The hydraulic, vacuum and non destruction testes as the structure test were carried out to confirm the strength of the components of the case and the characteristics of the thermal and structure were investigated through the ground combustion test.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.125-128
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• 2006

As the ministry of construction and transportation established quality standards for recycled aggregate in August, 2005, the consumption of recycled aggregates is expected to be increased in construction fields in the future. Thus the relations between compressive strength of general concretes and that of recycled aggregate concretes which are applied to actual structures are attempted to investigate through non-destruction testing method. Presently Schmitt-Hammer test method is that concrete compressive strength is predicted by measuring surface hardness of concretes, and is well known as the most convenient and simply operated method among many non-destruction testing methods. In this study, cylinder specimen and mock-up were constructed using recycled aggregate concretes made by the first class recycled coarse aggregates and recycled fine aggregates specified in KS F 2573 (recycled aggregate for concrete), and compressive strength of hardened concrete of middle ages was evaluated.

• Journal of Korean Society for Atmospheric Environment
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• v.18 no.1
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• pp.51-58
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• 2002

Destruction process of toluene using a wire-cylindrical BBD (Dielectric Barrier Discharge) reactor packed with catalysts was investigated to characterize the synergetic effects of non-thermal plasma and catalyst process. The catalysts used in the present study were ${\gamma}$-Al$_2$BO$_3$ and Pt/${\gamma}$-Al$_2$O$_3$. Under the numerous test conditions, specific energy density (SED (J/L)) and the conversion of toluene, defined as (1 -[C$_{f}$]/[C$_{i}$]), were measured. The test results showed that toluene decomposition efficiency followed the pseudo-first order in the case of plasma only process. The pseudo-first order process, however, was modified to pseudo-zeroth order reaction in the case of catalyst-assisted plasma process. This modification of the reaction order was verified based on a simple kinetic model proposed in the present study. Owing to the modification of reaction order, which resulted from the catalytic process, the specific energy to achieve the high removal efficiencies, i.e. 80~90%, was reduced significantly.y.y.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2013.05a
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• pp.69-70
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• 2013

This is an foundational study to adequacy the non-destruction testing for the estimation of compressive strength of high strength concrete The results are as follows, In high strength concrete, H type is NR type rebound number rather than higher. The relation between rebound number and compressive strength of high strength concrete have lower coefficient. when compressive strength estimation of high strength concrete, it consider that rebound hardness test is not applied and should be consider to combined method or addition method.

• Journal of the Korea Institute of Building Construction
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• v.3 no.2
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• pp.119-127
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• 2003

Test specimen test was performed using concrete reinforced with fiber sheet and the test variables were based on the kinds of fiber and the number of reinforcement layers. Using steel-concrete reinforced with fiber sheet, compression tests were performed and the test variables were the kinds of fiber, number reinforcement layers and reinforcement layer order. The following results were obtained: 1) It was demonstrated that compressive strength of the test specimen reinforced during test specimen test and member test increased as the number of reinforcement layers increased. 2) It was shown that non-reinforced test, specimen were destroyed during the member tests, but the specimen reinforced with CFS destroyed and the GFS-reinforced specimen and composite reinforced specimen showed ductile destruction. 3) As a result of tests on kinds of reinforcement fiber, it was demonstrated that CFS-reinforced test specimen had higher compressive strength in a 공시체 test. In the member test, 2ply-and 3ply-GFS reinforced specimens except lplied one had higher compressive strength. It was because partial destruction occurred due to the rate of height/section. 4) For layer strength order, compared with test specimen reinforced only with a single reinforced material, test specimen reinforced with CFS and GFS, and test specimen reinforced with CFS first showed better results in compressive strength and ductility judgement.

• Journal of the Korea Institute of Building Construction
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• v.3 no.1
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• pp.85-91
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• 2003

This study aims to provide basic data that can be applied to construct real structures. For this, an experimental structure was manufactured to identify durability according to age of fiber-reinforced concrete which contains fiber reinforcement materials (polypropylene fiber, steel fiber, cellulose fiber) and structural property about flexural behavior and destruction of reinforced concrete beam, and a relation between load and deflection, crack and destruction according to increase of load and ductility capacity was examined. Fiber-reinforced concrete materials and other constructional materials were experimented and the result is presented as follows: The results obtained through material test of concrete and static experiment of members usings 1. The experiment shows that compressive strength of fiber-reinforced concrete was lower than that of non-reinforced concrete. 2. As a result of strength experiment according to different kinds of fiber, compressive strength of an experimented structure that contains cellulose fiber was the highest when age was 28. 3. When deflection of reinforced concrete beam was examined, it was reported that ductility capacity of the experimented structure that contains fiber-reinforced concrete was raise than that of non-reinforced concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05a
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• pp.23-25
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• 2011

The purpose of this study is to suggest documentation with determination of concrete then property, according to demolition and restoration the Youngdo bridge which has valuable meaning to modern technique as an only bascule bridge in Korea.

• Journal of Korean Association for Spatial Structures
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• v.16 no.4
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• pp.75-82
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• 2016

Building hardware joints are welded in most cases, which have risks of fire and explosion. Besides, the secondary damage of the destruction of the welded parts can be caused by the horizontal displacement of the structure due to earthquake or wind load. This paper compared the horizontal displacement following abilities of welded building hardware and non-welded building hardware. To do this, We conducted actual formation shake table test, and checked on the horizontal displacement following ability of structure by comparing their responses to earthquake load. We made the 2m-high framework to examine the responses of the actually constructed building hardwares, and analyzed the displacement responses of the welded-typed, non-welded-typed, and cruciform bracket building hardwares. We conducted the test by increasing acceleration rate until displacement reached 40mm corresponding to allowable relative story displacement II. The result of the test showed that the building hardware using welding work made cracking and breakage on welded connections of welded building hardware, but non-welded building hardware with no use of welding work and cruciform bracket building hardware make no problem, and that non-welded building hardware is superior to that of the welded building hardware in the horizontal displacement following ability due to earthquake or wind load.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.464-469
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• 2003

The traditional and still most widely used, test methods for concrete structures are destructive method, such as coring, drilling or otherwise removing part of the structure to permit visual inspection of the interior. While these methods are highly reliable, they are also time consuming and expensive, and the defects they leave behind often become focal point for deterioration. In this study, tomography by theoretical inversion method in case of elastic wave using impact-echo method among concrete non-destruction test method was made. Taken model experiments are theoretical inversion method and time domain and frequency domain test on pier test model at laboratory level. Also experiment concerning frequency domain on 3 kinds of tunnel model with I-dimension form was carried out.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.208-209
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• 2021

In 2017, 100 aftershocks with a magnitude of 2.0~3.0 and 615 minor earthquakes in Pohang in Korea caused the collapse and destruction of aggregate, tile, glass, and other structural components of multi-family houses constructed as finishing materials for buildings, causing damage to vehicles and casualties. Based on this factor, seismic design standards were established for non-structural elements of buildings that were applied only to past structures. Therefore, this study reinterpreted various vibration response spectra transmitted to waterproof layers as well as the definition and concept of the waterproof layer demand response spectrum derived by developing various vibration response test evaluation devices through a new testing apparatus.