• Title/Summary/Keyword: Condition assessment

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Linear fracture envelopes for fatigue assessment of welds in bridges

  • Ghosh, A.;Oehlers, D.J.;Wahab, M.A.
    • Structural Engineering and Mechanics
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    • v.4 no.4
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    • pp.347-364
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    • 1996
  • Presently welded components are designed using S/N curves which predict only the fatigue life of the component. In order to ascertain the condition of the weld at any intermediate period of its life inspection is carried out. If cracks are detected in a weld fracture mechanics is used to find their remaining life. A procedure for assessment is developed here that can be used to verify the condition of a weld before inspection is carried out to detect cracks. This simple method has been developed using linear fracture envelopes by combining S/N curves with linear elastic fracture mechanics.

A Study on the assessment of the marine traffic safety at the Pusan approaching waters (부산항부산항 접근수역에 대한 해상교통안전성평가에 관한 연구)

  • 강영식;박영수;정재용;박진수
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2000.10b
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    • pp.89-100
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    • 2000
  • Recently, marine traffic engineering has been developed until that possible to estimate a change in traffic flow caused from some transformations of the traffic condition and to assess whether changed traffic condition is can be accepted as a useful thing in navigation or not by compute simulation. This paper's main substance is assessment of the present marine traffic safety at these area adjacent to Pusan harbor. Also in this study, it was carried out in order to be convinced of validity of round about TSS to expect changing in traffic flows by the institution of round about TSS and to assess expected traffic flows by using Environmental Stress assessment model.

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The credit market of Russia: the assessment of condition, the development of tendency

  • Vyborova, E.N.
    • East Asian Journal of Business Economics (EAJBE)
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    • v.5 no.2
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    • pp.12-37
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    • 2017
  • The analysis of results of the market of loans granted to legal entities, the physical persons are provided in the work. The assessment of condition of industry segments of the market of the credits of legal entities is carried. The results of assessment of the market of the credits of physical persons by types of the granted loans are provided. The correlation and regression analysis on the industry segments of crediting of legal entities is carried out. The dynamics of development of debt on the industry segments of crediting is determined. The results show that: Hypothesis 1. The amount of the issued credits to the legal entities steadily in-creases on all industries of economy. Communication between the industry segments of market very high. Hypothesis 2. Crediting of physical persons is characterized by relative stability. The structure of overdue debt repeats the structure of the issued credits to the physical persons.

Representative Rating of Bridges using Condition Assessment Data (상태평가 결과를 이용한 교량의 대표등급 산정방법)

  • Oh, Byung-Hwan;Kim, Kwang-Soo;Shin, Kyung-Joon;Lee, Sang-Cheol
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.6 no.1
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    • pp.111-118
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    • 2002
  • Currently, the inspection of bridges is conduced for the parts or elements of a bridges and the results of inspection are depicted for those local elements. Therefore, the representative rating of a bridge as a whole bridge system is not presented. The purpose of the present study is to purpose a reasonable method which can yield realistic representative rating for an actual bridge. The purpose method consists of two steps, i.e, visual inspection step and safety assessment step. The importance of members is considered by introducing the weighting factors and the number of spans is also considered to obtain the representative rating of a whole bridge system. The purpose method may be efficiently used to calculate the realistic representative rating bridge structures.

Assessment of Insulation Condition in Rotating Machine Stator Windings (회전기 고정자 권선의 절연상태 평가)

  • Kim, Hee-Dong
    • Proceedings of the KIEE Conference
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    • 2001.07c
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    • pp.1706-1708
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    • 2001
  • Nondestructive tests are used to evaluate the insulation condition of stator windings in rotating machine. These tests included ac current, tan delta and maximum partial discharge. The insulation condition of stator windings was assessed by three test items. The stator windings were generally in good condition, wash, reimpregnation and rewind. It was confirmed that nondestructive tests were most useful method to indicate the insulation condition of stator windings.

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DGA Interpretation of Oil Filled Transformer Condition Diagnosis

  • Alghamdi, Ali Saeed;Muhamad, Nor Asiah;Suleiman, Abubakar A.
    • Transactions on Electrical and Electronic Materials
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    • v.13 no.5
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    • pp.229-232
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    • 2012
  • DGA is one of the most recent techniques developed to diagnose the fault condition on oil filled insulation transformers. There are more than 6 known different methods of DGA fault interpretation technique and so there is the likelihood that they may vary in their interpretations. A series of combined interpretation methods that can determine the power transformer condition faults in one assessment is therefore needed. This paper presents a computer program- based system developed to combine four DGA assessment techniques; Rogers Ratio Method, IEC Basic Ratio Method, Duval Triangle method and Key Gas Method. An easy to use Graphic User Interface was designed to give a visual display of the four techniques. The result shows that this assessment method can increase the accuracy of DGA methods by up to 20% and the no prediction result had been reduced down to 0%.

