• 한국터널지하공간학회 논문집
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• 제21권4호
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• pp.455-478
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• 2019

본 논문에서는 고강도 강관을 이용한 강관 보강 그라우팅의 보강 효과 검증을 통해 현장 적용성에 관한 실험적 내용을 다루었다. 기존 강관보강 그라우팅 공법에는 SGT275 (구 STK400) 강관을 일반적으로 적용하고 있으나, 강관 보강 그라우팅이 적용된 터널의 붕락사례를 보면 강관의 과도한 꺾임, 파단 등의 사례가 발생되고 있다. 이러한 사례가 발생하는 여러 원인 중 굴착에 따른 터널의 이완하중에 대응하는 강관의 강성 부족이 그 원인이 될 수 있다. 최근 들어 고강도 강관(SGT550)의 개발로 강관의 강도가 증가했으나, 강도 증대를 고려한 보강방안에 대한 연구가 미흡하므로 이에 대한 연구가 필요한 실정이다. 따라서 본 연구에서는 고강도 강관과 일반 강관의 이음 유무, 주입재의 충전 여부 등 다양한 조건에 대해 인장강도 및 휨 전단력 실험을 수행하고, 기존 제시된 설계법을 통해 강관의 강도 차이에 따른 효율적인 현장 적용성에 대한 기초 연구를 수행하였다. 특히, 실제 현장에 고강도 강관과 일반 강관을 시공하고 굴착에 따른 강관의 변위형상과 응력에 대한 계측 결과를 통해 고강도 강관의 보강 효과를 검증하였다. 연구결과 고강도 강관은 휨 강도가 우수하여 보강효과가 우수한 것으로 나타났으며, 강도 증진효과로 인해 아칭효과도 기대된다.

• Structural Engineering and Mechanics
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• 제87권1호
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• pp.69-84
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• 2023

The use of steel pipe dampers (SPD) as fuses or interchangeable elements in the steel moment-resisting frames (MRF) is one of the newest methods for improving seismic performance. In the present study, the performance of steel pipe dampers in MRF has been investigated. Evaluation of MRF with and without SPD models were performed using the finite element method by ABAQUS. For validation, an MRF and MRF with steel pipe dampers were modeled that had been experimentally tested and reported in previous experimental research and a good agreement was observed. The behavior of these dampers in frames of 3, 6, and 9 stories was studied by modeling the damper directly. Nonlinear time history dynamic analysis was used. It was observed that by increasing the number of stories in the buildings, steel pipe dampers should be used to perform properly against earthquakes. The installation of steel pipe dampers in steel moment-resisting frames shows that the drift ratio between the floors is reduced and the seismic performance of these frames is improved.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.811-818
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• 2010

This paper presents the results of a numerical investigation on behavior of deep excavation wall system supported by steel pipe struts. A series of three-dimensional finite element analyses were carried out on a deep excavation project site which adopted steel pipe struts. The results indicated that the mechanical behavior of steel pipe supported deep excavation is comparable to that of a conventional H-pile supported deep excavation, although the steel pipe supported system is required less number of struts than the conventional H-pile strut system. Also shown is that the sectional stresses of the steel pipe support system are within the allowable values implying that the steel pipe support system can be effectively used as an alternative to conventional H-pile support system.

• 한국지열·수열에너지학회논문집
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• 제18권2호
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• pp.1-9
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• 2022

A novel steel-pipe energy pile is introduced, in which the deformed rebars for main reinforcing are replaced with steel pipes in a large diameter cast-in-place energy pile. Here, the steel pipes act as not only reinforcements but also heat exchangers by circulating the working fluid through the hollow hole in the steel pipes. Under this concept, the steel-pipe energy pile can serve a role of supporting main structures and exchanging heat with surrounding mediums without installing additional heat exchange pipes. In this study, the steel-pipe energy pile was constructed in a test bed considering the material properties of steel pipes and the subsoil investigation. Then, the thermal performance test (TPT) in cooling condition was conducted in the constructed energy pile to investigate thermal performance. In addition, the thermal performance of the steel-pipe energy pile was compared with that of the conventional large diameter cast-in-place energy pile to evaluate its applicability. As a result, the steel-pipe energy pile showed 11% higher thermal performance than the conventional energy pile along with much simpler construction processes.

• 한국환경보건학회지
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• 제29권3호
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• pp.65-71
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• 2003

The injection concentration of corrosion inhibitor increases under the pH 7, temperature of 2$0^{\circ}C$, and alkalinity of 35 mg/l (as CaCO$_3$), the corrosion rate gradually decreased. When the corrosion inhibitor of 10 mg/l is injected, the corrosion rate for carbon steel pipe, galvanized steel pipe, and copper pipe reduces for 37, 66 and 61 % respectively that it is more efficient on galvanized steel pipe and copper pipe. As a result of examination of corrosion rate at pH 6, 7, and 8 when injecting 10 mg/l of corrosion inhibitor under the conditions of 2$0^{\circ}C$ in water temperature and 35 mg/l (as CaCO$_3$) in alkalinity, the efficiency of the corrosion inhibitor increases as the pH increases. For carbon steel pipe, it does not show much a difference with the change of the pH condition, but galvanized steel pipe and copper pipe clearly show the corrosion rate depending on the change of the pH condition. The efficiency of corrosion inhibitor is low as the concentration of residual chlorine is high, but it does not show a great influence at 0.4 mg/l or less. For each pipe type, in the case of carbon steel pipe, the range of increase of corrosion speed following the residual chloride is higher than the other pipe types. In the meantime, the effect following the residual chlorine in copper pipe is low.

