수리구조물의 골조 설계를 위한 구형 RC-기둥의 구조해석

이정재,최진용,김한중,조래청 서울大學校 農業生命科學大學 農業開發硏究所 1997 서울대농학연구지 Vol.22 No.1

본 연구는 축하중과 함께 2축 휨모멘트를 동시에 받고 있는 구형 복단면 부재에 대한 구조해석을 위하여, 철근콘크리트의 기본 가정과 기본 이론으로부터 전산프로그램을 개발하고, 이를 이용하여 쉽게 사용할 수 있는 설계도표를 작성하였으며 기본설계 가정에 대한 적정성을 판단하고 설계도표의 이용가능성을 제시하였다. 그 주요한 결과를 요약하면 다음과 같다. 1. 철근과 콘크리트의 강도설계법에서와 같이 탄성한계를 가정한 상태에서, 2축 휨을 받는 구형 복단면의 구조해석이 가능한 프로그램을 개발하였다. 2. 개발된 구조해석 프로그램을 이용하여 작성한 설계도표가 구형단면 및 복단면 부재설계에 적용할 수 있음을 알았다. 3. 개발된 구조해석 프로그램에 의하여 단위축하중-합성단위모멘트도의 작성이 가능하며, 이를 이용하여 설계물의 초기 설계변수를 손쉽게 결정할 수 있었다. ◁그림삽입▷(원문을 참조하세요) Marine structures, such as sea dike sluices with columns composed of more-than-one section, have been paid little attention by civil engineers. The aims of this study were to analyze an arbitrary shape of short columns composed of multiple section, subjected to axial loads and biaxial bending moments, with the aid of strength design method. The main conclusions in this study are summarized as follows; a computer program has been developed upon the basis that elastic limits of concrete and steel bar are 0.85 ??_ck and ??_y respectively. Using the model, design charts have been constructed for double rectangular reinforce concrete columns. The strength reduced factor for the members subjected to axial load and biaxial bending moments, can be easily checked by simple comparison of unit resultant resisting moment with the one applied externally. Using the design charts, optimum design values including the sectional sizes and reinforcements can be obtained easily and accurately.

暗渠排水 施設導入에 따른 汎用畓의 土壤物理性 變化

趙來淸,金善柱,陳成基,都德鉉 건국대학교 생명과학연구원 1994 생명과학지 Vol.1 No.-

In an existing rice paddy, we established an subsuface drainage and a auxilialy drainage at proper intervals to accelerate the underground drainage. In the process of building up a rotation field. we studied the little physical change of the soil over 24 months. Various tests were conducted (a. Munsell soil color test b. Constant head permeability and permeability test c. Examination of aeration, degree of hardness, waterproof quality d. Shear resistance and friction resistance test e. Moisture content and specific gravity test and f. Measurement of moisture content and void ratio by nuclear density meter). These tests were conducted by many people on soil from each plot. Results of the study are as follows. Paddy fields of Korea have a particularity different from the European countries and America that drain the excess soil water from the shallow surface soil layer. The facing problems on the planning and designing of subsurface drainage are determining the spacing of main subsurface drainage system, combination design of main and auxiliary subsuface drainage system and the structure of subsuface drainage ditch. The structure of subsurface drainage ditch consist of drainage pipe and filling materials such as rice bran and pebbles. The width of subsuface drainage ditch is 20cm in case of trencher operation and 30cm in case of back hoe excavation. The advisable depth of subsuface drainage ditch is below 50cm. In an subsuface drainage plot, the supporting force and the plate sinking volume increased, But the moisture content and specific gravity test, according to the tests had a tendency to decrease. Similarly, moisture content and void ratio as indicated by the nuclear density meter generally showed a tendency to decrease. In addition, aeration, degree of hardness, and the waterproof aggregates percent of soil generally incleased in an subsuface drainage plot. From the above results, we found that when an subsuface drainage was establshed in a silty rice paddy having poor permeability, the physical qualities of that rice paddy became those of a dry field.

