• Title/Summary/Keyword: end anchorages

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An Investigation of fan type anchorages applied to end of CFRP strips

  • Kara, M. Emin;Yasa, Mustafa
    • Steel and Composite Structures
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    • v.15 no.6
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    • pp.605-621
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    • 2013
  • CFRP strips are widely used nowadays for repair/strengthening or capacity increase purposes. Sharp bending at the ends of the CFRP strips is frequently encountered at these applications. In this study, Reinforced Concrete (RC) beam specimens that were produced with 10 MPa compression strength concrete were strengthened by using bonded CFRP strips with end anchorages to tension region. The parameters that were investigated in this study are the width of the strip, the number of applied fan anchorages and whether additional layer of CFRP patch is used or not at the strip ends. Specimens were strengthened with 100 mm wide CFRP strips with one or two anchorages at the ends. In addition CFRP patch with two and three anchorages at the ends were tested for investigating the effect of the patches. Specimens that were strengthened with three anchorages at the ends with patches were repeated with 60 and 80 mm wide CFRP strips. The most successful result was obtained from the specimen that was strengthened with 80 mm wide CFRP strips with 3 end anchorages and patches among the others at the experimental program. The numbers of anchorages that were applied to ends of CFRP strips were more effective than the width of the CFRP strips onto strength and stiffness of the specimens. Due to limited space at the ends of the strips at most three anchorages could be applied.

Analysis of RC beam with unbonded or exposed tensile steel reinforcements and defective stirrup anchorages for shear strength

  • Wang, Xiao-Hui;Liu, Xi-La
    • Computers and Concrete
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    • v.10 no.1
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    • pp.59-78
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    • 2012
  • Although the effect of corrosion of reinforcing bar on the shear behavior of the reinforced concrete (RC) beam had been simulated by tests of the beam with unbonded, half-exposed or whole-exposed tensile steel reinforcements as well as defective stirrup anchorages, theoretical methods to accurately predict remaining capacity of this kind of RC beams, especially shear capacity, are still lacking. Considering the possible position of the critical inclined crack, the actual pattern of strains in the concrete body within the partial length and the proposed compatibility condition of deformations of the RC beam, shear strength of the RC beam with unbonded or exposed tensile steel reinforcements and/or defective stirrup anchorages is predicted. Comparison between the model's predictions with the experimental results published in the literature shows the practicability of the proposed model. Influence of the length of unbonded or exposed tensile steel reinforcements and the percentage of stirrups lacked end anchorages on the shear strength of the RC beam is discussed. It is concluded that, the shear strength of the RC beam with unbonded or exposed tensile steel reinforcements and/or defective stirrup anchorages is greatly influenced by the length of unbonded or exposed tensile steel reinforcements and the percentage of stirrups lacked end anchorages, this influence can be adverse, insignificant or even favourable, dependent on the given parameters of the corresponding normal bonded RC beam.

RC beams retrofitted using external bars with additional anchorages-a finite element study

  • Vasudevan, G.;Kothandaraman, S.
    • Computers and Concrete
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    • v.16 no.3
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    • pp.415-428
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    • 2015
  • Study on flexural retrofitting of RC beams using external bars with additional intermediate anchorages at soffit is reported in this paper. Effects of varying number of anchorages in the external bars at soffit were studied by finite element analysis using ANSYS 12.0 software. The results were also compared with available experimental results for beam with only two end anchorages. Two sets of reference and retrofitted beam specimens with two, three, four and five anchorages were analysed and the results are reported. FE modeling and non-linear analysis was carried out by discrete reinforcement modeling using Solid65, Solid45 and Link8 elements. Combin39 spring elements were used for modeling the frictional contact between the soffit and the external bars. The beam specimens were subjected to four-point bending and incremental loading was applied till failure. The entire process of modeling, application of incremental loading and generation of output in text and graphical format were carried out using ANSYS Parametric Design Language.

An Experimental Study on Flexural Performance Evaluation of RC Beams Strengthened with Anchored CFRP Plates (CFRP판을 단부정착한 RC보의 휨성능 개선에 관한 실험적 연구)

  • Kim, Hyung-Jin;Hong, Ki-Nam;Han, Sang-Hoon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.10 no.4
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    • pp.167-174
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    • 2006
  • The purpose of this paper is to analyse and compare experimentally flexural behavior of RC beams strengthened with CFRP plates by different methods, which are divided into three classes: externally-bonded without end anchorage, externally-bonded with end anchorages, and anchored after prestressing of CFRP plates. Test results show that the RC beams strengthened with end anchorages have the improvement of ductility and flexural performance evaluation including ultimate strength and deflection, compared with only external bonding. Especially, RC beams with prestressed and anchored CFRP plates increase ultimate strength and ductility significantly.

