• Title, Summary, Keyword: steel pipe reinforcement

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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 Analytical Model for the Reinforcement Bar Connection in Grout-Filled Steel Pipe Sleeve (모르터 충전 강관 슬리브를 이용한 철근 이음의 해석 모델)

  • 황재호;이용재;이원호;이리형
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.519-526
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    • 1997
  • The purpose of this study is to develop the analytical model for the reinforcement bar connection in group-filled steel pipe sleeve, which consists of beam elements for the reinforcement bar and shell elements for the sleeve and the mortar and spring elements for the bond stress-slip relationship. In the reinforcement bar connection using grout-filled steel pipe sleeve, the major variables are the bond stiffness between reinforcement bar and mortar($K_1$) and between sleeve and mortar($K_2$). It is nearly difficult to predict the exact bond stiffness with the experimental results. Therefore, The linearly elastic analyses using ABAQUS, FEM package show the validity of the mathematical equations for the bond stiffness and the choice of material elements in this paper. To predict the behaviour between yield and ultimate tensile strength, the nonlinear analyses must be performed henceforth.

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Field Evaluation of the Swelled Steel Tube Rockbolts (튜브형 강관 록볼트의 현장 적용성 평가)

  • Son, Sung-Gon;You, Jin-O;You, Joung-Hoon;Chung, Jae-Min
    • Proceedings of the KSR Conference
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    • pp.1149-1156
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    • 2011
  • A rockbolt is one of the most important reinforcement of on-site soil, as with the shotcrete and steel rib. The rockbolt by setting within the tunnel can prevent the deformation of the ground profile; furthermore it improves the structural behavior of soil and rock. In general, the rockbolt is mainly used with reinforced steel. However, steel pipe or the materials with the same strength can be used depending on the soil conditions, ground water outflow condition, and the surrounding of applying location. In Korea, most tunnel construction sites have used cement mortar or resin for steel reinforcement on the rock. Due to the ground water outflow in the construction site, the usability of steel reinforcement is poor and it requires curing time especially after installation. To improve exist above problems, this study introduces the development of a swelled steel pipe rockbolt, as well as presents the field testing and performance results.

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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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A Case Study on the Slope Reinforcement by Improved Steel Pipe Nailing (개량 강관네일링 공법을 이용한 사면 보강사례 연구)

  • Choi, Dong-Nam;Lim, Heui-Dae;Song, Young-Su;Lee, Kyu-Hwan
    • Journal of the Korean Society of Safety
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    • v.22 no.1
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    • pp.54-60
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    • 2007
  • This paper describes typical design and construction practice for in-situ ground reinforcement technique using improved steel pipe pressure grouting. A case history is presented to illustrate the benefit gained by application of the technique. This technique was applied to cut slopes developed in the construction of auxiliary spillway of 00 dam. Applicable conditions, method of survey, slope stability analysis and construction are given in this parer. As for the construction method, a procedure is given and the main points are the control of construction work. As a result of the pull-out test, it is shown that seel pipe nailing is particularly useful for stabilizing rock slope.

Analysis of Reinforcement Effect of Steel-Concrete Composite Piles by 3-Dimensional Numerical Analysis (3차원 수치해석을 이용한 강관합성말뚝의 보강효과 분석)

  • Kim, Sung-Ryul;Lee, Si-Hoon;Chung, Moon-Kyung;Lee, Ju-Hyung
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.404-411
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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 load-movement relations and the reinforcement effect by the outer steel pipe in the steel-concrete composite pile were analyzed by performing three-dimensional numerical analyses, which can simulate the yielding behavior of the pile material and the elasto-plastic behavior of soils. The parameters analyzed in the study include three pile materials of steel, concrete and composite, pile diameter and loading direction. As the results, the axial capacity of the composite pile was 1.9 times larger than that of the steel pipe pile and similar with that of the concrete pile. At the allowable movement criteria, the horizontal capacity of the composite pile was 1.46 times larger than that of the steel pile and 1.25 times larger than that of the concrete pile. In addition, the horizontal movement at the pile head of the composite pile was about 78% of that of the steel pile and about 53% of that of the concrete pile, which showed that the movement reduction effect of the composite pile was significant and enables the economical design of drilled shafts.

