• 한국지반공학회논문집
• /
• 제28권7호
• /
• pp.67-75
• /
• 2012

교량기초의 지지층인 조밀한 화강풍화토 지반에서 얕은 기초의 침하에 대한 크기효과를 평가하고자 하였다. 이를 위해 지반조건이 유사한 2개 현장에서 재하판 크기를 다르게 하여 평판재하시험을 수행하였다. 시험결과 재하판 하부 및 주변 지반의 파괴는 관찰되지 않았으며 하중 증가에 따라 침하가 비례하여 증가하였다. 이러한 결과는 대상지반에 지지되는 기초의 안정성 또는 사용성은 침하가 지배하는 것을 의미한다. 침하에 대한 기초크기 효과는 압력-침하곡선의 기울기로 표현되는 지반반력계수와 기초폭의 관계로 표현하였다. 기존에 제안된 관계식과 비교해 볼 때 본 실험결과는 크기효과가 더 크게 나타나며, 이는 기존에 제안된 관계식은 조밀한 화강풍화토 지반에 지지된 기초의 침하를 과소평가할 수 있음을 나타낸다.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
• /
• pp.181-182
• /
• 2015

The use of non-bearing light weight wall has increased recently due to the increase of high-rise buildings and supply of long-life housing. Light weight wall has advantages such as reducing the self-weight of the building, convenience in installation, and shortening construction period, however, must have a sufficient strength to external force. This study standardized the impact resistance test method for light weight walls by using the actual impact load obtained through load analysis test in previous studies. The impact resistance test method was divided into the test method that uses soft body and the one that uses hard body. The size of specimen was set up as height 2.4m and width 3.0m. The size and shape of the body followed those used in BS 5234-2 and so on for the compatibility with the test method used overseas. The judgment criteria for impact resistance based on test results were not defined uniformly as the assessment of functional damage can vary depending on the type of material, structural method, purpose of wall, and so on even when the same impact load was applied.

• 통합자연과학논문집
• /
• 제14권3호
• /
• pp.123-129
• /
• 2021

This research examines the effect of positively skewed population distribution on the two sample t-test through simulation. For simulation work, two independent samples were selected from the same chi-square distributions with 3, 5, 10, 15, 20, 30 degrees of freedom and sample sizes 3, 5, 10, 15, 20, 30, respectively. Chi-square distribution is largely skewed to the right at small degrees of freedom and getting symmetric as the degrees of freedom increase. Simulation results show that the sampled populations are distributed positively skewed like chi-square distribution with small degrees of freedom, the F-test for the equality of variances shows poor performances even at the relatively large degrees of freedom and sample sizes like 30 for both, and so it is recommended to avoid using F-test. When two population variances are equal, the skewness of population distribution does not affect on the t-test in terms of the confidence level. However even though for the highly positively skewed distribution and small sample sizes like three or five the t-test achieved the nominal confidence level, the error limits are very large at small sample size. Therefore, if the sampled population is expected to be highly skewed to the right, it will be recommended to use relatively large sample size, at least 20.

• Journal of Advanced Marine Engineering and Technology
• /
• 제12권3호
• /
• pp.57-67
• /
• 1988

Although handicapped by the inability to bridge the size gap between small laboratory sample and large engineering component, the V charpy test sample method does possess certain advantages, such as each of preparation, simplicity of test method, speed, low cost in test machinery, and low cost per test. On the other hand, the COD test method does posses advantages, which reduce the size gap between the laboratory sample and actual engineering component. Consequently, the correlation between V charpy absorbed energy and the critical COD value is required for estimating critical COD value from the simple V charpy test results. In this paper, the high tensile strength steel AH36 plate specimens having a single edge cracked notch were investigated to find out the correlation between V charpy absorbed energy and critical COD value in the welded parts under such various welding methods as shielded metal arc welding, the submerged arc welding and the electro gas welding by means of V charpy impact test and static 3-point bending test. Main results obtained are as follow ; 1. The relationships between V charpy absorbed energy Wc' and critical COD value ($\delta_c$)show; $\delta_c$=0.0065 Wc'+0.1906. 2. Ductile- brittle transition behaviours can be estimated by means of fracture appearance and general yielding behaviours. 3. The V charpy absorbed energy of SMAW is higher than that of SAW, EGW and similar relationships are obtained in the COD tests.

