• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.6
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• pp.1109-1117
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• 2017

Recently, 3D printer technology has been attracting attention in various industrial fields, and research papers are being conducted to utilize 3D printers in the construction industry. Actual structures such as bridges and buildings are being printed to 3D printers, and various applications such as mock-up structures using 3D printers are being proposed. In order to utilize 3D printer technology in the construction field, a 3D model is required, and the 3D BIM data produced at the design stage can be printed by a 3D printers, saving the cost and time of 3D model generation. However, 3D BIM data often does not satisfy the conditions for 3D printer output, causing many errors on output. In this paper, authors propose a problem analysis for 3D BIM model output to 3D printer and a method for reducing errors in 3D printing process of 3D BIM model. In addition, this paper presents a practical application of 3D model output from 3D printer.

• Journal of the Korea Society for Simulation
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• v.32 no.3
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• pp.1-8
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• 2023

Modeling of artificial targets in Synthetic Aperture radar (SAR) mainly simulates radar signals reflected from the faces and edges of the 3D Computer Aided Design (CAD) model with a ray-tracing method, and modeling of the clutter on the Earth's surface uses a method of distinguishing types with similar distribution characteristics through statistical analysis of the SAR image itself. In this paper, man-made targets on the surface and background clutter on the terrain are integrated and made into a three-dimensional (3D) point cloud scatterer model, and SAR image were created through computational signal processing. The results of the SAR Stripmap image generation of the actual automobile based SAR radar system and the results analyzed using EM modeling or statistical distribution models are compared with this 3D point cloud scatterer model. The modeling target is selected as an bridge because it has the characteristic of having both water surface and ground terrain around the bridge and is also a target of great interest in both military and civilian use.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1029-1034
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• 2009

3자원 정보모델에 기반한 건설프로세서의 혁신이 새로운 추세가 되고 있고 고속철도와 같이 시스템엔지니어링에 해당하는 경우에는 가장 좋은 활용 사례가 될 수 있다. 정보모델은 3차원 영상에 기반하고 다양한 구성요소가 가진 기본정보와 설계와 유지관리에 이르는 생애주기 정보를 저장하고 재활용할 수 있도록 한다. 이 논문에서는 호남고속철도의 한 구간을 대상으로 이미 제안된 철도시설물정보모델의 개념에 근거하여 3차원 정보모델을 구성하였다. 구성된 정보모델에 기반하여 2차원도면, 해석, 견적, 시뮬레이션 등의 각 솔루션으로의 연동성 확보를 위한 시범사업의 결과를 정리하였다. 콘크리트 박스 교량을 대상으로 하는 시범사업을 통해서 생산성 향상 및 3차원 모델의 재활용성을 확보하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.2
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• pp.239-245
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• 2020

Recently, BIM (Building Information Modeling) are widely being utilized in Construction industry. However, most structures that have been constructed in the past do not have BIM. For structures without BIM, the use of SfM (Structure from Motion) techniques in the 2D image obtained from the camera allows the generation of 3D model point cloud data and BIM to be established. However, since these generated point cloud data do not contain semantic information, it is necessary to manually classify what elements of the structure. Therefore, in this study, deep learning was applied to automate the process of classifying structural components. In the establishment of deep learning network, Inception-ResNet-v2 of CNN (Convolutional Neural Network) structure was used, and the components of bridge structure were learned through transfer learning. As a result of classifying components using the data collected to verify the developed system, the components of the bridge were classified with an accuracy of 96.13 %.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.2
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• pp.67-76
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• 1999

Resonance of the bridge can be occurred with the coincidence between a natural frequency of the bridge and a crossing frequency of moving loads which is determined from the speed and effective beating interval of the vehicle. In case of the railway bridge, the effective beating interval of the vehicle is fixed under the passage of specific trains. In the present study, resonance and cancellation of the bridge subjected to moving high-speed train are analyzed with the variations of span length. A steel-concrete composite railway bridge is idealized by the combinations of plate elements and space frame elements. High-speed train is idealized with moving constant forces and a 3-dimensional full modelling. From analyzing dynamic responses of D.M.F of vertical displacement, maximum vertical acceleration of the slab, and end rotation according to the variations of span length of the bridge, design criteria of span length of the bridge which satisfies dynamic safety is discussed.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.521-524
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• 2010

현재 국내에서는 상품 생산을 위한 각 공정의 업무를 통합관리 해 줄 수 있는 PLM(Product Life-cycle Management)시스템을 건설업에 도입하려는 움직임이 있으며 실제 건설 구조물에 대한 통합환경 시스템인 CPLM(Construction Product Lifecycle Management) 관련 연구를 진행 중에 있다. 통합 시스템 내에서 건설 구조물 생산을 위한 각 업무분야에서는 시스템이 추구하는 업무진행의 흐름에 맞추어 작업을 수행 할 수 있도록 하는 각자의 프로세스를 개발해야 한다. 이 연구에서는 토목구조물을 대상으로 협업환경 내에서 활용 가능한 3D 정보모델인 BIM기반의 해석 및 설계 프로세스를 구축하고 국내외 토목건설산업 분야에서 차세대 설계프로세스로 유력한 BIM기반의 구조해석 및 설계 프로세스의 실용화를 위한 기초자료를 제공함을 목적으로 하며 해석 및 설계 대상 구조물로 아치교량을 선정하여 연구를 진행하였다.

