In this study, a magnetic flux leakage (MFL) method that is known as a suitable non-destructive evaluation (NDE) method for continuum ferromagnetic members was applied to detect the various types of local damages of the steel wire ropes. 3types of artificial damages, such as cutting, corrosion and compression, were formed on wire rope specimen. A multi-channel MFL sensor head that can maintain the constant lift-off was fabricated to scan the wire rope specimen. The fabricated MFL sensor head measured the magnetic flux signals from the three types of damaged specimens. The capability of damage detection according to damage type was verified from the measured MFL signals from each type of damage. And, the characteristics of the MFL signals were compared and analyzed by type of damage.

In this study, the scope of facilities subject to performance evaluation and the status of facilities subject to performance-based evaluation are discussed, and the methods for improving performance-based evaluation performance assessment performance status through review of performance assessment order status

In this study, the relation between the direction of the reinforcing bars and the arrangement of the electrodes in the concrete resistivity measurement was experimentally examined. The results showed that the apparent resistivity was lower in the parallel measurement with the reinforced concrete bars, and the value of the apparent resistivity was higher as the measurement direction is closer to perpendicularity against the rebar.

In this study various investigations were carried out to analyze the causes of leakage for 20 years on the slope of the downstream side of the dam during the ○○ dam precision safety diagnosis. Analysis showed that the possibility of underground water flowing through the valley section of the mountain area extremely low, and that direct leakage of the reservoir's freshwater was confirmed as the main leakage path.

In case of cable supported bridges, the cable system is a very important element that transfers the load of the girder to the pylon or substructure is the most important feature. The safety management of these cable systems is very important because they are directly linked to the safety of the entire bridge. This paper presents the applicability of the acoustic emission (AE) method is one of the non-destructive evaluation methods, is evaluated for the detection and monitoring of bridge cable damage. In order to verify the performance of the cable inspection method using the AE sensor, experiments were conducted. As a result, it is considered that the acoustic emission technique will be able to detect corrosion breakage and signs of rupture of cables if sufficient database of AE signal with various environmental conditions is secured.

The number of deteriorated buildings is increasing every year, and the number of accidents is increasing due to the lack of timely diagnosis, maintenance, and reinforcement. The number of specialized institutions that can diagnose this is limited compared to the number of deteriorated buildings, and a lot of time and resources are invested in the absence of advanced diagnostic techniques based on the evaluation factors of deteriorated buildings. Therefore, it is necessary to build an improved building diagnosis platform by examining the reliability of existing diagnostic evaluation factors for accurate and rapid building diagnosis.

In this study, hydrological safety assessment on dam facilities was estimated using dam hydrological safety evaluation result and in-depth inspection assessment result and considering climate change scenario. Hydrological safety assessment of the existing dam was performed by calculating the PMP/PMF using the climate change scenario. In this study, it was evaluated hydrological safety assessment of existing dam considering climate change scenario(RCP 8.5).

The purpose of this experimental study is to investigate performance for atmosphere purification of concrete sidewalk block using high performance Nano TiO2 Carrier. As a result, concrete sidewalk block using high performance Nano TiO2 Carrier was confirmed to be superior than commercial TiO2 concrete sidewalk block to atmosphere purification.

Measurement items of phenomena reflecting the overall condition of the structure during the measurement for safety management in the dam include water volume and displacement depending on the number of water leaks. Leakage measurements, which are important indicators to be measured on a dam, require significant accuracy and reliability. However, the dam design basis includes general measurement equipment, but the lower the limit for calculating the water leakage, and the lack of accuracy and reliability is a phenomenon. Therefore, in order to improve accuracy and reliability of the dam's major measurement items, the standards of the dam water measuring meter and the suitability of the water leak calculation formula (based on USBR) are reviewed to elicit problems and suggest solutions.

The purpose of this experimental study is to develop an water soluble silicone acrylic surface finishing material of car parks. The heavy metal contents test was conducted in order to supply a guideline for developing a top finishing material. As a results, the sample was satisfied with the quality standard regarding heavy metal contents which is prescribed in KS F 3888-2 of En 71-3. As conclusion, this study confirmed that the developed top finishing material could be an optimized material usable for car parks’ deck.

