• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 1999년도 봄 학술발표회 논문집
• /
• pp.193-200
• /
• 1999

팽창토에 설치된 직경 305 mm 현장타설말뚝의 18개월간에 걸친 거동을 관찰하였다. 계절적 함수량 변화에 따른 말뚝주변 흙의 부피 변화가 발생시킨 말뚝의 인발력을 측정하였고, 측정한 인발력에서 말뚝 단위 표면적당의 전단 응력을 계산하였다. 본 실험 말뚝에서는 최대 전단 응력은 54 kPa이 계산되었다.

• 한국해양공학회지
• /
• 제23권3호
• /
• pp.20-29
• /
• 2009

This study investigated the shear strength characteristics of waste tire powder-added lightweight soil (WTLS), which were developed to recycle dredged soil, bottom ash, and waste tires. The WTLS used in this experiment consisted of dredged soil, bottom ash, waste tire powder, and cement. Test specimens were prepared with various contents of waste tire powder ranging from 0% to 100% at 25% intervals and bottom ash contents of 0% or 100% by the weight of the dry dredged soil. In this study several series of direct shear tests were carried out, which indicated that the shear properties of WTLS were strongly influenced by the mixing conditions, such as the waste tire powder content and bottom ash content. The unit weight, as well as the shear strength of the WTLS, decreased with an increase in waste tire powder content. The shear strength of WTLS with bottom ash was 1.34 times greater than that of WTLS without bottom ash. An average increase in cohesion of 30 kPa was obtained in WTLS with the inclusion of bottom ash due to the bond strength induced from the pozzolanic reaction of the bottom ash. In this test, the maximum value of the internal friction angle was obtained with a 25% content of waste tire powder.

• Architectural research
• /
• 제7권1호
• /
• pp.27-38
• /
• 2005

No specific guidelines are available for computing the bearing strength of connection between steel coupling beam and reinforced concrete shear wall in a hybrid wall system. There were carried out analytical and experimental studies on connection between steel coupling beam and concrete shear wall in a hybrid wall system. The bearing stress at failure in the concrete below the embedded steel coupling beam section is related to the concrete compressive strength and the ratio of the width of the embedded steel coupling beam section to the thickness of the shear walls. Experiments were carried out to determine the factors influencing the bearing strength of the connection between steel coupling beam and reinforced concrete shear wall. The test variables included the reinforcement details that confer a ductile behavior in connection between steel coupling beam and shear wall, i.e., the auxiliary stud bolts attached to the steel beam flanges and the transverse ties at the top and the bottom steel beam flanges. In addition, additional test were conducted to verify the strength equations of the connection between steel coupling beam and reinforced concrete shear wall. The proposed equations in this study were in good agreement with both our test results and other test data from the literature.

• Steel and Composite Structures
• /
• 제14권6호
• /
• pp.587-604
• /
• 2013

There are few technical documents regulated structural performance and engineering criteria in domestic market for Structural insulated panels in Korea. This paper was focused to identify fundamental performance under monotonic loading and cyclic loading for SIPs in shear wall application. Load-displacement responses of total twelve test specimens were recorded based on shear stiffness, strength, ultimate load and displacement. Finally energy dissipation of each specimen was analyzed respectively. Monotonic test results showed that ultimate load was 44.3 kN, allowable shear load was 6.1 kN/m, shear stiffness was 1.2 MN/m, and ductility ratio was 3.6. Cyclic test was conducted by two kinds of specimens: single panel and double panels. Cyclic loading results, which were equivalent to monotonic loading results, showed that ultimate load was 45.4 kN, allowable shear load was 6.3 kN/m. Furthermore the accumulated energy dissipation capability for double panels was as 2.3 times as that for single panel. Based on results of structural performance test, it was recommended that the allowable shear load for panels should be 6.1 kN/m at least.

• 한국지반신소재학회논문집
• /
• 제2권1호
• /
• pp.39-45
• /
• 2003

보강토 지반에서 가장 중요한 부분은 보강재와 흙사이의 접촉부분으로서 이 부분의 전단강도 및 전단거동은 보강효과에 직접적인 영향을 미친다. 보강토 지반에서 접촉부분의 전단특성을 얻는 방법으로서 인발시험방법과 직접전단시험방법 등이 있다. 실제 보강토 구조물내에서 보강재와 흙사이에 인발이 되는 부분, 전단이 되는 부분 등이 존재한다. 전단이 되는 경우에도 보강재가 전혀 변형을 하지 않는 경우와 보강재 자체가 변형이 되는 경우 등으로 나눌 수 있다. 본 연구에서는 대형 전단시험기를 이용하여, 부직포/모래, 지오그리드/모래 등의 접촉면을 갖는 2종의 토목섬유를 이용하여, 토목섬유의 인장변형이 허용되는 자유조건과 인장변형이 억제되는 고정조건 등 두가지 방법으로 직접전단시험을 실시하였다. 실험결과 자유조건에 비해 고정조건으로 시험을 행한 경우가 마찰각이 더 컸다. 그리고 전단응력이 피크가 되는 전단변형의 크기는 자유조건의 경우가 더 큰 값을 가졌다. 잔류응력의 경우는 고정법의 경우가 컸지만 잔류응력비는 자유법의 경우가 더 큰 값을 가졌다.

