The safety issue of PSC box girder bridge stood out. So, we developed material testing method and procedures and applied them to existing bridge. Consequently, We found that the procedure we developed is very reasonable.

Domestic social infrastructures have been rapidly growing based on economic growth in the 1970s. Recently, the construction of various methods has been continuously being carried out in accordance with the development of construction technology. Due to these influences, Maintenance work is becoming as important as construction.

Collapse of reinforced earth retaining wall due to improper design and construction is still occurring during construction and operation. While most studies of reinforced retaining walls are focused on the mechanistic behavior, there is little study on the improvement of assessment item, which is used to examine the safety of retaining wall, based on the existed inspection data. This study proposed new weighting factor of assessment item by utilizing multiple regression analysis technique, AHP method, and entropy method for the existed inspection data of reinforced earth retaining wall. Compared to the existed weighting factor, the value and the rank of proposed weighting factors are changed. By applying the proposed weighting factors to the existing retaining walls of 161 sites, fragility region of 47 sites is changed.

Ballast track has been widely used because of convenient maintenance. However, ballast deterioration requires frequent maintenance due to increasing speed, weight, and traffic of trains. Fouling is known as deterioration and expedites irregular settlement. In this paper, non-destructive methods were applied and investigated in order to evaluate ballast conditions such as thickness of fouling layer. Ground Penetrating Radar (GPR) and Dynamic Cone Penetrating (DCP) Test resulted in reasonable detection of fouled layer.

By amending of the special law on the safety management of the facility, coastal structures(breakwaters) has been incorporated into kinds of facilities. In this paper, a case study for condition assessment of coastal structures(breakwaters) is conducted according to the detailed guidelines established for coastal structures(breakwaters).

The signal characteristic of radar wave on concrete decks is determined by the attenuation of the radar due to the conversion of EM(Electromagnetic) energy to thermal energy through electrical conduction, dielectric relaxation, scattering, and geometric spreading. In this study, it is found that the attenuation of radar signal received on top rebars in bare deck concrete with 2 way travel time shows a general decreasing linear trend because of its same relative permittivity and conductivity. The radar signal after depth-normalization, can then be interpreted as being principally influenced by the content of chlorides penetrating cover concrete, which caused corrosion of rebars in bridge decks.

본 연구에서는 철근의 인장시험에서 변형률에 대한 상세 측정을 위하여 이미지 프로세싱을 이용하고, 변형률 분포와 넥킹구간을 평가하였다. 이미지 프로세싱 방법으로는 기존의 회색조영상을 이용한 방법이 아닌 칼라영상의 색상정보를 분석하여, 원하는 타겟과 가장 일 치하는 영역과 그 외의 영역으로 구분하여 이진영상으로 변환하는 방법을 사용하였다. 변환된 이진영상에서 개별 타겟들의 도심점을 산출한 후 각 도심점의 상대변위값을 변형률로 환산하였다. 인장실험은 ASTM A615 기준으로 제작된 grade 60 철근 중 D22와 D29에 대해서 시험을 수행하였다. 이미지 프로세싱을 이용하여 계측된 변형률 결과를 기존 변형률 게이지를 이용하여 계측한 결과와 비교하여, 본 연구에서 사용한 이미지 프로세싱 방법에 대해서 검증하였다. 이미지 프로세싱을 이용하여 초기 탄성구간의 변형률 뿐만 아니라 넥킹구간에서 발생한 0.5 (50%) 이상의 변형률도 계측이 가능한 것을 확인하였다. 본 연구결과 이미지 프로세싱을 통하여 기존 변형률 게이지의 계측한계를 극복가능 하고, 다양한 지점에서 자유롭게 계측할 수 있음을 알 수 있었다.

In this study, we analyzed the effect of the drainage slope to collapse. The presence of drainage has a low correlation with the collapse of the slope. But drainage of the drainage has an important role in preventing the decay slope. Therefore, the drain state is very important in order to evaluate the drainage.

In this study, repair and reinforcement priority determining method for each component of existing dams is suggested. Condition assessment results from in-depth inspection followed by “specific guide for in-depth inspection on dams” are used. Condition assessment is subdivided into several steps and evaluation indices are determined by considering weights such as influence coefficients and adjustment factors for each component through all of the steps. These weights are counted backward to determine the priority for each component and facility. An algorithm is designed to analyze this procedure and 4 target dams are adopted to verify the method. This method can be used for establishing an efficient maintenance strategy related to the repair and reinforcement priority determination.

