• Title/Summary/Keyword: Transfer Girder

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Evaluation of Diaphragm Effect for Hybrid Structural Systems Using Finite Element Method (유한요소법을 이용한 주상복합건물의 강막작용에 의한 영향 평가)

  • 김희철;최성우;홍원기
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.16 no.1
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    • pp.19-32
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    • 2003
  • The structural system of a hybrid building is composed of upper shear wall which resist lateral force by bending deformation and lower frame which resist lateral force by shear deformation. A deep transfer girder is used to transfer gravity load safely from super structures to structural frame beneath. Because of the vertical discontinuity, a building with transfer girder must be analyzed by dynamic analysis. However, this structural system has many problems in performing dynamic analysis that cannot be solved by general analysis procedure. The slabs In transfer floor are considered as either a Plate element or a rigid diaphragm in finite element analysis without appropriate evaluation of their characteristics. Therefore, a reasonable analysis method is proposed in this study by evaluating the diaphragm effect of a hybrid structure system.

A Study on Torsional Stress ratio and Torsional ratio of Curved Girder Bridge by Transfer Matrix Method (전달행렬법에 의한 곡선거더교의 비틀림 응력비와 비틀림 정수비에 관한 연구)

  • Lee, Wong-Hong;Lee, Yoon-Young
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.10 no.1
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    • pp.173-182
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    • 2006
  • In the design of curved girder bridges, the engineer is faced with a complex stress situatiorl. since these types of mutiple-I girder. mono-box girder and twin-box girder are subjected to both bending and torsional force. In general, the torsional forces consist of two part, St. venant's and warping. Thus the procedure for determining the induced stresses in a curved girder is difficult. The transfer matrix method is extensively used for the structural analysis because its merit in the theoretical background and applicability. The technique is attractive for implementation on a numerical solution by means of a computer program coded in Fortran language with a few elements. To demonstrate this fact. it gives good results which compare well with finite difference method. Therefore, in this paper, to clarify the range where the torsional warping stress can be approximated by pure torsional analyzed a critical value of relationships between the torsional stress ratio and torsional ratio.

A Study on the Estimation of Prestress Losses in Prestressed Concrete Box Girder Bridges (프리스트레스트 콘크리트 박스 거더 교량의 프리스트레스 손실 추정에 관한 연구)

  • Oh, Byung-Hwan;Yang, In-Hwan;Kim, Ji-Sang
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.5 no.2
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    • pp.111-120
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    • 2001
  • This paper aims at estimating instantaneous prestress losses by measuring the actual prestress forces in prestressed concrete (PSC) box girder bridges. Measurement were taken to study initial prestress losses such as friction losses and slip losses. A new strain gauge system was developed to measure strains in internal tendons. The system was installed on a total of 20 tendons in a PSC box girder bridges. The variation of prestress forces were monitored during prestressing tendon and after prestress transfer. The prestress losses are also calculated including friction losses and slip losses. The measured data were compared with the theoretical values. The result shows that the measured prestress forces agree well with the theoretical values. It is shown that prestress force of each strand in the same tendon is a bit different. This study also shows that prestress losses of continuity tendons during prestress transfer are significantly different each other, which results from the variety of buttress location and tendon profile. The present study provides realistic information on the estimation of actual prestress forces and losses in PSC box girder bridges.

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A Study on Theoretical Analysis for Reinforced Concrete Transfer Girder of Hybrid Structures (복합구조의 철근콘크리트 전이보에 대한 이론적 해석 연구)

  • 권기혁;이춘호;김민수;이한선;고동우
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.10a
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    • pp.623-628
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    • 2000
  • In this paper, the behavior for transfer girder of the upper-wall and lower-frame structures was studied by the nonlinear finite element analysis. It was analyzed and compared with the experimental results. Analysis results showed that failure modes were progressed by a initial diagonal crack in the shear span between the edges of the load and intermediate support plate. The nonlinear finite element analysis could predict deformation, principal stress, ultimate load and concrete crack. Also analysis results showed good agreement the test results.

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Development and application of a hybrid prestressed segmental concrete girder utilizing low carbon materials

  • Yang, Jun-Mo;Kim, Jin-Kook
    • Structural Engineering and Mechanics
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    • v.69 no.4
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    • pp.371-381
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    • 2019
  • A hybrid prestressed segmental concrete (HPSC) girder utilizing low carbon materials was developed in this paper. This paper introduces the hybrid prestressing concept of pre-tensioning the center segment and assembling all segments by post-tensioning, as well as the development process of the low carbon HPSC girder. First, an optimized mix proportion of 60 MPa high strength concrete containing high volume blast furnace slag was developed, then its mechanical properties and durability characteristics were evaluated. Second, the mechanical properties of 2,400 MPa high strength prestressing strands and the transfer length characteristics in pre-tensioned prestressed concrete beams were evaluated. Third, using those low carbon materials and the hybrid prestressing concept, the HPSC girders were manufactured, and their structural performance was evaluated. A 30-m long HPSC girder for highway bridges and a 35-m long HPSC girder for railway bridges were designed, manufactured, and structurally confirmed as having sufficient strength and safety. Finally, five 35-m long HPSC girders were successfully applied to an actual railway bridge for the first time.

