In this study database on the results of in-depth inspection was built and statistical analysis was performed on the major faults for concrete dams. using condition evaluation results for existing concrete dams.

콘크리트는 매우 우수한 건설 재료로서 교량, 빌딩 등을 포함한 대다수의 사회기반시설물 건설에 이용되었으며 향후에도 지속적으로 사용되리라 예상된다. 그러나, 콘크리트가 건설 재료로서 아무리 우수하다고 하더라도 시공시의 조건과 방법에 따른 시공 품질 변화와 완공 후 공용 과정에서의 환경과 외력 변화에 의한 열화나 손상을 피할 수는 없으며, 경우에 따라 이러한 요인들은 콘크리트의 내구성과 안전성에 심각한 문제를 유발할 수 있다. 따라서, 시공 과정에서 콘크리트 품질의 적절성을 판단하고 완공 후 공용 과정에서는 콘크리트의 열화와 손상 정도를 진단할 수 있는 기술의 확보는 콘크리트의 안전하고 경제적인 시공 및 유지 관리에 있어서 매우 중요한 부분이다. 시공 또는 공용 중 콘크리트 구조물의 역학적/내구적 상태를 진단 및 평가할 수 있는 다양한 현장 및 실내 시험 방법에 대한 연구가 많이 이루어지고 있으며, 특히 시험 대상 구조물에 손상이나 파괴를 유발하지 않고 구조물의 상태를 진단할 수 있는 비파괴검사(Nondestructive Testing; NDT) 기술은, 시설물 유지 관리에 관한 실무에서의 높은 관심과 수요로 인해 최근에 기술이 빠르게 발전하고 있는 분야이다. 본 특집기사에서는 콘크리트 구조물의 품질 점검 및 손상/열화 진단을 위해 현재 개발이 진행되고 있는 첨단 NDT 기술의 동향과 응용 사례를 소개함으로써, 관련 기술에 관심을 갖고 있는 실무자나 연구자에게 유용한 자료를 제공하고자 한다.

본 연구는 균열을 인식할 수 있는 영상기반 균열검사 알고리즘을 개발하고 성능을 검증하기 위한 모의 균열을 생성하는 방법에 관한 것이다. 균열검사 알고리즘을 개발하기 위해서는 균열 영상 데이터가 필요하다. 이러한 균열 영상들은 실제 균열이 발생한 콘크리트 벽면을 촬영하거나 일정한 하중을 가해 시편에 균열을 발생시키는 방법으로 획득하고 있다. 하지만 균열을 검사하기 위한 영상처리 알고리즘을 검증하기 위해서는 균열 폭이 일정한 정량화된 균열 영상이 필요하다. 이러한 정량화된 균열을 생성하기 위하여 크랙게이지와 같이 검은 명암을 가지는 표면 부착형 모의 균열이 사용되기도 한다. 표면 부착형 모의 균열을 사용하면 원하는 형태와 크기를 가지는 균열을 묘사하기 유리하며, 다양한 콘크리트 표면에 부착하여 균열 영상을 획득하고 이를 균열검사 프로그램의 개발에 활용할 수 있다. 특히 균열의 정확한 크기 측정이나 인식률을 정량적으로 검증하는데 매우 효과적이다. 하지만 표면 부착형 모의 균열과 실제 균열의 유사성에 대해서는 아직 검증되지 않았다. 본 연구에서는 표면 부착형 모의 균열과 콘크리트 시편에 유도한 균열을 제작하여, 영상 촬영한 후 명암, 질감, 콘트라스트, 선명도를 분석하여 두 균열간의 특성을 분석하고 유사성을 검증하였다. 영상은 다양한 거리와 조도에서 촬영하여 거리와 조도의 변화와 두 가지 균열의 특성 변화와의 관계를 알아보았다.

