• Title/Summary/Keyword: Lateral creep

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Experimental Investigation on the Creep Behavior of Pultruded FRP Composite Columns (인발성형 FRP 복합소재 기둥부재의 크리프거동에 대한 실험적 분석)

  • Kang, Jin Ook;Abdul Hamid Zureick
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2003.10a
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    • pp.299-306
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    • 2003
  • This paper presents the results of an experimental investigation pertaining to the creep behavior of fiber-reinforced polymeric (FRP) pultruded components subjected to sustained eccentric axial loading. Six different axial load/eccentricity combinations were investigated through the experiments. The test duration of these experiments was 2,000 hours (90 days), during which the mid-height lateral deflections of the components were recorded continually. Analytical formulations based on the Schapery's quasielastic method and a power law model were used for the prediction of the creep lateral deflection.

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Prediction of Time-dependent Lateral Movement Induced by Differential Shortening in Tall Buildings Using Construction Stage Analysis

  • Ha, Taehun;Kim, Sangdae;Lee, Sungho
    • International Journal of High-Rise Buildings
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    • v.6 no.1
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    • pp.11-19
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    • 2017
  • High-rise buildings move during construction due to time-dependent material properties of concrete (creep and shrinkage), construction sequences, and structural shapes. The building movements, including vertical and horizontal displacements, result from the sum of axial and lateral deformation of vertical members at each level. In addition to the vertical shortenings, the lateral movement induced by differential shortening can have adverse effects on the construction tolerance and serviceability of non-structural elements such as elevators and curtain walls. In this study a construction stage analysis method is developed to predict lateral movement induced by shortening, including the effect of creep and shrinkage. The algorithm of construction stage analysis is combined with the FE analysis program. It is then applied to predict lateral movement of a 58-story reinforced concrete building that was constructed in Kuala Lumpur, Malaysia. Gravity induced lateral movement of this building is predicted by the construction stage analysis. A field three-dimensional laser scanning survey is carried out to verify the prediction results, and satisfactory agreement is obtained.

Uplift Capacity and Creep Behavior of Concrete Pile Driven in Clay (점토지반에 타입된 콘크리트 말뚝의 인발저항 및 크리프 거동)

  • 신은철;김종인;박정준;이학주
    • Proceedings of the Korean Geotechical Society Conference
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    • 2001.03a
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    • pp.371-378
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    • 2001
  • The working load at pile is sometimes subjected to not only compression load but also lateral load and uplift forces. Pile foundation is essential and uplift load can be applied because of buoyancy, a typhoon, wind or seismic forces. This study was carried out to determine the uplift capacity of concrete pile foundation driven in clay. Pile was driven in clay, between pile and clay adhesion factor was estimated, and it is the mean value between the cast-in-situ-pile and steel pipe pile. When pile foundation is loaded for long time, creep behavior occurs. The behavior of creep is originated from the clay creep contacted with pile. The creep behavior of pile foundation embedded in clay is heavily depended on the thickness of clay around the pile shaft, pore water pressure in clay, and creep behavior of clay.

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Utilization of wheel derailment test facilities (차륜탈선 시험설비의 활용방안)

  • Ham, Young-Sam;You, Won-Hee
    • Proceedings of the KSR Conference
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    • 2011.05a
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    • pp.1128-1133
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    • 2011
  • This is a testing equipment system to analyze variation of creep force according to wheel-rail tread profile, running speed of vehicle, vertical and lateral force, wheel/rail contact point, attack angle and so on. The creep force affect vehicle derailment, especially climbing derailment. This system is composed of main frame, wheelset and rail disks driver, hydraulic actuator, controller, environmental chamber, safety system and so on.

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Long-Term Behaviors of Reinforced Concrete Pier Structures Considering Long Column Effects (철근콘크리트 장주 교각의 시간에 따른 거동)

  • Jung, Hyun-Soo;Kim, Su-Man
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.11a
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    • pp.69-72
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    • 2005
  • For reinforced concrete column under sustained loads, the member suffers additional lateral deflection due to creep. This deflection leads to additional bending in the member, which in turn causes the column to deflect still further. Therefore the secondary moment due to additional deflection causes an increase in primary moment and the strength of column is reduced. And also creep buckling may occur. On this study, nonlinear analysis of reinforced concrete long column including crack effects is carried out and then the strength of long column is revaluated.

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Studies on Evaluation for Long-Term Structural Performance of Pinus densiflora Sieb. et Zucc. (I) -Shear Creep and Mechano-Sorptive Behavior of Drift Pin Jointed Lumber-

  • Hong, Soon-Il;Park, Jun-Chul
    • Journal of the Korean Wood Science and Technology
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    • v.34 no.5
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    • pp.11-18
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    • 2006
  • This study was carried out to evaluate the mechano-sorptive deflection of shear creep of drift pin jointed solid wood. Specimens were the solid wood of Pinus densiflora. The joint was composed with steel plate and drift pin, 85mm in length and 10mm in diameter. The creep tests were conducted under the constant loads in an variable environment. Five different shearing loads were applied parallel to the grain of specimens. The shearing loads applied were 170, 340, 510, 680 and 850 kgf. The stress levels were 10, 20, and 30, 40 and 50% of the bearing strength obtained from the tension-type lateral strength test. The creep tests for specimens were carried out for 10300 hours. A few general conclusions could be drawn from this study: The mechano-sorptive deflection (${\delta}$ ms) is defined as ${\delta}\;ms={\delta}\;t-({\delta}\;c+{\delta}\;sh)-{\delta}\;o$, where ${\delta}$ t is the total deflection, ${\delta}$ c is the pure creep, ${\delta}$ sh is shrinkage-swelling behavior, and ${\delta}$ o is the initial deflection. Changes of relative humidity may cause more severe creep deflection than those of constant humidity, especially during the drying process. The mechano-sorptive behaviors of specimens, except the effects of shrinkage and swelling, gradually increased with increasing time. The deflection is increased in desorption process and recovered in adsorption process. The deflections of drift pin jointed solid wood under different loads showed almost same tendency in all specimens. Although the creep deflection tendencies of each series are very similar, the specimens subjected to a large shearing load exhibit large creep deflections in the desorption process than do those to the small shearing load specimens.

