• Title/Summary/Keyword: 전단파괴

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Shear Stiffness of Shear connections in Full-Depth Precast Concrete Deck Bridge (프리캐스트 바닥판 교량 전단연결부의 전단강성)

  • Shim, Chang Su;Chung, Chul Hun;Kim, Chul Young;Chang, Sung Pil
    • Journal of Korean Society of Steel Construction
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    • v.10 no.4 s.37
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    • pp.749-758
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    • 1998
  • The evaluation of shear stiffness of shear connection in composite bridges with CIP concrete deck is analysed. Shear stiffness of shear connection in full-depth precast concrete deck bridges is obtained from experiments. 3-dimensional finite element analyses of push-out specimen are carried out to investigate the effects of characteristics of filling material strength in shear connection on shear stiffness and local stress distribution. The load-slip relations obtained from the analyses are compared with those of experiments. The equation of initial shear stiffness of shear connection in precast concrete deck bridge is proposed. Linear analyses are performed to evaluate the effects of the shank diameter of shear connector and the strength of mortar on the characteristics of deterioration and failure load obtained by the failure criterions of each material. The failure loads are estimated and compared with test results.

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An Experimental Study on the Effects of Bolted Connection Type on the Block Shear Failure (볼트이음방식의 블록전단파괴에 미치는 영향에 대한 실험적 연구)

  • Lee, Chin-Ok;Park, Gyung-Hyeon;Moon, Jiho;Lee, Hak-Eun;Lim, Nam-Hyoung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.11
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    • pp.5566-5571
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    • 2012
  • Block shear failure is one of limit states, and demands great caution in designing the tension member or connection joint of steel structures. From many studies and design specification, it is shown that the effect of the bolted connection type on the block shear failure was not considered. In order to investigate the effect of the bolted connection type(bearing type connection and slip critical connection) on the mode/strength of the block shear failure, tensile experiment is conducted in this study. Differences about the failure mode according to the design specification, bearing type connection, and slip critical connection are proposed from the analysis of test results. The variation of the block shear failure strength due to the frictional force in the slip critical connection is also investigated.

Demand Strength Spectrums of Low-Rise Reinforced Concrete Buildings Consisted of Extremely Brittle, Shear and Flexural Failure Systems (극취성·전단·휨파괴형 수평저항시스템으로 구성된 저층 철근콘크리트 건물의 요구 내력 스펙트럼)

  • Lee, Kang-Seok;Kim, Jeong-Hee;Oh, Jae-Keun
    • Journal of the Korea Concrete Institute
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    • v.19 no.5
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    • pp.529-537
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    • 2007
  • The purpose of this study is to discuss how strength and ductility of each system in low-rise reinforced concrete buildings composed of extremely brittle, shear and flexural failure lateral-load resisting systems have influence on seismic capacities of the overall system, which is based on nonlinear seismic response analyses of single-degree-of-freedom structural systems. In order to simulate the triple lateral-load resisting system, structures are idealized as a parallel combination of two modified origin-oriented hysteretic models and a degrading trilinear hysteretic model that fail primarily in extremely brittle, shear and flexure, respectively. Stiffness properties of three models are varied in terms of story shear coefficients, and structures are subjected to various ground motion components. By analyzing these systems, interaction curves of demand strengths of the triple system for various levels of ductility factors are finally derived for practical purposes. The result indicates that demand strength levels derived can be used as a basic information for seismic evaluation and design criteria of low-rise reinforced concrete buildings having the triple lateral-load resisting system.

Estimation of Shear Plane at Failed Landfill Using Field and Laboratory Tests (현장 및 실내실험을 이용한 매립지 전단활동면 추정에 대한 연구)

  • Choi, Hoseong;Kim, Tae-Hyung;Kim, Sung-Wook
    • The Journal of Engineering Geology
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    • v.29 no.3
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    • pp.315-327
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    • 2019
  • Back analysis has been used to evaluate the factor of safety and circular failure plane at the landfill failure site. However, the estimated circular failure plane by back analysis is quite different from what is observed in the field. Thus, this study was conducted to estimate an actual shear failure plane inside the ground which gives a more accurate failure plane. Cone penetration test (CPT), boring test, soft X-ray image scan, density logging, and ultrasonic logging were conducted at the field and laboratory. The result of CPT showed significantly lower cone resistance, pore pressure, and undrained shear strength at a particular part. This part is a possible shear failure plane inside the ground. To validate, the soft X-ray scan images were analyzed and found the disturbed (inclined) bedding plane induced by shear activity at the estimated shear failure plane. Density and ultrasonic logging tests also found a similar result. Thus, the method in this study is possible to estimate the shear failure plane inside the ground.

Performance of Geogrids for Retarding Reflection Crack of Asphalt Overlay Pavement (아스팔트 덧씌우기의 반사균열 지연을 위한 지오그리드의 적용성 연구)

  • Kim, Kwang-Woo;Doh, Young-Soo;Kim, Bun-Chang;Lee, Moon-Sup
    • International Journal of Highway Engineering
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    • v.7 no.2 s.24
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    • pp.1-12
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    • 2005
  • This study was conducted to evaluate effect of geogrid and fabric, which are used underneath the overlaid asphalt pavement for retarding reflection cracking by simulated laboratory test. In this study, an interlayer at the interface between old concrete pavement surface and overlaid asphalt mixture, and polymer-modifier were used as an effort of retarding reflection crack initiation and for strengthening mixture. Five products were used in preparation of asphalt concrete beam specimen which was tack coated on top of jointed concrete block. Simulated Mode I and II fracture test were conducted under wheel loading and results were compared among those products. From the test results, several material and reinforcement combinations were observed to have a significant retardation effect against reflection cracking. The most effectively strengthened pavement against reflection cracking was found to be the LDPE-modifier asphalt mixture with a grid reinforcement at the bottom.

