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  • Title/Summary/Keyword: 인장 전단 시험

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Structural Performance Evaluation of Prestressed Concrete Trapezoidal Girders Using Socket Joint System (소켓연결 방식을 이용한 프리스트레스트 콘크리트 제형 거더의 구조성능 평가)

  • Shim, Won-Bo;Min, Kyung-Hwan;Choi, Hong-Sik
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.11
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    • pp.7244-7249
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    • 2015
  • In this study, in order to asses the structural performance of trapezoidal PSC girder using a socket joint system and it is possible to calculate the optimized cross-section of the web element tests were carried out for each specimens. we conducted a socket joint performance test, web bending and shear performance tests and all tests were performed at 4 point loading method. The initial crack load of socket joint specimen was significantly lower than the reference specimen but post peak behavior was no significant differences. And the length of the loop joint of the reinforcing bars had no significant effect on the maximum load. As a web shear tests, to obtain a maximum load of the specimen has a prestressing rod reinforced at tension side. As a web flexural tests, to obtain higher diagonal cracking load in specimen of reinforced using prestressing rod than reference specimen.

Experimental Study on the Flexural Behavior of Inverted T-Shaped Steel·Concrete Composite Deck for Bridges (역T형강·콘크리트 합성바닥판의 휨거동에 관한 실험적 연구)

  • Kim, Sung Hoon;Park, Young Hoon;Lee, Seung Yong;Choi, Jun Hyeok
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.3A
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    • pp.331-340
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    • 2008
  • This study is to suggest the details of new concept of bridge deck. Experimental studies on the behavior of a inverted T-shaped steelconcrete composite deck were carried out. The part of inverted T-shaped steel is embedded in concrete. Reinforced concrete deck specimen and composite deck specimens were fabricated and static bending fracture tests were conducted. The ultimate strength and fracture strength of specimens were evaluated. The effects of shear hole crossing bars of composite deck were also analyzed. From the results of experiments, composite deck with shear hole crossing bar increased shear strength, and showed typical tensile failure. Ultimate strength and fracture strength of composite deck with shear hole crossing bar are higher than those of reinforced concrete deck. The displacement of composite deck is higher than that of reinforced concrete deck.

Confining Effect due to Geosynthetics Wrapping Compacted Soil Specimen (geosynthetics로 보강된 다짐토 공시체의 구속효과)

  • Kim, Eun-Ra;Iizuka, Atsushi;Kim, You-Seong;Park, Hong
    • Proceedings of the Korean Geotechical Society Conference
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    • 2004.03b
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    • pp.348-355
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    • 2004
  • 본 연구에서는 geosynthetics로 보강된 다짐토의 보강 메카니즘을 파악하기 위한 목적으로 실내시험 및 수치계산 수행하였다. 본 연구에서 고려하는 보강 메카니즘은 전단에 의한 다짐토의 체적 팽창(부의 다일렌탄시)을 geosynthetics에 의해 구속 억제하는 과정에서 생성되는 효과로 생각한다. 먼저, 실내실험을 위한 구제직인 방법으로서, geosynthetics의 보강효과를 정량직으로 파악하기 위하여 사질토를 다짐하여 공시체를 만들어 그 주위에 geosynthetics를 설치하여 전체적으로 압축전단 시험을 실시하였다. 또한, 다짐토의 다짐도를 달리 하고 한 가지 종류만의 geosynthetics를 이용하여, 다짐토와 geosynthetics의 상호작용에 따른 압축력 변화, geosynthetics의 인장력 변화 및 공시체의 파괴 진행상황 등을 살펴보았다. 수치계산에서는 다짐토의 다일렌탄시 특성에 대하여 표현 가능한 탄소성 구성모델을 이용하였다. 또한, 탄소성 구성 모델에서의 항복 이전의 탄성영역의 거동을 묘사하기 위하여 Hashiguchi(1989)가 제안한 subloading surface의 개념을 도입하였고, 유한요소(FEM)해석을 통해 얻어진 결과들을 실내시험의 결과와 비교 분석하였으며, 그 결과 양자 양호한 결과를 얻었다.

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The Behavior of Silt due to Volume Deformation Tendency (체적변형 경향에 따른 실트의 거동)

  • Jeong, Sang Seom
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.13 no.5
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    • pp.255-260
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    • 1993
  • The behavior of pure silt was investigated by using an automated triaxial testing device. The stress-strain behavior of silt due to the volume deformation tendency was compared with the behavior of clay prior to failure and behavior at failure under monotonic undrained compression and extension conditions. A pure silica flour was chosen to form samples. The isotropically normally-consolidated samples with 450 kPa of effective mean confining pressure and overconsolidated samples through unloading were tested. Based on the experimental results, it was qualitatively identified that the undrained strength of normally-consolidated silt increases due to its dilatant nature which is not seen in clay. Also the overconsolidated silt shows a significantly different behavior under the monotonic loadings due to the volume deformation tendency.

