According to NEI 07-13 R8, in aircraft impact analysis for new plant design, global structural damage of the target structure can be evaluated analytically using one of the following methods of evaluation:
1) Force time-history analysis method. 2) Missile-target interaction analysis method.
It depends on the availability of data on the dynamic characteristics and the intended level of detail of analysis. The purpose of this study is to evaluate the effect on the analytical results of the aircraft impact analysis method. Several impact analyses using various method were performed for the simplified external SC wall of the APR+ nuclear power plant structure.
With the recent decreasing of available land, the usage of underground for constructing underground parking lots, subway, underground shopping centers and roads is becoming more frequent than before. Subsequently, due to the changes of the ecosystems and the depletion of ground water in the underground environments are being negatively affected due to coming into contact with corrosive and hazardous substances. In particular, the durability, safety and convenience of the people who reside or utilize these underground structures are reduced by the environmental problems originating from underground ecosystems. Currently there exist a large number of on-going topics of discussion intended to solve the problems, but in order to consolidate a proper and standardized procedure of maintaining waterproofing techniques for these underground structures, a testing method to evaluate the performance of waterproofing and waterleakage resistance in underground structures is necessary.
The remaining service life (RSL) of the concrete structures built in the past has become a social issue with the concerns of the sustainable construction. In the previous studies, some simple methods for estimation of the RSL of the concrete structures were proposed. However, most of the existing studies on the RSL evaluation method have focussed on the investigation of the single deteriorating factor. In this study, the combination effect of various factors related with durability performances of the concrete structure, such as concrete carbonation and chloride penetration were considered by utilizing the fuzzy and reliability theory.
These days structures with ultra high strength concrete and steel are increasing because of the rising demands for high-rise buildings and long span bridges. The techniques of high strength material has been developed rapidly, as they have a lot of benefits such as the reduction of the amount.
In this paper, we performed the basic research of practical application examples of the bridge and the structural characteristics of ultra-high-strength concrete and steel strand.
Among the costs composing the life-cycle cost of nuclear containment, the expected loss due to leakage of radioactive material is usually exorbitant, and it takes large amount in the evaluation of life-cycle cost. This study presents a process to determine optimal target reliability for nuclear containments, mainly focuses on its expected loss. It is estimated considering the surrounding environment of nuclear containment. Target reliability of containments having different lifespan can be determined by revising the expected loss estimated from the 20, 40 and 60 years of operation.
Throughout this basic study of the design items for standardization in foundation structures are suggested. Reliablity-based methods of desin skills and data analysis are suggested in this paper for standardization. Limit state design method for retaining wall structures are standardized as the National Design Guide.
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.
A pipe-rack structure exposed to various environmental conditions is one of the critical structures for the safety of a plant industry. Based on a selected, typical pipe-rack structure, this study evaluated the behavior of the pipe-rack structure accounting for the operating condition of the pipe and at the same time the effect of environmental conditions.
This study was conducted to investigate the Structural Health Monitoring(SHM) system built in large-scale structures. Recently large-scale structures such as bridges and high-rise building have installed SHM system and using the SHM system, large-scale structures are monitoring the status of structures. In many practical cases, SHM systems are used sensor, such as strain gauge, inclinometer, accelerometers, seismic, wind anemometer, GPS, to monitor status of structures. This case study foreground potential future research dealing with SHM system using integrated sensor module.
The goal of this study is to investigate an evaluated aerial work flatform for structure maintenance and repair. This study includes technical components and economic aspect. The investigation is extend and helpful to accomplish successful business according to foreign and domestic business.
The most commonly used material of construction structures is steel. In this study, Epoxy-based coating materials and Ceramic-based coating materials durability were investigated. Exposed water immersion, chloride immersion, temperature changes, freezing and thawing for severe environments to simulate and environmental conditions are showed degraded in epoxy-based coating materials.
Cracks in concrete structures should be measured periodically to assess potential problems in durability and serviceability. Conventional crack measurement problems in durability and serviceability. Conventional crack measurement systems depend on visual inspections and manual measurements of the crack features using microscope and crack gage. However, conventional methods take time as well as manpower, and lack quantitative objectivity resulted by inspector. In this study, crack width detection of concrete structures using image processing and present a hardware specification throughout the experiment.
