• Title/Summary/Keyword: eccentric behavior

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Influence of Concrete Strength and Lateral Ties on Behavior of High-Strength Concrete Columns Subjected to Eccentric Compressive Load (편심 압축력을 받는 고강도 콘크리트 기둥의 거동에 미치는 띠철근 및 콘크리트 강도의 영향)

  • Lee, Young Ho;Chung, Heon Soo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.11 no.3
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    • pp.95-104
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    • 2007
  • This study was focused on the effect of concrete strength and lateral ties of concrete columns subjected to eccentric compressive loads. The twenty-four concrete columns with $200mm{\times}200mm$ square cross-section were tested. The main variables were concrete strength, spacing and configuration of lateral ties, and eccentricity ratios. From the experiment, the followings were investigated ; 1) In all cases, it was observed that the increase of concrete compressive strength led to the decrease of ductility. Also, as the eccentricity ratios increased, the effect of ductility enhancement by lateral ties decreased. 2) As the ties spacing decreased from 100mm to 30mm, the magnitude of axial load acting on the concrete column showed an enhancement of 1.1~1.2 times and the descending curve after a peak moment presented a smooth decline. 3) The high-strength concrete columns required a design of lateral ties to increase the volumetric ratios and density of tie spacing to sustain a proper strength and ductility. Accordingly, regardless of concrete strength, the current AIK design code to specify the maximum tie spacing of concrete columns was proven to lead to the poor strength and ductility for seismic design. Therefore, it is necessary to develop a new seismic design code that connects volumetric ratios and tie spacing of concrete columns with concrete strength.

Influence of Column Aspect Ratio on the Hysteretic Behavior of Slab-Column Connection (슬래브-기둥 접합부의 이력거동에 대한 기둥 형상비의 영향)

  • Choi, Myung-Shin;Cho, In-Jung;Ahn, Jong-Mun;Shin, Sung-Woo
    • Journal of the Korea Concrete Institute
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    • v.19 no.4
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    • pp.515-525
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    • 2007
  • In this investigation, results of laboratory tests on four reinforced concrete flat plate interior connections with elongated rectangular column support which has been used widely in tall residential buildings are presented. The purpose of this study is to evaluate an effect of column aspect ratio (${\beta}_c={c_1}/{c_2}$=side length ratio of column section in the direction of lateral loading $(c_1)$ to the direction of perpendicular to $c_1$) on the hysteretic behavior under earthquake type loading. The aspect ratio of column section was taken as $0.5{\sim}3\;(c_1/c_2=1/2,\;1/1,\;2/1,\;3/1)$ and the column perimeter was held constant at 1200mm in order to achieve nominal vertical shear strength $(V_c)$ uniformly. Other design parameters such as flexural reinforcement ratio $(\rho)$ of the slab and concrete strength$(f_{ck})$ was kept constant as ${\rho}=1.0%$ and $f_{ck}=40MPa$, respectively. Gravity shear load $(V_g)$ was applied by 30 percent of nominal vertical shear strength $(0.3V_o)$ of the specimen. Experimental observations on punching failure pattern, peak lateral-load and story drift ratio at punching failure, stiffness degradation and energy dissipation in the hysteresis loop, and steel and concrete strain distributions near the column support were examined and discussed in accordance with different column aspect ratio. Eccentric shear stress model of ACI 318-05 was evaluated with experimental results. A fraction of transferring moment by shear and flexure in the design code was analyzed based on the test results.

Predicting the stiffness of shear diaphragm panels composed of bridge metal deck forms

