• Computers and Concrete
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• v.22 no.2
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• pp.143-152
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• 2018

This paper deepens the finite element modeling (FEM) method to reproduce the compressive behavior of partially steel-jacketed (PSJ) RC columns by means of the Concrete Damaged Plasticity (CDP) Model available in ABAQUS software. Although the efficiency of the CDP model is widely proven for reinforced concrete columns at low confining pressure, when the confinement level becomes high the standard plasticity parameters may not be suitable to obtain reliable results. This paper deals with these limitations and presents an analytically based strategy to fix the parameters of the Concrete Damaged Plasticity (CDP) model. Focusing on a realistic prediction of load-bearing capacity of PSJ RC columns subjected to monotonic compressive loads, a new strain hardening/softening function is developed for confined concrete coupled with the evaluation of the dilation angle including effects of confinement. Moreover, a simplified efficient modeling approach is proposed to take into account also the response of the steel angle in compression. The prediction accuracy from the current model is compared with that of existing experimental data obtained from a wide range of mechanical confinement ratio.

• Structural Engineering and Mechanics
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• v.74 no.2
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• pp.201-214
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• 2020

This study aims at evaluating composite moment frame structures (CFS) using wavelet analysis of the displacement behavior of these structures. Five seismic damage mitigation systems' models of 9-story CFS are examined namely, basic (Model 1), reinforced (Model 2), buckling restrained braced (BRB) (Model 3), lead rubber bearing (LRB) (Model 4), and composite (Model 5) moment frames. A novel integration between continuous and discrete wavelet transforms is designed to estimate the wavelet power energy and variance of measurements' behaviors. The behaviors of the designed models are evaluated under influence of four seismic loads to study the dynamic performance of CFS in the frequency domain. The results show the behaviors of models 3 and 5 are lower than other models in terms of displacement and frequency performances. Model 3 has been shown lower performances in terms of energy and variance wavelets along the monitoring time; therefore, Model 3 demonstrates superior performance and low probability of failure under seismic loads. Furthermore, the wavelet variance analysis is shown a powerful tool that can be used to assess the CFS under seismic hazards.

• Geomechanics and Engineering
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• v.21 no.2
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• pp.133-142
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• 2020

Submerged floating tunnel (SFT) is a type of tunnel which causes the tunnel segments to float in the water. When the SFTs are connected to the ground, the connection between the SFT and the subsea bored tunnel is fragile due to the difference in behavioral characteristics between the two types of tunnels. Therefore, special design and construction methods are needed to ensure the stability of the area around the connection. However, since previous research on the stability of the connection site has not been undertaken enough, the basic step necessitates the evaluation of ground behavior at the shore connection. In this study, the numerical analysis targeting the shore connection between the subsea bored tunnel and the SFT was simulated. The strain concentration at the shore connection was analyzed by numerical simulation and the effects of several factors were examined. The results showed the instability in the ground close to the shore connection due to the imbalance in the behavior of the two types of tunnels; the location of the strain concentration varies with different environmental and structural conditions. It is expected that the results from this study can be utilized in future studies to determine weak points in the shore connection between the submerged floating tunnel and the subsea bored tunnel, and devise methods to mitigate the risks.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.168-173
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• 2004

Fretting is a kind of surface degradation mechanism observed in mechanical components and structures. The fretting damage decrease in 50-70% of the plain fatigue strength. This may be observed in aircraft, automobile and nuclear power plant used in special environment and various loading conditions. In the present study, the characteristics of the fretting fatigue are investigated using the two aluminum alloy(Al2024-T3511 and Al7050-T7451). Through the experiment, it is found that the fretting fatigue strength of the Al7050-T7451 alloy decreased about 50% from the plain fatigue strength, while the fretting fatigue strength of the Al2024-T3511 alloy decreased about 45%. The tire track was widely observed in fracture surface area of oblique crack which was induced by contact pressure. These results can be the basic data to the structural integrity evaluation of aluminum alloy subjected to fretting damage.

