• Corrosion Science and Technology
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• v.7 no.1
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• pp.6-12
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• 2008

Non-metallic composite overwrap repair methods utilize resin based fiber-reinforced composite materials, which have higher specific strength to weight ratio and stiffness, superior corrosion and fatigue resistance, and substantially reduced weight when compared to carbon steel. Non-metallic repair methods/systems can allow desired functional properties to be achieved at a respectable economic advantage. For example, non-metallic composite repair systems have at least a 50 year design stress of 20 ksi and approximately 25% of the short term tensile strength of fiberglass. For these systems, the contribution of the repaired steel to the load carrying capability need not be considered, as the strength of the repair itself is sufficient to carry the internal pressure. Worldwide experience in the Oil & Gas industry confirms the integrity, durability, inherent permanency, and cost-effectiveness of non-metallic composite repair or rehabilitation systems. A case study of a recent application of a composite repair system in Saudi Aramco resulted in savings of 37% for offshore subsea line and 75% for onshore above grade pipeline job. Maintaining a pipeline can be costly but it is very small in comparison to the cost of a failure. Pipeline proponents must balance maintenance costs with pipeline integrity. The purpose is not just to save money but also to attain a level of safety that is acceptable. This technology involves the use of an epoxy polymer resin based, fiber-reinforced composite sleeve system for rehabilitation and /or repair pipelines.

• IE interfaces
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• v.18 no.3
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• pp.308-316
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• 2005

Delayed repair to the failure of weapon system can cause enormous damages to military operation. Various materials like diagnostic equipment, general and special tools, technical manuals(maintenance manual and illustrated parts breakdown) and drawing documents are required for maintenance. For existing weapon systems the distributed environment of these various materials reduces the maintenance effectiveness of maintenance crew. In this paper, to provide the information of maintenance procedures and supply to the maintenance crew we develope a digital interactive electronic technical manual of the technical documents which can be used easily in computer through question and answer method and improve maintenance effectiveness and minimized repairing time.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.5
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• pp.148-155
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• 2017

In this study, by using the international standards ISO TS 16774, Part 2 Test method for chemical resistance as a quality control method of injection type repair material used for leakage crack of underground concrete structure, the performance requirement against of chemical environment of underground concrete structures for repair materials was tested. For this testing 3 types for each of the 2 classes of repair materials(synthetic rubber, cement), with a total of 9 types repair materials, were selected and examined. As a result, the test results showed that the smallest performance deterioration by the change in the mass was with the synthetic rubber(RG) type as opposed to the cement type system, showing that the synthetic rubber type had the strongest relative resistance to chemical exposure. Furthermore, it is necessary to investigate the material with high resistance to chemical substances and to examine the material which can increase resistance to sodium hydroxide and sodium chloride in cement system. These results can be used as a basic index for the selection of repair materials with the strongest resistance to chemical environment found in concrete structures. In addition, it is expected that the test results derived in this study can be used as reference data that can be reflected in the quality improvement of the maintenance material to be developed later.

• Journal of the Korea Institute of Building Construction
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• v.23 no.1
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• pp.57-68
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• 2023

To maintain the normal function of an aging building, regular inspection, repair, and reinforcement must be performed. However, the form of information and decision-making generated in the current building maintenance stage still depends on inefficient methods. This causes an increase in cost and waste of time in building maintenance. Therefore, this study proposed a COBie-IM document for building inspection and maintenance information management by benchmarking COBie, and suggested a method of checking information by linking it with BIM. In addition, a method for visualizing the designation of colors according to the damage grade of defects occurring in the building was suggested. Through this, we are able to systematically integrate and manage the information generated during inspection and maintenance in the building maintenance stage. This is expected to increase work efficiency by supporting decision-making that determines the priority of repair and reinforcement for defects.

• Journal of the Economic Geographical Society of Korea
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• v.22 no.2
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• pp.160-177
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• 2019

