• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.2
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• pp.92-108
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• 2017

Present work shows a numerical method to analysis of interaction analysis between solitary wave and onshore bridge. Numerical simulation is carried out by TWOPM-3D (three-dimensional one-field model for immiscible two-phase flows), which is based on Navier-Stokes solver. To do this, the solitary wave is generated numerically in numerical wave channel, and numerical results and experimental results were compared and analyzed in order to verify the applicability of force acting on an onshore bridge. From this, we discussed precisely the characteristics of horizontal and vertical forces (uplift and downward forces) changes including water level and velocity changes due to the variation of solitary wave height, water depth, onshore bridge's location and type, and number of girder. Furthermore, It is revealed that the maximum horizontal and vertical forces acting on the girder bridge show different varying properties according to the number of girder, although each maximum force acting on the girder bridge is proportional to the increasement of incident solitary wave height, and the entrained air in the fluid flow affects the vertical force highly.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.8
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• pp.1242-1252
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• 2006

Many applications in computer graphics require complex, highly detailed models. However, to control processing time, it is often desirable to use approximations in place of excessively detailed models. Therefore, we have developed the notion of an optimal matrix to simplify the model surface which can then rapidly obtain high quality 2D patterns by flattening the 3D surface. Firstly, the woman's 3D body was modeled based on Size Korea data. Secondly, the 3D model was divided by shell and block for the pattern draft. Thirdly, each block was flattened by the grid and bridge method. Finally, we select the optimal matrix and demonstrate it's efficiency and quality. The proposed approach accommodates surfaces with darts, which are commonly utilized in the clothing industry to reduce the deformation of surface forming and flattening. The resulting optimal matrix could be an initiation of standardization for pattern flattening. This can facilitate much better approximations, in both efficiency and exactness.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.695-699
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• 2009

3D and BIM technology are presumed to be used more and more in the construction industry. The scope of this paper arose from a general wondering of how the constructor in general can benefit from the use of 3D models. Presented herewith is the first application of BIM in Korea to a actual bridge construction site located in Cheongpoong in Chooncheongbook-Do. This paper tries to integrate design, cost and schedule under location-based conditions with industry-specific solution for 3D modeling. 292 activities constitute the cable-stayed bridge of 442m long with a main span of 327m long. Integration of 3D model, cost and schedule is shown by comparing the measurements of works at a specific time by use of 2 different construction sequencing scenarios and cost breakdown structures.

• Structural Engineering and Mechanics
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• v.50 no.2
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• pp.241-255
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• 2014

The girder of self-anchored suspension bridge is subjected to large compression force applied by main cables. So, serious damage of the girder due to breakage of hangers may cause collapse of the whole bridge. With the time increasing, the hangers may break suddenly for their resistance capacities decrease due to corrosion. Using nonlinear static and dynamic analysis methods and adopting 3D finite element model, the responses of a concrete self-anchored suspension bridge to sudden breakage of hangers are studied in this paper. The results show that the sudden breakage of a hanger has significant effects on tensions of the hangers next to the broken hanger, bending and torsion moments of the girder, moments of the towers and reaction forces of the bearings. The results obtained from dynamic analysis method are very different from those obtained from static analysis method. The maximum tension of hanger produced by breakage of a hanger exceeds 2.2 times of its initial value, the maximum dynamic amplification factor reaches 2.54, which is larger than the value of 2.0 recommended for cable-stayed bridge in PTI codes. If two adjacent hangers on the same side of bridge break one after another, the maximum tension of other hangers exceeds 3.0 times of its initial value. If the safety factor adopted to design hanger is too small, or the hangers have been exposed to corrosion, the bridge may collapse due to breakage of two adjacent hangers.

• Structural Engineering and Mechanics
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• v.75 no.2
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• pp.271-282
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• 2020

The preservation of historic masonry-arch railway bridges is of paramount importance due to their economic benefits. These bridges which belong to past centuries may nowadays be expected to carry loads higher than those for which they were designed. Such an increase in loads may be because of increase in transportation speed or in the capacity of freight-wagons. Anyway, adequate increase in their load-carrying-capacity through structural-strengthening is required. Moreover, the increasing costs of material/construction urge engineers to optimize their designs to obtain the minimum-cost one. This paper proposes a novel numerical optimization method to minimize the costs associated with strengthening of masonry-arch railway bridges. To do so, the stress/displacement responses of Sahand-Goltappeh bridge are assessed under ordinary train pass as a case study. For this aim, 3D-Finite-Element-Model is created and calibrated using experimental test results. Then, it is strengthened such that following goals are achieved simultaneously: (1) the load-carrying-capacity of the bridge is increased; (2) the structural response of the bridge is reduced to a certain limit; and, (3) the costs needed for such strengthening are minimized as far as possible. The results of the case study demonstrate the applicability/superiority of the proposed approach. Some economic measures are also recommended to further reduce the total strengthening cost.

