• 한국지진공학회논문집
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• 제27권6호
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• pp.283-291
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• 2023

Unlike other facilities, maintaining processes is essential in industrial facilities. Pipe racks, which support pipes of various diameters, are important structures used in industrial facilities. Since the transport process of pipes directly affects the operation of industrial facilities, a fragility curve should be derived based on considering not only the pipe racks' structural safety but also the pipes' transport process. There are several studies where the fragility curves have been determined based on the structural behavior of pipe racks. However, few studies consider the damage criteria of pipes to ensure the transportation process, such as local buckling and tensile failure with surface defects. In this study, an analysis model of a typical straight pipe rack used in domestic industrial facilities is constructed, and incremental dynamic analysis using nonlinear response history analysis is performed to estimate the parameters of the fragility curve by the maximum likelihood estimation. In addition, the pipe rack's structural behavior and the pipe's damage criteria are considered the limit state for the fragility curve. The limit states considered in this paper to evaluate fragility curves are more reasonable to ensure the transportation process of the pipe systems.

• 한국건설관리학회논문집
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• 제24권4호
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• pp.25-34
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• 2023

본 연구의 목적은 플랜트 건설에서 현장시공과 모듈시공에 대한 공사비를 산정하여 비교하는 것으로 공사비를 산정하는 대상을 Pipe Rack으로 한정하였다. 이에, 현장시공으로 준공된 국내 석유화학플랜트 건설사업 1곳을 사례로 선정한 후 비용자료를 조사하여 도출된 결과는 다음과 같다. Pipe Rack의 현장시공에 대한 직접공사비는 560억원으로 Steel Structure 251억원, Piping 308억원이며, 모듈시공에 대한 직접공사비는 607억원으로 Steel Structure 238억원, Piping 297억원으로 산정되었다. 또한, 현장시공과 모듈시공의 증감률을 비교해 보면, 재료비 1.9%, 경비 192.1% 증액되었으나, 노무비는 -9.1% 감액되어, 전체 직접공사비는 8.4%(47억원)가 증액되었다. 그리고 공사원가는 현장시공이 761억원, 모듈시공은 810억원으로 모듈시공이 6.4%(49억원) 증액되는 것으로 나타났다. 이와 같은 결과는 Pipe Rack을 모듈로 시공하는 경우 공사비가 증감되는 현황을 확인하기 위한 참고자료로 활용이 용이한 반면에, 모듈시공에 따른 간접적인 효과(노무인력 감소, 안전사고 발생 감소, 공사기간 단축 등)에 대한 연구가 필요하다.

• 한국BIM학회 논문집
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• 제11권3호
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• pp.34-44
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• 2021

This study quantitatively analyzes the work performance of the structural safety diagnosis team that diagnoses pipe racks. To this end, a method for evaluating the performance of the structural safety diagnosis team using the queuing model was proposed. For verification, the case of applying the existing method and the method of introducing a 3D laser scanner for one site was used. The period, number of people, and initial investment cost of each project were collected through interviews with case project experts. As a result of analyzing the performance of the structural safety diagnosis team using the queuing model, it was possible to confirm the probability of delay in the work of each project and the amount of delayed work. Through this, the cost (standby cost) when the project was delayed was analyzed. Finally, economic analysis was conducted in consideration of the waiting cost, labor cost, and initial investment cost. The results of this study can be used to decide whether to introduce 3D laser scanners.

• Smart Structures and Systems
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• 제21권1호
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• pp.53-64
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• 2018

Nondestructive testing methods are required to assess the condition of civil structures and formulate their maintenance programs. Axial force identification is required for several structural members of truss bridges, pipe racks, and space roof trusses. An accurate evaluation of in situ axial forces supports the safety assessment of the entire truss. A considerable redistribution of internal forces may indicate structural damage. In this paper, a novel compressive force identification method for prismatic members implemented using static deflections is applied to steel beams. The procedure uses the Euler-Bernoulli beam model and estimates the compressive load by using the measured displacement along the beam's length. Knowledge of flexural rigidity of the member under investigation is required. In this study, the deflected shape of a compressed steel beam is subjected to an additional vertical load that was short-term measured in several laboratory tests by using fiber Bragg grating-differential settlement measurement (FBG-DSM) sensors at specific cross sections along the beam's length. The accuracy of midspan deflections offered by the FBG-DSM sensors provided excellent force estimations. Compressive load detection accuracy can be improved if substantial second-order effects are induced in the tests. In conclusion, the proposed method can be successfully applied to steel beams with low slenderness under real conditions.

• 한국안전학회지
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• 제29권4호
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• pp.110-115
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• 2014

It is crucial for important facilities to withstand strong earthquakes because their damage may cause undesirable socio-economic effect. A liquefied natural gas (LNG) receiving terminal is one of the lifeline facilities whose seismic safety needs to be guaranteed. Even though all operating LNG receiving terminals in Korea were seismically designed, old design codes do not guarantee to comply with the current seismic design codes. In addition, if the constructional materials have been deteriorated, the seismic capacity of facilities may be also deteriorated. Therefore, it is necessary that the seismic performance of LNG receiving terminals is evaluated and the facilities that lack of seismic capacity have to be rehabilitated. In this paper, a procedure of seismic performance evaluation of such facilities is developed such that the procedure consists of three phases, namely pre-analysis, analysis, and evaluation phases. In the pre-analysis phase, design documents are reviewed and walk-on inspection is performed to determine the current state of the material properties. In the analysis phase, a structural analysis under a given earthquake or a seismic effect is performed to determine the seismic response of the structure. In the evaluation phase, seismic performance of the structure is evaluated based on limit states. Two of the important facilities, i.e. the submerged combustion vaporizer (SMV) and pipe racks of one of the Korean LNG receiving terminals are selected and evaluated according to the developed procedure. Both of the facilities are safe under the design level earthquake.