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Analysis of Reinforcement Effect of Steel-Concrete Composite Group Piles by Numerical Analysis (수치해석을 이용한 강관합성 군말뚝의 보강효과 분석)

  • Kim, Sung-Ryul;Lee, Si-Hoon;Chung, Moon-Kyung;Lee, Ju-Hyung;Kwak, Ki-Suk
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.1132-1139
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    • 2010
  • 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 load-movement relations and the reinforcement effect by the outer steel pipe in the steel-concrete composite pile were analyzed by performing three-dimensional numerical analyses, which can simulate the yielding behavior of pile material and the elasto-plastic behavior of soils. The parameters analyzed in the study include three pile materials of steel, concrete and composite, pile diameter, pile distance and loading direction. As the results, the axial capacity of the composite pile was about 73% larger than that of the steel pipe pile and about 14% larger than that of the concrete pile. In addition, the horizontal movement at the pile head of the composite pile was about 51% of that of the steel pile and about 19% of that of the concrete pile.

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Study on the Application of Press in Steel Pipe Pile for Restoring Building of different settlement (부동침하 건축물 복원을 위한 압입강관파일 공법 현장 적용에 관한 연구)

  • Sin, Jae-Kwon;Lee, Hee-Seok;Sho, Kwang-Ho
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.85-86
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    • 2015
  • Recently, As the high rise buildings have been demanded due to the rising current of land price, the permanent drainage method have been applied during and after the construction as a way to reduce the buoyancy acting on the bottoms of the foundations in the basement. This method has brought about the consolidation subsidence of the ground and turned out to be the problems of sinking hole and foundation re-settlement. The representative methods to be used for extending the life cycle of the existing building structure which is tilted by the foundation re-settlement or differential settlement of the foundation can be divided into the building structures reinforcement and soil reinforcement. The purpose of this study is to analyze and present the application example of steel pipe pile method to extend the life cycle of the six -stories building tilted in a soft ground.

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Confining Effect of Mortar-filled Steel Pipe Splice

  • Kim, Hyong-Kee
    • Architectural research
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    • v.10 no.2
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    • pp.27-35
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    • 2008
  • Because of several advantages of mortar-filled sleeve splice in reinforced concrete buildings, this method is being applied increasingly at construction sites and various methods of the splice have been developed in Korea and other countries. In order to apply this system in the field, studies on mortar-filled sleeve splice have been mainly experimental research focused on overall structural performance. However, for understanding the structural characteristics of this splice more accurately, we need to study the confining effect of sleeve, which is known to affect bond strength between filling mortar and reinforcing bar, the most important structural elements of the bar splice. Thus, in order to examine the confinement effect of mortar-filled steel pipe sleeve splice, the present study prepared actual-size specimens of steel pipe sleeve splice, and conducted a loading. Using the test results, we analyzed how the confining effect of steel pipe sleeve affects the bond strength of this splice and obtained data for developing more reasonable methods of designing the splice of reinforcement.

Analysis on Reinforcing Effect at Fixed Part of Compression Anchor by Laboratory Element Tests (실내요소실험에 의한 압축형 앵커의 정착부 보강효과 분석)

  • 홍석우
    • Journal of Ocean Engineering and Technology
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    • v.16 no.5
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    • pp.49-55
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    • 2002
  • The compression anchor is characterized by decrement of progressive failure, simple site work, economy and durability compared with tension anchor. In this paper, compression anchor is analysed through the laboratory element tests. The formula to be estimate the grout strength in fixed part of compression anchor and the effective reinforcement method for several types of soil were suggested. The following conclusions were made from this study : (1) A formula, which is able to calculate the grout strength in the fixed part of the compression anchor, is suggested. (2) The strength increment ratios( $R_{si}$) are 100%, 132%, 147%, 217% according to the reinforcement method of grout. The reinforcement method is Non, Outside spiral, Inside-Outside spiral, Steel pipe, respectively. (3) The strength increment ratios( $R_{si}$) by reinforcing can be 8.23 times the strength increment effect according to the reinforcement types and ground confining pressure. (4) The steel pipe reinforcement is most effective in decomposed soil while, in the case of hard rock ground, high confining pressure is exerted on the grout, so there is no need to use reinforcements.