• Title, Summary, Keyword: Flexural rigidity

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Effective flexural rigidities for RC beams and columns with steel fiber

  • Bengar, Habib Akbarzadeh;Kiadehi, Mohammad Asadi;Shayanfar, Javad;Nazari, Maryam
    • Steel and Composite Structures
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    • v.34 no.3
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    • pp.453-465
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    • 2020
  • Influences of different variables that affect the effective flexural rigidity of reinforced concrete (RC) members are not considered in the most seismic codes. Furthermore, in the last decades, the application of steel fibers in concrete matrix designs has been increased, requiring development of an accurate analytical procedure to calculate the effective flexural rigidity of steel fiber reinforced concrete (SFRC) members. In this paper, first, a nonlinear analytical procedure is proposed to calculate the SFRC members' effective flexural rigidity. The proposed model's accuracy is confirmed by comparing the results obtained from nonlinear analysis with those recorded from the experimental testing. Then a parametric study is conducted to investigate the effects of different parameters such as varying axial load and steel fiber are then investigated through moment-curvature analysis of various SFRC (normal-strength concrete) sections. The obtained results show that increasing the steel fiber volume percentage increases the effective flexural rigidity. Also it's been indicated that the varying axial load affects the effective flexural rigidity. Lastly, proper equations are developed to estimate the effective flexural rigidity of SFRC members.

Flexural Rigidity Reduction of Multi-Delaminated Composite Beams (다층 층간분리된 복합적층보의 휨강성 감소)

  • Park, Tae-Hyo;Baek, Jae-Wook;Cho, Baik-Soon
    • Journal of Korean Society of Steel Construction
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    • v.13 no.3
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    • pp.233-244
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    • 2001
  • In this study, flexural rigidity reduction of multi-delaminated composite beams are investigated. In order to evaluate the flexural rigidity reduction. Performed theoretical analysis. In order to investigate flexural rigidity reduction about effects of delamination on composite beams, the general kinematic governing equations are derived and solved by dividing the delaminated beam and imposing the continuity conditions into each sub-beam. For condition to appear multiple delamination through the laminated composite beams, the flexural rigidity reduction are compared according to many stacking sequences and several forms for delaminations. The present study could be used to evaluate the flexural rigidity reduction of composite laminated beams on multi-delaminations.

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A new cable force identification method considering cable flexural rigidity

  • Wang, Long;Wu, Bo;Gao, Junyue;Shi, Kairong;Pan, Wenzhi;He, Zhuoyi;Ruan, Zhijian;Lin, Quanpan
    • Structural Engineering and Mechanics
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    • v.68 no.2
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    • pp.227-235
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    • 2018
  • Cables are the main load-bearing members of prestressed structure and other tensegrity structures. Based on the static equilibrium principle, a new cable force identification method considering cable flexural rigidity is proposed. Its computational formula is derived and the strategy to solve its implicit formula is introduced as well. In order to improve the reliability and practicality of this method, the influence of the cable flexural rigidity on cable force identification accuracy is also investigated. Through cable force identification experiments, the relationships among certain parameters including jacking force, jacking displacement, initial cable force, and sectional area (flexural rigidity) are studied. The results show that the cable force calculated by the proposed method considering flexural rigidity is in good agreement with the finite element results and experimental results. The proposed method with high computational accuracy and resolution efficiency can avoid the influences of the boundary condition and the length of the cable on calculation accuracy and is proven to be conveniently applied to cable force identification in practice.

Analysis of Structural Performance of Wood Composite I and Box Beam on Cross Section Component (I) - Calculation and Analysis of Flexural Rigidity and Deflection - (단면구성요소(斷面構成要素)에 관(關)한 목질복합(木質複合) I및 Box형 보의 구조적(構造的) 성능(性能) 분석(分析) (I))

