• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.281-284
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• 1999

Bridge structure is known as one of important infrafacilities for comfortable human life. Recent long-span bridges, such as Kwang-Ahn Grand bridge, S대-Hae Grand Bridge, Young-Jong Grand Bridge, etc, have been designed and constructed near the seaside without in-depth consideration of concrete durability problems, It is in particular noted that corrosion of reinforcement steel in concrete is very important for the durability enhancement of concrete structures. The objective of this experimental study is to investigate the corrosion degree of reinforcing steels in concrete specimens which are exposed to cyclic wet and dry saltwaters, and then to develop pertinent corrosion protection system such as rational cover depth, corrosion inhibitors, cathodic system for reinforced concrete bridges exposed to marine environment.

• Journal of the Korean housing association
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• v.16 no.6
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• pp.47-54
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• 2005

By 2019, Korea is expected to be an aged society, age group of 65 and older being over $14\%$ of the total population, considering their rapid increase today. Also the phenomenon of population structure are accelerated by a low birth rate and long life span. This study was intended to find out the inconvenient details in houses pointed out by the elderly. This survey was taken by trained interviewers from the people of ages 65 and older living in Daejeon city. Statistical analysis was implemented from 583 appropriate data out of 624 questionnaires using (SPSS PC+ 10.0). The results were as follows. The elderly were put to inconvenience noises in room, old facility in living room and outmoded facility in kitchen and bathroom in detached house. And they were put to inconvenience the size of room, living room and bathroom and old-fashioned facility in kitchen in apartment. The stairway and bathroom in detached house and balcony, elevator and bathroom in apartment were pointed out dangerous spaces in house.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.528-531
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• 2004

Nowadays, many of PSC bridges has constructed because high performance and long span bridge is required. Therefore, it is required that the evaluation of PSC bridges which retain various structure performance. In this study, nonlinear FEM analysis was performed with two parameter, concrete compressive strength and effective prestress force which is dominant factor for evaluating structural behavior of PSC bridge. Concrete compressive strength was adapted between 30Mpa and 100Mpa and effective prestress force was used the value which is considered effective rate for time-dependant effect. In the result of this study, it was showed that concrete compressive strength and effective prestress force is important factor for evaluating structural behavior of PSC bridge.

• Coupled systems mechanics
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• v.7 no.3
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• pp.269-280
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• 2018

Post-earthquake damages investigation in past and recent earthquakes has illustrated that the ground motion spatial variation plays an important role in the structural response of long span bridges. For the structural control of seismic-induced vibrations of cable-stayed bridges, it is extremely important to include the effects of the ground motion spatial variation in the analysis for design of an effective control system. The feasibility and efficiency of different vibration control strategies for the cable-stayed bridge under multiple support excitations have been examined to enhance a structure's ability to withstand earthquake excitations. Comparison of the response due to non-uniform input ground motion with that due to uniform input demonstrates the importance of accounting for spatial variability of excitations. The performance of the optimized designed control systems for uniform input excitations gets worse dramatically over almost all of the evaluation criteria under multiple-support excitations.

• Wind and Structures
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• v.7 no.3
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• pp.173-186
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• 2004

Flutter derivatives provide the basis of predicting the critical wind speed in flutter and buffeting analysis of long-span cable-supported bridges. In this paper, one popular stochastic system identification technique, covariance-driven Stochastic Subspace Identification(SSI in short), is firstly presented for estimation of the flutter derivatives of bridge decks from their random responses in turbulent flow. Secondly, wind tunnel tests of a streamlined thin plate model and a ${\Pi}$ type blunt bridge section model are conducted in turbulent flow and the flutter derivatives are determined by SSI. The flutter derivatives of the thin plate model identified by SSI are very comparable to those identified by the unifying least-square method and Theodorson's theoretical values. As to the ${\Pi}$ type section model, the effect of turbulence on aerodynamic damping seems to be somewhat notable, therefore perhaps the wind tunnel tests for flutter derivative estimation of those models with similar blunt sections should be conducted in turbulent flow.

• Wind and Structures
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• v.6 no.4
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• pp.279-290
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• 2003

Flutter stability is one of major concerns on the design of long-span cable-stayed bridges. Considering the geometric nonlinearity of cable-stayed bridges and the effects due to the nonlinear wind-structure interactions, a nonlinear method is proposed to analyze the flutter stability of cable-stayed bridges, and a computer program NFAB is also developed. Taking the Jingsha bridge over the Yangtze River as example, parametric analyses on flutter stability of the bridge are carried out, and some important design parameters that affect the flutter stability of cable-stayed bridges are pointed out.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.562-567
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• 2005

F.C.M applied from Jin Jung Li to Yang Su Li(660m) in Puk Han River Bridge(1,414m) construction part is a construction method on the double-track construction which is the third section part of work, called Chung Ang Railroad Line(Deok-So${\sim}$Won-Ju). This method is the beginning application on Railroad Bridge. After completing upper slab structure, there are several following works such as setting up ballast, sleepers and laying long rails. So it is important to consider the properties of Railroad Bridge while designing the length of bridge and its single span. After the physical process study the shrinkage and creep of concrete, bending up by prestressing in general PSM bridge, relaxation of tendons as time goes by after post-tension, the conclusion of such a study is applied to the Puk-Han River Bridge in this construction field.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.827-832
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• 2000

Bridge structure is known as one of important infrafacilities for comfortable human life. Recent long-span bridges, such as Kwang-Ahn Grand bridge, Seo-hae Grand Bridge, Young-Jong Grand Bridge, etc, have been designed and constructed near the seaside without in-depth consideration of concrete durability problem. It is in particular noted tat corrosion of reinforcement steel in concrete is very important for the durability enhancement of concrete structures. The objective of this experimental study is to investigate the corrosion behavior of reinforcing steels in concrete specimens which are exposed to cyclic wet and dry saltwaters, and then to develop pertinent corrosion protection system such as rational cover depth, corrosion inhibitors, cathodic system for reinforced bridges exposed to marine environment.

• Wind and Structures
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• v.7 no.1
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• pp.29-40
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• 2004

This study has focused on aerodynamics for a wind-resistance design about the single and tandem box girder sections to realize a super-long span bridge in the near future. Three-dimensional static analysis of flows around the fundamental single and tandem box girder sections with fairing is carried out by means of the IBTD/FS finite element technique with LES turbulence model. As the results of the analysis, computations have verified aerodynamic characteristics of both sections by the histories of aerodynamic forces, the separation and reattachment flow patterns and the surface pressure distributions. The relationship between the section shapes and the aerodynamic characteristics is also investigated in both sections. And the mechanism about the generation of fluctuating aerodynamic forces is discussed.

• YAKHAK HOEJI
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• v.60 no.2
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• pp.78-84
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• 2016

N-Phenylthiourea derivatives and catechol oxidase receptor complex was studied using molecular mechanics method. The starting structure was adopted from the protein databank and the calculation of energy minimization and molecular dynamics was performed with AMBER package. The molecular dynamics showed that the simulation time span of 20 ns was long enough to observe the interaction profile and stationary ligand-receptor configuration in the complex. The conformation of the ligand was related to the interaction to the receptor and the efficacy was also interpreted in this context.