• Journal of Welding and Joining
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• 제32권5호
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• pp.13-20
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• 2014

A brief overview is given of the corrosion and hydrogen diffusion behaviors of high strength pipe steel in sour environment. Firstly, hydrogen adsorption and diffusion mechanism of the pipe steel is introduced. Secondly, the effect of iron sulfide film precipitated as a result of the corrosion reaction on the steel surface on hydrogen reduction reaction and subsequent hydrogen permeation through the steel is discussed. Moreover, the hydrogen diffusion behavior of the pipe steel under tensile stress in both elastic and plastic ranges is reviewed based on a number of experimental permeation data and theoretical models describing the hydrogen diffusion and trapping phenomena in the steel. It is hoped that this paper will result in significant academic contributions in the field of corrosion and hydrogen related problems of the pipe steel used in sour environment.

• 한국터널지하공간학회 논문집
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• 제12권5호
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• pp.389-397
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• 2010

본 논문은 철근을 보강한 일반강관을 이용하여 지반을 보강할 경우 터널안정성의 효과에 대하여 연구한 것이다. 본 연구를 위하여 철근 보강형 강관과 일반강관의 휨강성을 이론과 실험을 통하여 비교 분석하였으며, 실질적으로 터널 안정성에 미지는 보강효과를 분석하기 위하여 수치해석을 실시하였다. 그 결과 일반강관에 비해 철근 보강형 강판의 경우 휨강성은 65% 증가되며, 터널 안정성 보강효과는 약 10% 내외 증가되는 것으로 나타났다. 따라서 철근 보강형 강판을 이용한 터널 보강공법의 경우 터널의 안정성을 경제적으로 확보할 수 있을 것으로 기대된다.

• 한국지열·수열에너지학회논문집
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• 제19권3호
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• pp.14-22
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• 2023

Steel-pipe civil structures, including steel-pipe energy piles and cast-in-place piles (CIPs), utilize steel pipes as their primary reinforcements. These steel pipes facilitate the circulation of a working fluid through their annular crosssection, enabling heat exchange with the surrounding ground formation. In this study, the cooling performance of a ground source heat pump (GSHP) system that incorporated steel-pipe civil structures was investigated to assess their applicability. First of all, the thermal performance test was conducted with steel-pipe CIPs to evaluate the average heat exchange amount. Subsequently, a GSHP system was designed and implemented within an office container, considering the various types of steel-pipe civil structures. During the performance evaluation tests, parameters such as the coefficient of performance (COP) and entering water temperature (EWT) were closely monitored. The outcomes indicated an average COP of 3.74 for the GSHP system and the EWT remained relatively stable throughout the tests. Consequently, the GSPH system demonstrated its capability to consistently provide a sufficient heat source, even during periods of high cooling thermal demand, by utilzing the steel-pipe civil structures.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.511-520
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• 2008

The steel pipe strut for a means of the retaining structure has been used generally in North America, Europe and China so far. However, Korea and Japan, two countries are much familiar with H-shape steel strut having its anisotropic strength on two different axes(named as strong and weak axes), even though they recognize the steel pipe's excellence of structural function associated with its compressive ability. This trend is mainly due to a number of its field application, accumulated know-hows and workmanship etc. This paper introduces particular features of a high-strength steel pipe strut in comparison with the H-shape steel strut and its application for two excavation sites in Seoul. As a result of field verification, the high-strength pipe steel strut is more effective than the H-shape steel strut in terms of construction costs, schedules, constructibility and structural stability.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 가을 학술발표회 논문집
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• pp.84-89
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• 2004

In this paper, cyclic plasticity model of SM490 TMC was formulated by basing on monotonic loading test and cyclic loading test. For exact description of cyclic performance and plastic deformation capacity of steel member using SM490 TMC, formulated cyclic plasticity model and finite deformation theory were applied to 3-dimensional elastic-plastic FE analysis. Cyclic plastic behavior of pipe-section steel column using SM490 TMC was clarified by carrying out numerical analysis. Also, in order to clarifying seismic performance of pipe-section steel column using SM490 TMC, analysis results were compared with analysis results of pipe-section steel column using SM490. A comparison of analysis results shows that SM490 TMC pipe-section steel column has a better cyclic performance for strength and energy dissipation than SM490 pipe-section steel column under cyclic loading