• Communications for Statistical Applications and Methods
• /
• 제3권3호
• /
• pp.25-30
• /
• 1996

In discriminant analysis the procedures commonly used to estimate the dimensionality involve testing a sequence of dimensionality hypotheses. There is a problem with the size of the test since dimensionality hypotheses are tested sequentially and thus they are actually conditional tests. The focus of this paper is to investigate in asymptotic sense what happens to the sequential testing procedure if the assumption of normality does not hold.

• 한국콘크리트학회:학술대회논문집
• /
• 한국콘크리트학회 1993년도 가을 학술발표회 논문집
• /
• pp.250-255
• /
• 1993

This research is aimed at the experimental investigation of the characteristic contribution of the structural parameters, such as concrete over, concrete strength and reinforcing bar size on the dowel strength of the reinforced concrete stuctures. A total of twenty four specimens were tested for eight experimental conditions. The test results showed relatively close agreements with the values calculated by Vintzeleou-tassios equation. From the observations of the test results, it was found that the concrete cover affected almost linearly on the dowel strength , while the var size and the concrete strength showed coupled effects.

• 한국구조물진단유지관리공학회 논문집
• /
• 제20권1호
• /
• pp.41-47
• /
• 2016

본 연구에서는 콘크리트에 표면매입된 FRP판의 부착거동에서, 전단키와 연단거리의 효과를 관찰하기 위한 부착시험을 실시하였다. 실험에서의 주요변수는 전단키의 위치, 형태 그리고 연단길이이다. 규격 $3.6mm{\times}16mm$의 FRP를 $400mm{\times}200(300)mm{\times}400mm$ 규격의 콘크리트 블록에 매입하고 에폭시로 고정시켜서 실험변수에 따라 총 10개의 부착실험체를 제작하였다. FRP의 연단에 인장력을 가한 뒤 파괴시까지 실험을 실시하고 하중을 기록하였으며, 미끄러짐과 FRP의 인장변형량을 기록하였다. 실험으로부터, 전단키의 위치는 가력부에서 멀리 떨어질수록 전단강도가 상승하는 것으로 나타났으며, 전단키의 직경이 커질수록 내력이 저하되는 것으로 나타났다. 특히 전단키가 일정 이상의 규격이 되면 전단키가 없는 경우에 비하여 내력이 저하되어 오히려 부착강도에 부정적인 영향을 미칠 수 있는 것으로 나타났다. NSM FRP에서 응력장용방향의 연단거리가 길어짐에 따라 동일 부착길이임에도 불구하고 내력이 일부 증가하는 것으로 나타났다. 표면매입 보강된 FRP의 부착실험에서, FRP와 콘크리트사이의 부착-미끄러짐은 전체거동을 지배하는 것으로 나타나므로 이에 따른 과도한 미끄러짐은 설계에 반드시 고려될 필요가 있다.

• 한국의류산업학회지
• /
• 제3권2호
• /
• pp.140-147
• /
• 2001

The purpose of this study is to suggest the standard size system of Saenghwal Hanbok for design development and popularization. As a sample, 20's and 40's female data among the 1997's National Somatometry Survey data were used because two groups have different somatic characteristics and design tastes with each other. The results are as follows; From t-test of 35 somatometric items in 20's and 40's female data, we knew that the differentiated size system proper to each age is needed. We also knew that the 38 Saenghwal Hanbok brands don't have consistent size system from investigation of size list and size application. From consideration on the number of size for production and coverage rate, we suggested regression formula by bust circumference and stature, and suggested advanced standard size system which are proper to each 20' and 40' female group.

• 대한기계학회논문집
• /
• 제19권6호
• /
• pp.1460-1468
• /
• 1995

The objective of this paper is to evaluate the material properties of SA106 Gr. C carbon steel and its associated weld manufactured for main steam system of Yonggwang 3,4 nuclear generating stations. A total of 43 tensile and 35 fracture toughness tests were performed and the effects of various parameters such as pipe size, crack plane orientation, test temperature, welding on material properties were discussed. Test results show that the effects of crack plane orientation, test temperature, and welding on fracture toughness were significant while the effects of pipe size, specimen orientation and test temperature on tensile properties were negligible. Especially the dependence of J-R curves on the crack plane orientation appears to be the characteristics of carbon steel.

• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 2003년도 춘계학술발표대회 개요집
• /
• pp.43-45
• /
• 2003

The empirical model for predicting the prior austenite grain size in low-alloy steel weld HAZ was developed through examining the effect of alloying element. The test alloys were made by vacuum induction melting. Grain growth behaviors were observed and analyzed by isothermal grain growth test and subsequent metallography. As a result, it was found that the grain growth might be controlled by grain boundary diffusion and the empirical model for grain growth was presented.