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An Experimental Study on the Effective Strain of Reinforced Concrete Beams Strengthened by Fiber Reinforced Polymer (FRP로 보강된 철근콘크리트 보의 유효 변형률 예측에 대한 실험적 연구)

  • Hwang, Hyun-Bok;Lee, Jung-Yoon
    • Journal of the Korea Concrete Institute
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    • v.19 no.2
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    • pp.145-151
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    • 2007
  • The shear failure modes of FRP strengthened concrete beams are quite different to those of the beams strengthened with steel stirrups. When the beams are externally wrapped with FRP composites, many beams fail in shear due to concrete crushing before the FRP reaches its rupture strain. In order to predict the shear strength of such beams, the effective strain of the FRP must be blown. This paper presents the results of an experimental study on the performance of reinforced concrete beams externally wrapped with FRP composites and infernally reinforced with steel stirrups. The main parameters of the tests were FRP reinforcement ratio, the type of fiber material (carbon or glass) and configuration (continues sheets or strips). The experimentally observed effective strain of the FRP was compared with the strain calculated using a proposed method.

A Study on the Side Shear Developed during Pullout of Suction Pile in Clays using 3D Numerical Analysis (3차원 수치해석을 이용한 점토지반에 설치된 석션파일 인발 시 발현되는 전단응력에 관한 연구)

  • Lee, Myungjae;Youn, Heejung
    • Journal of the Korean GEO-environmental Society
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    • v.15 no.2
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    • pp.59-66
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    • 2014
  • This paper presents the pullout behavior of suction pile using finite difference method; and the commercial software, FLAC3D, was employed for the numerical analyses. The ultimate pullout capacity of suction pile was predicted using conventional equations, and the results were compared with the results from numerical analyses with varying pile diameter, pile length, and the undrained shear strength of clays. Based on the results from 24 analyses, it was found that the failure pattern depends not only on the drainage condition of suction pile, but also on the pile dimensions and the material properties of surrounding soils. The developed side shear (DSS) along the internal surface of the suction pile was collected from numerical analyses, which was used to classify the failure type between sliding failure and tensile failure. Regardless of the external DSS, the high internal DSS tends to result in sliding failure in the numerical analyses, which conforms well to the estimation from conventional equations.

Evaluation of Design Method and Shear Transfer Capacity on the Horizontal Interface of PC Composite Beams (PC 합성보의 수평접합면 전단력 전달성능 평가 및 설계법 분석)

  • Moon, Jeong-Ho;Oh, Young-Hun
    • Journal of the Korea Concrete Institute
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    • v.25 no.1
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    • pp.81-90
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    • 2013
  • The purpose of this study is to evaluate the horizontal shear strength on the interface between PC and cast-in-place concrete for PC composite beams. Six specimens were tested to examine the structural performance of the horizontal interface with different surface condition and stirrup detailing. Except for SF-291B specimen failed in flexural compression, strengths and deformation capacities of five specimens were determined by horizontal shear failure. Horizontal shear strengths by composite horizontal shear or shear friction in current codes could be used to predict the horizontal shear capacity of the interface for specimens. Also detailing for stirrup by PCI design provision could be used to accomplish the composite action in the interface.

Shear Capacity of Corrugated rib Shear Connector (파형전단연결재의 전단저항 성능)

  • Ahn, Jin-Hee;Choi, Kyu-Tae;Kim, Sung-Hyun;Kim, Sang-Hyo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.3A
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    • pp.375-381
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    • 2008
  • This paper deals with the shear capacity of corrugated rib as the shear connector in composite structures. Corrugated rib is modified as perfobond rib shear connector type to evaluate the shear capacity. A total 12 push-out specimens with stud, perfobond rib, and corrugated rib connector were fabricated. Then, the influences of hole-crossing bars, concrete dowel, depth of corrugated panel and height of rib on the shear capacity were evaluated experimentally. As the results of these tests, the failure mechanisms of corrugated rib and perfobond rib specimens were associated with the bearing failure of the concrete slabs, but the failure of weld zone did not occur. The shear capacity of corrugated rib specimens improved as high to 96% compared to the perfobond rib shear connectors. Also, the hole-crossing bars were effective on the improvement of concrete dowel action, and consequently, shear capacity increased by 48%. It was also proven that the increment of the depth of corrugated panel and the height of rib increased the concrete bearing resistance, therefore increasing the shear capacity.

FRACTURE ANALYSIS OF REINFORCED CONCRETE BEAMS FALING IN SHEAR (전단에 파괴되는 철근콘크리트 보의 해석적 연구)

  • 김우종
    • Computational Structural Engineering
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    • v.1 no.2
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    • pp.111-120
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    • 1988
  • The behavior of shear crack is investigated analytically to get a better understanding of the fundamental natura of shear failure mechanism in reinforced concrete beams. Emphasis is placed on the exploration of the major cause of the initiation and the propagation of an inclined shear crack in reinforced concrete beams without web reinforcement. By utilizing a finite element method incorporated into a fracture mechanics, the quantitative reponse of reinforced concrete beams with varying amounts of cracking is examined. Progressions of the cracks are simulated. The analysis gives the information of the state of the stresses at various cracking stages. The results are compared with the experimental results.

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