In this paper, an experimental design of an experimental study was carried out to evaluate the pullout performance of an cast-in-place anchor. Then, an analytical examination of the planned experiment was carried out. The size of the specimen was determined by reference to the installation depth of the anchor. The test specimens were checked for bending cracks according to design standards. The numerical analysis model was constructed according to the final test plan, and the result of the analysis was that the crack occurred at the center of the section. Therefore, the ultimate specimen which cone fracture of concrete was induced by modeling by reinforcing steel reinforcement on the outside of specimen was planned.

The impact factor response spectrum of bridges are generated based on the number of vehicle axles (one and three axles) and their boundary conditions (simply supported and both ends-fixed). In order to investigate the impact factor variation, a RC slab bridge aged over 40 years is considered. The natural frequencies for the current and undamaged initial state are evaluated from field test and FE model, respectively. Considering the natural frequencies and the generated response spectrum, the impact factors for each state are determined. From the result, the impact factor ratio defined the current to initial impact factor are almost same except the one axle and both ends-fixed case.

In this study, we adapted very low resolution (240x320 = 76,800 pixels) images by which it is difficult to detect cracks. An automatic crack detection technique has been studied using digital image processing technology for low resolution images of sewage pipeline. Authors have developed two algorithms to detect cracks. The third step covers an algorithm developed to find optimal threshold value, and the sixth step deals with algorithm to determine cracks. As the result, in spite of very low-resolution images, the performance of crack detection turned out to be excellent.

Acoustic Emission (AE) technique applied to detect the crack occurrence of the actual beam element. An optimum position for a limited number of AE transducer was considered to accurately detect the location of the cracks in the three-dimensional space. Six AE transducer was used to detect cracks in the L400mm×H200mm×T100mm region, and several position combinations were applied. Considerable six position combinations were selected, and the weak or incorrect position detection was investigated. The optimum position applied to the experiment for actual beam element and the detected crack position was compared with the visual inspection location. A reliable crack position detecting was confirmed for loadings.

Generally, the dew condensation generated in the tunnel does not directly affect the concrete structure However, falling water due to dew condensation brings directly with a high possibility of defection to the train line. In addition, moisture inflow due to dew condensation may induce malfunction or failure of various electric and fire facilities installed in the tunnel, which may cause abnormal signals or accidents and so on. In this paper, we explain the case of dew condensation site and analyzed the cause.

In this paper, real-time damage assessment technology was developed for detection the damage of bridges in real time and the performance of the developed technology was verified by vibration test. Real-time damage assessment technology was developed by combining statistical pattern recognition technology and simulation technology. In order to verify the developed technology, the earthquake response acquisition experiment was conducted according to the cable damage of the model cable-stayed bridge. As a result, it was confirmed that the developed real-time damage assessment technology can provide information on the location of damaged cable.

The latest precise inspection for safety and diagnosis has found the clogging of transverse drainage pipes in NATM tunnel, resulting in hydraulic pressure generated on the outside of lining concrete that poses a safety threat to the tunnel structure. Accordingly, this paper aims to conduct a safety analysis on using NATM tunnel that currently suffers the clogging of transverse drainage pipes based on its numerical analysis.

This paper presents statistics that evaluate the results of a precision safety inspection and precision safety diagnosis over the past five years. The impact and degree of poor inspection and diagnosis were analyzed by dividing contract amount by rate, implementer, and managing body. The purpose of the analysis is to elicit problems and measures in the system.

This paper developed the guideline for the safety and health(S&H) file drawn by a client in construction plan stage. According to the announcement of revised Occupational Safety Health Act(February 9, 2018), the construction client should make or manage the three S&H files in the plan, design, and work stages respectively. By analyzing S&H management systems led by the client and surveying the opinion of construction participators, the contents and practical method of the S&H file in the plan stage was proposed. Client should control hazard in construction site through the S&H file. And, it should include important S&H condition dealt with design and work stages as well as selection method of competent designer and contractors with S&H capacity.

Recent development in North Korea has heighted the security situation in Northeast Asia region. Also, the discussion and interest relation to reunification of the government and academia including korean people have been actively developed. Therefore, this study should asserts the needs and plan of infrastructure improvement in the Korean Peninsula. Accordingly, The purpose of this study is as follows; First, it investigate the current status for the civil structures facility including the main infrastructures of North Korea. Second, it estimate on the risk and technology level of Infrastructure Based on questionnaire and interview refugees of North Korea.