In this study, we examined the distribution of dealers and the repair parts management system of a Japanese car manufacturer in the Chinese market in looking at the case of Toyota. We conducted our research by obtaining information from a GAC Toyota dealer about the current distribution of dealers and locations of warehouses throughout China, as well as the status of stocks and the distribution system for repair and maintenance parts. The results of our investigation showed that although GAC Toyota has 437 dealers throughout the country, there is an imbalance in distribution towards the coastal areas, after the population ratios and other measurements are factored in. Therefore, it can be said expansion towards the inland regions, where demand for automobiles has increased in recent years, has been stunted. On the other hand, there is a high correlation between gross GDP by region and the number of stores, and it can be pointed out that the company prioritizes the sale of high-priced vehicles in major coastal areas where the economy is large, rather than selling low-priced vehicles for inland consumers with a relatively small economic scale. The company also has difficulty in securing dealers that can provide sufficient after-sales service. According to the regulations of GAC Toyota, the company require dealers to have at least 1,500 repair and maintenance parts in stock. Also, when exchanging maintenance parts, GAC Toyota's emphasis is on increasing customer satisfaction by giving sufficient explanations for customers and obtaining consent from them. As a result, the company's dealers need financial resources to continue their business from a long-term perspective. However, it can be pointed out that such dealers are limited, and it is difficult to distribute profits among manufacturers and dealers.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.3
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• pp.1-11
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• 2023

After the collapse of the Seongsu Bridge in the 1990s in Korea, attention was focused on the maintenance of facilities. The government has established various policies since the enactment of the Act in 1995 until recently. In general, safety inspections are performed to evaluate the safety grade of facilities, and facilities are maintained and managed by performing repairs and reinforcements for defects. However, since the budget is limited, it is impossible to carry out repair and reinforcement projects for all defects. It is necessary to prioritize repair and reinforcement measures. Then, the priority index (PI) is presented considering the importance of members, the seriousness of defects, and economic feasibility. In this index, the degree of influence can be adjusted within the range of 50 to 100% according to the expert's subjective judgment, and the same weight is set for some specific members. Also, the effect through repair and reinforcement is not taken into account decisively, and most of them have a limit in which priority is determined by economic feasibility. Therefore, in this study, through several case studies, problems with the priority index were reviewed and an equation was presented to improve them.

• Korean Journal of Construction Engineering and Management
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• v.6 no.1 s.23
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• pp.169-176
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• 2005

The purpose of this study is to analyze the maintenance condition and cost in the past ten year on the subject of permanent Rental Housing in Seoul and Gyeong-Gi. It also suggests the problems and improvements related to long-term maintenance. The Interviews with thirty experts who have had experience in this area more than ten years and data analysis are adopted as basic methods. The data on the maintenance cost such as a budget in practice by a term and the real cost far the repair are analyzed. The primary findings of this study are as follows : 1) the rate of maintenance cost for 13 years is $4.56\%$ when the prime construction cost is regarded, while the figure is $6.70\%$ when the construction cost is considered 2) it is just of forced the basic lists for repair applied commonly to Rental housing. Hence, individually managers consider the features of housing and determine the detail lists.

• International Journal of Reliability and Applications
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• v.9 no.1
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• pp.113-122
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• 2008

In this paper, we consider a periodic preventive maintenance policy in which each preventive maintenance reduces the hazard rate of amount proportional to the failure intensity, which increases since the system started to operate. And the effect of preventive maintenance at each preventive maintenance epoch is different. The expected cost rate per unit time for the proposed model is obtained. We discuss the optimal number N of the periodic preventive maintenance and the optimal period x, which minimize the expected cost rate per unit time and obtain the optimal preventive maintenance schedule for given cost structures of the model. A numerical example is given for the purpose of illustrating our results when the failure time distribution is Weibull distribution.

• Journal of Applied Reliability
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• v.18 no.2
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• pp.104-113
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• 2018

Purpose: This paper proposes the non-periodic preventive maintenance policy based on the level of cumulative hazard intensity. We aim to construct a cost-effectiveness on the proposed model with relaxing the constraint on reliability. Methods: We use the level of cumulative hazard intensity as a condition variable, instead of reliability. Such a level of cumulative hazard intensity can derive the reliability which decreases as the frequency of preventive maintenance action increases. We also model the imperfect preventive maintenance action using the proportional age setback model. Conclusion: We provide a numerical example to illustrate the proposed model. We also analyze how the parameters of our model affect the optimal preventive maintenance policy. The results show that as long as high reliability is guaranteed, the inefficient preventive maintenance action is performed reducing the system operation time. Moreover, the optimal value of the proposed model is sensitive to changes in preventive maintenance cost and replacement cost.

• Journal of Korean Society for Quality Management
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• v.31 no.3
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• pp.193-204
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• 2003

In this paper, we consider a periodic preventive maintenance(PM) policy in which each PM reduces the hazard rate but remains the pattern of hazard rate unchanged. And the system undergoes only minimal repairs at failures between PM's. The expected cost rate per unit time is obtained. The optimal number N of PM and the optimal period x, which minimize the expected cost rate per unit time are discussed. Explicit solutions for the optimal periodic PM are given for the Weibull distribution case.