Prediction of compressive strength of concrete by Maturity Method is applied in construction site. However, due to the use of wired type high-priced equipment, economic efficiency and workability are falling. In this study, a newly developed concrete embedded wireless sensor is used to perform a mock-up test. Next, the concrete compressive strength of the Maturity Method is predicted using Saul and Plowman's function as measured temperature data. The predicted concrete strength at the beginning of the age was the actual strength and stiffness, but the error rate was less than 1% at 28th day.

This study analyzes the error factors of cable tension estimation method using linear regression and suggests the upper and lower limits of tension error. The tension estimation method using linear regression is affected by errors such as boundary condition, natural frequency, cable length, and mass density. The boundary condition error analyzes the error rate for the case where the error occurs the greatest. The error of mass density and length is analytically derived, and the error of measurement natural frequency is analyzed by Monte Carlo simulation. Among these errors, the boundary condition error and the measurement natural frequency error are expected to be able to present the upper and lower limits of the error that can be caused to the estimated tension by the corresponding error factor.

This study provides a simple introduction to photo-catalyst technology to self-clean the organic dirts and degrade the air pollution in urban environment. Moreover, it shows the spray coating technique was applied to effective coating on the surface of concrete specimen by using as-developed integral photocatalyst solution. In order to examine photo-catalytic activity and degradation effectiveness on the surface of the concrete specimen, the UV-LED lamp was used as a light source to activate the photo-catalysis. Methyl-orange dye was used as an indicating method to speculate the photo-catalytic reaction and UV-VIS spectrometer to determine the molar content of the organic dye.

The stability of the river in the restored river is an important issue in maintenance and management. Bed elevation change simulation can be an effective way to predict the direction of river restoration by predicting long and short term bed elevation change of river. A 2D numerical model (CCHE2D) was implemented to simulate the long-term bed elevation change. The study area is located in the Cheongmi-Cheon Notap-ri and 1.2 km long. The flow scenario was constructed using the flow data that was measured at the water level observatory located upstream at the Janghowon Bridge. The bed elevation change pattern according to restoration of abandoned channel was analyzed and the stability of river was evaluated.

The clogging of transverse drainage pipes in NATM tunnel is attributed to the hydraulic pressure generated on the outside of lining concrete and affects the safety of the whole structure in the long term, necessitating a keen attention in terms of its maintenance. Accordingly, this paper will introduce an analysis on the effect of the clogging of transverse drainage pipes on the lining structure based on the comparison between the inspection of the clogging of transverse drainage pipes and the visual inspection (leakage, efflorescence).

There are more than 9,300 bridges on the highway, of which about 34%(3,150) are PSCI bridges. The safety of these bridges is directly influenced by the tensile strength of the internal tendons(strand) and the strength of the concrete compared to the reinforcing bars from the design viewpoint. Therefore, in this paper, for the maintenance plan considering the damage of the internal tendons, the internal tendon cutting and truck loading test was conducted and deflection and appearance status change was analyzed. As a result of the test, deflection increased and flexural cracks occurred on center of the girder. And longitudinal direction cracks followed tendon placement occurred on a bottom flange.

Steel water gate can be vulnerable to corrosion problem, since it is generally contacted with water or maintained with relatively high humidity condition. In this study, to evaluate the level of corrosion damage of water gate, corrosion exposure test was conducted using monitoring steel plate and monitoring sensor in actual steel water gate. From exposure test results, corrosion rate and corrosion environment were examined depending on the height or the structural type of water gate.

It is important to operate appropriate measurement system of cable bridges for the efficient construction and maintenance. The main results of study on the optimal construction detail method of measurement for individual cable bridge are described. In this paper, the basic guidelines for the cable bridges measurement system is presented such as sensor classification, installation location and performance standard for the installation of the optimal measurement system of cable bridges on expressways.

A national infrastructure is a physical and human system that can have a significant impact on life, property, and the national economy if its function is paralyzed. It is also used for energy, telecommunications, transportation, finance, healthcare, nuclear energy, environment, important government facilities, etc. In this paper, we present a disaster risk assessment method and alternative method considering the regional characteristics of the national infrastructure through the evaluation of disaster risk.

The Ministry of the Interior and safety provides detailed guidelines for the establishment of a national infrastructure protection plan for each management agency in order to maintain a minimum functional continuity of the national infrastructure. However, in the case of the Guidelines for National Infrastructure Protection Plan, the proposed standards are based on common issues for the protection of the national infrastructure system and fail to provide the correct guidelines reflecting the characteristics of each sector. In addition, since the risk assessment procedures such as risk and impact analysis are conceptually presented, evaluation based on the characteristics of the facilities is insufficient, and in some agencies, it is performed perfunctorily. Therefore, the present study analyzes the present state of the National Infrastructure Protection Plans and draws common problems, and suggests ways to improve the vulnerable parts in the Guidelines for National Infrastructure Protection Plan through the case studies of advanced foreign countries.

This paper presents a methodology for assessing the old-age level of facilities. In order to evaluate the retirement level, a method of selecting the indicators related to the old age was presented and a method of assessing the old age level through the measures of the selected indicators is suggested to improve the reliability of evaluation results and to develop evaluation algorithm. In the future, it is expected that it will be possible to efficiently manage the old facilities through the convergence of the old- level evaluation method and IoT sensor, big data, and artificial intelligence.

In this study, the method of measuring cable tension using the vision-based system was proposed, and a portable digital camcorder was used as a sensor for the measurement of the cable tension positioned at remote distances, considering the user convenience and the cost-efficiency. The vibration method (accelerometer, vision-based system) was used to measure the cable tensions, and the result was compared and analyzed.

This study is proposed to establishment of collaborative environment utilizing BIM-based digital model for cable bridge oversea market entry. It is important to utilization of digital model based framework as such analysis interface, pre-construction technology, data sharing system by design company, general contractor, maintenance agent and government office.

This study aims to investigate the qualitative and quantitative performance of concrete defect using Pulsed Thermography (PT) and Pulse Phase Thermography (PPT) techniques. The experimental study was carried out on a concrete specimen in-placed artificial defects with various depths and sizes. The signal-to-noise technique was used to compare the contrast between the two methods. The results showed that the thermal images obtained from PPT show clearer than those from PT (using contrast-based method).

The durability of the steel structure can be affected by atmospheric corrosion environments as temperature, humidity, airborne salt etc.. However, atmospheric corrosion environments can be locally changed depending on structural condition and shape. To estimate the local atmospheric corrosion environments depending on structural member exposed to the marine environment, corrosion level of structural member in steel bridge was examined from exposure tests.

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 precautions for the preprocessing process.

Concrete has recently been modified to have various performance and properties. However, the conventional method for predicting the compressive strength of concrete has been suggested by considering only a few influential factors. so, In this study, nine influential factors (W/B ratio, Water, Cement, Aggregate(Coarse, Fine), Fly ash, Blast furnace slag, Curing temperature, and humidity) of papers opened for 10 years were collected at 4 conferences in order to know the various correlations among data and the tendency of data. The selected mixture and compressive strength data were used for learning the Deep Learning Algorithm to derive a prediction model. The purpose of this study is to suggest a method of constructing a prediction model that predicts the compression strength with high accuracy based on Deep Learning Algorithms.

In this study, the resistance of chloride penetration and sulfate attack of mortar substituted heavyweight waste glass were evaluated. As a result, chloride penetration depth and diffusion coefficient decreased with the substitution of waste glass, chloride penetration resistance is increased. For sulfate attack resistance, the effect of heavyweight waste glass was little.