건설해체공사와 유사한 특성을 갖는 원전 제염해체공사에서 구조적 리스크 관리는 매우 중요하다(DOE). 하지만 제염해체작업 중 발생할 수 있는 구조적 재난재해 및 위험요소는 크게 고려하지 않고 있다. 이로 인해, 구조적 재난 및 재해에 의해 발생할 수 있는 작업자 리스크 역시 체계적으로 정립되어 있지 않다. 또한, 재난 및 재해 그리고 리스크 분류체계는 작업의 특성(작업프로세스, 활용장비, 작업 위치 등)별로 분류되어 있지 않아 실제 해체공사를 위한 매뉴얼로 활용하기에 무리가 있다. 따라서 차폐 콘크리트 구조물 제염해체공사의 건설해체공사와의 유사성을 기반으로 작업의 특성별로 분류한 리스크를 도출하는 것은 원자력 발전소 해체공사 리스크 관리에 필수적으로 판단한다.
국내 공동주택 전단벽 구조시스템에 적용되는 감쇠장치는 대부분 인방형 형상으로 적용되고 있다. 인방형 감쇠장치는 좌우 전단벽을 연결하여 커플링 효과 및 추가 감쇠효과를 발휘하여 구조물 내진성능을 증대시킨다. 본 연구에서는 인방형 감쇠장치를 소개하고 감쇠장치가 적용된 구조물의 거동특성을 파악하였다. 제안된 감쇠장치는 힌지 및 변단면 형상으로 감쇠효과를 극대화시킨 구조로 유한요소 해석결과와 실험결과가 잘 일치하여 우수한 내진성능을 발휘하는 것으로 나타났으며, 해당 감쇠장치가 적용된 2차원 및 실제 공동주택 구조물을 대상으로 감쇠효과를 검토한 결과, 감쇠장치 커플링 효과로 기존구조물 대비 모든 구조물에서 내진성능 향상을 도모할 수 있었다. 본 연구에서 검토한 실제 구조물에 대해서는 비선형 정적해석 결과, 강도 및 연성능력이 향상되는 것으로 나타났고, 비선형 동적해석 결과, 층간변형각이 15%~18%, 층가속도가 20%~28%, 밑면전단력이 15%~20% 감소하는 결과를 나타냈다.
Chloride attack is one of the most critical deterioration due to rapid corrosion initiation and propagation which can cause structural safety problem. Extended service life through repairing is very important for determination of maintenance strategy. Conventionally adopted models for estimation of LCC (Life Cycle Cost) have shown step-shaped elevation of cost, however the extension of service life is much affected by quality of construction and repairing materials, which means engineering uncertainties in residual service life. In the paper, RC (Reinforced Concrete) column with three different mix proportions exposed to chloride attack are considered, and repairing numbers with related costs are evaluated through probabilistic technique for maintenance. When calculating repair frequency for intended service life through probabilistic model, the required repair frequency is evaluated to be 6.71 times for OPC, 4.09 times for SG30, and 2.95 times for SG 50, respectively. The probabilistic model for repairing cost is evaluated to be effective for reducing the repair frequency reasonably with changing the intended service life and design parameters.
With the recent earthquake measuring 5.4 in Pohang, attention is being raised to the effects of the structures caused by the earthquake. In this study, seismic effect of the tunnel structure was analyzed by the time history analysis method using the measurement results of the nearby structures. Most of the analysis results showed displacement and stress results of one tenth level of the artificial seismic wave using design seismic acceleration, and the actual field survey revealed that the effects of earthquakes were minor.
To suggest the preliminary data for effective maintenance of bridge structures, the damage patterns of expressway bridges are quantitatively analyzed in the present study. The defects are the primary damage, and the deterioration occurred around the joint.
This paper presents the effect of recycled aggregate on the structural design in replacement of natural aggregate. As an actual structure, the concrete airshaft in a subway under construction was chosen and design-criteria obtained from experiments in association with different ratios of recycled aggregate were applied. It was found from the analysis that recycled aggregate can be applied to real concrete structures considering just strength concept and also if other unknown problems such as quality, serviceability and so on be solved.
This study is to prepare prediction method of the durability establishment for the effective maintenance of reinforced concrete substation structures. For this study, we investigated research trends about the foreign practices relating durability design.
This study is the result of the survey on perception and anxiety of high - rise buildings in the general public. As a result of the survey, there was insufficient change in awareness before the construction of high - rise buildings such as landmarks was insufficient (before 2015). However, half of the citizens who felt uneasy that high-rise buildings were likely to collapse due to external influences were close. The anxiety was mainly due to the information of the press or the Internet. It is thought that the cause of anxiety comes from touching negative opinions about the high-rise buildings.
