• 한국건축시공학회지
• /
• 제8권1호
• /
• pp.71-76
• /
• 2008

Recently, the high-rise apartment housings have become a prototype of the urban residential dwelling in Korea and the numbers of one have steadily been increasing. According to this trend, the strength of the construction materials is also fortified to assure the stability and durability of the buildings. Specially, Re-bar of SD500 type is largely used at the construction sites of high-rise building. This study analyzes the current usage of SD500 high-strength re-bar at domestic construction sites. Through the result of this analysis, we develop Economic Evaluation Model that measure economic efficiency of lap splice and coupler splice, which are most commonly used in connection SD500. The evaluation method was applied to construction sites in Seoul in December 2006, and the result revealed that coupler splice is relatively superior in terms of cost efficiency when the re-bar diameter is longer and the concrete strength is lower.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
• /
• pp.408-415
• /
• 1997

Bond strength of reinforcing bar to high-performance concrete using Belite cement is explored using beam end test specimen. The key parameters for the bond test are slump of concrete, top bar effect, and strength of concrete in addition to concrete covers. Specimen failed in the typical brittle bond failure splitting the concrete cover as the wedging action. The test results show that for the group with portland cement I using superplasticizer additional slump does not decrease the bond strength of the top bar is less than bond strength of bottom bar, but the top bar factor satisfy the modification factor for top reinforcement. The result also show that bond strength is function of square root of concrete compressive strength and cover thickness. More detailed evaluation will be conducted from the test specimen with high strength concrete using the belite cement.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
• /
• pp.13-14
• /
• 2015

To minimize construction of nuclear facility, it is required to reduce reinforcing bar amount and solve reinforcing bar concentration and for this, it is necessary to develop appication design technology and modular of high strength reinforcing bar. Hence, KHNP reduces excessive reinforcing bar amount which can cause possibility of poor construction of concrete through design standard development and modular of nuclear facility structure using high strength reinforcing bar to raise economics and has its purpose to maintain high-level safety and durability as they are. After reviewing the rebar drawing of the NPP structures and performing the mock-up test, the rebar modulation method in the various area of the NPP Structure has been established.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 1997년도 춘계학술대회논문집
• /
• pp.106-110
• /
• 1997

A split Hopkinson bar has been used for obtaining material properties in high strain rate state, In this paper, the apparatus was modified to obtain the high strain rate properties of sheet metal for an autobody. From the experiments with the new apparatus, the material properties of SPCEN in the high strain rate state have been acquired and compared with quasi-static experimental results.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 춘계학술대회 논문집
• /
• pp.409-412
• /
• 2011

Maximum speed of the train could not exceed over 160km/h with R-bar system in the underground type tunnel structure. By the research to overcome this speed limit, maximum speed has reached up to 200~250km/h recently by new R-bar system. It is under discussion to construct Metro Express Line between Gyonggido and Seoul which requires maximum speed 180km/h~230km/h. New R-bar is an optimal system to achieve the speed improvement in this line. This study shows application of the high speed R-bar system in the underground tunnel section.

• Journal of Welding and Joining
• /
• 제27권5호
• /
• pp.68-73
• /
• 2009

The bar horn is designed to increase uniformity of the displacement on the output face through simulation and experiments. Three-dimensional modal analysis is conducted using the finite element method to calculate the vibration mode and displacement on the output face, and the design of experiment (DOE) technique is employed to determine the optimum dimensions of the groove and slot so that the high amplitude uniformity of the bar horn is produced. Displacement of the bar horn was measured using the Laser Doppler Vibrometer (LDV), and the experimental results show good agreements with the predicted results. High uniformity of the bar horn is achieved with the dimensions of the groove and slot determined using the design equations.

