• Journal of Korean Society of Steel Construction
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• v.17 no.6 s.79
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• pp.727-736
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• 2005

This study presents a method of determining the optimum cable tension forces for the proper initial equilibrium state of a cable-stayed bridge using the least square method. The proposed method minimizes the errors, i.e., the differences, such as the deflection and the moments of the girder and the tower, between the target values from a continuous beam by considering the cable anchor point as supports of the girder and the responses obtained from the analysis of the entire cable-stayed bridge system. Especially, the proposed method can selectively control the adjustment of the tower moment, the girder moment, and the deflections by introducing the weighing matrix. Through numerical analysis and comparisons with existing studies, the usefulness and validity of the proposed method was verified.

• Journal of Korean Society of Steel Construction
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• v.19 no.6
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• pp.715-723
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• 2007

A displacement-based seismic design procedure was proposed for mid-to-low-rise steel moment frames. The proposed method was totally different from the current R-factor approach in that it directly uses available connection rotation capacity as a primary design variable. To this end, the relationship between available connection rotation capacity and seismic response modification (R factor) was established first; this relationship has been a missing link in current ductility-based design practice. A step-by-step displacement-based iterative design procedure was then proposed and verified using inelastic dynamic analysis.

• Journal of Korean Society of Steel Construction
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• v.18 no.4
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• pp.447-456
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• 2006

In this study, a torsional test for U-type steel box girders was performed to observe the effects of the kind of panel for top lateral walateral bracings on the torsional behavior of the U-type steel girder system. For the structural tests, the test specimen with a two-thirds scale of the system actually constructed in the field was used. In the torsional test to observe the efects of top lateral bracings, the most economical arrangement of the top lateral bracing was found to be the panel width to length ratio of 1:1.5 with the inclined angle of $40^{\circ}$.

• 방재와보험
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• s.46
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• pp.73-75
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• 1990

화재로 인한 인명 및 재산상의 손실을 예방하고 신속한 재해복구와 인명피해에 대한 적정한 보상을 하게 함으로써 국민생활의 안정에 기여하게 함을 목적으로 1973년 2월 6일 법률 제 2482호로 공포된 "화재로 인한 재해보상과 보험가입에 관한 법률"에 의거 서울특별시, 5개직할시 및 전주시에 소재한 특수건물(4층 이상건물, 국유건물, 교육시설, 백화점, 시장, 의료시설, 흥행장, 숙박업소, 송장, 송동주택 등) 소유자는 "신체손해배생 특약부 화재보험" 에 의무적으로 가입토록 되어있다. 이밖에도 국가저액적으로 또는 국민 복지증진을 위하여 많은 종류의 의무보험을 실시하고 있으며, 특히 위 법률과 유사한 사례로 국내에는 "항공운송 사업진흥법" (제7조), "산림법" (제113조)에 보험가입에 대한 의무규정이 있다. 일본 동경해상화재보험(주)에서 발간한 "손해보험과 시장"과 영국에서 발간한 "Handbook of risk management"에 의하면 거의 대부분의 국가에서 책임보험등 의무보험제도를 실시하고있으며, 특히 스위스, 서독, 벨기에, 아이슬란드, 브라질에서는 특수건물 화재보험과 유사하게 건물에 대한 의무보험제도를 실시하고 있는데 이들 국가중 스위스에서는 이미 180여년전부터 26개 주 중 19개 주에서 모든 건물에 대하여 화재보험 가입을 의무화하고 있으며, 그 수용동산까지도 화재보험에 부부토록 강제화되어 있는 주도 있다. 한편 서독에서도 오래전부터 건물의 화재보험 가입을 의무화하고 있는 주가 많으며, 의무화를 실히하고 있지 않은 주도 보험가입은 임의적이나 가입시에는 반드시 주가 지정한 공영건물보험기관에 가입토록 하는 독접형태로 운영되고 있다. 따라서 외국의 의무보험 실태를 보다 구체적으로 파악해 보기 위하여 스위스 바젤주(Basel- Stadt- Kantons)의 건물보험법을 소개하고자 한다.