• Korean Journal of Construction Engineering and Management
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• v.23 no.2
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• pp.33-44
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• 2022

The simulation function by the 4D system is a representative BIM function in the construction stage. For the 4D simulation, schedule information for each activity must be created and then linked with the 3D model. Since the 3D model created in the design stage does not consider schedule information, there are practical difficulties in the process of creating schedule information for application to the construction stage and linking the 3D model. In this study, after extracting the schedule information of the construction stage using the HDBSCAN algorithm from the 3D model in the design stage, authors propose a methodology for automatically generating schedule information by identifying precedence and sequencing relationships by applying the topological alignment algorithm. Since the generated schedule information is created based on the 3D model, it can be used as information that is automatically linked by the common parameters between the schedule and the 3D model in the 4D system, and the practical utility of the 4D system can be increased. The proposed methodology was applied to the four bridge projects to confirm the schedule information generation, and applied to the 4D system to confirm the simplification of the link process between schedule and 3D model.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.5
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• pp.319-329
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• 2020

Among the bridges used in Korea, those that are more than 30 years old account for approximately 11% of the total bridges. Therefore, developing a seismic performance-evaluation method is necessary by considering the bridge age. Three composite steel-concrete box girder bridges with port, elastic-rubber, and lead-rubber bearings were selected, and a structural analysis model was developed using the OpenSEESs program. In this study, pier aging was reflected by the reduction in the area of the longitudinal and transverse rebars. Four conditions of 5%, 10%, 25%, and 50% in the degree of pier aging were used. As input earthquakes, 40 near-fault and far-field earthquakes were used, and the maximum displacement and maximum shear-force responses of the piers were obtained and compared. The result shows that as the aging degree increases, the pier strength decreases. Therefore, the pier displacement response increases. To analyze the effects of displacement response and shear resistance, displacement ratio D_ratio and shear-force ratio F_ratio were evaluated. The older the sample bridge is, the greater is the tendency of D_ratio to increase and the smaller is the tendency of F_ratio to decrease.

• Journal of the Society of Disaster Information
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• v.14 no.1
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• pp.43-50
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• 2018

This study presented 3D Finite Element (FE) analysis of curved beam structures subjected to static and dynamic loading conditions, which is particularly strong ground motions. It was shown that the results obtained from 3D FE analyses was similar to the theoretical solution within 1% convergency error, in order to validate the 3D solid FE models in this study. In particular, it was focusing on development of dynamic characteristics of curved beam structures subjected to three-different seismic ground motions: GyeongJu, Lomaprieta and Northridge earthquakes. Consequently, It was interesting to find that the results obtained from GyeongJu earthquake was detuned due to high frequency effect, but the Von-Mises of the curved beam structure under Lomaprieta earthquake was 647.824 MPa at 45 curvature degree.

• Journal of Korean Society of Steel Construction
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• v.23 no.2
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• pp.199-210
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• 2011

The cables in cable-stayed bridges are under high stress and are very sensitive to vibration due to their small section areas compared with other members. Therefore, it is reasonable to evaluate the cable impact factor by taking into account the dynamic effect due to moving-vehicle motion. In this study, the cable impact factors were evaluated via moving-vehicle-load analysis, considering the design parameters, i.e., vehicle weight, cable model, road surface roughness, vehicle speed, longitudinal distance between vehicles. For this purpose, two steel composite cable-stayed bridges with 230- and 540-m main spans were selected. The results of the analysis were then compared with those of the influence line method that is currently being used in design practice. The road surface roughness was randomly generated based on ISO 8608, and the convergence of impact factors according to the number of generated road surfaces was evaluated to improve the reliability of the results. A9-d.o.f. tractor-trailer vehicle was used, and the vehicle motion was derived from Lagrange's equation. 3D finite element models for the selected cable-stayed bridges were constructed with truss elements having equivalent moduli for the cables, and with beam elements for the girders and the pylons. The direct integration method was used for the analysis of the bridge-vehicle interaction, and the analysis was conducted iteratively until the displacement error rate of the bridge was within the specified tolerance. It was acknowledged that the influence line method, which cannot consider the dynamic effect due to moving-vehicle motion, could underestimate the impact factors of the end-cables at the side spans, unlike moving-vehicle-load analysis.