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Structural Performance and Fire Resistance Capacity of Inorganic Polymer Composites for Carbon Sheets Exposed to High Temperature (탄소섬유쉬트 보강 콘크리트용 무기계 폴리머 접착제의 내화 및 구조성능)

  • Chung, Lan;Park, Hyun-Soo
    • Magazine of the Korea Concrete Institute
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    • v.10 no.5
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    • pp.109-115
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    • 1998
  • 철근콘크리트 구조물이 과소설계되어 있거나 과다 하중이 작용하게 되면 그 구조물의 구조성능을 파악하여 보수.보강을 시행하게 된다. 최근에 가장 맣이 사용되는 보수.보강 재료로는 특히 휨내력을 보강하는데 탄소섬유를 들 수 있다. 탄소섬유쉬트는 내열성과 내호염성에 있어서 회재가 발생할 경우 보강재료로서 충분한 성능을 가지고 있다. 그러나 이를 접착시키는데 사용되는 에폭시는 유기계 물질로서 화재시 유독가스가 발생하고 내열성능도 300C정도에도 지탱하기 어려워 화재 발생이 가능한 구조물에 사용하기 어렵다. 이 연구에서는 무기계 폴리머 복합재료로 접착된 탄소섬유를 고온(약 800~1000C, 1시간)으로 가열한 후 가열된 섬유판의 인장, 휨 전단내력을 검토하여 내열성능을 파악하고 이 섬유쉬트로 보강한 철근콘크리트 부재의 휨 성능을 실험적으로 규명하여 화재의 위험이 있는 구조물에 구조적인 보강재료로 사용이 가능한가를 검토하였다. 연구 결과, 개발된 무기계 폴리머 복합체는 인장강도, 휨강도 및 접착강도가 유기계 접착제와 유사하게 나타났고 800~1000C 정도로 1시간 가열한 이후에도 상온 시험체 휨내력과 전단내력의 63%, 33% 정도를 유지하여 화재의 위험이 있는 부위에도 사용이 가능한 것으로 판단되었다.

Tensile Properties of CERP Composite with Different Resin Composition under Cryogenic Temperature (극저온 환경에서 탄소섬유강화 복합재료의 수지조성변화에 따른 인장 물성 측정)

  • Kim, Myung-Gon;Kang, Sang-Guk;Kong, Cheol-Won;Kim, Chun-Gon
    • Composites Research
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    • v.20 no.4
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    • pp.1-8
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    • 2007
  • In this study, carbon fiber reinforced polymeric (CFRP) composites with different resin composition were manufactured and resin formulation in composite materials were presented through tensile tests for cryogenic use. Thermo-mechanical cyclic loading (up to 6 cycles) was applied to CFRP unidirectional laminate specimens from room temperature to 150C. Tensile tests were then performed at 150C using an environmental test chamber. In addition, matrix-dominant properties such as the transverse and in-plane shear characteristics of each composite model were measured at 150C to examine the effects of resin formulation on their interfacial properties. The tensile tests showed that the composite models with large amounts of bisphenol-A epoxy and CTBN modified rubber in their resin composition had good mechanical performance at cryogenic temperature (CT).

Physical Properties of Different Automixing Resin Cements and the Shear Bond Strength on Dentin (수종 Automixing 레진시멘트의 물성과 상아질에 대한 전단결합강도)

  • Song, Chang-Kyu;Park, Se-Hee;Kim, Jin-Woo;Cho, Kyung-Mo
    • Journal of Dental Rehabilitation and Applied Science
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    • v.25 no.4
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    • pp.437-444
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    • 2009
  • The purpose of this study was to evaluate the physical properties of different automixing resin cements and the shear bond strength on dentin. For this study, two self-adhesive automixing resin cement(Rely-X Unicem(3M ESPE, St. Paul, USA), Embrace resin cement(Pulpdent, Oakland, USA)) and one chemical polymerizing resin cement(Resiment Ready-Mix(J.L.Blosser Inc., Liberty Missouri, USA)) were used. To evaluate the physical properties, compressive strength, diametral tensile strength and flexural strength were measured. The specimens were fabricated using Teflon mould according to manufacturers' instructions and stored for 24 hours in an atmosphere of 100% humidity. To evaluate the shear bond strength on dentin, each cements were adhered to buccal dentinal surface of extracted human lower molars in 2mm diameter. Physical properties and shear bond strengths were measured using universal testing machine(Z010, Zwick GmbH, Ulm, Germany) at a crosshead speed of 0.5mm/min. The physical properties and shear bond strength of different automixing resin cements were statistically analyzed and compared between groups using One-way ANOVA test and Schffe post-hoc test at the 95% level of confidence. The result shows that chemical polymerizing automixing resin cement represents the relatively higher physical properties and shear bond strength than self-adhesive automixing resin cements.

