This research presents an method to select explanatory variables to develop deterioration models for bridges. The ranking of candidate variables are estimated using the covariance analysis between the condition ratings and inspection data. To determine the most stationary set of explanatory variables, weighting factors associated with the investigated year and ranking are introduced. Yearly inspected bridge data are classified into multiple subsets using explanatory variables and the deterioration model is developed for each. The condition ratings for individual bridges are predicted using the deterioration model. The prediction error comparison shows that the more representative and stationary explanatory variables are selected when weighing factors are considered.

A monitoring technique of ground anchor force is now studying by measuring the strains distributed on a bearing plate. These distributed strains are measured by a fiber optic OFDR (Optical Frequency Domain Reflectometer) sensor. A sensing optical fiber was attached on the bearing plate at the two radial locations and tested by a universal test machine. The anchor forces can be calculated from the differences of these two trains.

In this paper, damage assessment technology based on statistical pattern recognition technology was developed for maintenance of structure and the performance of the developed technology was verified by vibration test. The damage assessment technique uses the improved Mahalanobis distance theory, which is a statistical pattern recognition technique, and developed to take account of the variability between the measured data. In order to verify the damage evaluation performance of the developed technology, a cable damage test was conducted for a cable-stayed bridge. Experimental results show that the developed damage assessment technology has the capability of extracting information that can determine the location of damage due to cable damage.

The 4th industrial revolution is promoting the development of efficient maintenance technology through fusion with advanced IT technology. Digital Twin technology, an advanced fusion IT technology, is widely used in the fields of plant facilities and processes, performance monitoring of wind turbines and engine. In this study, the application of digital twin technology to large civil engineering structures, especially bridges, was presented.

We are observing the cracking condition of HPC pavement. We used ultrasonic equipment and 3D GPR equipment to inspect cracks. The depth and the deterioration of cracks were good during observation. We are going to observe the crack with caution.

Recently, the number of facilities targeting youth in KOREA has been increasing, but safety standards & manual are absence, and accidents have increased. Therefore, this study should asserts the needs and plan of safety criteria and manual through advanced examples from overseas. Accordingly, The purpose of this study is as follows; First, it investigate the current status for the Youth adventure facility including the main infrastructures of Germany and Switzerland. Second, it suggest on the direction and strategy level of Infrastructures Based on safety and maintenance in Korea.

This research provides analysis result of the vibration behavior of cable-stayed bridge in the time to storm and it provides that vibration behavrior is able to be applied in bridge management.

The purpose of this study is to investigate the causes of corrosion of steel plate deck longitudinal U-ribs and to investigate the reinforcement method. It was confirmed that the corrosion of the longitudinal U-ribs occurred due to penetration water of the bolt hole of the shear key used in construction. The longitudinal U-ribs which were corroded were stiffened by attaching reinforcing plates, and finishing treatment was performed to prevent the surface water from flowing into the inside.

Last few years, many researches on deep learning-based crack detection model have been reported in order to develop an efficient structure inspection method. While developing crack detection deep learning model, many research results reported the importance of the training data. Since most of the research results only qualitatively discussed the importance of training data, this study examine the influence of the training data by experiment, especially in the case of negative samples such as construction joint, spider web and concrete blocks.

As the aging of the facility increases, the safety, durability, and serviceability that were originally possessed by the natural aging deteriorate. Accordingly, periodic safety inspections, repair and strengthening are the basic procedures for th maintenances of facilities. However, except for some facilities that are prescribed in the law, the safety and maintenance of facilities are still insufficient. Especially, social welfare facilities, which occupy the majority of small-scale vulnerable facilities, have a high proportion of old facilities with many years of age, leading to major damages that affect the durability and safety of facilities. The purpose of this paper is to identify the main damage and its causes according to the change of the years of social welfare facilities, and to use it as a basic data to suggest reasonable maintenance methods.

