Recently, measuring instruments for SHM of structures had being developed. In general, the wireless transmission of sensor signals, compared to its wired counterpart, is preferable due to its absence of triboelectric noise and elimination of the requirement for cumbersome cable. However, the research on the tall buildings with relatively small vibration levels is insufficient. Therefore, in this paper, we used the wireless MEMS sensor and iPad to compare and analyze the vibration measurements of three tall buildings and two towers.

Recently, measuring instruments for SHM of structures had being developed. In general, the wireless transmission of sensor signals, compared to its wired counterpart, is preferable due to its absence of triboelectric noise and elimination of the requirement for cumbersome cable. Preliminary studies on the continuous vibration measurement of high-rise buildings using MEMS sensors have been carried out. However, the research on the low-rise buildings with relatively small vibration levels is insufficient. Therefore, in this paper, we used the wireless MEMS sensor to compare and analyze the vibration measurements of three low-rise buildings.

The cases of conducting the vibration measurement using the mobile phone with regard to the building's horizontal vibration are very rare in Korea and foreign countries. Therefore, this study analyzed the horizontal vibration nature of the building using the mobile phone targeting 5 tall buildings, and reviewed about the applicability of the mobile phone vibration measuring instrument through the comparison/verification with the data of the existing vibration measuring instrument. The peak of the measured time series waveform was measured clearly and it showed a similar value to the existing natural frequency.

본 연구에서는 차량하중에 의한 상시진동기록을 이용한 교량의 손상추정기법을 연구하였다. 즉, 차량진행 중 측정된 신호로부터 구조물의 모드특성을 구하고, 이를 이용하여 손상위치 및 손상정도를 추정하는 알고리즘을 제안하였다. 제안기법의 검증을 위하여 차량하중을 재하할 수 있는 모형교량을 제작하여 손상실험을 수행하였다. 차량진행 중 교량의 수직가속도를 계측하였으며, 측정된 가속도시계열로부터 random decrement(RD) 기법을 사용하여 자유진동신호를 구한 후, 이로부터 구조물의 모드특성을 추정하였다. 추정된 모드특성을 기초로 신경망기법을 적용하여 손상위치 및 손상정도를 추정하였으며, 추정된 결과는 실제 손상과 비교적 잘 일치하였다.

In this research, the measurement of vibration for stay-cable installed in cable stayed bridge was carried out by using wireless accelerometer. The vibration measurement data can be used for the evaluation of safety and serviceability of cable stayed bridge. The acquired data was analyzed for the evaluation of maximum vibration, tension force and fatigue. To verify the reliability of data, the additional measurements with total station and video camera. The data from three different measurement methods showed similarity within 15 % gap.

High speed railway bridges should be strictly maintained due to its social importance. However, There are many problems to execute loading test for precision safety diagnosis. A numerical experiment with a numerical model which is updated for reflecting characteristics of an existing bridge can be useful for high speed railway bridge maintenance. Moreover, more efficient maintenance can be possible if only ambient vibration is needed for numerical model updating process. In this study, a numerical model updating process is introduced in which only ambient vibration is enough to execute the process. Also, the usability of updated numerical model is verified by comparing measured and analyzed acceleration.

This study presents a damage detection method for shear-building structure based on the change of diagonal terms of a modal flexibility matrix. Numerical simulation and experimental validation were conducted on a 5-story shear-building structure. The proposed damage detection method showed accurate and suitable results.

This study is a result of the dynamic characteristics of tall building located in Haewoondae. In order to analyze the natural frequency and damping ratio of the building, acceleration is measured through wind monitoring system during 6 months.

본 연구에서는 미국 뉴욕주 로체스터시 소재 강합성 데크 트러스 보도교를 대상으로 사용성을 평가하기 위한 상시진동 실험(ambient vibration test)을 수행하였고 이를 해석적 방법에 의한 결과와 비교하였다. 교량전체에 대한 상시진동실험은 수치모델 작성 시 도입되는 여러 가정들에 대한 타당성을 평가하는데 있어서 유용한 방법이며, 교량의 고유진동수나 모드형상과 같이 구조 동력학에서 중요한 구조적인 변수를 결정하는데 있어 중요한 역할을 한다. 본 연구에서는 교량의 수직방향 및 수평방향 진동 특성과 변위를 측정하기 위하여 실제 교량에서 보행자에 의해 발생하는 진동을 입력하중으로 사용하였다. 교량 구조물에 대한 모델링을 위하여 3차원 유한 요소법을 사용하여 해석을 수행하였으며, 이를 통하여 현장실험 결과와의 유효성을 입증하였다.