This paper carried out experiments on reinforced concrete beams strengthened with prestressed NSM CFRP tendons. One of test objectives is to find out strengthening effect with concrete damage rate 0%, 30%, and 60%. Test revealed that strengthening performance of specimens with 30% and 60% presented similar to 0% strengthening specimen.

In this study, the fatigue behavior of reinforced concrete beams strengthened with prestressed NSM CFRP tendons. One of test objectives is to find out strengthening effect with concrete strength 20MPa, 40MPa. As a result of the study, the fatigue behavior of the concrete beams strengthened with prestressed NSM CFRP tendons were considered to be good.

This study is a case of construction after bridge demolition due to the aging of bridges operating the railway. Due to the influence of the pier vibration on the railway, the influence of the railway line, the construction period, etc., the P.B.S technique was applied to the coping pile foundation. It was completed in 5 days per 1 bridge pier by the PBS method. Since it is constructed in the dry season (from October to April) without vibration and noise, it can be installed safely on the rail rail of the pier of the bridge .

In this study, the compressive force is evaluated for the SMA surface reinforcement member which is to improve the bond capacity at cold-joint in PC member. As a result, the total compressive force can be estimated according to the number of wires.

In this study, chloride penetration in a repaired concrete using magnesium polymer ceramic (MPC) was assessed based on the NT BUILD 492. To investigate the effect of repaired material on chloride penetration, a cylinder OPC concrete specimen was fabricated and attached on the surface with MPC. Then, chloride penetration test was carried out on the combined concrete sample at a constant applied voltage (30 V) for 6 hours. It was found that most of chloride sources was passed though the interface between OPC and MPC, resulting in a loss of chloride in the material. Thus, it is needed to modify the conventional chloride penetration test for the repaired concrete specimen.

This study evaluated the P-M interaction behavior of RC columns strengthened with section enlargement method with the supplementary V-ties. The estimated P-M interaction is well corresponded with test results.

This paper investigates the effect of nanomaterials on the piezoresistive sensing capacity of cement-based composites. Carbon nanotube, graphite nanofiber filament, carbon fiber were considered along with a cement composite which is included slicafume. After deriving optimum flowability, cement composites contained carbon materials were made respectively. Then, cyclic compressive test was performed with cement composite that contained 5% of each nano material.

In this study, compressive tests were carried out on seamless circular tubular short columns with corrosion-damaged end, and investigated change in compressive strength of columns with local corrosion at the end. Local corrosion was artificially introduced by milling machine, and differed in corrosion depth (0, 1.5, 3, 4.5 mm), corrosion height (0, 20, 60, 120 mm), and corrosion circumference (0, 90, 180, 360˚ ). As a result, the compressive loads were linearly decreased with increasing of corrosion degrees, and a quantitative evaluation for residual compressive strength of seamless circular tubular short column with corrosion-damaged end was suggested by using corroded volume loss ratio.

This paper presents an improved double diffusion model (DDM) for the alkali silica reaction. By this model we could simulate the diffusion process of alkali both in concrete (macro-scale) and aggregate (micro-scale). As the alkali source, either internal or outside cases can be analyzed through this model. Concrete with different size groups of aggregate distribution also can be analyzed. Numerical simulation is utilized to analyze the ion concentration both inside the concrete and aggregate at different moment of penetration.

The Bridge Safety Department of Seoul Metropolitan Government has regularly conducted precise inspection and precision safety inspection to maintain the bridge's function and safety. During a precise safety inspection in 2015, oil leakage progression was found on the cable anchorage system within the stiffened girder of Nilsen Arch bridge and as a follow-up measure, the cable replacement for the cable ACD11 was carried out in order to identify the relevant cause of the oil leakage and evaluate the integrity of the existing cable. The mechanical properties and fatigue performance tests of the cable strands of bridge inservice for about 20 years and comprehensive analysis of oil leakage were carried out. They were described hereby.

In this study, to develop a risk assessment tool for geotechnical risk evaluation of local reservoirs. Generally, local reservoirs had some problems which is ageing, poorly compaction, differential settlement, leakage of adjacent conduit, material problem of adjacent spillway etc. Therefore, this study to develop geotechnical failure mode scenario for local reservoirs, and risk assessment tool considering internal erosion process. In addition, to carried out risk evaluation for pilot reservoirs and analyzed failure probability.

In this study, the partial correlation between the expansion and the vertical displacement excluding the temperature and the correlation between the expansion and vertical displacement and the average temperature of the reinforced truss member was analyzed. The correlation coefficients between temperature and expansion, temperature and vertical displacement were .929 and .874, respectively. The correlation coefficient between vertical displacement and expansion was 0.860 and partial correlation coefficient excluding temperature effect was 0.268.

This study investigates the coating deterioration of water-borne inorganic zine under marine environment. In order to evaluate the corrosion environment at installed site, the corrosion currents were measured by atmospheric corrosion monitoring(ACM) sensor. The deterioration grade of water-borne inorganic zine was investigated by visual inspection method depending on ASTM D610. The deterioration grade of structural member was compared based on corrosion environment such as wet time, amount of deposited salt etc.

Painting system are widely used to prevent corrosion damage The coating method on various corrosion preventive method was usually adopted for the functional ability and excellent appearance. In this study, to evaluate the deterioration curve of coating system for steel bridge, the combined cyclic corrosion test was conducted base on ISO 20340. The deterioration areas were measured depending on corrosion cycle. The deteriorations of newly-built coating were compared with those of re-coating.

Corrosion durability of steel member can be related to its installed environmental conditions such as relative humidity, rainfall, atmospheric temperature, and air pollution(SO2, chloride). Also its installed environmental condition may differ depending on the shape of structural member. Therefore, In this study, to evaluate the difference in the corrosion damage according to the installation environment of steel structural members, outdoor exposure test was carried out from attaching unpainted monitoring plate and atmospheric corrosion monitoring sensor for actual steel bridge with various structural detail.

Recently, accidents caused by the aging of structures are occurring frequently in the world. As a result, maintenance and accident prevention of structures are required. In this study, for the purpose of addressing these issues to solve these problems, we developed a non - destructive inspection technique using thermal imaging and planned damage detection process. we set up a scenario to detect the invisible excursions, cracks, and internal damage by sensing and analyzing the thermal energy radiated by the stainless steel test piece (STS304) with infrared thermal imaging equipment.

This paper presents the measurement of earth anchor tension using fiber optic OFDR sensor. Fiber optic OFDR sensor was configurated with tunable laser source, APD with polarization beam splitter and high speed DAQ system. Strains of pressure plate and anchor head were measured and compared using strain gage and fiber optic OFDR sensor. Fiber optic OFDR sensor signal showed linear increase in both tension and compression direction as tensional force increase. This results shows the capability of fiber optic OFDR sensor for monitoring earth anchor tension.

In this study examined the strength of wall concrete using insulated molds and non-insulated forms by monitoring the strength of the structure using a wireless sensor network by maturity method. It was confirmed that the temperature and compressive strength of the structures are monitored in real time, along with effective strength control.

In this study, We introduce a case of reconstruction of ASSM tunnel with various leakage paths. The Reconstruction method applied NATM waterproofing system to ASSM because of various leak paths and leakage

Recently, the importance of facility maintenance has been increasing due to the problems caused by the occurrence of new types of disasters and the deterioration of facilities. However, it is difficult to maintain consistent facilities because the related laws are dispersed depending on the size and purpose of facilities. In addition, when a collapse occurs, there is difficulty in response activity. This paper analyzes the problems in the maintenance of facilities in accordance with the deterioration of facilities and draws out the Mediumand long-term development plans of facility maintenance field