In this study, Corrosion behavior in mortar was observed by the passage of time by using EIS method. As a result of EIS experiment, equivalent circuit and changes of Impedance parameter could be observed. In addition, it was confirmed that impedance of rebar in concrete and corrosion rate according to the amount of NaCl and LiNO2 were different.
In this paper, an magnetic hysteresis monitoring result for various PS tendon is indtoduced to apply the EM sensing technique to measure the tensile force of PSC bridge. The tensile force of PS tendon is a very important factor in the performance evaluation of PSC bridges. To measure the tensile force of PS tendons, the EM sensing based NDT method was developed but the proposed method cannot be applied to various class of PS tendons. The permeability of specimen was gradually decreased according to increase of tensile force.
In this study, in order to survey the concrete dam leakage use the Thermal Line Sensor (TLS) temperature monitoring instruments. The temperature monitoring locations are two drain hole of concrete dam and the upsteam water temperature of dam.
Many existing RC Buildings were built before the seismic code was established, they need seismic retrofit performance. In this study, presents the evaluations of seismic performance and displacement ductility for two type RC Frames : existing RC frame without SRF(Super Reinforcement with Flexibility) and RC frames strengthened with SRF.
Experimental investigation of the tuned liquid column damper (TLCD) is a primal factory task prior to its installation at a site and is mainly undertaken by a real-time hybrid simulation. In this study, a noncontact standalone vision sensing system is developed to replace a series of the conventional sensors installed at the TLCD tested. The versatile measurements of the system is theoretically and experimentally evaluated through a wide range of lab scale dynamic tests.
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.
Interest and requirement of seismic qualification for nonstructural components are increasing in South Korea after observing nonstructural component failures by Kyungju earthquake on 12, October, 2016. However, amplification of input motion by hight of building are not considered in most of seismic qualification or design for nonstructural components in South Korea. In this study, seismic loads are compared which is applied to seismic qualification or design for structural or nonstructural component. As a result, amplification effect by vertical location in a building for nonstructural component should be considered for efficient seismic qualifications. Also, further studies are needed how to apply those amplification effects to required response spectra.
In this study, the shake table tests were performed for seismic performance evaluation of fire protection riser pipes. The specimen was subjected to a tri-axial time history shake table test with acceleration levels corresponding to the 0.5g and 0.7g ZPA design level.
For the purpose of evaluating the strength of high-strength concrete, the strength of small diameter core was compared with 100, 50, and 30 mm cores. In case of high strength concrete, the smaller the core diameter, the lower the strength was. It is probably due to the disturbance of specimen during coring. Therefore, it is considered that it is difficult to apply in the field.
In this study, to verify the validity of the dynamic responses of cables with the image processing technique, the lift-off test and vibration method (Vision-based System) were used to measure the cable tensions, and the results were compared and analyzed.
In this study, a vision-based monitoring system was applied to measure the dynamic characteristics of the stay cable. The image was acquired during the day to measure the dynamic characteristics of the stay cable and the image filter processing algorithm was applied to reduce the analytical noise of the image.
Most of the domestic jetties of jacket structure were designed by SACS with design criteria based on “Design Standards for Harbour and Fishery Port”. In fact, companies of structural maintenance and Inspection fail to conduct proper safety assessment of jetties of jacket structure using SACS due to a manpower shortage. But instead, they are using MIDAS to conduct safety assessment of these jetties as an alternative to using SACS. The purpose of this study is to provide the rational way for MIDAS user to assess jetties of jacket structure using SACS.
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.
This study compared the result applying two analysis methods based on Newmark Sliding Block theory to calculate permanent displacement that is an estimating factor for seismic safety of Fill Dam. It was analyzed FEM numerical coupled-analysis and Makdisi-Seed method. The permanent displacement for the body of dam during earthquake indicated similar displacements with each of them at the same seismic load.
A fatigue crack occurred in the vicinity of the center-stay area is generated. Therefore, the stress and caused of occurrence of each member are analyzed by measurement. When similar cases occur in the future, they shall be utilized as basic data such as research methods and establishment of mesures for maintenance.
As the road sink phenomenon occurred at the center of Seoul area in 2014, the road sink phenomenon was emerged as a social issue in Korea. Even so far, governments, municipalities and related experts have been making a lot of efforts to prevent road sink, but it is still happening all over the country. The most effective way to prevent road sink phenomenon is judged as a policy alternative. Therefore, In this study, we analyzed the representative policy cases in the government for providing the behavioral procedures and checklists to be use person in charge.
In this study, Determine weight of damages, which were excerpt from analyzing inspection reports in Road Tunnel, using AHP technique. The result of weight of damages using AHP. is a slight difference from current weight one. So we need to think about this conclusion as new weight of damages in road tunnel.
In this study, we analyzed the effect of heating curing on apartment construction in clod weather frame construction. The temperature was measured using a temperature sensor in winter and in non-winter season, the temperayure difference in the winter concrete temperature history was more than 10 degrees.
As a result of evaluating the spalling properties using a restrained ring-type concrete specimen, in the case of rapid heating, the water vapor pressure rapidly rise and the surface spalling is repeated. In the case of low-speed heating, The water vapor pressure accumulated in the concrete exceeded the limit, and explosive spalling occurred inside.