The Design of long cantilever beam using post-tensioned tendons in Kumjung Stadium (포스트텐션을 이용한 장스팬 켄틸레버보의 설계)

  • 최동섭;김동환;김종수
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.10a
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    • pp.619-624
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    • 2002
  • A prestressed/precast concrete system was used to build the new Asian Olympic Stadium Project in Pusan, Korea. The stadium(mainly intended for cycle racing) is designed for the 2002 Asian Olympic Games and has a seating capacity of 20,000 spectators plus a few private suites. More than 1300 prestressed/precast components were used and they include single columns, primary beams, cantilever beams, double riser stands, and double tees. Especially, a total of 24 cantilever beams is used on the fourth story for the stands and double tees. These 8m long beams are post-tensioned to prevent cracking, to increase their durability and to serve serviceability by vibration. A cantilever section with cast-in-place topping is 800mm wide and 1500mm deep. Cantilever beams are connected to the column with the corbel by cast-in place concrete. Bonded post-tensioning tendons were assembled at the job site. Dead-end anchorages were installed in the end of cantilever beams and live-end anchorage is the opposite of them. This article presents the geometric layouts, design features and so on.

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Mechanical Behavior of Anchorage Zones in Prestressed Concrete Members with Single and Closely-Spaced Anchorages (단일텐던 및 복수텐던이 설치된 프리스트레스트 콘크리트 부재의 정착부 거동 연구)

  • Oh, Byung Hwan;Lim, Dong Hwan;Yoo, Seung Woon
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.14 no.6
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    • pp.1329-1339
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    • 1994
  • The purpose of present study is to explore the mechanical behavior of anchorage zones in prestressed concrete members with single and closely-spaced multiple tendon anchorages. The cracking loads and local stress distributions at these anchorage zones are studied. To this end, a series of experiments have been conducted. From this study, it is found that the failure of anchorage zones of the closely-spaced multiple tendon members is initiated by cracking along the tendon path and that the tensile stresses arising in the vicinity of anchorage zone of the first tendon are reduced due to additional compression of the second tendon. This results in the increase of cracking capacity of the member. The effects of multiple tendons are presented in the form of strain distribution and cracking load comparisons.

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An Experimental Study to Prevent the Delamination of the CFS with End-Anchorages (탄소섬유 보강부재의 단부탈락 방지 방안에 관한 실험적 연구)

  • 김두벽;이우철;정진환
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.11a
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    • pp.991-996
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    • 2001
  • The strengthening of concrete structures in situ with externally bonded fiber sheets is increasingly being used for repair and rehabilitation of existing structures. Because fiber sheets is attractive for this application due to its good tensile strength, resistance to corrosion, and low weight. But, debonding failure may occur at the beam ends that fiber sheet bonded to the soffit of a beam. The method which can prevent debonding failure is suggested and proved its efficiency by using CPS experimental test. And this paper summarized the results of experimental studies concerning the end-anchorage system. Results show that the suggested method is faithful in strengthening with CFS.

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Effects of concrete strength on structural behavior of holed-incrementally prestressed concrete (H-IPC) girder

  • Han, Man Yop;Kim, Sung Bo;Kang, Tae Heon
    • Advances in concrete construction
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    • v.3 no.2
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    • pp.113-126
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    • 2015
  • Holed-Incrementally Prestressed Concrete (H-IPC) girders are designed using the following new design concepts. At first, web openings reduce the self-weight of the girder, and also diffuse prestressing tendon anchorages. The reduced end anchoring forces decrease the web thickness of the end sections. Additionally, precast technology help to improve the quality of concrete and to reduce the construction period at the site. For experimentally verification, two 50 m full-scale H-IPC girders are manufactured with different concrete strength of 55 MPa and 80 MPa. The safety, stiffness, ductility, serviceability and crack development of H-IPC girder are measured and compared with each other for different strengths. Both girders show enough strength to carry live load and good stiffness to satisfy the design criteria. The experimental result shows the advantages of using high strength concrete and adopting precast girder. The test data can be used as a criterion for safety control and maintenance of the H-IPC girder.