이 연구에서는 플랜트 지하구조물의 상태평가를 위해 국내외 기준을 확인하고 플랜트 지하시 설의 핵심평가 요소 도출을 통하여 향 후 플랜트 지하구조물의 상태평가를 위한 기초 자료로 활용하고자 한다.

By amending of the special law on the safety management of the facility, pumping station has been incorporated into kinds of facilities. In this paper, a case study for condition assessment of pumping station is conducted according to the detailed guidelines established for pumping stations. Evaluation index between new and existing guideline is compared.

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.

본 연구에서는 디지털 의료용 X선을 이용하여 소듐냉각고속로 금속연료봉 내부의 소듐 충전상태를 평가 하고자 하였다. 의료용 X선은 디지털방사선(digital radiography, DR)시스템을 사용하였다. 최상의 공간분해 능을 도출하기 위해 X선관의 초점크기와 디지털영상후처리 방법을 변화시켰다. 이때 텅스텐을 이용한 에 지방법의 변조전달함수(modulation transfer function, MTF)를 사용하여 선예도(0.5 MTF)와 해상도(0.1 MTF) 를 평가하였다. 그 결과 소초점에서 영상후처리의 대조도를 강화시킨 조건에서 3.871 lp/mm (0.1 MTF)와 3. 290 lp/mm (0.5 MTF)의 공간분해능을 얻었다. 결론적으로 이러한 결과는 디지털 의료용 X선을 이용하여 소듐냉각고속로 금속연료봉 내부의 소듐 충전상태를 관찰할 수 있었다.

In the past, criteria and procedures for the design of concrete structures were primarily based on allowable stresses for structural components. However, it is now well recognized that the limit state approach is a better basis for design since it is difficult to determine the real safety margin of submerged structure.

Recently, Korea Bridge Design Code(limit state design method) was introduced in 2012.However, Korea Infrastructure’s Safety Inspection Guideline are still following the bridge safety assessment. The assessment methods are classified according to material and bridge superstructure. Steel box girder bridge safety assessment was carried out by the A.S.D. In this study, introduce of steel box girder bridge safety assessment in accordance with the standards change.

Pumping Station is amended ('15.1.6) a special law (hereinafter siteukbeop) on the safety management of the facility has been incorporated into kinds of facilities. This study aims to introduce siteukbeop drainage pumping stations as part of condition assessment techniques detailed guidelines established for drainage pumping stations being incorporated into the new facility as amended.

By the revision of Special Act on the Safety Control of Public Structures('15 .1.6), coastal structures(breakwaters) was selected as management target. In this study, it is aim to introduce assessment methods for performing precision check-up and precision safety inspection of the coastal structures(breakwaters).

최근 지구온난화로 인한 기상이변으로 전세계가 몸살을 앓고 있다. 우리나라도 같은 실정에 직면해 있으며 이에 대비하는 차원으로 대하천 정비사업을 실시한 바 있다. 제방에 대한 정비항목으로는 하천준설, 제내지와 제외지에 대한 성토 및 보강 등이 있으며 이로 인해 지하수 흐름양상이 변하게 될 것으로 추정된다. 그러므로 이와 같은 환경을 시뮬레이션을 통해 제내지와 제외지의 높이에 따른 제방의 파이핑 안정성을 분석해볼 필요가 있는 것으로 판단된다. 따라서 본 연구에서는 낙동강의 지류인 회천에 위치한 율지제를 중심으로 본 연구제방에 설치된 간극수압센서를 이용하여 제내지와 제외지의 표고변화에 따른 제방내부의 지하수 침투양상을 SEEP/W를 이용하여 정상류 및 부정류를 고려한 모의를 수행하고 안정성을 검토하였다. 모의결과, 제내지의 표고가 상승할수록 파이핑 안정성이 증가하는 것으로 나타났으며 제외지측은 표고와는 상관없이 하천수위에 따라 파이핑 안정성이 영향을 받는 것으로 나타났다. 그러므로 제방의 파이핑 안정성을 증대시키기 위해서는 제내지의 성토와 적정하천수위유지와 같은 제방의 외적 요소들도 함께 고려해야할 것으로 판단된다.

Recently, Korea Bridge Design Code(KBDC) adapts to the Limit State Design method(L.S.D) in 2012 according to the liberalization of construction market and the flow of international standardization of the design criteria. However, Korea Infrastructure’s Safety Inspection Guideline(KISIG) are still following the bridge safety evaluation applying the A.S.D and U.S.D methods. In this study, introduction of PSC bridge safety evaluation with L.S.D considered the traditional safety evaluation compared to the ASD and USD methods.