The widespread sensors in a structural monitoring system provide vital support to its operation. Data is obtainedf rom sensors in a structural health monitoring system for integrity assessment of the structure, and false alarm will be frequently triggered if a faulty sensor is detected. In this study, a proposed method based on machine learning algorithm and Gaussian distribution is present to identify sensor fault.

The camera movement can cause considerable error in the computer vision-based displacement measurement because the camera is generally placed far from the region of interest. The camera movement, which is difficult to avoid particularly in the long-term measurement, hinders real-world applications of the computer vision-based displacement method. This research proposes a practical means of long-term displacement measurement by using a novel camera system. In addition to the conventional camera-based measurement, an auxiliary camera is used to compensate the camera motion-induced error. Experimental validation is conducted in the laboratory environment.

This paper discusses the loads on bridges based on long-term measurements. Applied Loads such as winds, earthquakes, temperature variations and traffic effects have been monitored on an existing bridge from the completion of the structure to now. It is confirmed that the monitoring results are within the design values.

Safety, Durability, and Usability of the Concrete Structure affecting among, there are crack and leakage the main damage is crack and leakage. Especially, Leakage is accompanied by Efflorescence, and provoke steel corrosion, exfoliation. This leakage is leaked to the exterior of the concrete surface in the shape of line or face, the method of repair varies with the shape of leakage. Accordingly, this paper will introduce case analysis of the shape of the water leakage to water leakage site in the lining structure of the NATM tunnel for utilize investigation method and basic data for the method of repair.(leakage, Efflorescence)

Currently, the cable safety management of cable supported bridges is calculated by the ratio of the measured tension to the design tension. The measurement of the tension is performed by indirectly estimating the acceleration measured at the cable surface in terms of the tension. The method of converting the cable vibration response (acceleration) into the tension is disadvantageous in that the damage of the individual strand (or wire) in the cable is not clearly reflected in the tension because the measurement is not reliable and is managed only by the total tension. The purpose of this study is to improve the cable safety management system by evaluating how the damage of individual strand of MS type cable, which is mainly applied to cable-stayed bridges, affects the safety level managed by level of cable tension.

The statistical data from WIM has been used only for traffic management and fatigue evaluation of structures. In this study, the algorithm using ESAL for assessment of pavement condition is proposed. To verify the algorithm, WIM system using PVDF sensor was installed on the pavement of bridge deck, also the automatic assessment software was developed. For the reliability verification of the alogorithm, further comparative study based on the long-term data is needed.

In the cable wall system, the cable tension force can be changed by the various reasons. After 10 years from the construction of cable wall system in Hamad Medical City Womens Hospital of Qatar, an average of about 16% of the tension force was decreased. Since the tension loss can affect the structural capacity and stability, the re-tightening was carried out up to about 90% of the design tension. Also, the annual regular inspection including the measurement of cable tension is proposed as the maintenance plan.

Bridge maintenance should be performed on the basis of the shape and specifications data of the bridge in operation, but the paper and computerized drawings of 2D and 3D models are used in the field. Therefore, it is very difficult if not impossible to modify the specifications that change with the inspection cycle. Recently, advanced optical technology have enabled the acquisition of 3D digital data (LiDAR) scanned actual structure, overcoming the limitations that may arise from the maintenance of existing drawing bases. This paper will introduce bridge that utilizes digital pseudo-reality(DPR)based bridge maintenance system using 3D digital data obtained by scanning a bridge currently in operation.

Recently, measurement monitoring is actively used for safety management of facilities. However, since the field measurement data contains many outliers, a preprocessing process is required for reliable behavior analysis of the data. In this paper, we present a detection method of time series outliers and its applications. And we propose the precaution for the preprocessing process.

In this study, digital image processing was used to estimate the tensile forces of the remote hanger cable using image-based back analysis method. A portable digital camcorder was used as a vision-based system considering convenient and economical aspects for use. The ambient vibration test was performed on a suspension bridge to verify the validity of the image-back analysis method of measuring the hanger cable tensile force.