확율유한요소법을 이용한 균질 사면의 신뢰성 해석

조래청 ( Jo Rae Cheong ),도덕현 ( Doh Duk Hyun ) 한국농공학회 1996 韓國農工學會誌 : 전원과 자원 Vol.38 No.5

This study was performed to provide the design method for soil structure which guarantees proper safety with uncertainty of soil parameters. For this purpose, the effect of uncertainty of soil parameters for slope stability was analyzed by Bishop's simplified method and Monte Carlo simulation(MC). And reliability analysis program, RESFEM, was developed by combining elastic theory, MC, FEM, SFEM, and reliability, which can consider uncertainty of soil parameters. For factor of safety(FS) 1.0 and 1.2 by Bishop's simplified method, the probability of failure(Pf) was analyzed with varying coefficient of variation(c.o.v.) of soil parameters. The Pf increased as c.o.v. of soil parameters increased. This implies that FS is not the absolute index of slope safety, and even if FS is same, it has different Pf according to c.o.v. of soil parameters. The RESFEM was able to express the Pf at each element in slope quantitatively according to uncertainty of soil parameters. The variation of Pf with uncertainty of soil parameters was analyzed by RESFEM, and it was shown that the Pf increased as the c.o.v. of soil parameters increased.

방조제 시공시 침하유실량의 최소화에 관한 연구

조래청,도덕형 건국대학교 산업기술연구원 1994 건국기술연구논문지 Vol.19 No.-

The purpose of this study is to propose the method of minimizing the settlement and losses of embanking material during constructing the seadike. To get the purpose, it was studied foundation ground conditions, material quantities of designing and embanking, tidal velocity, tidal water level differences, embanking method and et al. After that, analyzing the reasons of the stettlement and losses of embanking material was carried out. The results obtained are as follows: Genenally, the larger seadike, the more settlement and losses of embanking material. And it occures large losses of embanking material when tidal velocity is fast and hydraulic rollers(turbulent flow) happens. It is very important that choose the appropriate position of the final closing after investigating the ground conditions and tidal flow, etc. It is belter idea to consider the variable rates of the settlement and losses of embanking material through the sections depending on the soil properties of foundation ground and all kinds of conditions than to decide the same rate on the whole seadike length in designing. It is unevitible that the settlement and losses of embanking material happens when constructing the seadike. It is because of decreasing bearing capacity by occurring excess pore pressures and influences of fast tidal velocity. So, appropriate method for avoding these should be decided. For minimizing the settlement and losses of material, proper sill length and width deciding is important in range of not forbiding the tidal current. It is good to decide higher sill elevation, if possible. Before the numerical analyses, water model analyses or site measurements are carried out, it is thought that it is had better estimate the stability of seadike considering experienced factors.

농촌주택 도면자료 질의를 위한 객체지향 자료구조의 개발

정남수,윤성수,조래청,김한중 ( Nam Soo Jung,Seong Soo Yoon,Rae Cheong Jo,Han Joong Kim ) 한국농촌계획학회 1997 농촌계획 Vol.3 No.1

농촌계획에 있어 다중회귀분석법에 의한 사업비 결정 - 경지정시사업비의 예 -

윤성수,이정재,조래청 ( Seong Soo Yoon,Jeong Jae Lee,Rae Cheung Cho ) 한국농촌계획학회 1996 농촌계획 Vol.2 No.2

농업기반정비사업 편익산정을 위한 지표 개선방안

김영주 ( Young Joo Kim ),최병한 ( Byeong Han Choi ),조래청 ( Rae Cheong Jo ),최영완 ( Young Wan Choi ),김윤식 ( Yun Shik Kim ) 한국농촌계획학회 2014 농촌계획 Vol.20 No.2

The purposes of this research are to review the current economic measures to be used to assess the economic effects of agricultural infrastructure projects, to find some effects not included into the current measures, and to suggest new additional economic measures. So thus, economic assessment for agricultural infrastructure projects has been criticized to be overestimated. For example, some research reported that the projects enhanced rice productivity by 20% or 30%. We suggest four new measures to evaluate economic effects of agricultural infrastructure projects: (1) enhancement in productivity, (2) switchover from low-income crops to high-income crops, (3) rises in land price, and (4) lower fluctuation in production.

한국농공학회 활성화 방안 좌담회

강문성,고보성,김병진,박종민,박태선,이달원,이봉훈,이정재,장예환,조래청,한경수 한국농공학회 2003 韓國農工學會誌 : 전원과 자원 Vol.45 No.3