• The Journal of Fisheries Business Administration
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• v.51 no.1
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• pp.1-17
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• 2020

This study is an analysis of the Aquaculture Industry Development Act that has recently been passed by the National Assembly. In order to improve the structural problem of Korea's aquaculture, a large revision of aquaculture related laws and regulations is needed. The enactment of Aquaculture Industry Development Act is necessary to that effect. It is adequate to aim for development as aquaculture industry not as aquaculture, to alleviate entry restriction of aquaculture, and to provision diverse promotion and support policies. However, it is a concern whether the current Aquaculture Industry Development Act can achieve its goal of enhancing the competitiveness of aquaculture and sustainability. Rather than to solve the problem, the act holds the possibility of further fixing or exacerbating the problem. So there is concern for side-effects after the enactment. This is due to the fact that it complicates terminologies by unnecessarily differentiating aquaculture related concepts from the existing Fisheries Act, lacks regulations regarding voluntary participation in aquaculture, and has limited methods to alleviate entry restriction. In addition, there are very few measures for the scale improvement of aquaculture along with the unlikeliness of a significant effect of the review and evaluation for re-licensing. Thus, the Aquaculture Industry Development Act should promptly be revised after its enactment.

• Bulletin of the Korean Chemical Society
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• v.28 no.6
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• pp.970-976
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• 2007

For the development of novel hepatoprotective agents, C11, C28, C2,3,23 or C2,23,28 functional groups on asiatic acid were modified, and their hepatoprotective effects were evaluated. Most of the prepared compounds displayed potent hepatoprotective activities against CCl4- and galactosamine (GaIN)-induced hepatotoxicity. Especially, compounds 16 and 20 showed the most significant hepatoprotective effects against GaIN-induced hepatotoxicity (54.2% and 46.4% protection at 50 mM, respectively).

• Korean Journal of Agricultural Science
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• v.35 no.2
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• pp.247-262
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• 2008

The purpose of this study is to evaluate farmer's general contents on the current direct payment schemes and to derive some improvement measures, based on the survey data for the three types of direct payment schemes currently executed in Korea; Rice Farmer's Income Support, Early Retirement Aged Farmer's Support and Less Favored Area Direct Payment. In recent years we have introduced diverse direct payment schemes that are expected to have immediate effects in a short term period without enough preparation of the policy, which raises some contradiction between the agricultural policy and the original purpose of the direct payments. The result shows some important revisions should be made related the direct payment schemes, such as farmer's income stability through the improvement of unit payment and the payment length jointed with criteria of the payment, in addition to keeping up multifunctionality of agriculture and enhancing the effect of structural adjustment in agriculture.

• Management & Information Systems Review
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• v.32 no.5
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• pp.233-260
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• 2013

This study reviewed previous studies about Relationships between Festival Participation and Festival Evaluations. Also relationships among the quality of festival participation and festival evaluation factors identified from previous researches were studied. According to the results in view of the relationship between the quality of festival participation and festival performances, hypotheses about the relationship between physical environment and contents identification and about the one between customer experience awareness and loyalty were rejected. On the other hand, the rest of hypotheses were supported having positive impacts.

• Journal of Korean Association for Spatial Structures
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• v.14 no.2
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• pp.79-86
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• 2014

The purpose of this study is intended to determine the validity of shear reinforcement by evaluating flexural performance in the hollow slab. The hollow slab is relatively light and second moment of inertia is large. Due to these characteristics, it can be used to slab system efficiently. Therefore the prediction of the structural behaviors is very important because of decrease of shear and flexural strength which is caused by hollow section of slab interior. In this study, the flexural test were performed to analyze the flexural capacity of the hollow slab w/ or w/o shear reinforcement. A total of six full scale specimens were tested. These specimens have three cases of reinforcing bar ratio, 0.009, 0.018 and 0.024. To verify the flexural behavior such as ultimate load, load-deflection and crack pattern, the flexural experiment were tested by using loading frame. Experimental results have shown that the flexural behavior are depend on the reinforcing bar ratio. Also the hollow slab with shear reinforcement have shown flexural behavior. Therefore, it is appropriate that the hollow slab is reinforced by shear reinforcement to improve the flexural performance of the hollow slab.

• Journal of Korean Association for Spatial Structures
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• v.17 no.1
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• pp.49-58
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• 2017

The result of the previous work leads to the idea that the inner area of the hyperbolic shell generator should be minimized for the cooling tower with higher first natural frequency. In this study the inner area of the hyperbolic shell generator was graphically established under varying height of the throat and angle of the base lintel. From the graph, several shell geometries were selected and analysed in the aspect of the natural frequency. Three representative towers reinforced differently due to different first natural frequencies were analysed non-linearly and evaluated using a damage indicator based on the change of natural frequencies. The results demonstrated that the damage behaviour of the tower reinforced higher due to a lower first natural frequency was not necessarily advantageous than the others.