• Title, Summary, Keyword: Compressive Creep

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Time-Dependent Analysis of Reinforced and Prestressed Concrete Structures Considering Tensile Creep of Concrete (인장크리프모델을 고려한 철근 및 프리스트레스트 콘크리트 구조의 시간의존적 해석)

  • 오병환;이형준
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.473-479
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    • 1996
  • Until now, we assumed in the time-dependent analysis of concrete structure that tensile creep has same characteristics as compressive creep has. But, in according to results of researches, it appears that tensile creep is different from compressive creep in quantity and in mechanics because tensile creep is affected significantly by micro cracking. The test results indicate that the creep behavior of concrete in compression and tension is rather different. The test data shows that the amount of creep under tensile loading is larger than that under compressive loading. In this paper, a realistic tensile creep model is suggested and incorporated in the formulation. In order to get more accurate results of time-dependent analysis. The present study indicates that the long-term deflection of concrete structures under realistic tensile creep model is somewhat larger than that under ordinary compressive creep model.

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Tensile and Compressive Creep Behaviors of Amorphous Steel Fiber-Reinforced Concrete

  • Truong, Gia Toai;Choi, Kyoung-Kyu;Choi, Oan-Chul
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.1 no.3
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    • pp.197-203
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    • 2013
  • In this study, the creep behaviors of amorphous steel fiber-reinforced concrete were investigated. Two different types of tests were carried out to evaluate the effect of amorphous steel fibers on the creep of concrete: compressive creep test and tensile creep test. Fiber volume fractions used in the test were 0.2% and 0.4% for tensile specimens, and 0.2% and 0.3% for compressive specimens. Based on the test results, the addition of fiber volume fraction of 0.2% into concrete could significantly reduce both compressive and tensile creep.

Creep characteristics and instability analysis of concrete specimens with horizontal holes

  • Xin, Yajun;Hao, Haichun;Lv, Xin;Ji, Hongying
    • Computers and Concrete
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    • v.22 no.6
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    • pp.563-572
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    • 2018
  • Uniaxial compressive strength test and uniaxial compression creep one were produced on four groups of twelve concrete specimens with different hole number by RLW-2000 rock triaxial rheology test system. The relationships between horizontal holes and instantaneous failure stress, the strain, and creep failure stress, the strain, and the relationships between stress level and instantaneous strain, creep strain were studied, and the relationship between horizontal holes and failure mode was determined. The results showed that: with horizontal hole number increasing, compressive strength of the specimens decreased whereas its peak strain increased, while both creep failure strength and its peak strain decreased. The relationships between horizontal holes and compressive strength of the specimens, the peak strain, were represented in quadratic polynomial, the relationships between horizontal holes and creep failure strength, the peak strain were represented in both linear and quadratic polynomial, respectively. Instantaneous strain decreased with stress level increasing, and the more holes in the blocks the less the damping of instantaneous strain were recorded. In the failure stress level, instantaneous strain reversally increased, creep strain showed three stages: decreasing, increasing, and sharp increasing; in same stress level, the less holes the less creep strain rate was recorded. The compressive-shear failure was produced along specimen diagonal line where the master surface of creep failure occurred, the more holes in a block, the higher chances of specimen failure and the more obvious master surface were.

Critical Compressive Strain of Concrete under a Long-Term Deformation Effect Part I. Experiments

  • Nghia, Tran Tuan;Chu, In-Yeop;Kim, Jin-Keun
    • International Journal of Concrete Structures and Materials
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    • v.4 no.2
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    • pp.89-96
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    • 2010
  • This paper focuses on the effect of creep on the critical compressive strain (CCS) of concrete. The strain of concrete corresponding to the peak compressive stress is crucial in the selection of the ultimate yield strength of the reinforcing bar used in reinforced concrete columns. Among the various influencing factors, such as the creep, shrinkage, loading rate and confinement, the effect of creep and shrinkage is the most significant. So far, investigations into how these factors can affect the CCS of concrete have been rare. Therefore, to investigate the effect of creep and shrinkage on CCS, an experimental (part I) and a parametric study (part II) were conducted, as presented in these papers (part I considers creep effect, part II considers effect of creep and shrinkage). In part I, experiments pertaining to the loading age, loading rate, loading duration and loading and creep levels were conducted to study the effect of these variables on the CCS of concrete. It was found that the effects of the loading rate, loading age, and level and duration on the CCS of concrete were negligible. However, it is very important to consider the effect of creep.

Creep analysis of CFT columns subjected to eccentric compression loads

  • Han, Bing;Wang, Yuan-Feng;Wang, Qian;Zhang, Dian-Jie
    • Computers and Concrete
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    • v.11 no.4
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    • pp.291-304
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    • 2013
  • By considering the creep characteristics of concrete core under eccentric compression, a creep model of concrete filled steel tubes (CFT) columns under eccentric compressive loads is proposed based on the concrete creep model B3. In this proposed model, a discrete element method is introduced to transform the eccentric loading into axial loading. The validity of the model is verified by comparing the predicting results with the published creep experiments results on CFT specimens under compressive loading, together with the predicting values based on other concrete creep models, such as ACI209, CEB90, GL2000 and elastic continuation and plastic flow theory. By using the proposed model, a parameters study is carried out to analysis the effects of practical design parameters, such as concrete mix (e.g. water to cement ratio, aggregate to cement ratio), steel ratio and eccentricity ratio, on the creep of CFT columns under eccentric compressive loading.

