국내 풍하중의 합리적인 확률모형을 개발하기 위하여 전국 25개 지역에서 수집된 풍속자료를 일관성을 가지도록 측정높이, 노풍도, 측정시간등에 대한 보정을 실시하여 이용하였다. 풍하중의 활률특성에 영향을 미치는 요소로는 풍속, 풍력계수, 속도압계수, 가스트계수 등의 확률특성이 고려되었다. 풍하중을 결정하는 각종 계수들의 확률특성으로부터 풍하중의 확률특성을 분석하기 위해서 널리 이용되는 Monte Carlo Simulation기법을 이용하였다. 풍하중의 확률분포로는 풍속과 같이 Gumbel의 Type-I 극한값 분포를 적용하였으며 simulation결과에서 상부 10%만을 이용하였다. 또한 어떤 특정 구조물에 최대풍속이 가장 불리한 방향에서 발생할 확률이 낮은 것을 고려하여 감소계수 0.85를 적용하여 모형화하였다.

본 연구에서는 사무실 적재하중을 체계적으로 조사.수집하여 등가등분하중을 산정하였다. 등가등분포하중은 슬래브, 보 기둥등의 부재별로 영향선을 이용하여 분석하였다. 여기에서 하중효과는 보와 슬래브에서는 휨모멘트, 기둥에서는 축력이 고려되었다. 산정된 등가등분포하중 자료로부터 적재하중의 확률적 특성과 영향면적과의 상관관계가 분석되었으며, 다른 하중조사결과와도 비교되었다. 분석된 적재하중의 확률모형을 이용하여 사용기간 동안의 극한값을 산정하였으며, 이 결과는 현행 설계적재하중과 비교되었다. 또한 보다 합리적인 설계적재하중을 결정할 수 있는 기초자료로서 영향면적에 따른 설게하중식을 제안하였다.

1960년대 이후 구조공학자들이 구조해석 및 설계시의 고려대상(하중, 부재저항력 등)에 내재하는 불확실성을 구조물 안전도의 중요 영향인자로 인식하게 됨에 따라 확률이론을 도입한 구조해석 및 설계법이 급속히 발달하였고, 이 분야의 연구결과에 히입어 최근에는 기존 시방서에 이러한 설계법의 도입이 활발히 이루어지고 있다. 이러한 세계적인 경향에 맞추어, 국내에서도 확률론적 설계법을 도입하기 위해서는 설계시 고려되어야 하는 작용하중의 확률적 특성을 규명하는 연구가 선행되어야 한다. 이에 본 연구에서는 아파트에 작용하는 적재하중의 자료를 체계적으로 수집, 통계처리하여 확률적 특성을 분석하였다. 또한 이 자료를 이용하여 사용기간 동안의 극한값을 분석하여 현행 설계하중과 비교하였고, 부재별로 합리적인 설계하중안을 제시하였다.

구조물이 대형화되고 복잡해짐에 따라 구조물의 체계신뢰도 평가는 매우 어려워지며 많은 계산량을 요구한다. 특히 작용하중들이 시간적 변화특성을 가지거나 구조물의 파괴모드가 여러가지인 경우는 더욱 복잡하다. 구조물에 작용하는 대부분의 하중들은 그 발생강도 뿐만 아니라 발생시기, 발생빈도 등이 무작위특성을 가지므로, 이러한 시간적 변화특성을 합리적으로 반영하기 위해서는 종래의 확률변수 모형보다는 확률과정을 이용한 모형화가 바람직하다. 구조물 체계신뢰도의 근사해법으로 3계구간식 상한치를 이용한 점추정식 근사해가 제안되어졌다. 이 3계 점추정식 근사해는 현재 많이 사용되는 다른 근사해들과 비교할 때 적은 계산량의 증가에도 불구하고 정확도가 상당히 높으며 체계파괴확률 함수의 연속성이 보장된다. 상시하중과 함께 여러 일시하중이 작용할 때, 하중 조합효과를 보다 효과적으로 반영하기 위해 기존의 하중합치법을 보완하여 넓은 한계수준에서 정확도를 높였다.

