• Title, Summary, Keyword: 강관 보강

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A study on the field application of high strength steel pipe reinforcement grouting (고강도 강관 보강 그라우팅의 현장 적용성에 관한 연구)

  • Shin, Hyunkang;Jung, Hyuksang;Ryu, Yongsun;Kim, Donghoon
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.21 no.4
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    • pp.455-478
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    • 2019
  • In this paper, we conducted experimental investigation on the field applicability through the verification of reinforcement effect of the steel pipe reinforcement grouting using high strength steel pipe. SGT275 (formerly known as STK400) steel pipe is generally applied to the traditional steel pipe reinforcement grouting method. However, the analysis of tunnel collapse cases applying the steel pipe reinforcement grouting shows that there are cases where the excessive bending and breakage of steel pipe occur. One of the reasons causing these collapses is the lack of steel pipe stiffness responding to the loosening load of tunnels caused by excavation. The strength of steel pipe has increased due to the recent development of high strength steel pipe (SGT550). However, since research on the reinforcement method considering strength increase is insufficient, there is a need for research on this. Therefore, in this study, we conducted experiments on the tensile and bending strength based on various conditions between high strength steel pipe, and carried out basic research on effective field application depending on the strength difference of steel pipe through the conventional design method. In particular, we verified the reinforcement effect of high strength steel pipe through the measurement results of deformed shape and stress of steel pipe arising from excavation after constructing high strength steel pipe and general steel pipe at actual sites. The research results show that high strength steel pipe has excellent bending strength and the reinforcement effect of reinforced grouting. Further, it is expected that high strength steel pipe will have an arching effect thanks to strength increase.

The effects of stability of the tunnel reinforced by rebar steel pipe (철근보강형강관이 적용된 터널의 안정성효과에 대한 연구)

  • Kim, Sang-Hwan
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.12 no.5
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    • pp.389-397
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    • 2010
  • This paper presents the effects of the tunnel stability using rebar steel pipe which is the steel pipe reinforced by rebar. In order to carry out this research, not only the theoretical and experimental study for bending stiffness of normal steel pipes and rebar steel pipes but also numerical analysis of tunnel stability are performed. It is clearly found from the results that 65% of bending stiffness of the rebar steel pipe is larger than that of the normal steel pipe. The results obtained from the numerical analysis of tunnel stability show that about 10% of tunnel stability is increased in case of the rebar steel pipe. The rebar steel pipe, therefore, may be very useful to develope the tunnel stability economically.

Study on the Ultimate Strength of Gusset Plate-Circular Hollow Section(CHS) Joint Stiffened with Rib-plate by End Restraint (단부 구속을 받는 리브 보강 플레이트 원형강관 X형 접합부의 극한내력 도출에 관한 연구)

  • Kim, Woo-Bum;Park, Hyun-Ho
    • Journal of Korean Society of Steel Construction
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    • v.24 no.4
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    • pp.383-398
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    • 2012
  • A finite element analysis study was performed to investigate the behavior and strength of a Plate-Circular Hollow Section joint stiffened with Rib-plate, Since The strength of plate-Circular Section joint is reduced by joint of stress and local plastic deformation which is caused by wall moment, rib plates are attached to the upper and lower Plate-Circular Hollow Section joint for redistribution of stress. The behaviors of joints stiffened with Rib-plate according to shape of rib and reinforcing method, etc are different from those of joints which is not stiffened. However, the criterion of hollow structural section was limited on some parts. Therefore, this study intends to investigate the behavior and structural capacity of Plate-Circular Hollow Section joints stiffened with Rib-plate and compare the Finite element analysis with the Design Equation. Finally, this study proposes the reasonable ultimate strength formula through the comparisons with other design guide.

Tensile Behavior of Concrete-Filled Square Steel Tubular Column-Beam Flange Connections with Stiffeners (강관 보강형 충전 각형강관 기둥-보 플랜지 접합부의 인장거동에 관한 실험적 연구)

  • Yoo, Yeong Chan;Kang, Hyun Sik;Moon, Tae Sup
    • Journal of Korean Society of Steel Construction
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    • v.13 no.1
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    • pp.1-8
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    • 2001
  • The purpose of this study is to examine the utility of concretefilled steel tubular column to H-beam connections with tubular stiffener. As a preliminary step. a tensile experiment was undertaken to scrutinize characteristics of the structural behavior that take place between beam flanges and column with tubular stiffener. A total of 4 types of experimental settings were developed as tabular stiffeners are made up 9, 18, and 27 mm of thickness and 50 and 80 mm of height respetively Along with the overall load subsequently the degree of displacement and strain were recorded. Based on the yield line theory results of this of this study were evaluated and further critically reviewed the applicability of the strength formula. This study found that collapse mechanism was emerged on the beam flange as reinforcing tabular stiffeners Complementary studies of this sort, including numerical analyses should be undertaken in order to develope specific design critera.

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A Numerical Study on the Behavior of Steel Pipes in Umbrella Arch Method (Umbrella Arch 공법 적용시 강관의 거동에 관한 수치해석적 연구)

  • 차민웅;이승도;문현구
    • Tunnel and Underground Space
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    • v.14 no.1
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    • pp.26-34
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    • 2004
  • The effectiveness of UAM is generally accepted, but there has not been much rigorous study on UAM and its mechanical support mechanism is yet to be established. Also, most of UAM installations depend on empirical judgement rather than on engineering knowledge. In this study, an attempt to confirm the support effects and to understand the support mechanism of UAM has been made by analyzing the mechanical behavior of umbrella pipes installed in various ground conditions. The effects of overburden thickness, pipe size, overlap length and the placement of steel arch are studied using a three-dimensional finite element method. From the numerical parametric study, the support mechanism of UAM has been confirmed by analyzing the structural forces in the umbrella pipes due to the excavation.

