• 한국자동차공학회논문집
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• 제7권8호
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• pp.180-189
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• 1999

This paper describes the collapse characteristics of the rectangular tube under eccentric compressive load. Local buckling stress and maximum crippling load are investigated. A thin-walled tube under load is controlled by local buckling or yielding of material according to the ratio of thickness to width (t/b) of the cross section, and subsequent collapse of the section. The relationship can be divided into three regions : elastic , post-buckling and crippling . the load-displacement relationship is theoretically presented in each region by introducing the stress distribution of the cross section in the loading process. And the maximum load carrying capacity is derived in the closed form as a function of normal stress on the flange and web.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(I)
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• pp.139-142
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• 2005

This paper presents a deformable strut-and-tie model of determining the shear strengths and ultimate deformations of the shear-dominant reinforced concrete members. The proposed model originates from the strut-and-tie model concept and satisfies equilibrium, compatibility, constitutive laws, and the geometric conditions of shear deformation. This study attempts to apply deformation patterns to strut-and-tie models. The yielding of flexural reinforcements determines yielding states and the ultimate states of reinforced concrete coupling beam are defined as the ultimate compressive strain of struts and the degradation of compressive strength due to principal tensile strain of struts. The validity and accuracy of the proposed model is then tested against available experimental data. The parameters reviewed include the ratios of truss action and arch action, the reinforcement ratios, and the shear span-depth ratio. It is expected that this model can be applied to displacement-based design methods.

• 설비공학논문집
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• 제20권5호
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• pp.351-356
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• 2008

In this study, we had the stress analyses of TBP used in Tall Building and determined the working pressure of TBP. We knew the four fact. First, the place acted maximum stress is axial direction of branched part. Second, working pressure is more than 2.0 MPa. Third, stress in branched part is less than yielding strength at hydrostatic test pressure. Fourth, the ratio(stress/yielding stress at hydrostatic test pressure) is $0.4{\sim}0.6$(KS D 3562 Sch 40), $0.3{\sim}0.4$(KS D 3576 20S).

• 한국작물학회지
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• 제44권1호
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• pp.59-63
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• 1999

Yield and growth characteristics were compared for five rice cultivars; a new Tongil-type, so called "super-rice", Dasanbyeo, an old Tongil-type Milyang 23, two japonicas Dongjinbyeo and Ilpumbyeo, and a new plant type (NPT)line IR65600-27-1-2. The objective of this stusy was to clarify the high yielding capacity of Dasanbyeo in terms of growth characteristics. The average grain yield (9 t/ha) of Dasanbyeo was higher than that of Milyang 23 by ca. 9% that of japonicas by 20 to 30%, and that of NPT line by ca. 100%. The higher grain yield of Dasanbyeo was attributable not only to the greater dry matter production but also to the higher harvest index (HI). Dasanbyeo showed the greatest dry matter at harvest owing not only to the rapid leaf expan-sion at early growth stage and the resulting high LAI through the entire growth stage but also to the high NAR despite the high LAI. The rapid leaf expansion of Dasanbyeo at early growth stage seemed to be related in part to the profuse tillering capacity. HI was 0.53 in Dasanbyeo, 0,51 in Milyang 23, 0.41 in japonicas, and 0.35 in NPT line. Dasanbyeo was indebted for its higher HI to the relatively high grain filling ratio in spite of a much greater sink size than the other cultivars. Dasan had a greater source to sink ratio during grain ripening as measured by LAD/spikelet and dry matter production/spikelet which showed positove correlations with the grain ripening ratio. New plant type (NPT) line showed the lowest grain yield owing to the small sink size and the low grain filling ratio which seemed to have resulted from the abundant occurrence of weak-strength spikelets. The weak sink strength, in turn, seemed to have suppressed photosynthesis during the grain ripening stage.