  • Oh, Sei-Chang;Lee, Phil-Woo
    • Journal of the Korean Wood Science and Technology
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    • v.19 no.2
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    • pp.40-55
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    • 1991
  • To investigate the influence of cross section geometries on the behavior of composite beams in the case of small span to depth ratio and deep beams. the static flexural behavior of composite I-beams and Box- beams was evaluated. 12 types of composite I -beams composed of LVL flanges and particleboard or plywood web and 3 types of composite Box-beams composed of LVL flanges and plywood web were tested under one-point loading. The load-deflection curves were almost linear to failure, therefore, the behavior of tested composite beams was elastic. The theoretical flexural rigidity of composite beams was calculated and compared with observed flexural rigidity. The highest value was found in I-W type beams and the lowest value was found in G-P type beams. The difference between theoretical and observed flexural rigidity was small. Theoretical total deflection of tested composite beams was calculated using flexural rigidity and compared with actual deflection. Shear deflection of these beams was evaluated by the approximation method, solid crosss section method and elementary method. The difference between actual deflection and expected deflection was not found in D, E and F type beams. This defference was small in G, H and I type beams or Box-beam.

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The Influence of Volume Fraction and Fiber Orientation of CERP Layer on Flexural properties of A17075/CFRP Multi-Layered Hybrid Laminate Material (Al Shee/CFRP 다적층 하이브리드 복합재료의 굴곡강도에 미치는 카본섬유 체적률 및 배열방향 영향)

  • Yoo Jae-hwan
    • Journal of the Korean Society of Safety
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    • v.19 no.4
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    • pp.31-35
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    • 2004
  • The A17075/CFRP multi-layered hybrid laminate material consists of the alternating A17075-T6 sheets and carbon/epoxy prepregs of M40 fade. The influence of volume fraction and fiber orientation of A17075/CFRP layer on flexural properties of A17075/CFRP laminate alternating A17075-T6 and carbon/epoxy prepreg was investigated. The results obtained from the experimental analysis are as follows: 1. In the $0^{\circ}$ fiber orientation, the mont of increase of the flexural rigidity was $20.5\%$ at the $26.5\%$ volume fraction and $38.0\%\;at\;the\;35.7\%$ volume fraction compared with the flexural rigidity level(20.0GPa) of the $10\%$ volume fraction of CFRP. 2. In the $\pm45^{\circ}$ fiber orientation the amount of decrease of the flexural rigidity was $23.5\%\;at\;the\;20.0\%$ volume fraction and $31.5\%\;at\;the\;33.3\%$ volume fraction compared with the flexural rigidity level of the $10\%$ volume fraction of CFRP. 3. In the $0^{\circ}$ fiber orientation, the flexural strength was 481.5MPa at the $10\%$ volume fraction of CFRP and 583.8MPa at the $26.5\%$ volume fraction and 653.7MPa at the $35.7\%$ volume faction. 4. In the $\pm45^{\circ}$ fiber orientation, the flexural strength was 354.0MPa at the $20.0\%$ volume fraction of CFRP and 340.5MPa at the $33.3\%$ volume fraction.

Valve Support Design for Improved Flexural Rigidity Against Strong Earthquake (강진 대비 굽힘 강성 향상을 위한 밸브지지대 형상 설계)

  • Kim, Dae Jin;Kim, Hyoung Eun;Seok, Chang Sung
    • Journal of the Korean Society of Safety
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    • v.32 no.6
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    • pp.75-80
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    • 2017
  • In this study, seismic performance of various types of valve supports in terms of flexural rigidity are evaluated by FEA using equivalent static load method. Flexural rigidity of the existing two types of valve supports can be effectively improved by simply adding one more bracket on the other side of support. New types of polygonal valve supports with a concept of fully stressed beam theory are suggested and it is verified that the new supports are rigid enough to withstand stronger earthquake which we should be prepared for.

A Study on Flexural Rigidity of Two-row Overlap Pile Wall for Deep Excavation Support (대심도 굴착면 지지를 위한 2열 겹침말뚝의 휨 강성에 관한 연구)

  • Choi, Won-Hyuk;La, You-Sung;Kim, Bum-Joo
    • Journal of the Korean Geosynthetics Society
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    • v.17 no.1
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    • pp.33-43
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    • 2018
  • Two-row Overlap Pile wall is a novel retaining wall system with high flexural rigidity and waterproofing for deep excavation support currently being developed in Korea. The Two-row Overlap Pile wall is constructed by making an overlap between consecutive four-axis (or two-axis) auger piles which themselves are overlapped and arranged in zigzag manner. In this study, the flexural rigidity of the Two-row Overlap Pile wall, including the effect of cross-sectional shape, was examined using both theoretical and numerical approaches. The results of investigation suggested that the Two-row Overlap Pile wall formed with two-row piles exhibit greatly higher flexural rigidity than conventional one-row pile walls such as Cast in place pile (CIP) and Secant pile wall (SPW), whereas the effect of overlap length between piles on the flexural rigidity is relatively minimal.