• 한국지반공학회논문집
• /
• 제22권4호
• /
• pp.51-59
• /
• 2006

본 고에서는 선행연구(홍성연, 2004)에서 개발한 대형직접전단시험기를 이용하여 조립질 토목재료의 시험밀도와 균등계수의 크기가 전단강도에 주는 영향을 분석하였으며, 아울러, 각 수직응력별로 한계상태에서 조립재료가 갖고 있는 마찰계수를 Wood(1998)가 제안한 방정식을 이용하여 산출하였다. 시험에 사용한 재료는 경상과 전라지역 석산에서 생산중인 조립재료이다. 시험결과 시험밀도 $2.10g/cm^3$의 전단강도의 크기가 $1.85g/cm^3$의 값보다 상대적으로 크게 나타났으며, 균등계수는 상대적으로 10.0보다 5.0일때 더 큰 전단강도를 갖는 것으로 나타났다. 한편, 조립질 토목재료가 갖고 있는 한계상태에서의 마찰계수는 각 시험조건별로 $1.0{\sim}1.6$의 범위로 나타났다.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2007년도 춘계학술대회A
• /
• pp.238-243
• /
• 2007

This paper is designed to estimate the adhesion strength of coating layer on galvannealed steel sheet using lap shear test. The single lap shear test is the most commonly used standard test for determining the strength of medium-strength and high strength bonds. The bond strength of bonded single lap joints on subjecting the substrates to loads is determined by lap shear forces in the direction of the bonded joint. In this study, specimen for adhesion strength test was made to attach coated sheet to cold rolled sheet and were heated in temperature of 180 for 20minutes. After test, detached parts of coatings on coated sheet were observed using SEM and EDX to identify substrate and complete detachment. The tested results showed that adhesive strength of coating is unrelated to anisotropy of sheet and is difficult to be extracted using conventional theory because of fine cracks of coating layers which were created during annealing process.

• 한국지반환경공학회 논문집
• /
• 제10권1호
• /
• pp.25-34
• /
• 2009

댐이나 항만 건설시 재료로 사용되는 조립재는 입자크기가 일반 토사에 비해 매우 크기 때문에 이러한 재료에 대해서 전단시험을 수행할 때에는 가급적 대형 전단시험장치를 사용하는 것이 보다 정확한 결과를 얻기 위해 바람직하다. 대형 전단시험장치로는 일반적으로 대형 직접전단시험장치와 대형 삼축압축시험장치가 있으나 일반 토질시험장치와 비교해 제작과 보급, 운영 등의 어려움 때문에 현재까지 국내에서 두 시험장치를 사용하여 시험을 수행한 실적은 많지 않은 편이다. 본 연구에서는 댐 축조재로 사용되는 입경이 큰 조립재료를 대상으로 시료의 평균 입자크기와 공시체 크기, 연직응력(구속압) 조건 등에 차이가 있는 총 6개 case에 대해서 대형 직접전단시험과 대형 삼축압축시험을 수행하고 두 시험간 전단강도 특성의 차이를 비교하였다. Mohr-Coulomb 강도규준에 의한 전단강도를 기준으로, 대형 직접전단시험을 통해 산정된 전단강도가 대형 삼축압축시험을 통해 산정된 전단강도보다 전체적으로 크게 나타났으며 또한, 1,000kPa 수직응력에 대해 두 시험간 산정된 전단강도를 비교한 결과 대형 직접전단시험에 의한 전단강도가 대형 삼축압축시험에 의한 전단강도보다 약 10~70% 크게 나타나 입경이 작은 일반 토사와 비교해 그 차이가 크고, 대형 직접전단시험결과의 분산도가 상대적으로 높은 것으로 나타났다.

• Computers and Concrete
• /
• 제15권3호
• /
• pp.357-372
• /
• 2015

This study reports the test results of twelve reinforced concrete deep beams. The deep beams were tested with loads applied through and supported by columns. The main variables studied were the shear span-to-depth ratios, and the horizontal and vertical stirrups. The shear strengths can be effectively enhanced for deep beams reinforced with both horizontal and vertical stirrups. The test results indicate the shear strengths of deep beams increase with the decrease of the shear span-to-depth ratios. The normalized shear strengths of the deep beams did not increase proportionally with an increase in effective depth. An analytical method for predicting the shear strengths of deep beams is proposed in this study. The shear strengths predicted by the proposed method and the strut-and-tie model of the ACI Code are compared with available test results. The comparison shows the proposed method can predict the shear strengths of reinforced concrete deep beams more accurately than the strut-and-tie model of the ACI Code.

• 대한치과기공학회지
• /
• 제38권4호
• /
• pp.291-298
• /
• 2016

Purpose: This study was to evaluate the effect of coloring liquids on the shear bond strength between zirconia and veneering ceramic. Methods: Zirconia(15 mm in diameter, 2.5 mm in thickness; n=40) used in the experiment were divided into 5 groups depending on the coloring liquid. Each specimen were polished using a polishing machine(LaboPol-2, Struers, UK). A cylinder of veneering porcelain(6 mm in diameter, 3 mm in thickness) was fabricated and fired on zirconia surfaces. The shear bond strength was measured using a universal testing machine(Model 4302, Instron, USA). All data were analyzed statistically using a one-way ANOVA and Tukey's multiple comparisons test. After the shear bond test, fracture surfaces were examined by SEM. Results: Colored zirconia showed a higher shear bonding strength than that of uncolored zirconia except for colored zirconia immersed in Zirkonzahn coloring liquid. In particular, colored zirconia immersed in Kuwotech coloring liquid showed the highest shear bond strength. After the shear bond test, mixed failure patterns were mainly observed in the failure between zirconia and veneering ceramic. Conclusion: Coloring liquid enhanced the shear bond strength zirconia and veneering ceramic than uncolored zirconia.