• Journal of the Korean Institute of Gas
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• v.15 no.4
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• pp.15-20
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• 2011

This study presents the behavior characteristics of buried three-layered pipeline subjected to pile driving loads corresponding to its cover depth. The analysis considered the driving energy caused by 7 tonf of ram weight and 1.2m of stroke with 20m distance from buried pipeline for all the analysis cases. A cover depth of pipe is varied 0.6m to 3.8m for this research. Vibration Velocity and stress are investigated at the center section in longitudinal direction. With same distance from pile, attenuation ratio of vibration velocity for increment of cover depth has shown an increasing trend. Also, Stress attenuation ratio of inner pipe is increased with cover depth.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.6
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• pp.460-465
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• 2016

Long pipe structures are usually installed in fixtures located with regular intervals or laid underground. Therefore, deflection and deformation could easily occur due to their weight or ground activity. A shape monitoring technique can be used effectively to evaluate the integrity of the pipe structures. Fiber Bragg grating (FBG) sensors, which have an advantage of multiplexing could be used to measure strains at multiple-points of a long structure. In this study, to evaluate the integrity of a pipeline, a shape estimation technique based on strain information was proposed. Furthermore, different experiments were conducted to verify the performance of the proposed technique. Thus, the proposed shape estimation technique can represent the shape according to the deformation of the specimen using the FBGs. Moreover, calculated deflection of the pipeline using the estimation technique showed a good agreement with the actual deflection of the pipeline.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.6
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• pp.651-656
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• 2014

Corrosion has a significant influence upon the reliability assessment and the maintenance planning of gas pipeline. Corrosion defects occurred on the underground pipeline can be obtained by conducting periodic in-line inspection (ILI). However, little study has been done for practical use of ILI data. This paper deals with remaining lifetime prediction of the gas pipeline in the presence of corrosion defects. Because a pipeline parameter includes uncertainty in its operation, a probabilistic approach is adopted in this paper. A pipeline fails when its operating pressure is larger than the pipe failure pressure. In order to estimate the failure probability, this paper uses First Order Reliability Method (FORM) which is popular in the field of structural engineering. A well-known Battelle code is chosen as the computational model for the pipe failure pressure. This paper develops a Matlab GUI for illustrating failure probability predictions Our result indicates that clustering of corrosion defects is helpful for improving a prediction accuracy and preventing an unnecessary maintenance.

• Journal of the Korean Institute of Gas
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• v.20 no.4
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• pp.33-43
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• 2016

Grinding, weld deposition, type A sleeve, type B sleeve, composite sleeve, hot tapping and clamp are used as the method to repair the buried pipelines in the United States, UK and Europe. In the event of defect to the pipeline, they have repaired the pipeline through the fitness-for-service assessments. In addition, they have guidelines for the possible repair methods to apply to each type of damage, which is occurred due to the 3rd party construction or corrosion. According to the KGS FS551, Safety Validation in Detail including ECDA(External Corrosion Direct Assessment) as one method of integrity management should be carried out for the old pipeline which supply natural gas as the middle pressure in Korea. Where a defect on the pipelines is found, on the result of Safety Validation in Detail, the pipelines should be repaired or replaced by new piping. However, there are no guidelines or regulations regarding the repair and reinforcement of pipeline, so that, cutting the damaged pipeline and replacing it as a segment of new pipe is the only way in Korea until now. We have suggested pipeline repair methods including type A, B sleeve, composite sleeve, after the survey of foreign repair method and standards including the method of United States and the United Kingdom, and after analysis of the results on pipeline repair test including type A, type B sleeve and composite sleeve.

• Journal of the Society of Disaster Information
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• v.13 no.1
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• pp.26-34
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• 2017

In this study, for the integrated information management of underground pipelines, each information management server software must have it's inter-operability. So Many kinds of smart-city integrated platform softwares were surveyed and the best platform software was selected. The interface software modules developed in this study was installed at the test system. Through this test system, when a sub system transfers an event message to the upper integrated server system, the inter-operability test between the upper system and a sub operating system was performed and its operability was resolved.