An Study on the Stiffened Effect of K-type Tubular Connection (강관 K형 접합부의 보강효과에 관한 연구)

  • Kim, Woo Bum;Lee, Young Jung;Kim, Kap Sun;Chung, Soo Young
    • Journal of Korean Society of Steel Construction
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    • v.13 no.6
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    • pp.609-619
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    • 2001
  • It is almost impossible to evaluate the ultimate strength theoretically, because the behavior of Gusset-Tube connection stiffened with rib-plate is considerably complicate. Therefore in this study a finite element model of gusset-tube connection stiffened with rib-plate was established. The validity of finite element analysis was examined through comparing with previous experimental result and the behavior and strength of the connection was examined. From the parametric study considering lateral force ratio, eccentricity, gusset length based on finite element model, the stiffened effect was estimated and stiffening method was proposed.

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Design of High Strength Underground FRP Septic Tank Stiffened by Circular Steel Pipe (원형강관으로 보강된 지중매립형 FRP 개인하수 처리시설의 설계)

  • Cho, Kwang Je;Kim, Sung Bo
    • Journal of The Korean Society of Civil Engineers
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    • v.32 no.3A
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    • pp.171-181
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    • 2012
  • The design of high strength underground septic tank stiffened by steel pipe is presented and the ultimate behavior is investigated according to the full scale experiments for three types of specimens. The limitation of the current design specification are pointed out and the general design procedure of private sewage treatment facility are newly developed considering thickness of FRP shell, types of steel pipe stiffer and diaphragm wall. The direct tensile and bending test for FRP material of septic tank were performed. The increase effect of ultimate strength due to the circular steel pipe are investigated by the full scale field test and compared with the results by the finite element analysis.

Analysis of Reinforcement Effect of Steel-Concrete Composite Piles by Numerical Analysis (I) - Material Strength - (수치해석을 이용한 강관합성말뚝의 보강효과 분석 (I) - 재료 강도 -)

  • Kim, Sung-Ryul;Lee, Juhyung;Park, Jae-Hyun;Chung, Moonkyung
    • Journal of The Korean Society of Civil Engineers
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    • v.29 no.6C
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    • pp.259-266
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    • 2009
  • The steel pipe of steel-concrete composite piles increases the pile strength and induces the ductile failure by constraining the deformation of the inner concrete. In this research, the numerical models and the related input parameters were analyzed to simulate the axial load-movement relations, which were obtained from the compression loading tests for the cylindrical specimens of the steel pipe, the concrete, and the steel-concrete composite. As the results, the behavior of the steel pipe was simulated by the von-Mises model and that of the concrete by the strain-softening model, which decreases cohesion and dilation angles as the function of plastic strains. In addition, the reinforcing bars in the concrete were simulated by applying the yielding moment and decreasing the sectional area of the bars. The applied numerical models properly simulated the yielding behavior and the reinforcement effect of the steel-concrete composite piles. The parametric study for the real-size piles showed that the material strength of the steel-concrete composite pile increased about 10% for the axial loading and about 20~45% for the horizontal loading due to the reinforcement effect by the surrounding steel pipe pile.

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Bolted Bonding Method of Steel Pipe Pile and Cap (볼트식 강관말뚝 머리보강 방법)

  • 박영호;김성환;장용채
    • Geotechnical Engineering
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    • v.14 no.6
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    • pp.57-71
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    • 1998
  • Present bonding methods which connect steel pipe and spread footing in pile foundation have been generally used. These methods however showed lots of difficulties in the quality control. A new bonding method, which is called 'Bolted Bonding Method(BBM)' , is developed. This method uses factory-made parts so that it may increase the degree of quality, and workability, and is being adopted in the Held concerned. The method is verified by the structural analysis and laboratory test and then a new design formula is proposed. In addition, a comparison test of the present methods and BBM are conducted to observe the applicability and economy of the latter. As results, it is observed that BBM shows 5 to 10 times faster in Held work and 9% to 50% cheaper in construction cost than the existing methods.

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Comparison of earth pressure around pipe-roof between UPRS and front-jacking method (UPRS 공법과 프론트잭킹 공법의 파이프루프 주변 현장토압 계측결과 비교)

  • Sim, Youngjong;Jin, Kyu-Nam;Song, Ki-Il
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.17 no.5
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    • pp.513-522
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    • 2015
  • This study is to confirm the effect of pre-installed pipe-roof by measuring earth pressure acting on the underpass. In recently developed trenchless methods pre-inserted steel pipes before ground excavation to form pipe-roof are connected each other with re-bars and filled with mortar. In this study, focusing on the Upgraded Pipe Roof Structure method (UPRS) and Front-Jacking, earth pressure around pipe-roof is measured after insertion of steel pipe to ensure the effect of earth pressure reduction. In case of the UPRS earth pressure is considerably reduced because of the reinforced effect of pipe-roof. In case of the Front-Jacking in which the whole underpass structure is pushed into the ground, earth pressure is not reduced as expected, because the pre-installed pipes are not needed to be reinforced.