• Steel and Composite Structures
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• 제48권4호
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• pp.367-383
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• 2023

A coupled wall consists of two or more reinforced concrete (RC) shear walls (SWs) connected by RC coupling beams (CBs) or steel CBs (hybrid-coupled walls). To fill the gap in the literature on the plastic hinge length of coupled walls, including coupled and hybrid-coupled shear walls, a parametric study using experimentally validated numerical models was conducted considering the axial stress ratio (ASR) and coupling ratio (CR) as the study variables. A total of sixty numerical models, including both coupled and hybrid-coupled SWs, have been developed by varying the ASR and CR within the ranges of 0.027-0.25 and 0.2-0.5, respectively. A detailed analysis was conducted in order to estimate the ultimate drift, ultimate capacity, curvature profile, yielding height, and plastic hinge length of the models. Compared to hybrid-coupled SWs, coupled SWs possess a relatively higher capacity and curvature. Moreover, increasing the ASR changes the walls' behavior to a column-like member which decreases the walls' ultimate drift, ductility, curvature, and plastic hinge length. Increasing the CR of the coupled SWs increases the walls' capacity and the risk of abrupt shear failure but decreases the walls' ductility, ultimate drift and plastic hinge length. However, CR has a negligible effect on hybrid-coupled walls' ultimate drift and moment, curvature profile, yielding height and plastic hinge length. Lastly, using the obtained results two equations were derived as a function of CR and ASR for calculating the plastic hinge length of coupled and hybrid-coupled SWs.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회논문집(I)
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• pp.297-302
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• 2000

This paper presents the effect of diaphragm spacing ratio(depth to span) on behavior and capacity of composite steel-concrete structures of sandwich system. Numerical analysis has been performed variety diaphragm ratio, behavior and load condition. As a results of this study, in case of shear behavior and concentrated load, the capacity of structure such as yielding and ultimate load improve according to diaphragm ratio because of concrete confining effect by steel plate and stress redistribution by diaphragm. But in case of bending behavior or uniform load, it proved that diaphragm ratio don't influence on behavior and capacity of composite structures of sandwich system.

• Applied Biological Chemistry
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• 제17권1호
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• pp.1-30
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• 1974

