기포가 포함된 다상흐름의 측정은 중요함에도 불구하고 많은 제약이 있었다. 특히, 공극률이 높은 다상 흐름은 밀도차의 급격한 변화와 두꺼운 공기-물 경계면으로 인해 측정이 매우 어렵다. 본 연구에서는 공극률에 상관없이 기포흐름을 측정할 수 있는 기포영상유속측정법과 다발 광섬유유동측정계를 소개하고자 한다. 기포영상측정기법의 경우, 화상측정시 발생하는 원근에 의한 오차를 최소화하고 추정할 수 있는 피사계 심도에 대한 계산방법을 제시하여 정도 분석을 위한 방안을 제시하였다. 다발 광섬유유동측정계는 얇은 광섬유의 특성을 이용해 다발로 제작하여 측정률을 증가시키고자 하였다. 제시된 두 기법을 기포플룸에 적용하여 신뢰도를 검토하였으며 잘 일치하는 것을 확인하였다. 소개된 기법으로 대표적인 하천 다상흐름인 도수흐름을 측정하여 그 적용성을 검토하였다.

Ground anchor method is one of the most popular reinforcing technology for slope in Korea. For the health monitoring of slope which is reinforced by permanent anchor for a long period, monitoring of the tension force of ground anchor is very important. Optical FBG sensors embedded tendon was developed to measure the strain of 7-wire strand by embedding FBG sensor into the center king cable of 7-wire strand. This FBG sensors embedded tendon has been successfully applied to measure the reinforcing force of ground anchor during four seasons through temperature compensation of the FBG sensors embedded tendon.

Rolling fatigue test was performed to study the behavioral characteristics of prestressed rib-type UHPC deck built-in optical sensors for cable-stayed bridges. As the result, it was verified that this deck has sufficient structural fatigue performance and serviceability as a bridge deck.

Rolling fatigue test was performed to study the behavioral characteristics of prestressed rib-type UHPC deck built-in optical fiber sensors for cable-stayed bridges. As the result, it was verified that this deck has sufficient structural integrity using optical fiber sensors

The FBG sensor responses simultaneously to changes in thermal strain as well as elastic strain. Thus the total strain measured from a single FBG sensor shall be corrected to obtain the elastic strain by removing the temperature effect. This paper addresses how the temperature effect can be removed when the FBG sensor is encapsulated in a 7-wire steel strand. For this purpose, fundamental properties of the FBG sensor are identified through tests using a controlled temperature chamber. Then field measurements on a UHPC pi girder with the size of 11.0 m long, 5.0 m wide, and 0.6 m high have been conducted for about one year, and the prestressing force is estimated using the raw data from the FBG sensor and by applying temperature correction technique proposed in this study. Estimated results indicate that the proposed correction technique is executable for extracting the elastic strain from monitoring data using the FBG sensor in civil infrastructures.

Since 2007, Korea Institute of Construction Technology (KICT) have developed UHPC (Ultra High Performance Concrete). In recent years, the bridge with the UHPC ribbed deck developed by KICT was demonstrated in site and measured by optic sensors.

Offshore plant structures must be secured of structural safety applying real-time monitoring technology because they are in a state of very poor ocean conditions. In this study, Fiber Bragg Grating (FBG), sensors were attached to the scaled model of offshore floating structure, and put in scaled model in the water tank, and then calculated strain after measuring scaled model's wavelength through optical spectrum analyzer