• Title, Summary, Keyword: prestressed concrete beam

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Experiment research on seismic performance of prestressed steel reinforced high performance concrete beams

  • Xue, Weichen;Yang, Feng;Li, Liang
    • Steel and Composite Structures
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    • v.9 no.2
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    • pp.159-172
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    • 2009
  • Two prestressed steel reinforced high performance concrete (SRC) beams, a nonprestressed SRC beam and a counterpart prestressed concrete beam were tested under low reversed cyclic loading to evaluate seismic performance of prestressed SRC beams. The failure modes, deformation restoring capacity, ductility and energy dissipation capacity of the prestressed SRC beams were discussed. Results showed that due to the effect of plastic deformations of steel beams encased in concrete, the three SRC beams exhibited residual deformation ratios ranging between 0.64 and 0.79, which were apparently higher than that of the prestressed concrete beam (0.33). The ductility coefficients of the prestressed SRC beams and the prestressed concrete beam ranged between 4.65 and 4.87, obviously lower than that of nonprestressed SRC beam (9.09), which indicated the steel beams influenced the ductility little while prestressing resulted in an apparent reduction in ductility. The amount of energy dissipated by the prestressed SRC beams was less than that dissipated by the nonprestressed SRC beam but much more than that dissipated by the prestressed concrete beam.

Flexural Behavior of Dual Prestress Concrete Beams Using High Performance Steel Fiber Reinforced Concrete Subjected to Cyclic Loading (고성능 강섬유보강 콘크리트가 적용된 반복하중을 받는 이중 프리스트레스 콘크리트 보의 휨 거동)

  • Park, Tae-Hyo;Yun, Sung-Hwan
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.61-64
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    • 2004
  • This study presents results from an experimental work for two normal prestressed concrete beams and three dual prestressed concrete beams. The dual prestressed concrete beams made with normal concrete in compression zone and high performance steel fiber reinforced concrete in partial depth of tension zone. Through cyclic loading test under low frequency, structural behavior and resistance to dynamic loading for dual prestressed concrete beams are investigated. Considerable increase of crack and yield load capacity of Dual prestressed concrete beam is shown compared with normal prestressed concrete beam. In addition, re-loading and un-loading rigidity of dual prestressed concrete beam under cyclic loading are increased comparing with normal prestressed concrete beam.

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A Study on the Load Carrying Capacity Assessment Method of the Prestressed Concrete Beam Bridges (연속 프리스트레스트 콘크리트 빔교의 내하력 평가 기법에 관한 연구)

  • 채원규
    • Journal of the Korean Society of Safety
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    • v.13 no.3
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    • pp.126-134
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    • 1998
  • In this paper, the field test by truck load and the structural analysis were performed on a prestressed concrete beam bridge to investigate the load carrying capacity of the prestressed concrete beam bridges. From the results of the field test and the structural analysis, CAF (composite action factor), TIF(transformed impact factor), and $P_n$(load carrying capacity) of the prestressed concrete beam bridges were studied, and the load carrying capacity assessment of the prestressed concrete beam bridges were carried out using these factors.

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A Study for Structural Capacity Evaluation of Embedded Steel Plate Connected with Prestressed Concrete Beam to Build Large Space Educational Facilities (대공간 교육시설 축조를 위한 프리스트레스트 보에 사용되는 접합 강재의 성능평가에 대한 연구)

  • Lee, Kyoung-Hun
    • The Journal of Sustainable Design and Educational Environment Research
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    • v.10 no.2
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    • pp.1-7
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    • 2011
  • An experimental study to evaluate structural capacity of an embedded plate connected with prestressed concrete beam was performed. Embedded steel plates and prestressed concrete beam were connected with stud-bolts at the ends of concrete beam specimens. About 1,000 kN concentrated load was applied at 450mm away from the end of beam specimen. A 3,000 kN capacity static Oil-jack was used to direct concentrated load. The maximum strain of stud-bolt recorded $90{\times}10^{-6}$(mm/mm) and wide width cracks were not founded. Any falling failures of concrete and large deformations were not founded either between steel plate and prestressed concrete specimen. As a result, construction performance can be improved using this embedded steel plate connection system apply to large space educational facilities.

An Experiment of the Externally Prestressed 2-span Concrete Beam (외부 프리스트레스트 콘크리트 2경간 연속보의 휨 실험)

  • Oh, Seung-Hyun;Lee, Sang-Woo;Kang, Won-Ho
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.313-316
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    • 2006
  • Externally prestressed structures have many advantages such as easy prestressing control and visible maintenance. Flexural strength of externally prestressed concrete members can be calculated by analysis of internal indeterminacy, which is different from internally prestressed concrete members. However, it needs nonlinear analysis considering member stiffness at strength limit state. Thus most of design codes proposed approximate methods which are empirical, based on test results. To reduce difference between accurate analysis and approximate design methods, many experiments and studies are continued. Since most of the experiments are single span beams. In order to adapt of continuous beam it needs further investigation for the continuous beam. In this study, we carried out externally prestressed 2-span concrete beam test to find out the flexural behavior and strength of externally prestressed concrete members.

