A small dam is of hydraulic structures, which is always exposed to risk by flood, and it’s very important to ensure structural safety. A probabilistic analysis, quantifying variable as a risk factor to ensure safety of small dam, identifying its coefficient of variation, which has become increasingly important. In this study, the risk of seepage failure of foundation within a small dam was estimated based on flood scenarios by rainfall quantile. The final compound risk was evaluated combining probabilities, related to seepage failure and flood level. The seepage failure probability was estimated by performing seepage analysis depending on the water level difference between upstream and downstream in small dam. The probable flood level was estimated by considering hydraulic uncertainty associated with channel geometry, and movable gate operation during the flooding season, applied a probable flood considering hydrologic uncertainty evaluated by Bayesian approach. The safety evaluation of small dam with probabilistic-based compound risk expect to use the index for hydraulic structure design in the future.
In this paper, laboratory tensile tests were performed for the basalt, glass and carbon fiber reinforced polymer. Epoxy resin was used as the polymer for this composite material. The procedure of the experiment was based on the criteria specified in ASTM D3039 / 3039M. Moreover, a Universal Testing Machine (UTM) with 100 kN capacity was used in this experiment. Results of the performance of each composite material were analyzed. In case of fiber type, carbon fiber reinforced polymer showed the best performance; followed by basalt fiber and glass fiber reinforced polymer with the elastic modulus of 37.03 MPa and 33.10 MPa, respectively.
The purpose of this study is to evaluate the structural safety of anchor bolts used for connecting between H-beam and reinforced concrete, which are considered to be the most vulnerable parts to external loads.
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.
Due to recent climate changes, damage to the soundproof wall due to typhoons and strong winds is on the rise. This study determine the fragility curve of aluminum frame, which is a weak member of the soundproofing wall, due to strong wind. The fragility was analyzed in term of aluminum frame thickness variation. Finite element analysis of the wall was performed with ABAQUS, a commercial program. Random wind loads applied to the structures were generated using the Monte Carlo simulation technique. Also, the limit state was set based on the analysis results. The fragility curves were developed with consideration of three influential factors which are installation location, wind exposure and thickness aluminium frame of soundproof wall.
In order to understand the seismic performance of weir structure under seismic events, concrete weir structure with infinite foundations was modeled in ABAQUS. Additionally, this study conducted the three different design response spectra based on KBC 2009, ASCE 7-05, and EuroCode 8. The results from numerical analyses showed that the seismic behavior of weir structure subjected to seismic ground motions was sensitive to natural frequency and mass participation factors.
This study presented the seismic performance of weir structures with infinite foundations subjected to seismic ground motions, rather than finite soil foundation to avoid the reflection of seismic wave propagation at the mesh boundaries. The analytical model of weir structures was developed in ABAQUS platform and then the seismic performance of concrete weir structure was evaluated through design response spectrum (KBC 2009). It was revealed that the maximum stresses obtained from infinite models was significantly increased, in comparison to the finite models.
In this study, wind fragility for anchor systems installed at sign structures was developed through Monte Carlo simulation method. The fragility is a conditional limit state probability, presented as a function of the 3-second gust wind speed, based on a relation between statistics of wind loads and anchor system resistances. Advertisement sign attached to concrete wall structure was investigated using probabilistic approach with consideration of anchor type, exposure category, and wind directionality. The results showed that the failure due to tension on anchor bolt was dominant and occurred at a very high wind speed. The fragility methodology described in this paper can be used to develop performance-based design guidelines for advertisement structure in high wind regions as well as to provide information on which to base structural safety or expected loss assessments.
In order to evaluate the seismic safety of weir structure subjected to seismic ground motions, simple linear elastic 2D plane strain Finite Model (FE) was developed in ABAQUS platform. Also, the 1994 Northridge earthquake as a ground motion uncertainty was selected. The numerical results showed that the compressive stress was significantly increased in comparison to the results from the design spectrum analysis but the horizontal displacement was reduced about 28%.
This study presents the seismic safety evaluation of weir structures subjected to earthquakes. In order to conduct the numerical analysis using KBC 2009 design spectrum, simple linear elastic 2D plane strain Finite Element (FE) model was modeled in ABAQUS. the results obtained from numerical analysis noted that the weir structure was more sensitive to tensile stress than compressive stress.
In this study, the tensile properties of FRP in the oceanic environment were compared. The tensile properties at room temperature and sea water temperature were compared and the tensile properties according to the the salt stress permeation duration are compared. It is appeared that the difference in the tensile properties of composite materials due to the temperature difference very little, and it is appeared that the tensile difference due to salt stress permeation by the types of glass fiber has a difference.
In this study, the GFRP resisting force panel was designed through the 3dimensional analytical modeling using ABAQUS which is the commonly used finite element analyzing program. For components in the resisting force panel, the shape and resource was decided based on the destruction pattern by buckling behavior.
As the interest in leisure sports is recently increasing domestically and internationally, the number of descending experience in the air facilities is increasing. Study on the cable and wire installed on a bridge has been actively preceded from the past to the present, but for descending experience in the air facilities for leisure sports, an accident occurs frequently and examination the structural safety of these facilities is still insufficient. Therefore, structural safety by dynamic impact is evaluated through 3-dimensional infinite element modeling and analysis of the steel cable for leisure sports previously installed. It is judged that more systematical safety than before could be secured based on this.
In recent year, a reduction of the damage to nonstructural components such as piping, ceiling, mechanical and electrical equipments or an improvement on the performance of nonstructural components has emerged as a key area of research. Therefore, the primary objective of this study was to evaluate and understand the seismic performance of the complex piping system such as a T-joint connection. Furthermore, it was targeted on evaluating the Finite Element (FE) Model of the T-joint connection based on moment-rotation relationship of the experimental tests. The results of FE analysis by OpenSees were in a good agreement with the experimental test result till the failure point in both models.
Concrete has been widely used due to its high performance per price ratio. However, its durability
is highly depended on the temperature, so it requires reinforcement on concrete structures. In this study, a long-term behavior analysis was conducted on a concrete strengthened by FRP tested on the freeze-thawing time increases, freeze-thaw evaluation. The result from this study revealed that as the frequency of freeze-thaw cycle increases, the flexural strength decreases, and the reinforcement effect, in turn, decreased. On the other hand, as the frequency increases, detachment at the binding site occurred due to the decreased durability of concrete
본 연구는 부착재료의 변화 및 동결융해에 따른 FRP-콘크리트구조물 경계면의 거동을 조사하였다. 실험 시 고려된 연구변수로는 부착경계면의 부착강도, 경계면 유효부착길이 등을 조사하였다. 경계면 부착재료에 따른 거동변화 실험체의 경우 FRP-구조물 부착경계면에 사용되는 에폭시의 종류를 각각 3가지로 분류하며 FRP-콘크리트간 다양한 부착길이를 고려하여 시편을 제작하였으며 동결융해에 따른 경계면 거동조사의 경우 0 cycle에서 300cycle까지 계속적으로 증가되는 주기에 대하여 실험체들을 제작, 장기거동 부착실험을 수행하였다. 본 실험결과, 적용 부착재료의 종류에 따라 최대 유효부착길이는 5~7% 차이가 있었으며 동결융해 주기증가에 따른 최대부착하중 및 유효부착길이의 경우 초기에 나타난 급격한 거동변화 이후 상대적으로 불규칙한 변화를 장기적으로 나타내었다.