수도저위(水稻低位) 생산력(生産力)의 원인구명(原因究明)에 관(關)한 영양생리학적연구(營養生理적硏究)로 여러 가지 생육조건하(生育條件下)에서 품종별(品種別) 양분흡수(養分吸收) 및 동화기능(同化機能)과 양분(養分)의 체내(體內)에서의 이행양상(移行樣相)을 추구(追究)하는 한편 고수량지(高收量地) 벼와 저수량지(低收量地) 벼에 대(對)한 생육시기별(生育時期別)로 양분(養分)의 흡수(吸收) 체내무기양분(體內無機養分)과 수량(收量) 및 수량구성요소(收量構成要素)와의 관계(關係) 등(等)을 추구(追究)하여 저수량지(低收量地) 벼의 영양생리적(營養生理的) 저수요인(低收要因)을 밝히고저 본연구(本硏究)를 수행(遂行)하였던 바 그 결과(結果)를 요약(要約)하면 다음과같다. 1. 양분(養分)의 흡수력(吸收力)은 품종(品種)에 따라 차이(差異)가 있으며 인산(燐酸) 및 가리(加里)의 흡수력(吸收力)이 강(强)한 품종(品種)은 구사부에, 진흥(振興)이며 낮은 품종(品種)은 팔달(八達)이었다. 2. 근(根)의 ${\alpha}-naphthylamine$의 산화력(酸化力)과 인산(燐酸)의 흡수력(吸收力)과는 유의적(有意的)인 상관관계(相關關係)가 있으며 산화력(酸化力)이 높으면 인산(燐酸)의 흡수(吸收)가 증대(增大)되었바. 3, 탄소동화력( 炭素同化力)은 품종(品種)에 따라 차이(差異)가 있으며 노인도(老人稻), 구대내조욱(九大耐潮組) 3호(號), 수원(水原)82호(號), 진흥(振興) 등은 강(强)하고 대구조(大脚租), 관옥(關玉), 육우(陸羽) 132호(號)가 약(弱)하였다. 4, 질소(窒素)의 증시(增施)는 소비(少肥)에 비(比)하여 동화량(同化量)은 증가(增加) 되나 등화산물(同化産物)의 이삭으로의 이전(移轉)은 적었다5. 정상(正常) 생육(生育)한 벼에 비(比)하여 인산(燐酸), 가리(加里) 및 마그네슘이 결핍(缺達)된 벼는 전탄소동화량이(全炭素同化量)이 정상(正常) 벼 100에 비(比)하여 40이하(以下)로 현저(顯著)히 낮으며 그 순서(順序)는 Mg>P>K이고, 동화물(同化物)의 이전(移轉)에 장해(障害)가 큰 것은 K>Mg>P의 순(順)이었다. 6. 고수량지(高收量地) 벼는 저수량지(低收量地) 벼에 비(比)하여 총건물(總乾物) 생산량(生産量)이 현저(顯著)하게 많고 특(特)히 유수형성기(幼穗形成期) 이후(以後)에 증가량(增加量)이 더욱 현저(顯著)하였다. 7. 고수량지(高收量地) 벼는 출수기(出穗期)에 옆면적(葉面積)이 최고(最高)에 달(達)하였다가 그 이후(以後) 완만(緩慢)하게 줄어지나 저수량지(低收量地) 벼는 출수이전(出穗以前)에 엽면적(葉面積)이 최고(最高)에 달(達)하였다가 출수이후(出穗以後)에 급격(急激)히 감소(減少)되며 그 원인(原因)은 하엽(下葉)의 조기고사(早期枯死)에 기인(起因)되었다. 8. 고수량지(高收量地) 벼는 저수량지(低收量地) 벼에 비(比)하여 생육초기(生育初期)에는 투과광율(透過光率)이 높고 생육후기(生育後期)에 낮았으나 투과광율대(透過光率對) 엽면적비(葉面積比)는 고수량지(高收量地) 벼에서 높았다. 9. 순동화량(純同化量)은 저수량지(低收量地) 벼에 비(比)하여 고수량지(高收量地)벼에서 많았으며 이는 또한 엽면적(葉面積)이 증가(增加)됨에 따라 감소(減少)되었다. .10. 고수량지(高收量地) 벼는 저수량지(低收量地) 벼에 비(比)하여 유수형성기(幼穗形成期) 이후(以後) 체내질소(體內窒素), 가리(加里) 및 규산(珪酸)의 함유율(含有率)이 높으면서 $K_2O/N$, $SiO_2/N$ 비(比)가 높았다.11. 저수량지(低收量地) 벼는 고수량지(高收量地) 벼에 비(比)하여 출수기(出穗期)에 보유(保有)된 질소(窒素), 인산(燐酸), 가리(加里) 및 마그네슘등이 출수이후(出穗以後) 이삭으로의 이행율(移行率)이 높았다. 이는 저수량지(低收量地) 벼가 생육후기(生育後期)에 양분(養分)의 흡술량(吸收量)이 부족(不足)하여 체내(體內) 저장양분(貯藏養分)이 재이동(再移動)되기 때문이며 따라서 하엽(下葉)은 양분부족(養分不足)으로 조길고사(早期桔死)가 많아지는 것으로추정(推定)되었다. 12. 고수량지(高收量地) 벼는 질소흡수(窒素吸收)가 전생육기간(全生育期間)을 통(通)하여 완만(緩慢)하며 출수이후(出穗以後)에도 흡수량(吸收量)이 많으나 저수량지(低收量總) 벼는 출수이전(出穗以前)에 많고 출수이후(出濾以後)는 거의 흡수(吸收)되지 않았다. 13. 출수기(出穗期)의 체내(體內) 질소(窒素), 가리(加里) 함유율(含有率)과 수량(收豊)과는 현저(顯著)한 정(正)의 상관(相關)이 성립(成立)되였으며 수확기(收獲期)의 가리(加里), 규산함유율(珪酸含有率) 그리고 $K_2O/N$, $SiO_2/N$과 수량(收量)과도 현저(顯著)한 정(正)의 상관관계(相關關係)가 성립(成立)되었다. 14. 출수기(出穗期)에 보유(保有)된 전분(澱粉)이 이삭으로의 이전(移轉)은 고수량지(高收量地) 벼가 약(約) 10%인데 반(反)하여 저수량지(低收量地) 벼는 약(約) 40%로 많았다. 따라서 저수량지(高收量地) 벼는 출수(出穗) 이후(以後) 동화의존도(同化依存度)가 높았다. 15. 고수량지(高收量地) 벼는 저수량지(低收量地) 벼에 비(比)하여 질소(窒素), 인산(燐酸), 가리(加里), 규산(珪酸) 및 망간의 흡수량(吸收量)이 현저(顯著)하게 많았고 생육시기별(生育時期別) 흡수량(吸收量)의 차이(差異)는 유수형성기(幼穗形成期) 전후(前後)에 현저(顯著)하였다. 16. 수확기(收穫期)의 질소(窒素), 인산(燐酸), 가리(加里), 석탄(石炭), 마그네슘, 규산(珪酸) 및 망간의 총흡수량(總吸收量)과 수량(收量)과는 고도(高度)의 정(正)의 상관관계(相關關係)가 인정(認定)되었다. 17. 수확기(收穫期)에 질소(窒素), 인산(燐酸), 가리(加里), 석탄(石炭), 마그네슘 및 규산(珪酸)의 흡수량(吸收量)과 수당입수간(穗當粒熱間)에, 질소(窒素) 및 가리(加里)의 흡수량(吸收量)과 수수(穗數)와는 유의적(有意的)인 정(正)의 상관관계(相關關係)가 성립(成立)되었다.