사질계(砂質系) 답토양(畓土壤) 유형별(類型別)로 질소(窒素), 인산(燐酸), 가리(加里) 및 Bentonite와 Zeolite를 동시(同時)에 전량전층시용(全量全層施用)이 수도생육(水稻生育)고 수량(收量) 및 토양개량(土壤改良) 효과(效果)에 미치는 영향(影響)을 포장(圃場) 시험(試驗)하였다. 수도수량(水稻收量)은 삼요소(三要素) 전량전층시용(全量全層施用)에 비(比)해 삼요소(三要素)와 점토광물(粘土鑛物) 동시(同時) 전량전층(全量全層) 시용(施用)이 증수(增收)되었는데 사양토(砂壤土)에서는 Zeolite 1.0 M/T, 사토(砂土)에서는 Bentonite 0.5 M/T, 시용(施用)이 각각(各各) 5%수준(水準)에서 유의성(有意性)이 있었고 사토((砂土)에서 Bentonite 1.0 M/T 시용(施用)은 1% 수준(水準)에서 유의증수(有意增收)되었다. 출수기(出穗期) 수도경엽중(水稻莖葉中)의 양분함량(養分含量)은 삼요소(三要素) 전량전층시용(全量全層施用)에 비(比)해 삼요소(三要素)와 점토광물(粘土鑛物)을 동시(同時)에 전량전층시용(全量全層施用)함으로써 질소(窒素)와 규산함량(珪酸含量)은 높아졌고 인산(燐酸) 및 염기(鹽基)의 함량(含量)도 증가(增加)하는 경향(傾向)이었다. 또 토양(土壤)의 pH와 염기치환용량(鹽基置換容量)은 다소 높아졌고 유효규산(有效珪酸) 및 치환성염기(置換性鹽基)의 함량(含量)이 증가(增加)하였다.

강-콘크리트 합성구조의 성능을 확보하기 위해서는 전단연결재가 설치된 전단연결부에 대한 전단강도 분석이 필수적이다. 전단연결부의 전단거동을 효율적으로 예측하기 위하여, 전단연결부의 push-out test에 대한 유한요소해석을 수행하였다. 유한요소해석에는 범용 프로그램인 ABAQUS가 사용되었으며, 대상 실험체는 Y형 전단연결재가 적용된 강-콘크리트 전단연 결부이다. 유한요소해석에서는 대상 실험체를 구성하는 재료들의 비선형성을 고려하였고, 비선형해석의 수렴문제를 해결하기 위하여 준정적해석을 사용하였다. 본 연구에서 수행된 유한요소해석 결과를 바탕으로 하중-변위곡선과 전단강도를 기존 실험결과와 비교한 결과, 준정적해석을 이용한 유한요소모델은 기존 실험결과를 잘 반영하는 것을 확인하였다.

In order to export Korean spray roses to the China, it is needed to analyse chinese preferences, rose attributes, and purchase intentions. The purpose of this study is to present the implications on the production and distribution of roses for export by analyzing the quality preference attributes and purchase intention of Korean rose for Chinese flower experts. A survey on the preference and purchase intention of Korean flower roses by Chinese flower experts was conducted through face - to - face interviews with flower show participants in China. Approximately 100 Chinese flower experts who participated in the Flower Show in 2016 received the questionnaire, and 86 survey results could be used for analysis. Survey data were analyzed using ordered probit and bivariate probit models. As a result of an analysis, it was found that Chinese flower experts were more likely to buy Korean roses than Chinese roses even if they consider flower color, leaf shape and size and color diversity. The probability of purchasing more than twice the price was higher than that of the color diversity considering the flower shape, leaf shape and size, but the bivariate order probit model was larger than that of flowers, leaves and size, and the order of probability size was changed. In order to increase the export of Korean spray roses to the Chinese market, We need to increase Chinese experts’ preferences and satisfaction. For this purpose, it is very important to develop export varieties of roses with large flower buds and shape / coloring, and to apply the useful post-harvest technology that can extend freshness and distribution period of export roses.

A steel tubular member has been generally used for the offshore structure. Its stucutral performance can be decreased due to corrosion damage under severe corrosion environment In this study, to examine the compression performance of steel tubular member depending on corrosion thickness, damaged ratio, FE analyses were conducted and compared.

Temporary structures are essential elements in the high-rise structures. They are various and one of them, prefabricated shoring system is very useful. Because it is easy to install prefabricated shoring system. But collapse disaster of prefabricated shoring system occurs every year. In most situations, design deficiency and lacking in strength of vertical member give rise to the collapse. In this study, buckling stability of prefabricated shoring system was analyzed in the design phase.

