• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.33 no.4
• /
• pp.1693-1705
• /
• 2013

To restore old aqueduct in Korea which is a irrigation bridge to supply water in paddy field area, it is needed to estimate approximate costs of restoration because the basic design for estimation of construction costs is often ruled out in current system. In this paper, estimating models of construction costs were developed on the basis of performance data for restoration of RC aqueduct bridges since 2003. The regression analysis (RA) model and case-based reasoning (CBR) model for the estimation of construction costs were developed respectively. Error rate of simple RA model was lower than that of multiple RA model. CBR model using genetic algorithm (GA) has been applied in the estimation of construction costs. In the model three factors like attribute weight, attribute deviation and rank of case similarity were optimized. Especially, error rate of estimated construction costs decreased since limit ranges of the attribute weights were applied. The results showed that error rates between RA model and CBR models were inconsiderable statistically. It is expected that the proposed estimating method of approximate costs of aqueduct restoration will be utilized to support quick decision making in phased rehabilitation project.

• Cartoon and Animation Studies
• /
• s.45
• /
• pp.235-258
• /
• 2016

As the first class Teaching Artists system is about to be brought to effect, the ability required for Teaching Artists to design educational contents, develop and manage education programs is not much different from that of a museum Educator. This system is necessary for resolving problems in existing Arts and Culture Education, such as overlapping programs and adjusting difficulty levels by age to meet the demand of educatee. It also deals with drawbacks in production-oriented curriculum originating from the preference in some subject. In addition, as progress in science and technology makes rapid changes in digital media and its subculture, increasing need for novel and interdisciplinary curriculum in the field of Arts and Culture Education puts further emphasis on the importance of this system. In this study, we focus on clarifying the significance of Educator as a professional and proposing curriculum for the system, trying to avoid restricting our discussion to current Arts Instructor Supporting Project which are merely aimed at supporting children and adolescents to grow up to enjoy culture and arts. Capacity for designing curriculum for culture and arts, the kernel of qualification for the first class Teaching Artists, requires a variety of comprehensive expertise and qualification such as doing preliminary research on contents related to animation, curating, determining potential of educational contents, organizing educational contents for appropriate educatee, understanding esthetic property and its role in education, and appreciating and enjoying cultural contents. Therefore, Teaching Artists plays roles not only in developing and running educational programs but also in supporting and cooperating with culture and arts institutions, designing and managing creative programs, combining and communicating with different social groups, and emphasizing mutual interchange in culture.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.18 no.6
• /
• pp.60-71
• /
• 2014

Cable-stayed bridge, which is one of the representative long-spanned bridge, needs prompt maintenances when a stay cable is damaged because it may cause structural failure of the entire bridge. Many researches are being conducted to develop abnormal behavior detection algorithms for the purpose of shortening the reaction time after the occurrence of structural damage. To improve the accuracy of the damage detection algorithm, ample observation data from various kinds of damage responses is needed. However, it is difficult to measure an abnormal response by damaging an existing bridge, numerical simulation can be an effective alternative. In most previous studies, which simulate the damage responses of a cable-stayed bridge, the damages has been considered as a load variation without regard to its stiffness variation. The analyses of using these simplification could not calculate exact responses of damaged structure, though it may reserve a sufficient accuracy for the purpose of bridge design. This study suggests Gradual Bilinear Method (GBM) which simulate the damage responses of cable-stayed bridge considering the stiffness and mass variation, and develops an analysis program. The developed program is verified from the responses of a simple model. The responses of a existing cable-stayed bridge model are analyzed with respect to the fracture delay time and damage ratio. The results of this study can be used to develop and verify the highly accurate abnormal behavior detection algorithm for safety management of architecture/large structures.

• Journal of the Korean Society for Railway
• /
• v.12 no.4
• /
• pp.574-581
• /
• 2009

Displacement of the bridge and additional rail stress due to interaction between track and bridge should be limited to the design criteria. Interaction analysis was conducted to investigate the displacement and additional rail stress on CWR in railway bridge of conventional line. Particularly, various parameters affecting interaction phenomena were taken into account in the analysis to enhance an applicability. These parameters included configuration of structure, stiffness of deck and support, steel/concrete bridge, ballast/concrete track and FM/MFM type etc. The results were presented in the form of the design chart which could be useful in preliminary design of the bridge.

