• Computational Structural Engineering
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• v.10 no.3
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• pp.233-240
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• 1997

The study presents the linear dynamic analysis of multi-girder steel bridges under vehicular movement to examine the performance characteristics due to the various structural and loading conditions. The road surface roughness and bridge-vehicle interactions are considered. The road surface profiles for the approaching roadway and bridge decks are generated from power spectral density functions for different road roughness conditions. A new filtering method using the wheel trace is proposed to obtain the more rational bridge-vehicle interactions from the randomly generated road surface. The possible settlement condition between the bridge deck and approaching roadway is also included. The dynamic responses of various bridges designed according to current design practice are examined, in which important structural parameters(such as span length, girder spacing, etc.) are considered systematically. In addition to the basic loading conditions due to a single truck passing on the bridge, the traffic conditions of multi-truck traveling either consecutively on the same lane or side-by-side on the adjacent lanes are also evaluated.

• Journal of Korean Society of Steel Construction
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• v.19 no.6
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• pp.671-680
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• 2007

In this study, we performed a loading test to evaluate the effect of load distribution on continuous two-span plate-girder bridges with or without bottom lateral bracing using one-fifth-scale bridge specimens. From the test results, when specimens with lateral bracing were loaded eccentrically, the load distribution capacity of the concrete deck and cross beam improved and greater loading was distributed to the other side of the girder subjected to loading. The load distribution rate of the specimens with and without lateral bracing system was evaluated from the analytical model that was verified by the test results. From the result of the quantitative evaluation, when specimen without lateral bracing was loaded eccentrically, mostly 21% of loading according to the concrete deck was distributed to the other side of the girder subjected to loading. However, when specimen with lateral bracing was loaded eccentrically, the load distribution rate increased by 1.7 times as all cross beams, bracing and concrete deck participated in load distribution. The reason is that the torsional rigidity increased as the model with lateral bracing behaved like a pseudo-closed box section.

• Journal of Animal Environmental Science
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• v.8 no.3
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• pp.129-134
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• 2002

This study was carried out to investigate the characteristic change of piggery slurry during the storage time and depth. The Piggery slurry was settled in a 10.0m diameter$\times$3.0m high storage tank for 6 months and then divided into three layers according to the storage time. The pollutants concentration, BODs(Biochemical Oxygen demand), CO $D_{Mn}$ (Chemical Oxygen demand) and SS(Suspended Solids) of the piggery slurry used in this study were 25,134, 15,840, 23,800mg/$\ell$, respectively. The initial fertilizer content of piggery slurry, N(Nitrogen), $P_2$ $O_{5}$(Phosphoric acid) and $K_2$O(Potassium oxide), were 0.69, 0.33, 0.40%, respectively. 6 months later, BO $D_{5}$, CO $D_{Mn}$ and SS of the Piggery slurry were 16,040, 8,098, 3,300mg/$\ell$ in top layer, 15,806, 8,309, 5,900mg/$\ell$ in middle layer and 39,530, 23,958, 51,000mg/$\ell$ in bottom layer, respectively. The fertilizer content of piggery slurry after 6 months, N, $P_2$ $O_{5}$ and $K_2$O, were 0.47, 0.07, 0.46% in top layer, 0.43, 0.08, 0.47% in middle layer and 0.60, 0.44, 0.40% in bottom layer, respectively. Consequently, in course of storage time, the pollutant concentration and fertilizer content were the highest in the bottom layer compared with the top and middle layer.

• Journal of the Korean Wood Science and Technology
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• v.43 no.6
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• pp.884-889
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• 2015

Appropriate evaluation of thermal insulation property of structural member and valid control of cooling/heating energy are important for improving building's energy efficiency. The typical heating system of house in Korea is the floor heating one. The radiation heating system is not only appropriate to climate and geographic conditions of Korea, but also advantageous to provide emotional comfort by the warm feeling of floor. Based on living conditions in Korea, scaled models of the wooden house and concrete house were designed. The ceiling was made of styrofoam insulation and the four sided walls and bottom were made of plywood and concrete, respectively. The floor was heated by heating film. Indoor vertical temperature distributions by floor heating system were measured by thermocouple, and surface temperatures on walls were measured by infrared thermography. Also, thermal insulation property of wooden wall was evaluated to build database for improving energy efficiency of wooden building. It is expected that collected data during tests of various types of floor and wall composition could be referenced for evaluating thermal environment of actual conditions of houses.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.1
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• pp.104-111
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• 2016

The steel frame modular housing of which the research and development has been actively carried out recently cannot be constructed through monolithic placement like the reinforced concrete deck of general structure due to the characteristics of construction method of production in the factory and assembly on the site. And floor vertical vibration and deflection caused by inhabitants' activities may become an important issue in the aspect of usability evaluation due to a decrease in the section size of member, a decrease in weight, and so on. Therefore, this study evaluated the vibration performance of deck by using formula of AISC Design Guide 11(hereinafter AISC formula) which was practically used in general for modules where a stud was and wasn't installed at the center of beam in the longitudinal direction in the modular housing to be studied, and examined the applicability of AISC formula through comparison with the results of analysis using a general-purpose analysis program. On the basis of this, a structural cause for an error to occur between analysis result and AISC formula in the deck of module in which a stud was installed was analysed, and measures for considering this were suggested. Besides, an analysis model with the variables of measures for improving the floor vibration performance of modular housing to be studied was established. And measures having excellent vibration performance and economic feasibility were suggested through vibration response analysis and economic evaluation.