• Journal of the Korean Institute of Gas
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• v.15 no.1
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• pp.22-29
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• 2011

Pipes buried in around a construction site of urbanized area tend to be affected by the vibration caused by construction loads. The behaviors of buried pipes affected by periodic vibration were analyzed through numerical analyses based on existing study and experimental results. From the results of theses analyses, the serviceability of buried pipes subjected to vibration was verified. This study analyzed the pipe behaviors subjected to dump truck loads with respect to burial depths, and this research was performed as foundation study to establish standards for managing buried pipes. The analyses were performed with burial depth of 0.6, 1.2, 1.8m and vehicle velocity of 10km/h. From theses analyses, the vibration velocity and occurred stress tend to decrease as a burial depth increases.

• Journal of Environmental Science International
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• v.15 no.9
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• pp.871-880
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• 2006

Water management treatment of coastal region has been an important problem in Jeju city since the distributions of pipeline of the pumping system made a bad view in coastal region. To solve the problem, we observed the pipelines that are on the surface around the coastal region from Tapdong to Doduhang. From the observations, we found that Todong and Dodu areas were not unsightliness because the all pipelines were located in underground. However, the other areas, such area Yongdam, Handugi, Yongdam fishing village, had a serious problem for the coastal landscape view. To solve the problem, at we estimated coastal land color characteristics of Jeju city based on the observation of the pipelines. The estimated color panel shows that the green, blue and grey colors are a dominant factors of the Jeju coastal region. Based on the color panel, we proposed two methods, that is, one is a short time treatment, the other is a long time one. The short is based on the colour treatment, which is pipeline colour changing into surround natural one. The long time is the construction plan design method. Although the later method was very useful in Jeju island. However, it takes a lot of time and money. Therefore, in the situation, the short time is the better than the long time one.

• Steel and Composite Structures
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• v.26 no.1
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• pp.55-66
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• 2018

In this paper, the response of an underground fibreglass reinforced plastic (FRP) composite pipe system subjected to realistic loading scenarios that may be experienced by an actual buried pipeline is investigated. The model replicates an arbitrary site with a length of buried pipeline, passing through a $90^{\circ}$ bend and into a valve pit. Various loading conditions, which include effects of pipe pressurization, differences in response between stainless steel and fibreglass composite pipes and severe loss of bed-soil support are studied. In addition to pipe response, the resulting soil stresses and ground settlement are also analysed. Furthermore, the locations of potential leakage and burst have also been identified by evaluating the contact pressures at the joints and by comparing stresses to the pipe hoop and axial failure strengths.

• Journal of the Society of Disaster Information
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• v.12 no.2
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• pp.122-129
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• 2016

In this study, a dual structured pipe for a preventive monitoring on a accident damage, a smartphone app program for a survey and a construction data collection and a server program for a real-time monitoring were developed. A pilot system was installed in the test field to analyze effects of a system developed in this study. The data for a damage prevention was detected by the attached sensors on the pipe. Exclusion was tested by the pressure sensors to be installed at regular intervals. The app and server programs was enabled to the real-time data collection and real-time monitoring linked by VRS survey equipments and a smartphone.

• Smart Structures and Systems
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• v.9 no.5
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• pp.461-472
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• 2012

This study proposes an optics-based active sensing system for continuous monitoring of underground pipelines in nuclear power plants (NPPs). The proposed system generates and measures guided waves using a single laser source and optical cables. First, a tunable laser is used as a common power source for guided wave generation and sensing. This source laser beam is transmitted through an optical fiber, and the fiber is split into two. One of them is used to actuate macro fiber composite (MFC) transducers for guided wave generation, and the other optical fiber is used with fiber Bragg grating (FBG) sensors to measure guided wave responses. The MFC transducers placed along a circumferential direction of a pipe at one end generate longitudinal and flexural modes, and the corresponding responses are measured using FBG sensors instrumented in the same configuration at the other end. The generated guided waves interact with a defect, and this interaction causes changes in response signals. Then, a damage-sensitive feature is extracted from the response signals using the axi-symmetry nature of the measured pitch-catch signals. The feasibility of the proposed system has been examined through a laboratory experiment.