• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.2
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• pp.1-8
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• 2024

The expansion joint is installed to offset the expansion of the superstructure and must ensure sufficient gap during its service life. In detailed guideline of safety inspection and precise safety diagnosis for bridge, damage due to lack or excessive gap is specified, but there are insufficient standards for determining the abnormal behavior of superstructures. In this study, a data-based maintenance was proposed by continuously monitoring the expansion-gap data of the same expansion joint. A total of 2,756 data were collected from 689 expansion joint, taking into account the effects of season. We have developed a method to evaluate changes in the expansion joint-gap that can analyze the thermal movement through four or more data at the same location, and classified the factors that affect the superstructure behavior and analyze the influence of each factor through deep learning and explainable artificial intelligence(AI). Abnormal behavior of the superstructure was classified into narrowing and functional failure through the expansion joint-gap evaluation graph. The influence factor analysis using deep learning and explainable AI is considered to be reliable because the results can be explained by the existing expansion gap calculation formula and bridge design.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.1
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• pp.1-29
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• 2019

Related to the previous paper on the typical crack pattern of tunnel lining with NATM, the characteristic defects in reinforced cement concrete lining of NATM tunnel have analyzed with the precise inspection with safety and diagnosis (PISD) by KISTEC. Depending on the reinforcing materials, steel rebar, steel fiber, and glass fiber have been implemented to reinforcing lining in various NATM tunnel constructions. Reinforcing lining with rebar are prevailed on NATM tunnel to countermeasure the weak geological circumstances, to pursuit the economical tunnel sections, and to resist the risk of tunnel deterioration. By the special act on the safety control of public facilities, the reinforced NATM tunnels for more than 1 km length are scrutinized closely to characterize defects; crack, reinforcement exposure, and lack of lining. Crack resistance by reinforcing is shown in comparison with the normalized crack to the length of tunnel. Typical exposed reinforcements in lining have exemplified with various sections. The lack of lining due to the mal-construction, spalling, fire, earthquake and leaching has been analyzed. The cause and mechanism with the field inspections and other studies has also been verified. Detailed cases are selected by the above concerns as well as the basic information from FMS (Facilities Management System). Likewise the previous paper, this study provides specialized defects in reinforced lining of NATM and it can be widely used in spreading the essential technics and reporting skills. Furthermore, it would be advised and amended for the detail guideline of Safety Diagnosis and PISD (tunnel).

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.4
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• pp.479-499
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• 2019

State assessment of an operational tunnel is usually done by performing visual inspection and durability tests by following the detailed guideline for safety inspection (SI) and/ or precision inspection for safety and diagnosis (PISD). In this study, 12 NATM tunnels, which have been operational for more than 10 years, were inspected to figure out the cause of longitudinal cracks for the purpose of modifying the scoring items in the state assessment NATM tunnel related to the longitudinal crack and the thickness of concrete lining. All investigated tunnels were classified into four groups depending on the shape and usage of each tunnel. The causes of longitudinal crack occurrence were analyzed by investigating the correlations between the longitudinal crack and the following four factors: the patterns of ground excavation; construction state of primary support system; characteristics of material properties of the concrete lining; and thickness of lining which was obtained by Ground Penetration Radar (GPR) tests. It was found that influencing factors causing longitudinal cracks in the lining were closely related with the construction condition of the primary support system, i.e. shotcrete, rockbolt, and steel-rib; crack occurrences were not much affected by the excavation patterns. As for the properties of concrete lining materials, occurrence of the longitudinal crack was mostly affected by the following three items: w/c ratio; contents of cement; and strength of lining. When estimating the lining thickness of the concrete lining by GPR tests and taking thickness effect into account in the statement assessment, it was concluded that increase of the index score by an average of 0.03 (ranging from 0.01 up to 0.071) is needed; a more realistic way of state assessment should be proposed in which the increased index score caused by lack of lining thickness should be taken into account.

• Korea Journal of Hospital Management
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• v.13 no.1
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• pp.42-64
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• 2008

This study was conducted to evaluate the quality in medical records by analyzing its completeness through setting up the level of record on the patient's past history and through examining the actual medial records. Targeting the information on the patient's past history in interns' records, residents' records and nurses' records toward 403 inpatients who were admitted first in 2004 at an university hospital due to stomach cancer. We analyzed whether the charts were recorded or not, recording level, the satisfaction with the expectant level of the records in the hospital targeted for a research and the level of agreement. The results were as follows; first, as for the rate of recording those each items, they were high in the chief complaint & present illness and the past illness history. Depending on the group of recorders, the recording rate showed big difference by items. Second, as a result of measuring the level after dividing the recording level of items for the patient's past history from Level 1 to Level 4 by each item, the admission history, the past illness history, and the family history were about Level 3, and the smoking history, the medication history, the chief complaint & present illness, the drinking history and allergy were about Level 2. In the admission department, it was excellent in the interns' records for the medical department. Third, as a result of its satisfactory level by comparing the expect level of a record and the actual record by item in information on the patient's past history, which was expected by the medical-record committee members of the hospital targeted for a study. And forth, we analyzed the level of agreement with Kappa score in the level of 'Yes' or 'None' related to the corresponding matter in Level 1, in terms of information on the past history in the intern's record, the resident's record, and the nurse's record. The level of agreement in the resident's record & the nurse's record, and in the intern's record & the resident's record was from "excellent" to "a little good". There were differences in the level of completeness and in reliability for the information on the past history by the recorder group or by the admission department. The encounter process that was performed by the admission department or the recorder group, indicated the result that was directly reflected on the quality of medical records, thus it was required further study about the medical record documentation process and quality of care. The items that showed the high recording rate quantitatively were rather low, consequently we'd should develop the tool for the qualitative inspection and evaluate the medical records further. And the items were needed to be detailed in the record level were rather low, and hence there needed to be a documentation guideline and education by the clinical departments.