The maintenance cost is rapidly increasing due to the increased of infrastructures such as railway and port etc., it is necessary management method of facility for measures and extend life. In the case of international infrastructure, in order to asset management to reasonably and effectively, asset management systems were developed for the management of facilities in various countries such as Australia and Canada etc. In this study, to develop the asset management process, the question investigation was conducted on maintenance site personnels for maintenance of the steel structure.
For steel structure, corrosion problem can be a major maintenance area. Even with the same steel structure, corrosion damage can be changed depending on the location and form of thes structural member. In this study, rherefore, In order to evaluate the relative corrosion enviornmnet depending on the installed condition of the structural steel member, the corrosion deterioration environment was monitored for the large-size steel frame structure.
The old electric transmission tunnel over thirty years old in northern Seoul is operated with Ttukdo substation as its starting point and 41km-length since March, 1980, and the trend is an icrease in embedded electric power structures over thirty years old beyond sixty kilometers. If the corrosion occur in reinforced concrete structures, it is considered as the important factor among deterioration factors .By examing the seventy-two cases of concrete carbonation and covering depth in order to analyze the concrete carbonation of electric power structures over thirth years old in Gangbuk-gu, this paper atempts to analyze carbonation coefficient, remaning service life, and concrete carbonation of old embedded electric power structures for reference to predict the concrete carbonation progress.
Recently, accidents caused by the aging of structures are occurring frequently in the world. As a result, maintenance and accident prevention of structures are required. In this study, for the purpose of addressing these issues to solve these problems, we developed a non - destructive inspection technique using thermal imaging and planned damage detection process. we set up a scenario to detect the invisible excursions, cracks, and internal damage by sensing and analyzing the thermal energy radiated by the stainless steel test piece (STS304) with infrared thermal imaging equipment.
The target in the design of base isolated structures is the selection of isolation system properties so that optimal performance is achieved among seismic levels and performance metrics. To withstand very rare ground motions, isolation system are frequently designed with significant strength or damping, and as a result such devices provide reduced isolation effect for more frequent seismic events. To investigate improvements to the design of isolated structures, a lot of research program is performed. Experimental investigations are presented to characterize smart base isolation capable of progressively exhibiting different hysteretic properties at different stages of response. Shear tests are conducted along the ISO standard, including harmonic characterizations tests. These tests included various input intensities, multi-component excitation. Behavior of the new smart base isolation system is compared with that of linear isolation systems with both nonlinear viscous and bilinear hysteretic energy dissipation mechanisms.
Frequent unstable natural disasters worldwide in recent year caused damage to large power plants, high-rise buildings, dams and public facilities, resulting in a growing sense of anxiety among people. This is result in the increase of concern for the safety of residential as well as public infrastructure. Considering this growing concern for the public infrastructure a systematic safety evaluation is require. Thus, in this paper, the fragility of weir structure by considering the scour effect of flood was the focused of study. The weir structure in this study was located in Daegu city; it served as the power and water supply and flood prevention. The study was performed by conducting penetration analysis on the variables of the adjacent ground.
The transition piece of the offshore wind power support structure transmits the load of the tower stably to the support structure on the lower side. The transition piece of the offshore wind power support structure should solve the stress concentration problem in design. In this paper, in order to solve the stress concentration problem occurring at the transition piece of the offshore wind power support structure, the location and the mitigation of the stress concentration have been studied.
Recently, the frequency of natural disasters in Korea is increasing due to the influence of global climate change, and the importance of quick and accurate monitoring and corresponding response is frequently and strongly stressed in terms of disaster management. In this regard, this study describes a development of realtime safety evaluation system (RSEE) which enables to carryout real-time measurement and safety evaluation of some important SOC water infrastructures (dams, weirs, cut slopes, retaining walls, levees and bridges) installed along the nation registered large scale rivers.
The Integrated Water Infrastructures Safety Management Platform(WINS+) provides safety information of water infrastructures such as dams, weirs, bridges, cut slopes, retaining walls and levees designated as the first class infrastructures to be maintained according to the nations’s safety law. The WINS+ is incorporated with a computerized Standard Operating Procedure (SOP) system that provides crisis warning level (green/blue/yellow/orange/red) to central and individual disaster response managers of waterside structures. Thus it is expected that by using the WINS+ we may strengthen disaster responsiveness and reduce the time for recovery and response at emergency.
The extent damages of concrete structures due to fire occurrence are evaluated. The evaluation of fire safety is evaluated by using the inspection, non-destruction test, fracture test(concrete SEM analysis, concrete heat analysis, rebar fracture test. The criteria for determining the safety of concrete structures are presented using evaluation results.