• Title/Summary/Keyword: Structural wall

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Equivalent Continuum Model for the Single Wall Carbon Nanotube (Single Wall Carbon Nanotube의 등가 연속체 모델에 대한 연구)

  • 김병구;전흥재
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2003.04a
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    • pp.227-234
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    • 2003
  • In this study, an equivalent continuum model for single wall carbon nanotube is proposed. The model links interatomic potentials and atom structure of a materials to a constitutive model on the continuum level. The Young's modulus and shear modulus were predicted by the model. The predictions were in good agreement with the prior experimental results available in the literatures. Also, the strain energy of the carbon nanotube was predicted as a function of the radius of the carbon nanotube.

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Structural Performance of the RC Boundary Beam-Wall System Subjected to Axial Loads (축하중이 작용하는 철근 콘크리트 경계보-벽체 시스템의 압축성능 평가)

  • Han, Jin-Ju;Son, Hong-Jun;Kim, Dae-Jin
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.35 no.1
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    • pp.57-64
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    • 2022
  • This study investigated the structural performance of the RC boundary beam-wall system subjected to axial loads that required lesser construction quantity and smaller floor height in comparison with the conventional RC transfer girder system. Four specimens of 1/2 scale were constructed, and their peak strengths under axial loads and failure characteristics were compared and analyzed. Test parameters included the ratio of the lower to the upper wall length, lower wall thickness, and stirrup details of the lower wall. In addition, three-dimensional nonlinear finite element analysis was performed to verify the effectiveness of the boundary beam-wall system. The peak strength of each specimen was similar to the nominal axial strength of the lower wall, indicating that the axial load was transferred smoothly from the upper to the lower wall. The contribution of the lower wall cross-section was high if the ratio of the lower to the upper wall length was small; the contribution was low if the out-of-plane eccentricity existed in the lower wall. The specimen with smaller stirrup distance and cross-ties in the lower wall showed higher initial stiffness and peak load than other specimens.

Structural Components of Cell Wall in Various Parts of Korean Ginseng(Panax ginseng C. A. Meyer) (고려인삼의 부위별 세포벽 구성성분)

  • 정영륜;박찬수
    • Journal of Ginseng Research
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    • v.7 no.2
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    • pp.169-171
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    • 1983
  • The structural components of cell wall in various parts of Korean ginseng were analysed. Pectin was abundant in the cortex and epidermis of root, and leaf. Hemicellulose in root was more than in other parts of ginseng. Cellulose content of stem and seed coat was much higher compared to other parts and lignin content was highest in seed coat.

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Relation of Left Atrial Wall Pathology to Atrial Fibrillation and Left Atrial Dimension in Mitral Valvular Diseases. (승모판질환에서 좌심방벽 생검소견과 심방세동 및 좌심방 크기의 관계)

  • 김광호
    • Journal of Chest Surgery
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    • v.21 no.1
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    • pp.1-9
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    • 1988
  • The left atrial [LA] dimension and atrial fibrillation [AF] in patients with mitral valvular heart diseases have been thought to be related to hemodynamic burden to the LA depending on severity of stenosis or regurgitation of mitral valve, left ventricular contractility and the heart conditions. If hemodynamic burden persists long, it can affect the LA wall and structural change of the LA wall itself can developed. So the structural change of the LA wall could be thought to be related to the LA dimension and AF. To verify this relation, the LA wall biopsy was performed in 26 patients with rheumatic mitral valvular heart disease at the left atriotomy incision margin which was posterior to the interatrial groove after completion of surgery to the mitral valve such as valve replacement or commissurotomy. Relation of the pathological state of the LA wall to AF and the LA dimension measured by M-mode echocardiography was studied. The conclusions were as follow. 1. There was tendency that degree of fibrosis of myocardium of the LA wall was related to the LA dimension. 2. There was more chance that patients who had severe fibrosis of myocardium of the LA wall had pre and postoperative AF. 3. There was no relation between reduction rate of the LA dimension before and after surgery and degree of fibrosis of myocardium of the LA wall.