Based on the study of considering thickness and diameter of the panel it was found that bigger the diameter of panel more efficient for support the water pressure and less displacement. It was found that rise depth had little influence for stress and displacement at small embossed panel. Also the biggest stress occured along the side of the embossed panel.

The water tanks are widely used for the safe storage of potable water, which are installed on either the basement or the top floor inside of the buildings. Therefore, the water tank systems assembled with many unit panels are generally adopted and the rectangular plan water tanks are most popular. To resist the water pressure acting on the side walls of tanks the internally reinforced system using metal tie-bars has been most commonly used. However, many problems related to the lattice internal reinforcement system require the development of the externally reinforced water tank, which does not have any latticed tie bars inside the tank. In this study two different systems have been developed using the external steel frames with either the SMC water tank panels or the PosMAC(coated steel) water tank panels. The experimental tests have been performed under the static hydraulic loadings as well as the seismic loadings through the shaking table test.

This study focuses on presenting a resistance capacity model of bridge which considers the surrounding environment. This model provides the timely decreasing characteristics of resistance capacity during the service life of bridge. The presented model is developed by using the statistical data announced to the public and the reliable research reports. The developed model is applied to evaluate the lifetime safety/reliability of a bridge. Based on the result of this evaluation, this study aims to accumulate the basic data of bridge maintenance works.

The expression 'Resistance capacity' in bridge engineering indicates the certain qualitative level of important characteristics that a bridge possesses, against the various types of action or load. Even if the bridges are constructed with similar feature, the resistance capacities evaluated from these bridges are different due to the uncertainties. This study focuses on presenting a resistance capacity model of bridge which considers the uncertainties caused from the statistical characteristics of bridge members. The developed model is applied to evaluate the lifetime safety/reliability of a bridge. Based on the result of this evaluation, this study aims to improve the effectiveness of bridge maintenance works.

Based on the study of chloride migration coefficient and hydration heat evolution, it was found that the use of ternary blended cement was effective to achieve desired service life and minimum crack index. On the other hand, a high level of compressive strength is required for marine concrete mix design.

Among the costs composing the life-cycle cost of nuclear containment, the expected loss due to leakage of radioactive material is usually exorbitant, and it takes large amount in the evaluation of life-cycle cost. This study presents a process to determine optimal target reliability for nuclear containments, mainly focuses on its expected loss. It is estimated considering the surrounding environment of nuclear containment. Target reliability of containments having different lifespan can be determined by revising the expected loss estimated from the 20, 40 and 60 years of operation.

This study represented simulation that analyzes extreme load effect based on reasonable probability model reflected actual traffic characteristics on a bridge. Through its simulation, vehicular loads for load carrying capacity assessment were developed by considering traffic characteristics and remaining service life, various structure. According to the analysis results on traffic characteristics through its simulation, extreme load effect tended to increase as the traffic volume and heavy vehicle proportion increase.

This study focuses on the push-out tests performed for verifying the performance of Y-type perfobond rib shear connectors. The end bearing resistance of the Y-type perfobond rib shear connector may be determined by the sizes of rib height and rib width. Therefore, in this study, the end bearing resistance is analyzed according to the rib widths and rib heights.

Based on the study of bridge live loads and traffic modes for using WIM datas, it was found that the structural integrity of bridges was damaged by overloaded heavy vehicles. The objective of the study is to investigate the statistical characteristics of vehicle loadings based on survey data collected, in which some major factors, such as vehicle configurations, vehicle weights, traffic modes, etc., are incorporated. The vehicle load effects due to single presence of heavy truck are also tested with several short- span bridges and probabilistic characteristics of current design practices are evaluated.

The trend of heaviness causes the increase in the number of overloaded vehicles on a bridge, which is a difficulty in the decision of design live load. However, there is no established system to control the overloaded vehicles. In this paper, a management system to control the total number of heavy vehicles on a bridge using BWIM. The traffic management system uses the control methods based on approaching time intervals.

Degree of damage of the bridge and safety level is closely related to the characteristics of the lifetime maximum load effect that occur on the bridge. Maximum load effect is dominated by traffic characteristics such as heavy vehicle composition and daily traffic volume. The purpose of the study is to analyze the structural characteristics of vehicle loading based on survey data collected, in which some major factors, such as vehicle configurations, vehicle wieghts, traffic modes by the probabilistic approach. Then, this study perform analysis of the safety level as compared with design criteria domestic highway bridges the current regulations are enclosed.