  • Egilmez, Oguz O.
    • Steel and Composite Structures
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    • v.24 no.2
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    • pp.213-226
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    • 2017
  • The behavior of building industry metal sheeting under shear forces has been extensively studied and equations have been developed to predict its shear stiffness. Building design engineers can make use of these equations to design a metal deck form bracing system. Bridge metal deck forms differ from building industry forms by both shape and connection detail. These two factors have implications for using these equations to predict the shear stiffness of deck form systems used in the bridge industry. The conventional eccentric connection of bridge metal deck forms reduces their shear stiffness dramatically. However, recent studies have shown that a simple modification to the connection detail can significantly increase the shear stiffness of bridge metal deck form panels. To the best of the author's knowledge currently there is not a design aid that can be used by bridge engineers to estimate the stiffness of bridge metal deck forms. Therefore, bridge engineers rely on previous test results to predict the stiffness of bridge metal deck forms in bracing applications. In an effort to provide a design aid for bridge design engineers to rely on bridge metal deck forms as a bracing source during construction, cantilever shear frame test results of bridge metal deck forms with and without edge stiffened panels have been compared with the SDI Diaphragm Design Manual and ECCS Diaphragm Stressed Skin Design Manual stiffness expressions used for building industry deck forms. The bridge metal deck form systems utilized in the tests consisted of sheets with thicknesses of 0.75 mm to 1.90 mm, heights of 50 mm to 75 mm and lengths of up to 2.7 m; which are representative of bridge metal deck forms frequently employed in steel bridge constructions. The results indicate that expressions provided in these manuals to predict the shear stiffness of building metal deck form panels can be used to estimate the shear stiffness of bridge metal deck form bracing systems with certain limitations. The SDI Diaphragm Design Manual expressions result in reasonable estimates for sheet thicknesses of 0.75 mm, 0.91 mm, and 1.21 mm and underestimate the shear stiffness of 1.52 and 1.90 mm thick bridge metal deck forms. Whereas, the ECCS Diaphragm Stressed Skin Design Manual expressions significantly underestimate the shear stiffness of bridge metal deck form systems for above mentioned deck thicknesses.

Half-Scaled Substructure Test for the Performance Evaluation of a Transmission Tower subjected to Wind Load (송전철탑의 내풍안전성 평가를 위한 1/2축소부분구조 실험)

  • Moon, Byoung-Wook;Min, Kyung-Won
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.20 no.5
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    • pp.641-652
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    • 2007
  • In this paper, a half-scaled substructure test was performed to evaluate the buckling and structural safety of an existing transmission tower subjected to wind load. A loading scheme was devised to reproduce the dead and wind loads of a prototype transmission tower, which uses a triangular jig that is mounted on the reduced model to which the similarity law of a half length was applied. As a result of the preliminary numerical analysis carried out to evaluate the stability of a specimen for the design load, is was confirmed that the calculated axial forces of tower leg members were distributed to $80{\sim}90%$ of an admissible buckling load. When the substructured transmission tower was loaded by 270% of its maximum admissible buckling load, it was failed due to the local buckling that is occurred in joints with weak constraints for out-of-plane behavior of leg members. By inspection of load-displacement curves, displacements and strains of members, it is considered that this local buckling was due to additional eccentric force by unbalanced deformation because the time that is reached to yielding stress due to the bending moment is different at each point of a same section.

Active Narrative of Digital Game and Improvisation (디지털 게임의 능동서사와 즉흥연기)

  • Yu, Hui-Beom;Sung, Jung-Hwan
    • Journal of Korea Game Society
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    • v.16 no.2
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    • pp.75-86
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    • 2016
  • Game studies of theatrical approach explained interactive property of game in humanistic background. Those studies analyze the game, and based on Aristoteles Poetic Attribute. But theatrical approach has a problem by user's unpredictable intervention in narrative (Active narrative). This paper intended to see in the glance of any impact on the Aristotelian model by active narrative. As a result of the active narrative remake the causality between materials of drama. Also, it can be seen to define a kind of the "Improvisation" in theatrical view. But it exposed a essential difference in the form an expression by substance and material of media. It was defined forms of improvisation in the gaming environment which are 'Self-generated Individuality', 'Self-definition Faction', 'Eccentric Behavior Contending', 'Trolling' and 'Bug Play'. Finally this paper proposes the characteristics of the improvisation of the game and the direction to be improved game analysis model in humanities through forms of improvisation in game environment.

Numerical Study on Interior Flat Plate-Column Connections Subjected to Unbalanced Moment (불균등 휨모멘트를 받는 플랫 플레이트-기둥 접합부에 대한 해석연구)

  • 최경규;황영현;박홍근
    • Journal of the Korea Concrete Institute
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    • v.14 no.6
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    • pp.949-960
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    • 2002
  • Flat plate structures under lateral load are susceptible to punching shear failure of the slab-column connection. To prevent such brittle failure, strength and ductility of the connection should be ensured. However, due to complexity in the behavior and difficulty in simulating the actual load and boundary conditions of the flat plate system, it is not easy to obtain reliable data regarding to the strength and ductility from the previous experimental studies. In the present study, a numerical study was performed for interior connections of continuous flat plate. For the purpose, a computer program for nonlinear FE analyses was developed, and the validity was verified by comparisons with the existing experimental results. Through the parametric studies, the variations of bending moment, shear, and torsional moment around the connection were investigated. Based on the findings of the numerical studies, the aspects which need to be improved in current design methods were discussed. The results of the present study will be used for developing a design method for the flat plate-column connection in the companion paper.