Ecological Health Assessment of Mountainous Stream in Mt. Sik-Jang using Multi-metric Models (다변수 메트릭 모델을 이용한 식장산 계곡천의 생태 건강성 평가)

  • Bae, Dae-Yeul;Kim, Yu-Pyo;An, Kwang-Guk
    • Journal of Korean Society on Water Environment
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    • v.24 no.2
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    • pp.156-163
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    • 2008
  • This study was to introduce a methodology of ecological health assessment for efficient management and to provide some diagnostic results of the survey. We evaluated ecological health assessment at five sampling locations of Sikjang Mountainous Stream using the index of biological integrity (IBI) and Qualitative Habitat Evaluation Index (QHEI) during May - October 2006. The health condition, based on the IBI model, averaged 32 and varied from 27 to 37 depending on the sampling sites. Thus, the stream health was judged as "good" to "fair" conditions. IBI values showed slight differences between upstream and downstream sites. Whereas, QHEI values varied from 75 (fair condition) to 196 (excellent condition) and QHEI at St. 4~5, indicating the downstream reach had significantly lower than the headwater site (St.1). Regression analyses also showed that QHEI values had a linear decrease from the headwater to downstream. This result indicated that habitat quality was rapidly degradated by human influence. Overall, data of IBI and QHEI suggested that the stream health was maintained well in the present but the habitat and biological quality were partially degradated in the downstream. So, the human interference should be minimized to protect the downstream environment.

Reliability-based condition assessment of a deteriorated concrete bridge

  • Ghodoosi, Farzad;Bagchi, Ashutosh;Zayed, Tarek;Zaki, Adel R.
    • Structural Monitoring and Maintenance
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    • v.1 no.4
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    • pp.357-369
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    • 2014
  • In the existing bridge management systems, assessment of the structural behavior is based on the results of visual inspections in which corresponding condition states are assigned to individual elements. In this process, limited attention is given to the correlation between bridge elements from structural perspective. Also, the uncertainty of parameters which affect the structural capacity is ignored. A system reliability-based assessment model is potentially an appropriate replacement for the existing procedures. The aim of this research is to evaluate the system reliability of existing conventional Steel-Reinforced bridge decks over time. The developed method utilizes the reliability theory and evaluates the structural safety for such bridges based on their failure mechanisms. System reliability analysis has been applied to simply-supported concrete bridge superstructures designed according to the Canadian Highway Bridge Design Code (CHBDC-S6) and the deterioration pattern is achieved based on the reliability estimates. Finally, the bridge condition index of an old existing bridge in Montreal has been estimated using the developed deterioration pattern. The results obtained from the developed reliability-based deterioration model and from the evaluation done by bridge engineers have been found to be in accordance.

Statistical evaluation of the cleft lip nose deformity image (구순열 환자 코변형(cleft lip nose deformity) 영상의 통계적 평가)

  • Nam, Ki-Chang;Kim, Jin-Tae;Hong, Hyun-Ki;Rah, Dong-Kyun;Kim, Deok-Won
    • Proceedings of the KIEE Conference
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    • 2005.05a
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    • pp.45-47
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    • 2005
  • Cleft lip is a congenital deformity condition with separation of the two sides of the lip and results in nose deformity. Evaluation of surgical corrections and outcome assessments in nose deformity resulting from the cleft lip depend mainly on doctor's objective judgment. Development of an objective assessment tool in evaluation of the condition and surgical outcome of cleft lip nose deformity patients will help in advancement and evaluation of surgical techniques of cleft lip. Hence, our study aimed on quantitative assessment of a cleft lip nose deformity condition by comparing following parameters gathered from a photographic image of a cleft lip patient: (1) angle difference between two nostril axis, (2) center of the nostril and distance between two centers, (3) overlapped area of two nostrils and (4) the overlapped area ratio of two nostrils. Assessment results of the nose deformity were determined by statistical analysis of evaluation results from three greatly experienced plastic surgeons. In addition, regression model was developed using correlation relationship and factor analysis of parameters from results of the image analysis.

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Condition assessment for high-speed railway bridges based on train-induced strain response

  • Li, Zhonglong;Li, Shunlong;Lv, Jia;Li, Hui
    • Structural Engineering and Mechanics
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    • v.54 no.2
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    • pp.199-219
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    • 2015
  • This paper presents the non-destructive evaluation of a high-speed railway bridge using train-induced strain responses. Based on the train-track-bridge interaction analysis, the strain responses of a high-speed railway bridge under moving trains with different operation status could be calculated. The train induced strain responses could be divided into two parts: the force vibration stage and the free vibration stage. The strain-displacement relationship is analysed and used for deriving critical displacements from theoretical stain measurements at a forced vibration stage. The derived displacements would be suitable for the condition assessment of the bridge through design specifications defined indexes and would show certain limits to the practical application. Thus, the damage identification of high-speed railways, such as the stiffness degradation location, needs to be done by comparing the measured strain response under moving trains in different states because the vehicle types of high-speed railway are relatively clear and definite. The monitored strain responses at the free vibration stage, after trains pass through the bridge, would be used for identifying the strain modes. The relationship between and the degradation degree and the strain mode shapes shows certain rules for the widely used simply supported beam bridges. The numerical simulation proves simple and effective for the proposed method to locate and quantify the stiffness degradation.