• Journal of Korean Society of Steel Construction
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• v.11 no.3 s.40
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• pp.259-270
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• 1999

In this study, establishment of standard design procedure and optimum dimension of the embedded steel-plate cellular bulkheads for seawall structures in deep water sites has been presented. A computer program was developed to asses feasible dimensions of steel-plate cell, and general equations to determine optimum cell diameter and embedment depth are derived for sand. A model experiment to verify the necessary driving force of vibratory hammer system was also performed and driving force data pertinent to optimum cell dimension are presented.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1436-1437
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• 2015

"국가를 당사자로 하는 계약에 관한 법률" 시행령 제9조 1항 제3호 및 같은 법 시행규칙 제5조 제2항에 근거 전기공사의 예정가격의 결정기준은 (1)거래실례가격 (2)표준품셈 (3)표준시장단가 (4)견적가격 등 4가지 방법을 사용하고 있다. 특히 표준시장단가제도는 이미 수행한 공사의 계약단가만을 고려하여 발표하는 "실적공사비"제도를 계약단가, 입찰단가, 시공단가 등을 고려한 "표준시장단가"제도로 2015년 3월 1일부로 개정되었다. 제도는 시행되었으나 표준시장단가의 산정기준, 절차 및 방법 등 세부적인 제도가 미흡한 상황이다. 따라서 과거 실적공사비 산정방식을 검토하되, 계약단가, 입찰단가, 시공단가 등을 고려한 합리적인 표준시장단가의 산정방식을 제시함으로써, 예정가격결정시 적정공사비를 확보하고, 원 하도급간의 거래가격 투명성 및 객관성을 통해 전기공사의 품질 및 안정성이 확보될 것으로 사료된다.

• Journal of Korean Society of Steel Construction
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• v.12 no.2 s.45
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• pp.143-150
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• 2000

Depending upon the combination of tolerances specified in the standards on bolt, nut and washer for high tension bolt sets, there arises center-to-center deviation between bolt and washer. This deviation nay cause loss of effective contact area between nut- and washer-faces, which leads to some dispersion of the torque coefficient K. By adapting circular arc surface instead of flat surface for the nut, it is shown through numerical analyses that the dispersion of the torque coefficient can be minimized. In this way, optimum radius of curvature of the nut bearing surface is proposed.

• Journal of Korean Society of Steel Construction
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• v.18 no.2
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• pp.181-189
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• 2006

This study analyzes the effects of the curvature friction coefficient, the wobble friction coefficient, and the increased strength of concrete, reinforced tendon on optimum de signs by using the optimum-design program, to minimize the cost of a PSC box girder bridge using the full staging method. The objective of this study is to find a proper tendon for the friction coefficient, and thereafter, to indicate the direction of the study development about tendons and to indicate the direction of a study on the increased strength of used materials. This program used the SUMT procedure and Kavlie's extended-penalty function to allow infeasible design points in the process. Powel's direct method was used in searching design points, and the gradient approximate method was used to reduce the design hours.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.253-259
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• 2010

This experiment was conducted to evaluate water use efficiency of barley, wheat, and millet as a substitution crop for rice of fallow paddy field. Dry weight (DW), evapotranspiration, and transpiration of crop grown on the lysimeters controlled with 5 levels of groundwater table (GWT), 0, 25, 50, 75, and 100 cm were evaluated for optimum GWT and water use efficiency. All the lysimeters randomized with four replication arrangements were filled up sandy loam and were adjusted to the constant bulk density treated with twice water infiltration from bottom side to upper side of lysimeter. DW of barley, wheat, and millet in the plot of 0cm GWT that is saturated soil showed 34.9%, 44.7%, and 37.1% of that in the plot of 100 cm GWT, respectively showing a serious obstacle in crop growth. Evapotranspiration ratios calculated by evapotranspiration volume (mL) per DW were 166~605 mL for barley, 136~481 mL for wheat, and 81~418 mL for millet showing the order of barley > wheat > millet. Evapotranspiration ratio was increased with decrease of groundwater table that is the condition of moisture saturation. Estimation of GWT for maximum DW of wheat was 76 cm, and those of barley and millet were 100 cm below. The volumetric moisture content of lysimeter soil with cropping was markedly decreased as increase of crop growth because moisture supplying capability by capillary rise of water was less than amount of moisture required by crop.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.251-259
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• 2016

This study examined the DO concentration distribution and ORP distribution using microbubbles on pilot-scale aeration tanks. As a result of MLSS mixing and oxygen transfer phenomenon using microbubbles, different DO concentrations were observed depending on the circulation of the liquid with the microbubble supply location on the lateral of an aeration tank. The simulation results of CFD (computational fluid dynamics) program showed that MLSS mixed with a microbubble supply in the middle the reactor is much better than on the left side of the reactor. A single reactor containing an anaerobic, anoxic, and aerobic zone, was evaluated without partition according to the location of the microbubble supply based on the experiments and CFD analysis. MLSS was separated into solid-liquid by the microbubble supply in the aeration tank. Consequently, selecting the appropriate microbubble size is important for MLSS mixing and was maintained at the proper DO concentration for biological treatment.