• Earthquakes and Structures
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• 제19권4호
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• pp.273-286
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• 2020

The pile group foundation is widely used for gravity pier of high-speed railway bridges in China. If a moderate or strong earthquake occurs, the pile-surrounding soil will exhibit obvious nonlinearity and significant pile group effect. In this study, an improved pushover analysis model for the pile group foundation with consideration of pile group effect is presented and validated by the quasi-static test. The improved model uses simplified springs to simulate the soil lateral resistance, side friction and tip resistance. PM (axial load-bending moment) plastic hinge model is introduced to simulate the impact of the axial force changing of pile group on their elastic-plastic characteristics. The pile group effect is considered in stress-stain relations of the lateral soil resistance with a reduction factor. The influence factors on nonlinear characteristics and plastic hinge distribution of the pile group foundation are discussed, including the pier height, longitudinal reinforcement ratio and stirrup ratio of the pile, and soil mechanical parameters. Furthermore, the displacement ductility factor, resistance increase factor and yielding stiffness ratio are provided to evaluate the seismic performance of soil-pile system. A case study for the pile group foundation of a railway simply supported beam bridge with a 32 m-span is conducted by numerical analysis. It is shown that the ultimate lateral force of pile group is not determined by the yielding force of the single one in these piles. Therefore, the pile group effect is essential for the seismic performance evaluation of the railway bridge with pile group foundation.

• 한국지반공학회논문집
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• 제21권5호
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• pp.51-58
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• 2005

본 연구에서는 말뚝지지 전면기초에 대한 대규모 모형실험을 실시하여 여러 가지 조건에 따른 하중분담률을 측정하였다. 모형실험은 동일한 조건하에서 비접촉 무리말뚝과 말뚝지지 전면기초 두가지 상태로 실시되었고, 지반의 상대밀도와 종류, 말뚝길이, 간격, 배열상태와 말뚝관입방법 등의 조건들을 변화시켜 실험을 실시하였다. 모형실험 결과, 말뚝관입방법과 지반 종류에 따른 하중-침하 곡선은 큰 차이가 없는 것으로 나타났다 재하하중이 작은 경우에는 대부분의 하중을 말뚝들이 부담하지만, 하중이 커지면 래프트도 상당한 하중을 분담하는 것으로 나타났다. 모래지반의 상대밀도가 높을수록 말뚝지지 전면기초의 하중분담률은 감소하는 경향을 나타내며, 말뚝간격이 넓어지고, 말뚝길이가 길어질수록 하중분담률은 증가하는 경향을 나타냈다. 그러나 말뚝관입방법과 하부 지반의 종류는 말뚝지지 전면기초의 하중분담률에 큰 영향을 주지 않는 것으로 평가되었다.

• 한국안전학회지
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• 제25권6호
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• pp.128-136
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• 2010

In according with concrete structural design standard, it is common designing flexure reinforcement concrete to induce tension failure. So reinforcing ratio is limited to inducing tension failure. And maximum reinforcing ratio is regulated to protecting concrete compression strength caused by over reinforced building. Minimum reinforcing ratio is also limited in designing standard to protecting brittle failure as extremely using less reinforcing bar. But in minimum reinforcing ratio it is extremely conservative or it is sometimes impossible to induce stable tension-failure because they are depending on yield failure and experienced method and concrete designing standard strength. Therefore the purpose of the present paper is to evaluate the flexural behavior of minimum steel ratio of reinforced concrete of beams and to propose the guide-line of equation of minimum steel ratio by performing static flexural test of 16 beams according to size effect, number of steel, yielding stress of steel, and concrete compressive strength which are presumed effective variables. From experimental results, the equation of minimum steel ratio was newly proposed considered size effect.