To suggest the preliminary data for effective maintenance of bridge structures, the damage patterns of expressway bridges are quantitatively analyzed in the present study. The defects are the primary damage, and the deterioration occurred around the joint.

In this study, the grouting condition and the corrosion of prestressing steel in old PSCI bridges were investigated. There are many places where the construction quality of the grout is poor to prevent the corrosion of prestressing steel. Partial surface corrosion was found regardless of the construction condition of the grout.

Post-tension system was applied most PSC bridges in Korea. Also Grouting was applied to prevent corrosion of the strand. For this reason, it is difficult to inspection the condition of the strand after completion. Therefore, in this paper, the Nondestructive testings(NDTs) developed at domestic and foreign was investigated. In addition, the current level and limit of the NDTs were analyzed considering the existing bridge environment. As a result of the study, Strand condition inspection using NDTs have been analyzed to have technical and environmental limitations.

After Po-Hang earthquake(Magnitude 5.4, Nov.15. 2017), total 55 cut slopes along the expressway within 25km from earthquake source were examined if there were any signs of instabilities such as rockfalls, surface failure, cracks and wood tumbles. Examination revealed that no cut slope showed any abnomality. This result raise an issue if design of slope against seismic activity is necessary. In this paper, necessity and seismic analysis method are discussed.

A detailed guideline was prepared to explain the contents of underground safety management guideline and to prevent confusion in the initial implementation of the law to underground safety impact assessment and underground safety inspection subjects. "Special Law on Underground Safety Management", which was created to prevent the safety of the people from frequent occurrences due to frequent occurrence of subsidence, has been systematically settled in the course of design, construction and maintenance of underground facilities. When it works smoothly, it can be said that national security is guaranteed.

Bridge inspection based unmanned aerial vehicle (UAV) has received considerable attention due to its several advantages such as reliability and safety as well as saving time and cost. An unmanned inspection equipment for bridge inspection is composed of UAV and imaging devices such as RGB cameras and infrared cameras. However, many challenging issues should be solved in order to apply this technology to the field. In this paper, an UAV based crack detection method is investigated. To detect the cracks, the image processing techniques with deep learning algorithm are used. To build the spatial information of aging bridge, 3D point cloud based background model is generated.

It is necessary to improve the structure inspection system that integrates various new technologies such as artificial intelligence, big data, and the internet of things, which are core technologies of the 4th industrial revolution in oder to cope with continuously increase in the number of structures and to maintain efficient maintenance against aging.

Steel structures have been prevented from corrosion damage using by paint coating. The durability of paint coating can be changed by installed environment condition of steel structures. In this study, thus, deterioration test of paint coating was conducted for various environmental condition. Deterioration levels of paint coating specimens exposed by each artificial environment were examined from visual inspection.

In this study, the regular inspection check-list for vulnerable areas of debris flow was developed in order to cope with expected debris flow in urban areas. First, items for regular inspection were obtained by the Delphi technique, and the regular inspection check-list was developed based on obtained items. The check-list was verified and improved by means of applying it in 2 test-bed site.

According to this study, small-scale construction projects with a construction value of less than 300 million won are placed in the blind spot of safety management inspection. Therefore, it is necessary to improve the management and inspection system that reflects characteristics of small-scale construction sites.

The purpose of this research is to consider the qualitative and quantitative performance of reinforced concrete deteriorations using active infrared thermography (IRT) technique. An experiment of five different cases of environmental conditions was conducted on a concrete slab in laboratory. A comparison of the IRT results between normal and reinforced concrete is also discussed. The results showed that the absolute contrast between defective area and non-defective area increases with the increment of ambient temperature. Besides, the values of absolute contrast above delamination obtained from normal concrete showed high than those under effect of reinforcing steel bar.

There are some risk and inefficiency when inspectors make an inspection of the bridge. To remove the risk, many demonstration studies of bridge inspection based on the unmanned inspection equipment are actively in progress recently. Because the unmanned aerial vehicles enable the inspectors to be more safe. This study investigates the demonstration project of bridge inspection based on the unmanned inspection equipment in USA and Japan.

This research aim to investigate the qualitative and quantitative performance of concrete deteriorations using Pulse Square Thermography (PST) technique. An experimental test of ten cases was conducted on a concrete slab specimen under different meteorological conditions. The results showed that the absolute contrast between defective area and sound area decreases with the falling of ambient temperature. Besides, the delamination with identical size but placed at a deeper position indicates lower absolute contrast than the shallow delamination.

In this study, the integrated management code of damage information in bridges using the data from unmanned inspection equipment (i.e., drone with hybrid imaging equipment) was proposed. It was found that the integrated management code could be used in developing bridge management system based on 3-dimensional information model of bridge.

Due to limited human resources, budget and difficulties in accessibility, inspections are not available at proper time. Advanced Technology such as ICT, Sensing, and AI can innovate the management of structure. So, we introduce our developed equipment and future management plan.

The ground settlement has been occurred recently, therefore, it is necessary to conduct the safety inspection of ground settlement. This study suggests the case study on the ground settlement safety inspection.

In this study, the integrated management code of damage information in bridges using the data from unmanned inspection equipment (i.e., drone with hybrid imaging equipment) was proposed. It was found that the integrated management code could be used in developing bridge management system based on 3-dimensional information model of bridge.

Due to limited human resources, budget and difficulties in accessibility, inspections are not available at proper time. Advanced Technology such as ICT, Sensing, and AI can innovate the management of structure. So, we introduce our developed equipment and future management plan.