Compressive Creep Behavior of Fruits

  • Kim, M.S.;Park, J.M.
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • pp.1329-1339
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    • 1993
  • Creep tests were performed to determine the nonlinear viscoelastic properties of apples and pears with the creep experiment apparatus designed in this study. Compressive creep characteristics of fruits were tested at two kinds of storage conditions, four periods of storage and three levels of initial stress. Ten replications were made at each treatment combination. The creep behavior of the fruits could be well described by the nonlinear viscoelastic model as a function of initial stress and time. however, for each level of initial stress applied, the compressive behavior of the samples was satisfactorily represented by Burger's model. For all sample fruits, the longer the samples was stored, the higher the instantaneous elastic strain was observed, and the creep progressed at a high rate. These phenomena were even more remarkable on the fruit stored at the normal temperature storage rather than at the low temperature storage.

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Evaluation of the Creep Properties of High Strength Concrete according to Moisture Evaporation and Compressive Strength (수분증발조건 및 압축강도에 따른 고강도콘크리트의 크리프 특성 평가)

  • Bae, Chang-O;Kim, Gyu-Yong;Ham, Eun-Young;Koo, Kyung-Mo;Kim, Hong-Seop;Yoon, Min-Ho
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.75-76
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    • 2012
  • In this study, it was evaluated about creep properties of high strength concrete according to compressive strength and moisture evaporation condition. As a results, creep strain and creep coefficient was greatly affected by moisture evaporation conditions rather than compressive strength. Also, the effect of fiber mixed was not show big difference.

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High Temperature Creep Behavior of Cr3C2 Composites (크롬-카바이드 복합체의 고온 크리프 거동)

  • 김지환;한동빈;김기태
    • Journal of the Korean Ceramic Society
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    • v.32 no.11
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    • pp.1219-1226
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    • 1995
  • Creep behaviors of Cr3C2 composites containing 90 wt% Cr3C2 and 10 wt% Ni were studied at high temperature. Compression tests at 100$0^{\circ}C$ and bending tests at 100$0^{\circ}C$ and 105$0^{\circ}C$ were done in argon environment. In all test conditions primary and steady-state creep behaviors were observed. Stress exponent and activatiion energy were determined from the experimental data. By microstructural analysis of Cr3C2 composites after creep test, the separate agglomerations of Ni phase were observed. Numerical analysis was also studied to analyze bending creep behaviors of Cr3C2 by assumming different tensile and compressive creep behavior in a bending sample. From the analysis, it was found that the stress state at the compressive region as applied stress increased. The observed creep rates were compared with the predicted creep rates by estimating power-law creep parameters from bending test data.

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Creep and Shrinkage of High Performance/High Strength Concrete

  • Suksawang, N.;Nassif, H.;Mohamed, A.;Hwang, Eui-Seung
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.529-532
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    • 2006
  • This paper presents results from creep and shrinkage tests performed on different High Strength Concrete (HSC) mixes (with compressive strengths up to 90 MPa). Results were compared with those from various Code prediction models. The effects of pozzolanic materials on the creep and shrinkage were also investigated. Results show that while fly ash increases the compressive creep of concrete, silica fume decreases it. Moreover, current creep and shrinkage prediction models need to be revised for the HSC mixture.

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Studies on the Acoustical Characteristics of Violin Bridges and SDM Simulation (바이올린 브릿지의 음향적 특성 및 SDM 시뮬레이션에 관한 연구)

  • 정우양
    • Journal of the Korea Furniture Society
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    • v.12 no.1
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    • pp.47-55
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    • 2001
  • Violin bridge blank cut from maple wood with good quality has typical pattern of the radial direction in the side edge with minimal dispersion. This experimental study was designed and carried out to examine the effect of the physical and macroscopical characteristics on the compressive creep of violin bridge blank which had been imported from European manufacturer. This research arose from the idea that the maple solid wood with heterogeneous wood density and ray direction in the side edge would have uneven rheological property of violin bridge blank which is supposed to be pressed by the tension of strings. Experimentally, the compressive creep of bridge blank became smaller with the higher density of imported maple wood and showed clear density-dependence for the duration of load under the string tension of 5 kgf. Every bridge blank showed the behavior of primary creep stage(stress stabilization) having logarithmic regression creep curve with high correlation coefficient under the designed stress level. Even though the relationship between compressive creep and ray direction on the side edge of bridge was not so clear contrary to expectation, we could conclude that wood density and ray direction should be the quality decisive factors affecting the acoustical characteristics and performance of the bridge, the core member of violin-family bow instruments.

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