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Improvement and Evaluation for Seismic Resistant Capacity of Reinforced Concrete Shear wall with Connection Types and Diagonal Reinforcement (철근콘크리트 전단벽의 접합방식과 대각보강에 따른 내진성능 평가 및 개선)

  • Shin, Jong-Hack;Ha, Gee-Joo;An, Joon-Suk;Ju, Jung-Jun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.3 no.3
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    • pp.139-147
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    • 1999
  • Six reinforced concrete shear wall, constructured with fully rigid, slit, and infilled types, were tested under both vertical and cyclic loadings. Experimental programs were carried out to evaluate the seismic performance of such test specimens, such as the hysteretic behavior, the maximum horizontal strength, crack propagation, and ductility, under load reversals. All the specimens were modeled in one-third scale size. Based on the test results, the following conclusions can be made. For the diagonal reinforced slit and infilled shear wall specimens, it was found that the failure mode shows very effective crack control and crushing due to slippage prevention of boundary region and reduction of diagonal tension rathar than the brittle shear and diagonal tension failure. The ductility of specimens designed by the diagonal reinforcement for the slit and infilled shear wall was increased 1.72~1.81 times in comparison with the fully rigid shear wall frame. Maximum horizontal load-carrying capacity of specimens designed by the diagonal reinforcement ratio the slit and infilled shear wall was increased respectively by l.14 times and l.49 times in comparison with the standard fully rigid shear wall frame.

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Fire resistance tests of LSF walls under combined compression and bending actions

  • Peiris, Mithum;Mahendran, Mahen
    • Steel and Composite Structures
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    • v.43 no.4
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    • pp.483-500
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    • 2022
  • Cold-formed steel wall panels sheathed with gypsum plasterboard have shown superior thermal and structural performance in fire. Recent damage caused by fire events in Australia has increased the need for accurate fire resistance ratings of wall systems used in low- and mid-rise construction. Past fire research has mostly focused on light gauge steel framed (LSF) walls under uniform axial compression and LSF floors under pure bending. However, in reality, LSF wall studs may be subject to both compression and bending actions due to eccentric loading at the wall to-roof or wall-to-floor connections. In order to investigate the fire resistance of LSF walls under the effects of these loading eccentricities, four full-scale standard fire tests were conducted on 3 m × 3 m LSF wall specimens lined with two 16 mm gypsum plasterboards under different combinations of axial compression and lateral load ratios. The findings show that the loading eccentricity can adversely affect the fire resistance level of the LSF wall depending on the magnitude of the eccentricity, the resultant compressive stresses in the hot and cold flanges of the wall studs caused by combined loading and the temperatures of the hot and cold flanges of the studs. Structural fire designers should consider the effects of loading eccentricity in the design of LSF walls to eliminate their potential failures in fire.

Study on the Making Wall Techniques behind the Buddha in Main Building of Bongjeongsa Temple (봉정사 대웅전 후불벽체의 제작기법에 관한 연구)

  • Jeong, Hye-Young;Han, Kyeong-Soon
    • Journal of Conservation Science
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    • v.23
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    • pp.53-65
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    • 2008
  • This research investigated and analyzed the structure and material feature of the wall behind the Buddha of main temple in An-dong Bongjeonsa through applying the natural scientific method, in order to closely examine its production technique. As a result of the research, the structural and material feature of the wall has been clarified and its production technique applied to the structure has been understood in a comprehensive sense. The target sample basically adopted the two-layer wall system, which showed a symmetric structure to the center made with the wooden material, and is estimated to follow the structural tendency of a general wall which is organized with the first layer, the midterm layer, and the painting wall layer. Each layer formed by the production procedure showed difference in the material and production method according to its characteristics and roles. And it was identified that, in general, the higher a layer lies, the finer grains it has. Combination of the main materials and the additives, used for the wall forming, was presumed to contribute to improving its durability and conservativeness. Also interaction between the materials generating the conservativeness and the producer's technical effect seemed to fortify solidity of the wall.