Creep & Tensile Properties of Thermally Grown Alumina Films (열 생성 알루미나 박막의 크리프 및 인장 특성)

  • Ko, Gyoung-Dek;Sun, Shin-Kyu;Kang, Ki-Ju
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.31 no.6 s.261
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    • pp.665-670
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    • 2007
  • Alpha-phase alumina TGO(Thermally Grown Oxide) forms on the interface between zirconia top coat and bond coat of thermal barrier coating system for superalloys during exposure to high temperature over $1000^{\circ}C$. It is known to provide a good protection against hot corrosion and to cause surface failure such as rumpling and cracking due to difference in thermal expansion coefficient from the substrate metal and the lateral growth. Consequently, mechanical properties of the alumina TGO at the high temperature are the key parameters determining the integrity of TBC system. In this work, by using Fecralloy foils as the alumina forming substrate, creep tests and tensile tests have been performed with various TGO thicknesses$(h=0{\sim}4{\mu}m)$ and yttrium contents(0, 200ppm) at $1200^{\circ}C$. Displacement-time curves and load-displacement curves for each TGO thickness(h=1,2,..) were measured from the creep and tensile tests, respectively, and compared with the curves without TGO thickness(h=0). As the result, the intrinsic tensile and creep properties of TGO itself were determined.

The research on wear simulation between wheel and rail at inclined of Korea High Speed Railway (경사선로에서의 차륜과 레일간 상호작용에 따른 마모 현상 연구)

  • Moon Tai-Seon;Seo Bo-Pil;Choi Jeung-Hum;Han Dong-Chul
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2003.11a
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    • pp.112-117
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    • 2003
  • The purpose of this work is to general approach to numerically simulating wear in rolling and sliding contact area between wheel and rail interface based on the analysis of dynamics with general MBS package. A simulation scheme is developed that calculates the wear at a detailed level. The estimation of material removal follows Archard's wear equation which states that the reduction of volume is linearly proportional to the sliding distance, the normal applied load and the wear coefficient and inverse proportional to hardness. The main research application is the wheel-rail contact of Korea High Speed Railway.

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Mechanical analysis of the bow deformation of a row of fuel assemblies in a PWR core

  • Wanninger, Andreas;Seidl, Marcus;Macian-Juan, Rafael
    • Nuclear Engineering and Technology
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    • v.50 no.2
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    • pp.297-305
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    • 2018
  • Fuel assembly (FA) bow in pressurized water reactor (PWR) cores is considered to be a complex process with a large number of influencing mechanisms and several unknowns. Uncertainty and sensitivity analyses are a common way to assess the predictability of such complex phenomena. To perform such analyses, a structural model of a row of 15 FAs in the reactor core is implemented with the finite-element code ANSYS Mechanical APDL. The distribution of lateral hydraulic forces within the core row is estimated based on a two-dimensional Computational Fluid Dynamics model with porous media, assuming symmetric or asymmetric core inlet and outlet flow profiles. The influence of the creep rate on the bow amplitude is tested based on different creep models for guide tubes and fuel rods. Different FA initial states are considered: fresh FAs or FAs with higher burnup, which may be initially straight or exhibit an initial bow from previous cycles. The simulation results over one reactor cycle demonstrate that changes in the creep rate and the hydraulic conditions may have a considerable impact on the bow amplitudes and the bow patterns. A good knowledge of the specific creep behavior and the hydraulic conditions is therefore crucial for making reliable predictions.

Numerical modeling of the aging effects of RC shear walls strengthened by CFRP plates: A comparison of results from different "code type" models

  • Yeghnem, Redha;Guerroudj, Hicham Zakaria;Amar, Lemya Hanifi Hachemi;Meftah, Sid Ahmed;Benyoucef, Samir;Tounsi, Abdelouahed;Bedia, El Abbas Adda
    • Computers and Concrete
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    • v.19 no.5
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    • pp.579-588
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    • 2017
  • Creep and shrinkage are the main types of volume change with time in concrete. These changes cause deflection, cracking and stresses that affect durability, serviceability, long-term reliability and structural integrity of civil engineering infrastructure. Although laboratory test may be undertaken to determine the deformation properties of concrete, these are time-consuming, often expensive and generally not a practical option. Therefore, relatively simple empirically design code models are relied to predict the creep strain. This paper reviews the accuracy of creep and shrinkage predictions of reinforced concrete (RC) shear walls structures strengthened with carbon fibre reinforced polymer (CFRP) plates, which is characterized by a widthwise varying fibre volume fraction. This review is yielded by three commonly used international "code type" models. The assessed are the: CEB-FIP MC 90 model, ACI 209 model and Bazant & Baweja (B3) model. The time-dependent behavior was investigated to analyze their seismic behavior. In the numerical formulation, the adherents and the adhesives are all modelled as shear wall elements, using the mixed finite element method. Several tests were used to demonstrate the accuracy and effectiveness of the proposed method. Numerical results from the present analysis are presented to illustrate the significance of the time-dependency of the lateral displacements and eigenfrequencies modes.