• Journal of the Korean Society for Railway
• /
• v.12 no.4
• /
• pp.565-573
• /
• 2009

Displacement of the bridge and additional rail stress due to interaction between track and bridge should be limited to the design criteria. Interaction analysis was conducted to investigate the displacement and additional rail stress on CWR in high speed railway bridge. Particularly, various parameters affecting interaction phenomena were taken into account in the analysis to enhance an applicability. These parameters included configuration of structure, stiffness of deck and support, steel/concrete bridge, ballast/concrete track and FM/MFM type etc. The results were presented in the form of the design chart which could be useful in preliminary design of the bridge.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.4A
• /
• pp.611-620
• /
• 2006

The composite two plate-girder bridges are generally defined as a non-redundant load path structure because the bridge can collapse if one of the two girders is seriously damaged by a fatigue crack. In this paper, a numerical study on the evaluation of the after-fracture redundancy of the composite two-girder bridges was accomplished. The evaluation has been performed on the simple and three-span continuous bridges with I-section cross beams which serve as transverse bracing, and with or without the bottom lateral bracing system. The load carrying capacities of the intact and damaged bridges with or without lateral bracing were evaluated from material and geometric nonlinear analysis, respectively and the redundancy was evaluated for each case. It was acknowledged from the analytical results that both simple and continuous intact two-girder bridges have sufficient redundancy even without lateral bracing, but it takes an important role to improve the redundancy of damaged bridges.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.7 no.6
• /
• pp.9-15
• /
• 2003

This paper describes a vibration control by using tuned mass damper(i.e., TMD) for an existing footbridge. The footbridge is the simple steel box girder bridge with main span length of 47.7m. This bridge has light weight, low damping and the 1st bending frequency of 1.84㎐. Its frequency is close to a walking cycle, which is 2㎐. Therefore the uncomfortable resonant vibrations due to a pedestrian walking have occurred frequently. The vibration control by means of TMD for suppressing the pedestrian induced vibration was conducted. Taking into account economical benefits and the easiness of installation, a compact TMD installed within a handrail was designed. From field tests of the TMD, it was confirmed that the structural damping of the bridge via. the compact TMD was enhanced by 13 times and the resonant vibration due to pedestrian walking was suppressed.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.9 no.1
• /
• pp.65-71
• /
• 2009

In this study, dynamic serviceability of PSC, PreStressed Concrete, simple railway bridge with 25m span was estimated. All of the high speed and general train loads were considered at estimation. Natural frequency is estimated about 8Hz and includes within optimum natural frequency extent of the railway bridge. Also, the bridge was detected that resonance occurrence possibility does not exist. When travel the Moogunghwa train, acceleration response was measured to 0.43g that exceed limitation value 0.35g. Also, rotation angle of girders end did not satisfy design standard of railway bridge for high speed train, but impact coefficient and deflection satisfied design standard. As a result, that railway bridge was detected that is securing dynamic safety and serviceability partially, but methods to decrease vibration acceleration response are required.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.6 no.5
• /
• pp.59-66
• /
• 2002

Long-rails in railways and high-speed railway are subjected to additional stresses resulted from the displacements inconsistence between upper structures, and this phenomenon is more remarkable in continuous bridges than in simple bridges. For the sake of safety, railways have to guarantee trains to stop safely without derailment even in the event of earthquake. The influences of acceleration, braking, and temperature were analyzed by static nonlinear method. But earthquake loads that require dynamic nonlinear analysis are not considered in these methods. Because linear relation between relative displacements of decks and rail stresses is not guaranteed at the nonlinear systems such as long rails on the bridges, it is required compute to rail stresses considering both braking and earthquake load by nonlinear dynamic analysis method. In this study, dynamic analysis method with material non-linearity for rails on continuous bridges according to the Taiwan High Speed Railway(THSR) Design Specification volume 9 was developed. And additional stresses and displacements of long rails for acceleration, braking, and earthquake loads were analyzed by this method.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.28 no.3A
• /
• pp.305-313
• /
• 2008

A reliability based calibration of dynamic load allowance (DLA) of highway bridge is performed by numerical dynamic analysis of various types of bridges taking into account of the road surface roughness and bridge-vehicle interaction. A total of 10 simply supported bridges with three girder types in the form of prestressed concrete girder, steel plate girder, and steel box girder is analyzed. The cross sections recommended in "The Standardized Design of Highway Bridge Superstructure" by the Korean Ministry of Construction are used for the prestressed concrete girder bridges and steel plate girder bridges while the box girder bridges are designed by the LRFD method. Ten sets of road surface roughness for each bridge are generated from power spectral density (PSD) function by assuming the roadway as "Average Road". A three dimensionally modeled 5-axle tractor-trailer with its gross weight the same as that of DB-24 design truck is used in the dynamic analysis. For the finite element modeling of superstructure, beam elements for the main girder, shell elements for concrete deck, and rigid links between main girder and concrete deck are used. The statistical mean and coefficient of variation of DLA are obtained from a total of 100 DLA results for 10 different bridges with each having 10 sets of road surface roughness. Applying the DLA statistics obtained, the DLA is finally calibrated in a reliability based LRFD format by using the formula developed in the calibration of OHBDC code.