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Numerical study on the structural stability of the precast joint buttress wall (프리캐스트 조인트 방법을 사용한 부벽식 옹벽의 구조적 안정성에 대한 수치해석 연구)

  • Kim, Joonseok
    • Journal of the Society of Disaster Information
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    • v.12 no.4
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    • pp.366-372
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    • 2016
  • Recently in case of the concrete retaining wall precast technological change in the field assembled by the way. A precast wall is devied into upper and lower respectively, and the way, assembled in field is being performed. But the assembled part could have been damaged by the earth pressure in a relatively high buttress wall. And, it have been pointed out that large-scale disaster can be occurred. Thus, in this thesis, a structural stability for the buttressed retaining wall with pre-cast joint method was analyzed by a numerical analysis method. The structural stability of the three height retaining wall(7.6m, 8.5m, 10m) was conducted respectively for earth pressure. The maximum principal stress applied to the concrete retaining wall was analyzed to occur locally in the vicinity of the fixing anchor as 23.3 ~ 43.2 MPa.

A Study on the Elastic Restoration Characteristics According to Environmental Resistance Condition of Structural Sealing Finishing Materials (구조용 실링마감재의 내환경 조건에 따른 탄성복원 특성 연구)

  • Jang, Pil-Sung;Kang, Dong-Won;Hong, Soon-Gu;Kim, Young-Geun;Kim, Sung-Rae
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.1
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    • pp.6-12
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    • 2018
  • Recently, The use of the curtain wall method is increasing in construction. The curtain wall construction is widely applied to the exterior wall of the building for shortening construction period and economical efficiency. However, the replacement of deterioration of the weather resistance and structural behavior of the sealing material connecting the curtain wall method and the glass frame is necessary for introduction of the stable curtain wall method and quality improvement in accordance with KS F 4910 standard. In this study, the elastic restoring force test was performed in the external environment. In this study, the deterioration of the sealant was evaluated for structural sealants. In Korea, studies on the variable displacement behavior of structural sealants are lacked. In this study, the reproduced results in laboratory conditions are compared with the deteriorating conditions exposed to the external environment, and they are reflected in the design of sealing materials in the future. According to the results of the study, it was confirmed that the existing structure sealant meets the quality standard of KS F 4910, but in the conditions performed in this study, adhesion failure of the specimen and cracking of the surface occurred. Especially, in the weather resistance test, it is necessary to evaluate the long-term durability performance of the structural sealant used in the curtain wall method by checking the insoluble state of all the test pieces. Therefore, in order to apply a conventional structural sealant to the site, it is necessary to introduce another durability performance evaluation.

Load-Displacement Formulations of Low-rise Unbounded RC Shear Walls with or without Openings

  • Lou, K. Y.;Cheng, F. Y.;Sheu, M. S.;Zhang, X. Z.
    • Computational Structural Engineering : An International Journal
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    • v.1 no.2
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    • pp.117-130
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    • 2001
  • Investigations of low-rice unbounded reinforced concrete shear walls with or without openings are performed with comparison of analytical and experimental results. Theoretical analysis is based on nonlinear finite element algorithm, which incorporates concrete failure criterion and nonlinear constitutive relationships. Studios focus on the effects of height-to-length ratio of shear walls, opening ratio, horizontal and vertical reinforcement radios, and diagonal reinforcement. Analytical solutions conform well with experimental results. Equations for cracking, yielding and ultimate loads with corresponding lateral displacements are derived by regression using analytical results and experimental data. Also, failure modes of low-rise unbounded shear walls are theoretically investigated. An explanation of change in failure mode is ascertained by comparing analytical results and ACI code equations. Shear-flexural failure can be obtained with additional flexural reinforcement to increase a wall's capacity. This concept leads to a design method of reducing flexural reinforcement in low-rise bounded solid shear wall's. Avoidance of shear failure as well as less reinforcement congestion leer these walls is expected.

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