• Title/Summary/Keyword: 탄소섬유 스트립

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Experimental Study of Flexural Behavior of Steel Beam Strengthened with the Fiber Reinforced Polymer Plastic(FRP) Strips (섬유보강플라스틱(FRP) 스트립으로 보강한 철골보의 휨거동에 관한 실험적연구)

  • Choi, Sung Mo;Park, Jai Woo
    • Journal of Korean Society of Steel Construction
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    • v.26 no.2
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    • pp.69-79
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    • 2014
  • This paper presents the experimental results of flexural behavior of steel beam strengthened with fiber reinforced polymer plastic (FRP) strips subjected to static bending loading. Four H beams were fabricated strengthened with aramid strips and carbon strips and one control specimen were also fabricated. Among them two specimens were strengthened with partial length. The H-beams had two types of failure mode, depending on the length of the FRP strips:(1) strip debonding in beams with partial length reinforcement and (2) strip rupture in beams with full length reinforcement. From the test, it was observed that maximum increase of 16% was also achieved in bending-load capacity.

Performance of Reinforced Concrete Beams Strengthened with Bi-directional CFRP Strips (이 방향 탄소섬유 스트립을 사용하여 보강된 콘크리트 보의 거동에 대한 연구)

  • Kim, Changhyuk
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.6
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    • pp.30-36
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    • 2018
  • Researches on strengthening and rehabilitation are important since structural capacity is degraded by deterioration or damage of structural members. An effective strengthening scheme such as an externally bonded Carbon Fiber Reinforced Polymers (CFRP) can improve the structural performance of a concrete structure in a cost-effective way. Therefore, many experimental studies on strengthening methods have been widely carried out. In regards to the shear strengthening of a concrete beam, variables of the experimental studies were the amount of CFRP, the angle of the strip, the width of the strip, and the interaction between the materials. However, there are insufficient researches on bi-directional CFRP layout compared to the previous researches. In this study, a total of ten concrete beams were designed and tested to evaluate the shear strengthening effect using CFRP strips. The effectiveness of strengthening was investigated based on the shear contribution of materials, strain distribution of stirrup, and the maximum shear capacity of specimens.

Hysteretic Behavior Evaluation of Reinforced Concrete Columns Retrofitted with Iron-based Shape Memory Alloy Strips (철계 형상기억합금 스트립으로 보강된 콘크리트 기둥의 반복이력거동 평가)

  • Jeong, Saebyeok;Jung, Donghyuk
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.35 no.5
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    • pp.287-297
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    • 2022
  • This paper presents experimental and analytical studies on the lateral cyclic behavior of RC columns actively confined with iron-based shape memory alloy (Fe-SMA) strips. Based on the Anexperimental study, we investigated the effectiveness of active confinement through compression testings of concrete cylinders confined by Fe SMA strips and carbon fiber-reinforced polymer (CFRP) sheets. The test results showed that the specimens confined with Fe SMA strips significantly increased the deformation capacity of the concrete, even under lower confining pressures, compared to those specimensconfined with CFRP sheets. The experimental results were used to develop finite-element models of RC columns confined with Fe SMA or CFRP in their plastic-hinge region. After validating the proposed analytical model through comparison with the results from a previous RC column test, a series of lateral cyclic load analyses were carried out for the RC columns confined with Fe SMA and CFRP. The analytical results revealed that the lateral cyclic behavior of the Fe SMA-confined column was greatly enhanced in terms of deformation and energy dissipation capacities compared with tothat of the as-built and CFRP-confined columns.

Characteristics of Shear Behavior of Reinforced Concrete Beams Strengthened with Near Surface Mounted CFRP Strips (CFRP 스트립 표면매립공법으로 보강된 철근콘크리트 보의 전단거동 특성)

  • Han, Sang Hoon;Hong, Ki Nam;Shin, Byoung Gil;Lim, Jin Mook;Kwak, So Shin
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.5
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    • pp.178-189
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    • 2011
  • Tests and analyses were performed in this study to assess the shear strength of Reinforced Concrete(RC) members strengthened by the Near Surface Mounted(NSM) technique in shear, which is drawing attention as an alternative to the Carbon Fiber Reinforced Polymer(CFRP) bonding strengthening technique. Four-point bending tests were performed on 7 RC specimens without any shear reinforcement. The test variables such as the inclination of CFRP strip (45 degrees and 90 degrees), and the spacing of CFRP strip (250mm, 200mm, 150mm, 100mm) were considered. Through the testing scenarios, the effect of each test variable on the failure mode and the shear strength of the RC members strengthened by the NSM technique in shear were assessed. The test results show that the specimens with CFRP strips at 45 degrees go to failure as a result of the strip fracture, but the specimens with CFRP strips at 90 degrees go to failure as a result of the slip of strips. Strips at 45 degrees was the more effective than strips at 90 degrees, not only in terms of increasing beam shear resistance but also in assuring larger deformation capacity at beam failure. In addition, the RBSN analysis appropriately predicted the crack formation and the load-displacement response of the RC members strengthened by the NSM technique in shear.

A Study on Finite Element Methods for HSS(Hollow Square Section) Steel Columns Strengthened with Carbon Fiber Reinforced Polymer Plastic(CFRP) Sheets (탄소섬유쉬트(CFRP Sheets)로 보강된 각형강관(HSS)기둥의 유한요소해석 연구)

  • Park, Jai Woo;Yoo, Jung Han
    • Journal of Korean Society of Steel Construction
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    • v.28 no.3
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    • pp.185-194
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    • 2016
  • This paper presents the finite element method results for HSS(Hollow Square Section) steel columns strengthened with Carbon Fiber Reinforced Polymer Plastic(CFRP) sheets. 6 specimens were fabricated and the specimen groups were non-compact short columns, slender short columns, and non-compact long columns. Test parameter was the number of CFRP ply. The finite element analysis was performed by using ANSYS Workbench V.14.0 and the results of FEM were compared with those of Test for failure mode, load-displacement curve, maximum load, and initial stiffness. The comparisons between experimental observations and computed results show that the analyses provided good correlation to actual behavior. Finally, the buckling stress were calculated according to the AISC cold-formed structure provision and the retrofitting effect were verified for each section type.

Delamination Detection of FRP Sheet Reinforced Concrete Using Microstrip Patch Antenna (Microstrip Patch Antenna를 이용한 탄소섬유시트 보강콘크리트의 박리 탐사)

  • Rhim, Hong-Chul;Lee, Hyo-Seok;Woo, Sang-Kyun;Song, Young-Chul
    • Journal of the Korean Society for Nondestructive Testing
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    • v.27 no.2
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    • pp.134-141
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    • 2007
  • A series of experimental work has been conducted to evaluate the capability of microstrip patch antenna system in detecting delamination in fiber reinforced Plastic (FRP) sheet reinforced concrete. For that purpose, a prototype microstrip patch antenna was developed with 15 GHz center frequency and 1 GHz bandwidth. For the comparison, a horn antenna with 15 GHz center frequency and 10 GHz bandwidth was used for the measurements of the same specimens. The laboratory sire specimens have the dimensions of 600 mm (length) $\times$ 600 mm (width) $\times$ 50mm (thickness) with a series of delaminations of 300 mm (length) $\times$ 300mm (width) $\times$ 5, 10, 15 mm (thickness). FRP of 1.5 mm thickness and epoxy of 3 mm thickness were placed on the top of artificially created delamination to represent actual FRP reinforced concrete condition. In all cases, the delamination has deen successfully identified. Also, it was shown that imaging results in microstrip patch antenna were improved by signal processing.