The Response Modification Factor of Inverted V-type Braced Steel Frames (역V형 가새골조의 반응수정계수)

  • Ahn, Hyung Joon;Jin, Song Mei
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.17 no.1
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    • pp.1-9
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    • 2013
  • In this study of Eccentric Braced Frames have identified the following target eccentricity on the length of the inelastic behavior of the reaction by calculating the correction factor by comparing it to the value suggested by the earthquake provided material for the rational design aims to There are. As a variable-length V-braced frame analysis model stations were set up. Eccentricity faults in the model according to the length stiffness ratio, the maximum amount of energy dissipation were analyzed base shear and multi-layered model of the reaction from the eccentricity correction factor calculated on the length of the building standards proposed by KBC 2009 in response eccentricity correction factor calculated from The length varies. does not have the same response modification factor was confirmed.

An Experimental Study on Stength of Slender Square Tube Columns Filled with High Strength Concrete (고강도콘크리트충전 각형강관장주의 내력에 관한 실험적 연구)

  • Seo, Seong Yeon;Chung, Jin An
    • Journal of Korean Society of Steel Construction
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    • v.14 no.4
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    • pp.471-479
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    • 2002
  • In this paper, 18 square CFT columns filled with high-strength concrete were tested under concentric or eccentric axial loading. Two parameters of the experimental program included the buckling length-section depth ratio ($L_K$/D) and the eccentricity of the appled compressive load (e). In additon, mechanical properties such as the compressive concrete strength and compressive and tensile steel strength were measured and incorporated into the material models for the stress-strain relationships of concrete and steel. This model was used in an elasto-plastic analysis in order to predict the behavior of the slender CFT columns. Observtions of the failure mode during the tests under axial loadig were also presented. The strengths obtained from the analysis. Recommendations for Design, and Constructions of CFT structures were presented, as verified by the experimental results.

Hart Crane′s Aberrant English

  • Reed, Brian
    • Lingua Humanitatis
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    • v.5
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    • pp.167-192
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    • 2003
  • When Hart Crane′s poem cycle The Bridge was published in 1930, a group of influential reviewers accused Crane of immaturity, sentimentality, and lack of focus. They condemned crane′s wayward, fuzzy mysticism as backwards-looking and self-defeating. Even sympathetic critics, such as Harold Bloom, have consistently portrayed Crane′s poetry as the pyrotechnic final fizzle of late romanticism. These persistent, public reservations, however, have not prevented an impressive proliferation in secondary literature concerning Crane since the late 1960s. His promiscuity, alcoholism, erratic behavior, relative poverty, tragic death, and total commitment to art have since earned him the labels of New World Rimbaud and proto-Beat. His colorful career thus explains in part his retrospective fame. Nevertheless, living hard and dying young do not guarantee artistic immortality. This article poses questions as to why Crane has mattered so much to subsequent generations of U.S. readers and what these readers find so compelling in his poetry. The answer, I would argue, lies in Crane′s idiosyncratic use of language. Far from striving for transparency, he writes in an inimitably obstructive, artificial manner. There is something seductive and absurd in his wild use of words here, I would further argue, we discover the reason behind both Crane′s enduring appeal and his supposed inadequacy as a writer. Crane did "torture" syntax, semantics, and conventional associations, not because he saw his unusual language as an eccentric mannerism but because he saw it as a tool in the service of constructing a "myth of America" and reintegrating the human and divine. Understanding thy he considered this to be the case clarifies Crane′s achievement and illuminates why his work still seems so relevant today.

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Buckling Behavior of I-Beam with the Elastic Support (탄성 경계를 고려한 I형보의 좌굴 거동)

  • Kang, Young Jong;Lee, Gyu Sei;Lim, Nam Hyoung
    • Journal of Korean Society of Steel Construction
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    • v.11 no.2 s.39
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    • pp.201-212
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    • 1999
  • A beam supported by a flexible elastic support is commonly used as structural elements, e.g., braced beam, railway track, etc. The elastic support can be located in arbitrary point in the cross-section. This paper investigates the effects of support eccentricity on the elastic buckling of beams with elastic supports. The effects of stiffness of the elastic support are also studied. A beam element with elastic supports and the analysis program are developed for elastic buckling analysis using finite element formulation. The elastic support is modeled by elastic spring element. Using the offset technique, the eccentricity of support is taken into account. A beam element having 14 degrees of freedom including the warping degree of freedom is used. Various numerical example analyses show that the present formulation and analysis program accurately and effectively compute the buckling load and mode of beams with elastic supports.

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