• International Journal of Internet, Broadcasting and Communication
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• v.16 no.1
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• pp.140-147
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• 2024

In Current artificial structures, we must periodically make their safety inspections. In this process, we should consider the safety of workers and the accuracy of safety checks and also consider time and cost savings for safety inspections. Additionally, in the fields of architecture and civil engineering, we are unavoidable the use of foreign commercialized BIM model tools. To address these challenges, we propose mapping crack areas and BIM 3D design drawings based on augmented reality (AR) for the safety inspection of Huge Bridges. For this purpose, we define indexing of 2D/3D drawing models, create the tabulation of all 2D/3D drawings into a database, analyze QR codes, and finally integrate with augmented reality devices. we may expect our method to improve the efficiency of safety inspections on bridge sites. Moreover, we will enable the domestics of our pure technology.

• Journal of Industrial Technology
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• v.24 no.A
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• pp.239-250
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• 2004

Numerical analysis were performed to investigate the stability and internal movement of tunnel located beneath the base of abutment of bridge according to the method of supporting tunnel. Two supporting methods of the multi-staged grouting method with steel pipes and the large diameter of pipe supporting method were used in the centrifuge model tests. The slip form of model lining, specially built to simulate the process of tunnel excavating under the condition of accelerated g-level, was used in the centrifuge model tests. Four centrifuge model tests were performed, changing the supporting methods of the multi-staged grouting method with steel pipes and the large diameter of pipe supporting method and the location of model abutment base of bridge. For internal displacement of tunnel, movements of the crown. The left and the right sides of spring line were measured during the proceeds of excavating tunnel in centrifuge model tests. Test results were compared with numerically estimated values of internal displacement of tunnel by using the commercially available FEM software of PENTAGON-3D. It was found that they were in good agreements and the large diameter of pipe supporting method was more stable than the multi-staged grouting method with steel pipes with respect to the internal movement of tunnel.

• Steel and Composite Structures
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• v.22 no.1
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• pp.1-12
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• 2016

Severe fatigue and noise problems of modular bridge expansion joints (MBEJs) are often induced by vehicle loads. However, the dynamic characteristics of single-support MBEJs have yet to be further investigated. To better understand the vibration mechanism of single-support MBEJs under vehicle loads, a 3D finite element model of single-support MBEJ with five center beams is built. Successive vehicle loads are given out and the vertical dynamic responses of each center beams are analyzed under the successive loads. Dynamic amplification factors (DAFs) are also calculated along with increasing vehicle velocities from 20 km/h to 120 km/h with an interval 20 km/h. The research reveals the vibration mechanism of the single-support MBEJs considering coupled center beam resonance, which shows that dynamic responses of a given center beam will be influenced by the neighboring center beams due to their rebound after the vehicle wheels depart. Maximal DAF 1.5 appears at 120 km/h on the second center beam. The research results can be utilized for reference in the design, operation and maintenance of single-support MBEJs.

• Earthquakes and Structures
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• v.18 no.1
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• pp.83-96
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• 2020

The main structural elements of historical masonry arch bridges are arches, spandrel walls, piers and foundations. The most vulnerable structural elements of masonry arch bridges under transverse seismic loads, particularly in the case of out-of-plane actions, are spandrel wall. The vulnerability of spandrel walls under transverse loads increases with the increasing of their length and height. This paper computationally investigates the out-of-plane nonlinear seismic response of spandrel walls of long-span and high masonry stone arch bridges. The Malabadi Bridge with a main arch span of 40.86m and rise of 23.45m built in 1147 in Diyarbakır, Turkey, is selected as an example. The Concrete Damage Plasticity (CDP) material model adjusted to masonry structures, and cohesive interface interaction between the infill and the spandrel walls and the arch are considered in the 3D finite element model of the selected bridge. Firstly, mode shapes with and without cohesive interfaces are evaluated, and then out-of-plane seismic failure responses of the spandrel walls with and without the cohesive interfaces are determined and compared with respect to the displacements, strains and stresses.

• Structural Engineering and Mechanics
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• v.23 no.3
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• pp.233-247
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• 2006

Most codes of practice state that for large in-plane structures it is necessary to account for the spatial variability of earthquake ground motion. There are essentially three effects that contribute for this variation: (i) wave passage effect, due to finite propagation velocity; (ii) incoherence effect, due to differences in superposition of waves; and (iii) the local site amplification due to spatial variation in geological conditions. This paper discusses the procedures to be undertaken in the time domain analysis of a cable-stayed bridge under spatial variability of earthquake ground motion. The artificial synthesis of correlated displacements series that simulate the earthquake load is discussed first. Next, it is described the 3D model of the International Guadiana Bridge used for running tests with seismic analysis. A comparison of the effects produced by seismic waves with different apparent propagation velocities and different geological conditions is undertaken. The results in this study show that the differences between the analysis with and without spatial variability of earthquake ground motion can be important for some displacements and internal forces, especially those influenced by symmetric modes.