Risk Based Inspection(RBI) Period was proposed for highway bridges in Korea. Hazard factors affecting bridge condition deterioration were found by analyzing condition data from Highway Bridge Management System(HBMS). Certain level of correlations between those factors and condition deterioration were found. They are used to evaluate hazard score. Summarizing several hazard factors, final hazard is classified as three level;high, moderate, low. Vulnerability is assessed only by the current state of bridge. Then, risk matrix is suggested for inspection periods. Inspection periods of the bridges with grade C, D, and E are maintained the same as before. But, those of grade A and B with moderate and high hazard score are elongated to maximum 6 years while the maximum inspection period is three years at present. By adjusting inspection period according to risk assessment, it was shown that 27% of average inspection manpower can be saved.

Usually, we have many difficulties in funding because of the prejudice that the bridge inspection facilities are not a critical part in bridges. Also, high initial cost resulted in the decrease trend in installing the bridge inspection facilities. But, in this research, we reached to the conclusion that installing fixed bridge inspection facilities are most economical and more effective in required time, input man-power and equipments than any other means to approach bridges by analysis considering LCC(Life Cycle Cost).

Inspection Stairs for bridge is basic facility for inspecting abutment. Based on the surveying for inspection stairs for bridge, basic guidelines for inspection stairs for bridge were proposed.

Risk Based Inspection(RBI) Period was proposed for highway bridges in Korea. Hazard factors affecting bridge condition deterioration were found by analyzing condition data from Highway Bridge Management System(HBMS). Certain level of correlations between those factors and condition deterioration were found. They are used to evaluate hazard score. Summarizing several hazard factors, final hazard is classified as three level;high, moderate, low. Vulnerability is assessed only by the current state of bridge. Then, risk matrix is suggested for inspection periods. Inspection periods of the bridges with grade C, D, and E are maintained the same as before. But, those of grade A and B with moderate and high hazard score are elongated to maximum 6 years while the maximum inspection period is three years at present. By adjusting inspection period according to risk assessment, it was shown that 27% of average inspection manpower can be saved.

Scanning technic is implemented with the underground structures: subway, tunnel, shaft, drainage path, spillway, and slurry wall. Both optical and laser scanning system have been conducted to the precise inspection of diagnosis and safety. Image and 3D coordinate from scanning can be utilized in monitoring scope and fundamental database of maintenance. There is a high possibility that the scanning will prevail on inspection and diagnosis.

To the present, technology of tunnel has developed more significantly than before. Due to the difficulty in assessment of long-term durability, it is more important to persistently maintain the tunnel to save the budget efficiently since its completion. Some aspects of the focused management section were written for some of the road tunnels which was recently inspected by KISTEC according to the special law for safety management of Infrastructure.

Recently, Advanced automated infrastructure measurements have been made in the Honam high speed railway test-bed. In the future, Real time measurements will be the common based on these technologies. Here, we looked at the domestic and international trends and utilizing the inspection method of Railway Structures using self-powered sensors and wireless network technologies.

Since then the Special Act on the Safety Control of Public Structures has been enforced, the precision safety Inspection result was being collected. but it was not performed to comprehensive analysis and D/B. In this study, statistical analysis was performed by utilizing the Precise Inspection for Safety of Dam.

Shin Geo-Je Bridge needs new inspection holes to improve the accessibility for various maintenances. This study evaluated the maximum effective stresses of the bottom flange when the inspection holes is made with an ellipse shape. The FEM analysis results show that the inspection installation is possible to the inflection point of the girder.

The purpose of this study is to estimate the weighting factor on inspection categories for risk assessment of buildings. For the purpose, survey of practitioners and experts conducted. By A.H.P.(Analytic hierarchy process), relative weighting factor in inspection categories were estimated.

In light of the maintenance of underground structures, the evaluation scope of precise inspection for safety and diagnosis have been revised. Crack, leakage, deterioration, and drainage system are evaluated with field inspection in maintenance manner. It also proposed that the additional revision of the precise inspection for safety and diagnosis.