Strength Properties of Old Korean Larch Pile (고(古)부재 잎갈나무 말뚝의 재질 특성)

  • Hwang, Kweonhwan;Park, Byung-Su
    • Journal of the Korean Wood Science and Technology
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    • v.35 no.6
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    • pp.23-30
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    • 2007
  • Round piles of Korean larch were excavated from the foundation of ex-Chosunchongdokbu (ex-Chosun Governer-General Building), which was constructed in 1916 and dismantled later in 1996. By the record (Huh, 1996), the Korean larch logs were logged from the Yalu river area near Mt. Baekdu in North Korea. At present, however, Korean larch is not so popular in South Korea. The latewood ratio profiles and strength properties (longitudinal compression, shear, longitudinal tensile, and bending) were obtained. The ratio of latewood from pith to bark increased up to 25 years, and then it showed constant tendency at 40% with some variances. From the microscopic observation, however, the latewood ratio decreased from the heartwood to the sapwood. Compression strength was greater and bending strength was a little lower than the previous reports (references 13~15), which might be attributed to the strength reduction of old structural members by aging or damage in the compression specimens than the bending ones. The flat-grained specimens for the shear and tension test showed higher coefficient of variation (COV) than the edge-grained ones. For the better comparison of results, in case of shear and tensile strength tests, the strength values of the edge-grained specimens were thought to be adopted rather than those of flat-grained ones.

Evaluation on Patching Materials for Asphalt Pavement (아스팔트 포장도로의 응급보수재료 평가에 관한 연구)

  • Shim, Jae-Pill;Jin, Jung-Hoon;Park, Tea-Soon;Lee, Jae-Sik
    • International Journal of Highway Engineering
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    • v.14 no.3
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    • pp.59-67
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    • 2012
  • This study presents the evaluation of the patching materials that are used to repair the distress of asphalt pavement. Four kinds of patching materials currently used in practice were tested in both laboratory and field. The laboratory tests included the dry and soaked Marshall stability test, indirect tensile test, wheel tracking test and adhesive strength between the asphalt pavement and the repairing material was tested as a performance test. The field study was conducted using the slab samples placed on the location of vehicle tire passing and the performance of the repairing materials were investigated as passing the traffic load. The result of the laboratory tests were satisfied with the current design criteria and material standard except for water-immersion stability. Type C patching material showed the highest adhesive shear strength among the patching materials tested. However, the mature distress, such as rutting and stripping were monitored after construction in 10 days. It was found that performance of patching material is lack of quality behavior when they were applied in the field and required to develop and applu to prevent the mature distress of the current patching materials.

An Experimental Study on Structural Characteristics of Reinforced Concrete Beams with the Perforative Opening (철근콘크리트 개방형 유공보의 구조적 특성에대한 실험적 연구)

  • 구해식
    • Magazine of the Korea Concrete Institute
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    • v.9 no.6
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    • pp.225-232
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    • 1997
  • 철근콘크리트 유공보에 있어서 기존 유공보의 연구는 유공위치를 보춤의 중앙에 위치하여 연구하였으나 철근코크리트 보의 역학적 특성활용과 시공상의 편의성을 위해 사각형 유공의 위치를 보춤 하단에 설치하여 개방형 유공보로 변형하였다. 본 연구에서는 사각형 유공보에 대한 유공크기의 세로길이를 보춤의 0.3배로 하고 가로길이를 세로길의의 1~3배로 변화시켜 보강 및 무보강 상태의 사각형 유공보와 이의 사각형 유공하부 콘크리트를 제외시킨 개방형 유공보에 있어서 총 10개의 시험체를 대상으로 하는 실험을 실시하여 시험체의 최대내력, 유공주위에서의 전단균열과 시험체의 휨인장균열, 주요위치의 변위조사, 주근 및 유공주위의 콘크리트와 보강철근의 변형도조사, 시험체의균열을 조사하여 상호변화를 비교.분석하였다. 이 연구결과로부터 개방형유공보의 유공주위 응력변형상태, 파괴메카니즘, 적절한 개방형 유공크기,설계시 고려사항을 제시하여 차후의 개방형 유공보의 계속적인 연구에 기여하고자 한다.