The purpose of this study is to estimate structural integrity evaluation of the concrete pontoon structure when the boundary condition and time changes. The structural integrity evaluation is conducted through the system identification method using dynamic properties. Dynamic properties are extracted with the structures when it is located on the ground and submerged in the sea. The variation of the structural stiffness due to a certain period time is discussed.

In this study, ends of reinforced concrete bridge damaged by the chloride attack was experimentally investigated. The effect of the lateral gradient was low. The results of this study will be used as a guideline for bridge maintenance to investigation of the characteristics of chloride penetration.

For the evaluation of the road cavity, GPR method is usually used widely. But the technique of image process is very difficult and confused owing to the similar signals. In this study, the deflection analysis is proposed for the supplement method of the GPR.

Effect of airpocket between CFS and concrete on surface resistivity was evaluated in this study. Rectangular CFS strengthened concrete specimens with different compressive strength and of voids, and resin thickness were fabricated and tested.

Recently, according to reinforced concrete is corroded by various environment, durability and stability of structures is decreasing and maintenance cost is increasing. Therefore, in order to supplement the reinforced concrete fault, the new member development called TRC was on the rise and accordingly, on trend of research was analyzed.

Computer vision-based displacement measurement is regarded as an excellent alternative to conventional displacement measurement devices due to its convenient installation process with high accuracy. Based on the strong potential, this study proposes a computer vision approach for displacement measurement with enhanced field applicability. Main features of the proposed method are (1) robustness against adverse light conditions and (2) convenient camera installation that allows the camera to be arbitrarily placed. An adaptive image processing procedure is developed to overcome false identification of target markers that can be induced by strong lights. Location information of the identified markers are used to obtain displacement using the homography transformation, which allows the camera to be installed in any place as long as the target markers are in the line of sight. With these features, the computer vision approach is experimentally proven to be practical in field testing for measuring structural displacement.

Recently, an indirect displacement estimation method using data fusion of acceleration and strain (i.e., acceleration-strain-based method) has been developed. This paper proposes an improved displacement estimation method that can be applied to more general types of bridges by building the mapping using the finite element model of the structure. An experimental validation of the proposed method was carried out on a prestressed concrete girder bridge, and the method provides the best estimate for dynamic displacements.

In this present study to investigate the seismic response of an offshore wind turbine, incorporating with bottom fixed Jacket support structure using semi-coupled analysis method. Fully coupled, aero-servo-hydro-elastic simulations and uncoupled seismic simulation have been done to carry out this investigation. The fully coupled simulation is accomplished and executed by FAST 8 (NREL, USA) to determine the global loads, which consists of six components of forces and moments at x-y-z directions of the tower base. In the uncoupled case, transient analysis has been done using the tower base loads as well as seismic loads by ANSYS. This paper presents a precise dynamic analysis, which can evaluate the dynamic response of three crucial points (tower top, tower base and mud line of substructure) under seismic load to make better decision in the case of structural design of wind turbine.

The objective of this research is to investigate the analytical behavior of a displacement amplification-type seismic control system, which is installed in a structure to increase the seismic energy dissipation of a damping system by amplifying displacement during the earthquake.

In here, a Modified Diagrid Structural System (MDSS) has been proposed to compare with diagrid structural system, Regular Frame with Optimized Single Tuned Mass Damper (RFwOSTMD) system and Regular Frame without Optimized Single Tuned Mass Damper (RFwoOSTMD) system. To this aim, a rectangular reinforced cement concrete (R.C.C) building and a diagrid R.C.C multi-storey building were considered, and analyzed without controlling device, with optimized TMD, Diagrid Structural System (DSS), and MDSS. All of the models are investigated by using SAP2000. All of the buildings are analyzed and evaluated under El-centro earthquake. The response of proposed MDSS under earthquake is compared with the RFwoOSTMD, RFwOSTMD and DSS. The results show that the proposed MDSS is preferable than the DSS, as well as RFwOSTMD.