• 한국한의학연구원논문집
• /
• 제18권2호
• /
• pp.139-149
• /
• 2012

Objectives : This is the study to understand of the pulse wave factor according to BMI and period of sterility on female, and to confirm the relationship of pulse wave factor among left and right inch, bar and cubit. Methods : The Questions and measurement of the pulse wave were operated with subjects(76 sterile females using on public health center). The measurement of the pulse wave was operated in 6 part of left and right inch, bar and cubit. The pulse wave was prior measured in part of left bar (i.e. interior pulsation part of radial process styloides in left hand), and next was measured in part of left inch and bar. And the pulse wave was operated samely in part of right inch, bar and cubit. Results : The results were as follows. The pulse energy of 6 part of left and right inch, bar and cubit was showed statistical significance and decreased in order of left inch, right inch, left cubit, right cubit, left inch, right bar. The left and right inch and cubit were showed numerical value of normal range, but left and right bar were showed lower pulse eneregy than normal range. Also left and right cubit were showed lower than left and right inch, and higher than left and right bar. In BMI, The pulse energy of left and right inch, cubit and the average of right hand was not showed statistical significance in the range of low-weight, normal, over-weight and obesity. But in the left and right bar and the average of left hand, the pulse energy of over-weight and obesity group were showed significantly higher than low-weight group. And the pulse wave factor was divided the pattern of h1 showing high numerical value in inch (Ap, As, Aw) and the pattern of Wm showing high numerical value in bar and cubit (RAI, Ad) Conclusions : The low pulse energy of bar was significant observation on the setting of oriental medical diagnostic index on sterilitas. Also, in the numerical value pattern of diverse pulse wave factor, it was divided the pattern of high numerical value in inch and the pattern of high numerical value in bar and cubit. On this, we think that the studies need in the future.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 1995년도 추계학술대회 논문집
• /
• pp.109-112
• /
• 1995

This paper analyzes high efficiency anti-vibration boring bars which increase stability against chatter vibration in boring operations. Structural analysis and mathematical modeling with considering dynamic properties for three types of existing boring bars are performed to search for optimal design parameters. The purpose of this paper is to find out design parameters for high efficiency anti-vibration boring bar.

• 한국정밀공학회지
• /
• 제26권11호
• /
• pp.99-107
• /
• 2009

Since a long work piece influences the natural frequency of the entire system with a miniature high speed spindle, a bar-feeder is used for a long work piece to improve the vibration characteristics of a spindle system. Therefore, it is very important to design optimally support positions between a bar-feeder and a long work piece for a miniature high speed spindle system. The goal of the current paper is to present an optimization method for the design of support positions between a bar-feeder and a long work piece. This optimization method is effectively composed of the method of design of experiment (DOE), the artificial neural network (ANN) and the genetic algorithm (GA). First, finite element models which include a high speed spindle, a long work piece and the support conditions of a bar-feeder were generated from the orthogonal array of the DOE method, and then the results of natural vibration analysis using FEM were provided for the learning inputs of the neural network. Finally, the design of bar-feeder support positions was optimized by the genetic algorithm method using the neural network approximations.

• 한국구조물진단유지관리공학회 논문집
• /
• 제12권6호
• /
• pp.180-192
• /
• 2008

본 연구에서는 보다 자유로운 형상의 슬리브를 만들 수 있는 구상흑연 주철을 이용하여 보다 효과적으로 구조성능을 발휘하면서 SD500 고강도 철근에 적합하게 개발된 모르타르 충전식 슬리브 철근이음을 대상으로 실물크기의 19개 실험체를 제작하여 반복가력실험을 실시하였다. 그리고 강도, 강성, 슬립을 중심으로 한 구조성능에 대하여 본 실험의 주요한 변수에 따르는 영향을 분석하고, 국내기준을 비롯한 주요기준의 요구 성능과 비교하였다. 본 연구결과에서는 SD500 고강도 철근용으로 개발한 모르타르 충전식 슬리브 철근이음은 반복하중이 작용하는 경우에 대하여 국내기준을 비롯한 주요기준에서 요구하는 구조성능을 보유하고 있는 것이 확인되었고, SD500 고강도 철근용 모르타르 충전식 슬리브 철근이음에 대한 구조설계 기준 정립에 필요한 정량적인 기술 데이터를 제시하였다.