• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.8-16
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• 2016

This study presents the visualization of shape information based on Octree using 3D laser scanning. The process of visualization was established to construct the Octree structure from the 3D scan data. The scan data was converted to a 2D surface through the mesh technique and the surface was then converted to a 3D object through the Raster/Vector transformation. The 3D object was transmitted to the Octree Root Node and The shape information was constructed by the recursive partitioning of the Octree Root Node. The test-bed was selected as the steel bridge structure in Sungkyunkwan University. The shape information based on Octree was condensed into 89.3%. In addition, the Octree compressibility was confirmed to compare the shape information of the office building, a computer science campus in Germany and a New College in USA. The basis is created by the visualization of shape information for double-deck tunnel and it will be expected to improve the efficiency of structural health monitoring and maintenance.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.2
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• pp.231-248
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• 2017

Government plans to construct a double-deck tunnel under a portion of Gyeongbu Expressway that will solve traffic problems and could also be used as a flood storage facility. Divergence tunnels connect the main tunnel to the urban areas and their construction effects on adjacent structures at shallow depth need to be analyzed. This study primarily includes the numerical analysis of construction effects of divergence tunnels on utility tunnels. The utility tunnel was analyzed for three cases of volume loss applied to the divergence tunnel and two cases of the angle between main tunnel and divergence tunnel ($36^{\circ}$ and $45^{\circ}$). The results show that the more the volume loss was applied and the shorter the distance was between utility tunnel and divergence tunnel, the more the utility tunnel was affected in terms of induced displacements, angular displacement and stability. The worst scenario was found out to be the one where the angle between main tunnel and divergence tunnel was $36^{\circ}$ and the distance between divergence tunnel and utility tunnel was 10 m, resulting in the largest displacement and differential settlement at the bottom of the utility tunnel. A relationship between the angular displacement and the distance to diameter ratio was also established.

• Journal of Korean Tunnelling and Underground Space Association
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• v.21 no.1
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• pp.177-188
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• 2019

The purpose of the optimization of the installation of supply/exhaust ports for tunnels with transverse ventilation system is to supply fresh air from outside to inside of tunnels uniformly and exhaust pollutant from tunnels properly for creating safe and clean environment for tunnel users. For this purpose, a ventilation port area optimization program was developed to obtain a uniform supply or exhaust air volume inside a great depth double deck tunnel with transverse ventilation system. In order to area optimize the developed port sizing program, the wind velocity was measured in the duct of the currently operated tunnel with semi-transverse ventilation. Also 3D cfd was performed on the same tunnel and cfd results were compared to the measured value. As a result, the error rate between the predicted value from the program and measured value was 6.72%, while the error rate between the predicted value from the program and 3D cfd analysis value was 4.86%. Both of comparison results show less than 10% of error rate. Thus It is expected that supply/exhaust port optimization design of transverse ventilation tunnel can be possible with using this large exhaust port area optimization program.

• Journal of the Society of Naval Architects of Korea
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• v.36 no.3
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• pp.8-14
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• 1999

The flor characteristics around the KRISO 3600TEU container ship model have been experimentally investigated in a subsonic wind tunnel. The mean velocity and turbulence characteristics in the stern and wake regions were measured using an x-type hot-wire probe. The flow characteristics in the stern and near wake regions revealed a complicated three-dimensional flow pattern. The measured results showed clearly the formation of longitudinal vortices and their effect on the flow pattern in the wake region. The shear layer developed along the ship model expands showly to the downward direction. The turbulence statistics measured can be used as comparative data of numerical simulations and provide insights into development of accurate turbulence models for the ship design.

• International Journal of Highway Engineering
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• v.19 no.6
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• pp.57-66
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• 2017

PURPOSES : This study develops eco-friendly asphalt reinforcement materials applicable to bridge deck pavement. The main purpose is to ensure highly reliable quality applicable to structures and the possibility of practical application. The main target of the study is to develop materials that are environmentally friendly and capable of improving performance. METHODS : The application of double-reinforcement fiber improves the performance of the road pavement. 1. We use recycled film for application of sheet-typed reinforcement. 2. We use preprocessing fibers to reinforce the properties of composite pavement materials. RESULTS : The developed products may produce materials that fit the purpose of achieving stability and environmental friendliness. Sheet-typed reinforcements use more than 50% recycled resin. The most important type of damage to the asphalt layer is deflection (plastic deformation). These products have a very high deflection resistance of not less than 6,000 cycles/mm. In addition, all performance is excellent. Thus, it will be easier to access the field in the future. CONCLUSIONS : Fiber-reinforced asphalt pavement showed excellent performance. Sheet-typed reinforcements containing 50% recycling resin produced good performance in terms of functionality as well as environmental friendliness. Thus, enhancing the field applicability will enhance the usability of the reinforcements.