This feasibility study examines if the tensile stress on bonded PSC tendon could be estimated by means of measuring electrical impedance. The impedances of the five beam specimens with different tensile stress levels were measured. As tensile stress on the tendon increases, the impedance of the tendon considerably decreases. Thus, it seems that the estimation of the tensile stress on the tendon could be possible by measuring the electrical impedance.

In this study, in order to enhance the quality of concrete dam it is mentioned that the influenced factors which effect on the water leak and methodology for weak zone repair and retrofit before filling water of concrete dam.

A modified pullout tester using a post-installable break-off bolt is presented. For the purpose of the this research, a test was conducted on normal concrete(24MPa) to measure the compressive strength and pullout load. It was found that the correlation between compressive strength and pullout load is very obvious and the modified pullout tester is a useful method to evaluate concrete strength.

These days, inexpensive and high efficiency UAV(Unmanned Aerial Vehicles) of disaster prevention and spatial information has been given more attention. But studies about test of accuracy of UAV were not enough despite high interest. UAV technology has been developed for military purposes, but in recent years, it has been used for various purposes in different forms in the private sector as spread to the public sector. However, since the study applying the UAV technologies to the inspection and maintenance of structures are insufficient so far, this study suggests an application method of UAV technology for inspection and investigation of infrastructure facilities. If the UAV technology is used in inspection and investigation of infrastructure facilities, it will be able to conduct a safety check and inspect high areas and narrow passages, which are difficult or impossible to access by manpower, and further improve the safety of the structure.

Waterproofing materials applied in underground structures are commonly exposed to environmental factors such as rain water, vibration, structural movement. Particularly in the case of rain waters, the pollutants and chemical substances penetrate into the waterproofing layer surface and cause complex degradation. Approaching this problem with only conventional leakage preventative measures may prove difficulties in solving it. In this regard, 3 dimensional material evaluation methods (waterproofing system structure) should be employed over 2 dimensional methods, and a testing method that allows the simultaneous testing of various degradation conditions found in underground environments is necessary.

This study has been considering cable stayed bridge for structural health monitoring purpose . To monitor the bridge, 6 different locations (like 2 points from deck, 2 points from pylon, 1 points from side span and 1 points from girder) were introduce to find the satellite signal received from the GPS antenna. According to the World Geodetic System 1984(WGS-84) coordinate system, the GPS station signal was measured in the 6 observed points. After that, Statistical moment analysis is applied to assess the condition of those 6 position of this long span bridge. Finally, the Statistical moment analysis results clearly indicate the present condition of the long span bridge at 6 different locations. The time series statistical moments really able to detect the damage condition and localization of the long span bridge.

The results of considerations on the current state of PSC Box girder safety maintenance with external tendons, it appears the extra suggestion of safety maintenance and popularization of technique is needed.

The recent revision of Housing Act allow vertical extension up to maximum 3 stories and increase the ratio of floor area to site up to 15%. Currently, the feasibility of performing vertical extension is evaluated based on safety diagnosis provisions and manuals for vertical extension with preliminary investigations on slope, deflection, load-bearing capacity, and durability. However, a need for more reasonable evaluation methodology for the preliminary investigation is still required because the current procedures are borrowed from safety diagnosis provisions and manuals for reconstruction without detailed examinations on evaluation criteria and sampling methods. Accordingly, this study is intended to suggest a method to obtain feasible sampling numbers for durability assessment by analyzing field data on concrete carbonation, chloride content, and steel corrosion. The results of this study are expected to be beneficial for establishing more reasonable field sampling number, and in turn, more reliable durability assessment protocol for vertical extension.

Tried to photographing of aerial Image using unmanned aerial vehicle for applied to safety inspection on a large area or inaccessible. In result, 3D Spatial Information data were acquired, understand the overall terrain and coastline to based on data, compared to traditional aerial images and analyzed. Finally, identified the regions to requiring continuous monitoring by assessment of a disaster risk. We hoping to help build to continues data for identified the changing shape over time.