Reinforced concrete structures are deteriorated in a few decades due to various causes, such as carbonation. Therefore it is important to evaluate the accurate carbonation depth in order to secure the durability of the structure. In this paper, carbonation depth by drilling excavation and splitting core sample are compared. Also, the procedure for estimating the appropriate repair zone is proposed, with the result of carbonation depth and steel bar detection.
This paper aims at featuring dynamic characteristic of cable-stayed bridge by means of an artificial filter bank(AFB), for the purpose of effective acquirement of real-time valid dynamic(acceleration) responses. The AFB was embedded into a wireless sensing system. Also, through modal testings performed on a model of cable-stayed bridge, its dynamic characteristics were featured on natural frequency. They were evaluated in comparison to wired measurement responses and FE analysis. Finally, the dynamic wireless measurement system on the basis of AFB were found technologically and economically effective by obtaining valid dynamic(acceleration) responses whose size was compressed over the frequency range of interest.
The Korean electric power industry autonomously developed the Korea Electric Power Industry Code (“KEPIC”) with political support from the government with a view to creating domestic codes and standards for electric power facilities. Since KEPIC was initially issued in November 1995, the Korea Electric Association (“KEA”) has consistently updated it, developing new codes and standards like Structural Maintenance Inspection and so on.
In this paper, decentralized data process based system identification(SI) method for building structure is proposed. For verification of the method, an experimental study was performed and the validity of the method was confirmed using unused displacement response in SI.
Large span roof structures require an analysis of their static and dynamic behavior depending on the physical parameters defining the structures. Therefore, it is highly desirable to estimate the parameters from observations of the system. However, the study of the behavior of such structures shows the existence of critical parameters. A small change in such parameters causes a significant change in the motion behavior. In this paper we study the parameter identification problem for shallow sinusoidal arches considering damping effect.
본 연구에서는 철골 골조 구조물의 안전성 모니터링을 위하여 계측한 변형률을 통해 구조물에 작용한 하중을 식별하는 알고리즘을 제안한다. 기존의 시스템 식별 연구에서 구조물의 강성 등을 변수화한 것과는 다르게, 본 연구에서는 구조물에 작용한 하중과 이로 인해 구조물에 발생하는 변형률 간의 관계를 행렬로 정의하고, 이 행렬 및 작용한 하중을 변수화 한다. 계측한 변형률과 변수를 통해 추정한 변형률사이의 차이를 오차함수로 설정하고 이를 최소화시키기 위해 최적화 알고리즘 중 하나인 유전자 알고리즘을 적용한다. 구해진 변수와 계측변형률을 통해 작용한 하중을 식별하고 구조물의 하중 변화 시 미계측 지점의 응답을 추정한다. 본 연구에서 제안하는 하중 식별 알고리즘을 검증하기 위해 3차원 철골 골조 구조물의 정적 가력 실험을 수행하였고, 계측한 변형률을 통해 가해진 하중을 낮은 오차 수준으로 식별할 수 있었다. 또한, 하중 조건 변화 시, 계측한 변형률을 통해 모니터링 대상이 되는 미계측 지점의 변형률을 0.17~3.13%의 오차 범위로추정하였다. 본 연구가 제안하는 식별법이 철골 구조물의 보다 현실적인 안전성 모니터링에 효과적으로 적용될 것으로 기대된다.
본 연구에서는 개인 컴퓨터의 플래시 메모리가 충분하지 않을 경우 대용량의 플래시 메모리를 필요로 하는 구조해석을 컴퓨터 프로그램으로 수행하는 방법론을 연구하였다. 이러한 문제점의 해결방안으로 강성행렬의 블록화기법 -강성행렬이 몇 개의 블록으로 나뉘고 각각의 블록에 대하여 행렬분해가 수행되는 방법- 을 제안하였으며 제안된 방법론을 바탕으로 컴퓨터 프로그래밍이 가능한 알고리즘을 제시하였다. 끝으로, 본 연구를 바탕으로 구조해석 프로그램을 개발하였으며 몇 가지 기초적인 구조해석 예제를 통하여 개발 알고리즘의 정합성 및 효율성을 확인할 수 있었다.