• Structural Engineering and Mechanics
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• v.39 no.4
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• pp.521-539
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• 2011

Jilin highway concrete bridge is located in the center of Jilin City, which is positioned in the middle part in Jilin Province in the east north of China. This bridge crosses the Songhua River and connects the north and the south of Jilin City. The main purpose of damages inspection of the bridge components is to ensure the safety of a bridge and to identify any maintenance, repair, or strengthening which that need to be carried out. The damages that occur in reinforced concrete bridges include different types of cracks, scalling and spalling of concrete, corrosion of steel reinforcement, deformation, excessive deflection, and stain. The main objectives of this study are to inspect the appearance of Jilin highway concrete bridge and describe all the damages in the bridge structural members, and to evaluate the structural performance of the bridge structure under dead and live loads. The tests adopted in this study are: (a) the depth of concrete carbonation test, (b) compressive strength of concrete test, (c) corrosion of steel test, (d) static load test, and (e) dynamic load test. According to the damages inspection of the bridge structure appearance, most components of the bridge are in good conditions with the exception arch waves, spandrel arch, deck pavement of new arch bridge, and corbel of simply supported bridge which suffer from serious damages. Load tests results show that the deflection, strain, and cracks development satisfy the requirements of the standards.

• Proceedings of the KWS Conference
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• 2005.06a
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• pp.285-287
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• 2005

During fabrication of deck house block in passenger ships, the problem of unexpected large deformation and distortion frequently occurs. In this case, line and spot heating method were widely used to correct the distortion of thin plate structure. Spot heating was especially used for the case under 5mm thickness. Few papers are available on the working conditions of spot heating method but only little information on deformation control. In this study, evaluation was carried out on the temperature distribution of spot heating methods using FEA and practical experiments for various heating time. IIn FEA, heat input model was established using Tsuji's double Gaussian heat input mode (Tsuji, I., 1988). This model was verified by comparing with experimental data. Also radial shrinkage and angular distortion due to spot heating were determined and compared with experimental results. Thermo elasto-plastic analysis was performed using commercial FE code, MSC/MARC. Radial shrinkage and angular distortion were measured using 3D measuring apparatus. Based on these results, simplified analysis model for deformation by spot heating was established.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.88-89
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• 2015

In cold weather, the speed of concrete strength development is slow. As a result, construction speed becomes slow and it is problem for all construction site to solve this. So in this study, to shorten removing frame time after placing concrete, mix proportion using early-strength-binder(ESB) and curing method such as using heat line in concrete was considered. At first, concrete mix proportion was examined at -5℃ temperature between ordinary portland cement(OPC) and ESB. And second step, concrete, using mix proportion with OPC, was examined according to curing method(: 1) heat line used and 2) no heat line) and kinds of form (: 1) Deck slab, 2) Half PC slab and 3) SOG slab). All cases are same condition: slab thickness is 1,500mm, double-bubble sheet is used as a curing sheet after placing concrete. After the test, OPC is enough to get strength compared to ESB in special condition and 48~60 hours is needed according to form condition.

• Steel and Composite Structures
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• v.51 no.5
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• pp.563-573
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• 2024

This research experimentally evaluated the local stress distribution along the cross-section of composite beams under both positive and negative moments. The experiment utilized a large-scale, two-story, two-by-three bay steel gravity frame with a concrete on metal deck floor system. The composite shear connections, which are nominally assumed to be pinned under gravity loading, can develop non-negligible moment-resisting capacity when subjected to lateral loads. This paper discusses the local stress distribution, orshear lag effects, observed near the beam-to-column connections when subjected to combined gravity and lateral loading. Strain gauges were used for measurements along the beam depth at varying distances from the connection. The experimental data showed amplified shear lag effects near the unconnected region of the beam web and bottom flange under the applied loading conditions. These results indicate that strain does not vary linearly across the beam cross-section adjacent to the connection components. This insight has implications for the use of experimental strain gauge data in estimating beam demands near the connections. These findings can be beneficial in informing instrumentation plans for future experimental studies on composite beams.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.24 no.6
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• pp.645-654
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• 2011

Temporal supports is proposed for the large block construction of a double-deck truss girder of a bundle type cable-stayed bridge. The design force of the temporal bents cannot be evaluated by a conventional design procedure with gust factored static wind loads. The uplift forces in BS5400 also can not estimate the design forces of the temporal bents properly for the turbulent wind loads. A frequency-domain buffeting analysis is performed to evaluate the design forces of the temporal bents considering the interactions between the girder and temporal supports. Two cases of modeling are compared to estimate the stiffness contribution of temporal supports in determining design forces, i.e., an analysis model including temporal bents in the structural analysis modeling and an analysis model with fixed supports at the bent tops neglecting the stiffness of temporal bents. The consideration of bent stiffness usually generates smaller reaction forces than rigid support modeling. Consequently, the effectiveness and usefulness of the buffeting analysis procedure with full modeling of temporal supports are demonstrated for the design of a temporal bents of the construction of a bundle type cable-stayed bridge.