The Modified Coefficient of the Orthotropic Flexural Rigidity for Stiffened Plates with Rectangular Ribs Considering the Dimensions of Ribs (리브 제원을 고려한 평강 리브 보강판의 직교이방성 휨 강성 수정 계수)

  • Chu, Seok Beom
    • Journal of Korean Society of Steel Construction
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    • v.19 no.2
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    • pp.161-170
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    • 2007
  • In this study, to improve on the inaccurate results of the orthotropic plate analysis, we aim to propose a modified coefficient of the orthotropic flexural rigidity for stiffened plates with rectangular ribs considering the dimensions of ribs. The sensitivity of the flexural rigidity and the maximum displacement according to the dimensions of stiffened plates were analyzed and the parametric study on the modified coefficient of the orthotropic flexural rigidity of stiffened plates was performed. The results show that the ratio of modified coefficients can be expressed as a function for each rib height, space and thickness regardless of plate thickness and the modified flexural rigidity can be easily estimated from the ratio functions of modified coefficients. The application of the coefficient function to various types of stiffened plates with different boundary conditions, aspect ratios, rib arrangement and loading size shows that the proposed function improves the accuracy of the orthotropic plate analysis compared with the results of the reference. Therefore, the orthotropic plate analysis of stiffened plates with rectangular ribs can easily achieve more accurate results using the coefficient function proposed in this study.

Development of a Nondestructive Seismic Technique for Flexural Rigidity of Concrete Track as Slab Displacement Index (콘크리트 슬래브궤도의 휨강성 평가를 위한 비파괴 탄성파 기법의 개발)

  • Cho, Mi-Ra;Joh, Sung-Ho;Lee, Il-Wha
    • Journal of The Korean Society of Civil Engineers
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    • v.28 no.6D
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    • pp.905-913
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    • 2008
  • Recently, concrete tracks are introduced into high-speed railroads as an alternative to ballast tracks. Concrete tracks are superior to ballast tracks in the aspect of durability, maintenance and safety. However, deteriorated stiffness of railroad bed and settlement of soft ground induced by trapped or seepage water lead to problems in safety of train operation. In this research, flexural rigidity of concrete tracks was employed as an index of track displacement and a new seismic technique called FRACTAL (Flexural-Rigidity Assessment of Concrete Tracks by Antisymmetric Lamb Waves) method was proposed to delineate flexural rigidity of concrete tracks in a 2-D image. In this paper, to establish theoretical background, parametric research was performed using numerical simulations of stress-wave tests at concrete tracks. Feasibility of the FRACTAL technique was proved at a real concrete track for Korean high-speed trains. Validity of the FRACTAL technique was also verified by comparing the results of impulse-response tests performed at the same measurement array and the results of DC resistivity survey performed at a shoulder nearby the track.

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Analysis of Behaviors of SPS Underground Composite Frames Considering the Rigidity of RC Wale-Steel Beam Joint (RC 띠장-철골 보 접합부의 고정도에 따른 SPS 지하복합골조 거동 해석)

  • Kim, Seung-Hun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.8 no.3
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    • pp.243-250
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    • 2004
  • In SPS system, steel beams are used as not only temporary struts supporting the wale but main flexural members of building. Previous experimental works show that RC wale-steel beam joints have some flexural rigidity. In this paper, nonlinear analysis is performed using DRAIN-2DX program to investigate the behaviors of the underground composite frames constructed with SPS system when the rigidity of RC wale-steel beam joints change. Analysis variables are the procedure of construction, magnitude of lateral forces, and flexural rigidity of the RC wale-steel beam joint with stud connector. Analysis results show the effects of joint rigidity for the yielding process of frame and the moment and deflection at the mid-span of beam.