In this paper, the utilization of PZT’s dual piezoelectric effects (i.e., dynamic strain and electro-mechanical (E/M) impedance responses) for damage detection in beam-type structures are presented. In order to achieve the objective, the following approaches are implemented. First, global vibration-based and local impedance-based methods to detect the location of damage are presented. Then, the vibration-based and impedance-based damage detection methods using the dual piezoelectric responses are evaluated from experiments on a lab-scaled beam.

This study introduces an efficient image-based three-dimension motion tracking system for civil structures. The proposed system consists of hardware (four camcorders, a commercial PC and frame grabber) and software. The effective software and measurement scheme are developed to obtain the dynamic motion with six degrees of freedom. Several laboratory tests were conducted to verify the effectiveness of the proposed system with the maximum error of less than 3%.

In this study trying to develop a monitoring system for temperature and humidity measurement of quality control methods suitable for curing concrete nuclear power plant structures. This experiment is divided part of data logger, sensors, control program in a accordance with standar of quality control Nuclear power plant hot weather/the middle of summer. This measuring method is expected to development quality control nuclear power plant

This paper presents that acquiring 3D-shape through reverse-engineering of the old facilities using 3D-Scanning method and suggesting means of enhancing old facilities management and replacement time for application of BIM. In the experiment, we use the equipment which is multi-laser 3D-Scanning to calculate the distance from objective to it. And then, we could get 3D-shape data for application of BIM which model more information of building. This BIM is taken advantage of prevention or prediction of risk by current facilities

Consequently, Vehicle-mounted GPR System turned out to be effective on swiftness in the field. In this study, the Ground Penetrating Radar(GPR) mounted a vehicle was tested to evaluate the condition of concrete decks. Vehicle-mounted GPR System's result could be evaluated by comparing with collected cores as a high reliability system

Since thermal damage of concrete causes the formation of micro-defects according to physicochemical changes, the adoption of a sensitive nondestructive evaluation method is required. This study introduces an nondestructive evaluation method for thermally damaged concrete, which is on the baasis of nonlinear resonance characteristic. The test was investigated to evaluate thermal damage of concrete and to demonstrate the suitability of the proposed method

Vibration resonance tests offer an efficient NDE method to identify and characterize shallow (near-surface) delamination defects that afflict RC structures. However, efficient implementation of effective modal analysis methods for this purpose is hindered by practical testing limitations. This paper studies vibration resonance data from square, rectangular, and circular near-surface delamination defects in concrete using air-coupled impact resonance test.

Recently, air-coupled impact-echo (IE) tests for rapid damage detection in concrete structures have been popularly employed, but they typically require an acoustically shielded, high sensitivity, pre-polarized air-pressure sensor. In this study, two types of air-coupled sensors (condenser and dynamic microphones) and one contact sensor (displacement sensor) are evaluated with regard to characterization of delamination damage in a concrete slab using the IE method. The contact and contactless IE tests were carried out over a simulated slab with artificial delaminations. Results show that even the dynamic microphone successfully captures impact-echo signals in a contactless manner and without acoustic shielding.

Steel deck plate is a preferable structure in the long span bridge construction because of the weight decrease and the aesthetic enhancement. But its orthogonal anisotropic structure is connected with various subsidiary materials so that the fatigue transfer is complex. This study will be conducted with the a few strain gauge is installed in the weak range of hot spot stress where the actual fatigue crack is anticipated and will compare it with the fatigue crack range and the allowable fatigue stress category of the steel deck plate in home and abroad

The aim of this study is to evaluate performance of wind-resistant for existing bridges. For this purpose, It is examined the necessity of dynamic wind tunnel test for existing bridge by theoretical equations before implementation of the test, and the method of wind-resistant performance evaluation is presented so that wind tunnel test would be determined whether it needs to conduct.

64 percent of overall highway is concrete pavement, and the age of Chungbu highway is over. It is desirable to use same material for the maintenance of concrete pavement, but asphalt overlay is commonly used because lane closure time is directly related to the curing time of concrete. However, there is no study conducted on structural performance of concrete pavement after damaged surface cutting. Therefore, falling weight deflectometor was used to evaluate structural evaluation of both asphalt pavement overlay concrete after cutting and asphalt pavement overlay, and 1.5 time higher deflection and 5.5% reduced load transfer efficiency were observed in cutting overlay comparing against non-cutting overlay. These observations indicate that there is high possibility of reflective cracking in case of cutting overlay due to increased deflection and reduced load transfer efficiency