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Design of P.C. Beam Bridge using High Strength Concrete (고강도 콘크리트를 사용한 P.C. Beam교의 설계)

  • 강상규;윤석구;이형준;정원기;이규정
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.446-449
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    • 1997
  • The use of high strength concrete in the fabrication and construction of prestressed concrete beam bridges can result in the increase of girder spacings for standard shapes, as well as the increase of span lengths. The increase of girder spacings corresponds to the reduction of the required number of girders. This study shows that the use of high strength concrete make prestressed concrete beam bridges the economical alternative to any other bridge types. Also, this study has the purpose of giving aids to design of prestressed concrete beam. To achieve this purpose this study provides the plots resulting from research on relationships between the concrete strength of prestressed concrete beam, girder spacing and the number of strands in various span lengths.

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Design curves for prestressed concrete rectangular beam sections based on BS 8110

  • Subramaniam, Kolluru V.L.;Sinha, S.N.
    • Structural Engineering and Mechanics
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    • v.3 no.6
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    • pp.555-567
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    • 1995
  • Design curves have been prepared for prestressed rectangular beam section based on BS 8110, for determining area of steel for any given cross section, for stresses in concrete and steel and for the design moment. The design moment and the area of steel have been expressed in dimensionless form in terms of cross sectional dimensions and the characteristic strength of concrete. The choice and combination of design parameters result in considerably less number of curves as aid for design of rectangular prestressed beam sections, than those reported in CP 110 (Part 3).

The Shear Strength of Prestressed Hollow-Core Slab on flexible steel beams (철골보에 연결된 프리스트레스 할로우 코아 슬래브 전단강도)

  • Hong, Sung-Gul;Park, Kyoung-Yeun;Jo, Bong-Ho
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.397-400
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    • 2004
  • This research aims to estimate the shear strength of the composition of prestressed hollow-core slab and steel beam. The shear strength of prestressed hollow-core slab combined with the steel beam decreases, as the beam deflection increases to a considerable extent. Existing studies on the shear strength of prestressed hollow-core slab are mostly limited to 265mrn- and larger thickness slab on concrete beam. This study investigates the slab of 100mm-thickness combined with steel beam instead of concrete beam. Five shear connector methods are proposed and the shear strength is estimated with or without the beam deflection for each composition method, respectively. Finally the reduction coefficient $(\beta)$ for the transverse shear stress$(\tau_{zx})$, which is critical for the failure of prestressed hollow-core slab, is proposed.

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Balanced Ratio of Concrete Beams Internally Prestressed with Unbonded CFRP Tendons

  • Lee, C.;Shin, S.;Lee, H.
    • International Journal of Concrete Structures and Materials
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    • v.11 no.1
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    • pp.1-16
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    • 2017
  • The compression or tension-controlled failure mode of concrete beams prestressed with unbonded FRP tendons is governed by the relative amount of prestressing tendon to the balanced one. Explicit assessment to determine the balanced reinforcement ratio of a beam with unbonded tendons (${\rho}^U_{pfb}$) is difficult because it requires a priori knowledge of the deformed beam geometry in order to evaluate the unbonded tendon strain. In this study, a theoretical evaluation of ${\rho}^U_{pfb}$ is presented based on a concept of three equivalent rectangular curvature blocks for simply supported concrete beams internally prestressed with unbonded carbon-fiber-reinforced polymer (CFRP) tendons. The equivalent curvature blocks were iteratively refined to closely simulate beam rotations at the supports, mid-span beam deflection, and member-dependent strain of the unbonded tendon at the ultimate state. The model was verified by comparing its predictions with the test results. Parametric studies were performed to examine the effects of various parameters on ${\rho}^U_{pfb}$.

Factors governing redistribution of moment in continuous prestressed concrete beams

  • Kodur, V.K.R.;Campbell, T.I.
    • Structural Engineering and Mechanics
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    • v.8 no.2
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    • pp.119-136
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    • 1999
  • The failure load of a continuous prestressed concrete beam depends partially on the amount of redistribution of moment that occurs prior to failure. Results from a parametric study, carried out using a nonlinear finite element computer program, are presented to demonstrate the influences of various factors on redistribution of moment in two-span, continuous bonded prestressed concrete beams. Trends in the data from the numerical studies are compared with those from a theoretical expression for percentage of redistribution, and it is shown that the redistribution of moment occurring in a continuous prestressed concrete beam is a function of number of parameters.