• Journal of the Korean Wood Science and Technology
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• v.32 no.3
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• pp.33-41
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• 2004

In ancient wooden structures, the mechanical properties of the structural members have been reduced by time-dependent degradations such as fatigue or creep. Also, the external and internal deterioration was caused by environmental condition, fungi, bacteria, or insect, and then reduced the quality of structural members. However, the previous methods for evaluating the deterioration have been mainly depended on the visual inspection. In this study, therefore, ultrasonic stress wave test, accelerometer stress wave test were used to evaluate the deterioration of structural wood members in ancient wooden structures. Based on the results, the quantitative criteria of stress wave transmitted velocity were proposed to evaluate the deterioration of structural member. The proposed criteria were related to the degree of deterioration. In accelerometer stress wave, the criteria of deterioration of wave reciprocal velocity was below 1800 ㎲/m at incipient deterioration (below 12% ratio of deterioration), between 1800 and 2200 ㎲/m at moderate deterioration (12~17%) and above 2200 ㎲/m at severe deterioration (above 17%). The ultrasonic stress wave, the criteria of deterioration were 800 and 950 ㎲/m at below 8% and above 15% of the degree of deterioration respectively.

• Journal of the Korean Institute of Educational Facilities
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• v.13 no.4
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• pp.15-23
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• 2006

The purpose of this study is to establish the objective deterioration grades and evaluation criteria of building equipment system of educational facilities available for reasonable maintenance and remodeling of them. For the purpose of it, the actual conditions of building equipment systems of the 148 buildings of 84 middle and high schools in Seoul 20 years after construction are investigated and surveyed through one-on-one interviews and questionnaires. And, deterioration grades of them are estimated by the evaluation criteria which is proposed in this study. As a result of this study, the 10 deterioration grades and the 4 evaluation criteria of the 6 performances of building equipment system, which are heating and cooling, water supply and drainage, hot water supply and electrical power performance, are suggested. And, as a result of the survey, it showed that 24% of the investigated school buildings were estimated C grade which needs partial remodelling, and 51% of the school buildings were estimated D grade which needs extensive remodelling. And, 25% of the school buildings were estimated E grade which needs overall remodelling or alteration of building equipment system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.3
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• pp.123-130
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• 2016

This study introduced deterioration evaluation item and criteria that could be applied to industrial facilities with the most widely used carbon steel pipe installed for ordinary piping (KSD 3507). Experimental industrial pipes were evaluated with pipe sectionalizing method combined with the established evaluation item and criteria to measure and manage semi-continuously for overall piping system. After applying outcomes from this study to a plant of incineration facility, a 42% saving in repairing and remodeling cost was achieved.

• Journal of the Korean housing association
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• v.17 no.2
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• pp.77-85
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• 2006

This study aims to propose the comprehensive evaluation of performance multi-family housing. Most of the existing studies for the reproduction have evaluated by the safety of structure. Therefore those pass over the functional factors which is important for the evaluation of residential qualities. This study represents that the reproduction renovation should not be secured the safety of structure but established the quality of lift. And questionnaire asking expert's opinion also supplemented. As a result, the item for examination and the weight for evaluation are suggested in functional deterioration. The results of this study are summarized as follows: 1. Existent redevelopment criteria are not appropriate to decide the environmental comfort, the vital function of housing and the residential management finance. 2. The future criteria have to evaluate the existing environmental comfort, be reconstructed to put first general deterioration. 3. Evaluation elements was extracted throughout the document research, evaluation elements analysis system was separated in residential area, suburb of dwellings, community, and housing complexity environmental assesment, 4. Each category of influence ratio was extracted to assess total deterioration throughout the expert question survey. 5. Each category analysed (1) $0{\sim}30%$: function is good (unnecessary to improve) (2) $31{\sim}40%$: average (necessary of partial improvement) (3) $41{\sim}59%$: bad (necessary of total improvement) (4) $60{\sim}100%$: the worst (unable to improve throughout the repair)

• Geomechanics and Engineering
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• v.19 no.6
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• pp.499-511
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• 2019

The reliability of reinforced concrete structures is frequently compromised by the deterioration caused by reinforcement corrosion. Evaluating the effect caused by reinforcement corrosion on structural behaviour of corrosion damaged concrete structures is essential for effective and reliable infrastructure management. In lifecycle management of corrosion affected reinforced concrete structures, it is difficult to correctly assess the lifecycle performance due to the uncertainties associated with structural resistance deterioration. This paper presents a stochastic deterioration modelling approach to evaluate the performance deterioration of corroded concrete structures during their service life. The flexural strength deterioration is analytically predicted on the basis of bond strength evolution caused by reinforcement corrosion, which is examined by the experimental and field data available. An assessment criterion is defined to evaluate the flexural strength deterioration for the time-dependent reliability analysis. The results from the worked examples show that the proposed approach is capable of evaluating the structural reliability of corrosion damaged concrete structures.

• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2008.04a
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• pp.225-230
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• 2008

High-rise and high-density apartment complexes has been built and supplied on a large scale in the metropolis and metropolitan areas since 1980s in order to solve housing shortage in cities. Recently they are raising deterioration problems for aging more than 20 years. moreover, those problems show very special characters such as simultaneity and a large scale. The purpose of this study is to propose a direction for the development of the evaluating indicators to measure the level of deterioration of apartments. The level of deterioration of apartments can be evaluated by housing performance. In order to evaluate the deterioration comprehensively, the housing performance indicators should be developed on the social, economical, and physical dimension. This study analyzed the concept of the apartment deterioration and compared housing performance indicators through literature review. First of all, when considering various factors in the evaluation of the deteriorated apartments, such as evaluating ranges, attributes and dimensions, housing performance indicators should be structured with the hierarchical framework. Second, housing performance indicators evaluating the level of deterioration of apartments should include social, psychological, and cultural aspects of home environments in order to understand adequately the attitude of the middle class toward services that apartments provide. Third, in previous researches, most criteria have been developed and weighted based on only expert opinions regarding performance indicators. So, It is necessary to include residents' opinions in developing performance indicators since they can provide more practical and feasible aspects the experts could not experience or understand.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.10a
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• pp.136-143
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• 1998

Elastomeric bearing is used as one of the most useful way for isolation structures, because the horizontal stiffness is much lower than the vertical stiffness. The quality of Elastomeric bearing depends on the vulcanization procedure to manufacture, which produces the elasticity of the rubber from the compound of rubber and sulphur. The durability of Elastomeric bearing is affected by the deterioration due to ozone and ultra-violet attack. but the durability during the design life of bridges can be assured by the sufficient size of the bearing in spite of the deterioration in surface. In the design criteria of Elastomeric bearing, the stability of the bearings is evaluated by shear strain due to compression, lateral displacement, and rotation. The question how soft rubber can sustain heavy structure is now able to be solved by Ultimate capacity test of Laminated elastomeric Bearings, which results 1,200kg/$\textrm{cm}^2$ of the max. compressive stress and this shows what a sufficient safety factor Elastomeric bearing has!

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.6
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• pp.197-205
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• 2020

In 2014, The Housing Act amended to allows vertical extension and increases the units of housing (or total floor area) to site. Currently, the feasibility of performing vertical extension is evaluated based on safety diagnosis provisions and manuals with 1st investigation stage on slope, uneven settlement, load-bearing capacity, and durability. However, a need for more reasonable evaluation criteria for the investigation is still required because there had not been any other case study on the diagnosis for the vertical extension, and the engineering basis on evaluation criteria were not suggested. Accordingly, this study is intended to suggest feasible evaluation criteria on the carbonation, chloride ion contents, corrosion of reinforcements, crack and surface deterioration of concrete for durability assessment by codes and standards of domestic and foreign countries. The results of this study are expected to be beneficial for establishing more reasonable durability evaluation criteria, and in turn, more reliable assessment protocol for vertical extension.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.3
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• pp.238-247
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• 2007

Genetic Algorithms(GA) which searches optimum solution using natural selection and the law of heredity has been applied to learning algorithms in order to estimate performance deterioration of the aircraft gas turbine engine. The compressor, gas generator turbine and power turbine are considered for engine performance deterioration and estimation for performance deterioration of a single component at design point was conducted. As a result of that, defect diagnostics has been conducted. The input criteria for the genetic algorithm to guarantee the high stability and reliability was discussed as increasing learning data sets. As a result, the accuracy of defect estimation and diagnostics were verified with its RMS error within 3%.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.2
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• pp.239-244
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• 2017

The demand for electric power is increasing every year. All facilities operating at power stations and all facilities used in transmitting high volumes of electric power are therefore expected to operate with a high degree of reliability. 6.6 kV XLPE 100 SQ 1C cables are used to deliver high levels of generated electric power. Depending on the method of manufacture, installation environment, and usage conditions, the deterioration processes of power cables start from the instant of operation. Cable junctions may break down in three years from the start of operation due to manufacturing or construction defects. We have invented the first device in Korea to monitor the status of live cables and installed these at Korea Western Power Co., Ltd.. We have set the criteria to determine deterioration status and specified the degree of deterioration at which one should replace the cables. In this paper, we present the effect of insulation layer and sheath on the insulation resistance status in cables.