• Proceedings of the SAREK Conference
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• 2007.06a
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• pp.177-177
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• 2007

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.63-64
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• 2011

조명용 전기 에너지의 효율적인 이용을 위해서는 사용 환경에 따라 조명 기구를 부분 조광(local dimming) 제어할 필요가 있다. 본 연구에서는 LED 면광원의 부분 디지털조광 시스템을 개발하고 부분 조광된 면광원의 발광영역 및 밝기와 조명 대상물의 조도 분포와의 관계를 측정하고 평가하였다. LED 면광원을 16개의 구역으로 나누고 FPGA와 FET 스위치를 이용하여 각 구역의 점등 및 광량을 디지털 제어하였다. 또한 실험용 암실을 만들어 암실 바닥면을 91등분하고 각 지점의 조도를 측정하여 부분 조광제어에 따른 조도 분포를 평가하였다.

• Journal of Korean Society of Steel Construction
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• v.8 no.4 s.29
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• pp.105-113
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• 1996

본 연구에서는 철골모멘트골조의 패널존변형을 명시적으로 고려한 탄성층 간변위의 근사해석 방법을 제안하였다. 본 방법은 고전적 포탈법의 가정 및 D 치법에 기반한 해석적 접근법이다. 즉 포탈법의 가정에 따라 횡력을 받는 골조를 보-기둥 부분 골조로 분해한 후 대표적 내부 부분골조의 보, 기둥 및 패널존에서 기인하는 모든 횡변위 성분을 해석적으로 계산한다. 이때에 필요한 모든 내력(가령 패널존 전단변형 산정을 위한 보의 불균형모멘트)의 결정에 D 치법을 이용한다. 구조바닥의 강막작용을 고려하면 위의 과정을 통하여 산출된 대표적 내부 부분골조의 횡변위는 전체 골조의 횡변위와 거의 동일할 것으로 기대할 수 있다. 본 방법의 타당성 여부는 반강절 접합요소를 사용한 해석적 엄밀해와 비교하여 검증하였으며 만족스런 결과를 주는 것을 확인하였다. 본 연구의 방법에 의해 컴퓨터해석에 의하지 않고도 철골모멘트골조의 탄성층간변위를 실용성있는 정확도로서 신속하게 산정할 수 있으므로 본 연구의 결과는 예비적 횡강성 평가에 유용하게 사용될 수 있다. 또한 본 방법의 적용과정에서 해석자는 철골모멘트골조의 횡변위 기동에 관한 물리적 감각을 증진시킬 수 있을 것으로 사료된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.513-516
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• 2007

임하다목적댐은 낙동가 하구로부터 약 356 km 상류에 위치하며 댐체의 길이 515 m, 높이 73 m의 rockfill 댐으로서, 총저류량은 595 백만$m^3$이다. 댐의 정상표고는 El. 168 m이고, 저수위 El. 137.0 m와 계획홍수위 El. 164.7 m 사이에서 운영되고 있다. 임하다목적댐의 표면취수설비는 댐우안 도수로 입구에 위치하며 콘크리트구조물로서 높이는 44.0m이다. 취수탑의 바닥표고는 EL.124.0 m이며 월류수심은 7.0m이다(한국수자원공사, 2004). 최대취수량은 $119.2m^3/s$이며 취수문은 직선형다단식게이트형식이고 폭 10.0m, 높이 6.0m의 게이트 5조와 폭 10.0m, 높이 3.25m의 게이트 1조로 구성되어있다. 본 연구에서는 미국 YSI사에서 제작한 ADV-6600을 이용하여 저수지에서 취수시 유속을 측정하여 취수구간이 저수지의 연직방향 유속에 미치는 영향을 분석하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1976-1981
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• 2010

하천사업이 자연친화적인 사업으로 변화하면서 친수성을 가진 다양한 형태들의 호안블록이 개발되고 있다. 호안블록의 다양성에 비해 유수에 대한 안정성을 검증할 수 있는 항력 양력계수, 상당조도 등의 수리특성인자에 대한 연구가 미진한 실정이다. 따라서 본 연구에서는 수리모형 실험을 통해 호안블록의 역학적인 특성을 분석하여 유수가 호안블록에 미치는 영향을 규명하였으며, 호안공법에 대한 수리모형 실험방법의 적용성을 모색하였다. 수리실험은 수로의 상류로부터 수류의 안정화가 이루어지는 9m 지점의 수로 바닥에 블록을 설치하였으며, 4분력계와 전자유속계를 이용하여 수리특성인자의 계측을 실시하였다. 단체실험은 형태가 다른 6개의 호안블록을 이용하여 실험을 실시하였으며, 단체실험결과에 의한 항력과 양력이 양호한 호안 4로 군체실험을 실시하였다. 군체 실험을 통해 상당조도가 0.163에서 0.165로 증가하는 것으로 확인되었으며, 상당조도의 증가에 따른 유속 저감 정도를 파악할 수 있었다.