A Study on the Temperature Crack Control for Analysis of Hydration Heat of Mass Concrete Transfer Girder with Design Strength $40N/mm^2$ (설계강도 $40N/mm^2$ 매스콘크리트인 전이층보의 수화열 해석을 통한 온도 균열 제어에 관한 연구)

  • Lee, Jong-Suk;Kim, Ju-Sang;Kang, Youn-Woo;Kim, Jae-Hwan;Lee, Sang-Soo;Song, Ha-Young
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2007.04a
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    • pp.33-36
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    • 2007
  • In order to select the optimum mix for the required fluidity and strength of mass concrete which is applied to transfer girder and to choose the optimum curing method depending on circumstances through hydration heat analysis of mass concrete, this study examined slump flow, air content and elapsed variation (0, 30, 60, 90) in unhardened concrete properties and reviewed compressive strength characteristics in hardening properties. And hydration heat analysis results through simulation are as follows; 1) Fluidity changes of unhardened concrete showed no significant difference, and those of elapsed variation also showed no difference but a bit of tendency to increase in comparison with the initial properties. 2) The higher the water-binder ratio was, the lower the compressive strength properties were, and the higher the fly ash replacement rate was, the lower the compressive strength development was. 3) In case of $Fc=40N/mm^2$, the optimum mix was fly ash replacement rate of 15% from water-binder ratio of 33.0%. 4) Hydration heat analysis results showed that in case of bundle cast, concrete temperature profile characteristics around transfer girder was unfavorable, and in case of separate cast, constant curing for at least seven days guaranteed thermal cracking index of 1.2.

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Static Aanlysis of Curved box Girder Bridge with Variable Cross Section by Transfer Matrix Method (전달행렬법에 의한 변단면 곡선 상자형 거더교의 정적해석)

  • Kim, Yong-Hee;Lee, Yoon-Young
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.7 no.4
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    • pp.109-120
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    • 2003
  • The state-of-art of curved box girder bridge with cross section design has advanced in various area. In these days, several analytical techniques for behaviors of curved box girder bridges cross section are available to engineers. The transfer matrix method is extensively used for the structural analysis because its merit in the theoretical background and applicability. The technique is attractive for implementation on a numerical solution by means of a computer program coded in Fortran language with a few elements. To demonstrate this fact, it gives good results which compare well with finite element method. Therefore, this paper proposed the static analysis method of curved box bridge with cross section by transfer matrix method based on pure-torsional theory and the optimal span ratio/variable cross section ratio of 3 span continuous curved box girder bridge.

A Study on the Moment and Shear Resisting Performance of Steel Girder - R/C Column Connection (철골 보 - 철근콘크리트 기둥 접합부의 휨 및 전단 저항성능에 관한 연구)

  • Choi, Kwang Ho
    • Journal of Korean Society of Steel Construction
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    • v.12 no.4 s.47
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    • pp.429-436
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    • 2000
  • The composite system, which is consisted of the steel girder and reinforced concrete column has some advantages in the structural efficiency and the construction productivity by complementing the shortcomings between the two materials. This research is aimed at the development of the composite beam-column connection system by which the steel beam can be connected to the R/C column with smooth stress transfer. And, to ensure safety of this system, the tests of moment and shear resisting performance have been carried out for actual size specimen. From the test, the connection system has been preyed to take good resistance and stress transfer between steel girder and reinforced concrete column.

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Investigation on the Applicability for Method of Setting Time Difference by Super Retarding Agent for Reducing Hydration Heat of Transfer Girder Mass Concrete (전이보 매스콘크리트의 수화열저감을 위한 초지연제 응결시간차 공법의 적용가능성에 대한 검토)

  • Yoon Seob;Hwang Yin Seong;Baik Byung Hoon;Han Cheon Goo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.05a
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    • pp.128-131
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    • 2004
  • This paper is to investigate the mock up test results of mass concrete for transfer girder using setting time difference with super retarding agent(SRA) to reduce hydration heat. According to test results, the temperature history of plain concrete without placing lift had a steep rising curvature, and plain concrete had a big temperature difference between surface and middle section of mass concrete, which may result in occurrence of temperature crack. However, considering placing method B, because setting time of middle section concrete was retarded with an increase in SRA contents, higher hydration heat temperature was observed at surface section concrete compared with that at middle section concrete at early age, which can lower the possibility of hydration heat crack. In case of placing method C, although peak temperature of hydration heat was much lower, at early age, high crack occurrence possibility of the hydration heat attributable to the big temperature difference between middle section and bottom section of concrete was expected at bottom section concrete. Therefore, the structure above the ground like transfer girder is not applicable to consider the placing method C.

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Behavior Analysis According to the Shear Wall Layout of Column-Supported Wall System Subject to Vertical and Lateral Loads (연직 및 횡하중이 작용하는 상부벽식-하부골조구조물의 벽체 배치유형에 따른 거동 해석)

  • Lee, Dae-Hyeon;Kim, Ho-Soo
    • Journal of Korean Association for Spatial Structures
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    • v.4 no.2 s.12
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    • pp.53-61
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    • 2004
  • Recently, most of residential-commercial buildings and apartment houses which are being constructed in the downtown area mainly adopt hybrid structural systems to compose various spaces. Especially, column-supported wall system which is one of the hybrid systems includes shear wall and rigid frame structure and these structures are connected by the transfer floor. But this system is very disadvantageous from the viewpoint of structural safety and is difficult to find out the stress distribution at the transfer floor. Therefore, this study analyzes the behavior and stress distribution according to the shear wall layout of transfer girder system subject to vertical and static lateral loads. Also, this study recognizes load paths and stress concentration based on the analysis results nearby the transfer floor and presents guidelines for the effective design of wall and transfer girder.

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