본 연구에서는, 모드유연도 행렬 기반 변위를 이용한 고층빌딩의 손상진단 알고리즘을 제안한다. 손상에 의해 유발되는 손상유발 층간 변위의 관계식을 통해 고층빌딩의 손상진단을 위한 손상지수를 제안하였으며, 다중손상의 손상추정을 위한 베이스라인 변경기법을 제안했다. 제안된 방법은 수치모 델이 필요하지 않으며, 계측된 신호처리만을 통해 고층빌딩의 손상추정이 가능하다는 점, 그리고 다중손상에 대한 손상추정이 가능하다는 장점을 지닌다. 제안된 방법의 성능검증을 위해 10층 빌딩모 델에 대한 일련의 수치해석을 수행했다.

The spatial focusing of time reversal Lamb waves on a plate has attracted considerable attention for identifying the location of an input source. This study investigates the spatial focusing performance on a plate with respect to the number of piezoelectric (PZT) sensors for varying locations of input sources. In particular, a small number of PZT sensors produce spatial focusing through the virtual sensor effect due to reflection of Lamb waves at plate edges. The spatial focusing performance with respect to the number of PZT sensors is quantified in terms of signal to noise ratio through numerical simulation and its implication is discussed

본 논문에서는, 자이로스코프를 이용한 각속도 계측과 가속도계를 통한 가속도 계측을 통해, 기존 의 가속도 계측만을 통한 교량구조물의 건전성평가의 단점을 극복하고자 한다. 교량의 경우, 지점 부근에서는 각속도 변화가 큰 반면, 중앙경간으로 갈수록 그 값은 작아지고, 가속도 변화가 크게 발생한다. 이러한 교량의 거동 특성을 통해 가속도 계측을 통한 건전성 평가에서 간과할 수 있는 지점 부근의 손상을 지점 부근에서 계측된 각속도를 이용해 보상하는 방법이다. 즉, 가속도 계측치를 이용하여 구조물의 모드유연도 행렬을 구성하고, 이를 이용하여 일차적인 손상진단을 수행한다. 추가 적으로 지점부근의 각속도 계측을 이용해 얻어진 회전 모드유연도 행렬을 이용하여 지점부근에서의 손상진단을 수행한다. 제안된 방법의 검증을 위해서 단순보를 이용한 수치해석을 수행했다. 중앙 부근의 손상과 지점 부근의 손상을 모사하였으며, 제안된 방법의 우수성 검증을 위해 가속도 계측만 을 통한 결과와 이종 데이터 계측을 통한 결과에 대한 비교연구를 수행했다.

Infrastructure has been managed by precise diagnosis and repair․rehabilitation. Generally, more than 0.3mm cracks are repaired by injection method regardless of the time of repair and location of crack. In this papar, considering the feature of crack variation at three tunnels, it suggested that current diagnosis and repair methods should be improved.

The research measured cracks by visualizing them through mechano- luminescence(ML) paint. By applying M-L paint on the surface of the specimen and using the 3-point bending test. Through the results of this research, we confirmed the crack propagation speed by section and the mechanical correlation such as between loads and cracks and between deflection and cracks, which means this research was quite successful in analyzing the characteristics of cracks.

Tunnel scanner is the most powerful and applicable technic for tunnel inspection. The enlargement or diminishment of defects is compared and analyzed by the scanning images. The pattern of crack is classified with the direction, shape, and location depending on the original lining and reinforced lining.

For this study, Inspection and test was carried out in Tunnel. After this process, Numerical Analysis was accomplished by 3D. A result of inspection and test, It couldn't find the reason why the upper slab crack was detected. The result of 3D Numerical Analysis, The reason was found that the Demage on upper slab was caused by moment change. The Moment was changed by column interval transition. To figure out the cause of cracks, we are using FEM. This Study can help developing designation and maintenance about Tunnel.

The purpose of this study is to suggest new improving solution about problems of non-destructive test through the analysis of present status of non-destructive test and report. For this, we analyzed problems of non-destructive test operating into concrete structures and collected data by questionnaire of non-destructive test at the inspection and diagnosis work for the diagnosis company and suggested plans for improvement based on analyzed opinion and result.

Recently, an interest in volcanic eruption of the Mt. Baekdu is increasing. If the Mt. Baekdu has volcanic eruption, volcanic ash and earthquake will occur. These can give moderate or severe damages to the structure. But the studies of volcanic earthquake and structural damage by volcanic earthquake is not enough. In this paper, structural damages by volcanic earthquake were investigated and analyzed in connection with VEI-Magnitude and Distance-Magnitude relationships.