• 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.

• Structural Engineering and Mechanics
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• v.65 no.1
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• pp.19-31
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• 2018

In this paper, a new quasi-3D sinusoidal shear deformation theory for functionally graded (FG) plates is proposed. The theory considers both shear deformation and thickness-stretching influences by a trigonometric distribution of all displacements within the thickness, and respects the stress-free boundary conditions on the upper and lower faces of the plate without employing any shear correction coefficient. The advantage of the proposed model is that it posses a smaller number of variables and governing equations than the existing quasi-3D models, but its results compare well with those of 3D and quasi-3D theories. This benefit is due to the use of undetermined integral unknowns in the displacement field of the present theory. By employing the Hamilton principle, equations of motion are obtained in the present formulation. Closed-form solutions for bending and free vibration problems are determined for simply supported plates. Numerical examples are proposed to check the accuracy of the developed theory.

• Korean Journal of Remote Sensing
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• v.23 no.5
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• pp.447-453
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• 2007

The demand for more accurate and realistic 3D urban models has been increasing more and more. Many studies have been conducted to extract 3D features from remote sensing data such as satellite images, aerial photos, and airborne laser scanning data. In this paper a technique is presented to extract and reconstruct 3D buildings in urban areas using airborne laser scanning data. Firstly all points in a building were divided into some groups by height difference. From segmented laser scanning data of irregularly distributed points we generalized and regularized building boundaries which better approximate the real boundaries. Then the roof points which are subject to the same groups were classified using pre-defined models by least squares fitting. Finally all parameters of the roof surfaces were determined and 3D building models were constructed. Some buildings with complex shapes were selected to test our presented algorithms. The results showed that proposed approach has good potential for reconstructing complex buildings in detail using only airborne laser scanning data.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.4
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• pp.403-411
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• 2010

This research demonstrates a 3D virtual visualization of urban environment and video fusion for effective damage prevention and surveillance system using open standard. We present the visualization and interaction simulation method to increase the situational awareness and optimize the realization of environmental monitoring through the CCTV video and 3D virtual environment. New camera prototype was designed based on the camera frustum view model to project recorded video prospectively onto the virtual 3D environment. The demonstration was developed by the X3D, which is royalty-free open standard and run-time architecture, and it offers abilities to represent, control and share 3D spatial information via the internet browsers.

• Wind and Structures
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• v.7 no.1
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• pp.13-28
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• 2004

A method of numerical analysis without conducting 3D wind tunnel model tests was examined in our previous study for predicting vortex-induced oscillation of bridge girders with span-wise varying geometry. The aerodynamic damping forces measured for plural wind tunnel 2D models were used in the analysis. A further study was conducted to examine the precision of solution obtained by this method. First, the responses of vortex-induced oscillation of two rocking models and a taut-strip bridge girder model with span-wise varying geometry were measured. Next, the responses of these models were numerically analyzed by means of this method, and then a comparison was made between the obtained $Vr-A-{\delta}_a$ contour diagram of each 3D model in the wind tunnel test and the diagram in the numerical analysis. Since close correlations were observed between each two $Vr-A-{\delta}_a$diagrams obtained in the model test and in the analysis in cases where the 3D model did not have strong three-dimensionality, our findings revealed that the predicted solution proved to be reasonably accurate.

• 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 Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.731-739
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• 2017

As Additive Manufacturing (AM), so-called 3D printing technology, has become visualized, its potential for Mass-Customization, production costs and time savings has extended the scope of utilization to the architecture domain. Several cases that produced facilities, building elements and components using 3D printing technology have been announced mainly on the outside. There is also the development of foundation technologies including 3D printing-specific materials and equipment in Korea. As 3D printing technology in the architecture domain is currently in the early stages of adoption, realistic and systematic strategies are needed to advance it to the commercialization stages, considering the current circumstances of the industry. With this background, this study surveyed experts to investigate the status of the perception of 3D printing technology for adoption in domestic architecture industry. 3D printing technology is expected to be commercialized in areas of irregular-shape buildings and interior markets rather than general construction area. 3D printed products expected to be commercialized are limited to the level of building elements and the aesthetic factor is regarded as the most competitive factor. To enhance the possibility of the commercialization of 3D printed products, the 3D printing-specific construction method, related policies and systems are required along with the performance and stability of the materials and equipment.

• Korean Journal of Construction Engineering and Management
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• v.22 no.4
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• pp.29-40
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• 2021

Recently, interest in Building Information Modeling (BIM) has increased globally, and 3D modeling is a start for the application of BIM at construction sites. However, while many studies have been conducted on the efficiency of 3D modeling focused on civil facilities, there is a lack of research on the earthwork BIM. In particular, since 3D slope often has complex shapes depending on the ground models, the efficiency method for 3D slope are needed. This study analyzed the interfaces and procedures of other software to find out what functions users need. Then the functions to enter intervals between 3D faces, select multiple ground models, and improve the interface are reflected on the developed system and is able to efficiently perform modeling with only five steps, and reduce the number of clicks and inputs. As a result of conducting the test to verify the efficiency, using the developed system made skilled users complete modeling at least 1.8 times faster and unskilled people at least 2.4 times faster than using other software. This is expected to perform 3D slope modeling more efficiently, as well as to contribute to the activation of future BIM adoption for housing construction projects.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.4
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• pp.363-371
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• 2008

The aim of this study is to compare the numerical results obtained by 2-D and 3-D models which are used to examine the wave field around a permeable submerged breakwater. At first, the numerical model, which is able to consider the flow through a porous medium with inertial, laminar and turbulent resistance terms and determine the eddy viscosity with LES turbulent model, is used and validated by comparing with existing experimental data. And then, the numerical test on the wave field around a permeable submerged breakwater is performed. It is revealed from the numerical results that, at the onshore side of the submerged breakwater, the wave height by 2-D analysis is higher than that by 3-D analysis. Also, the time-averaged mean flow around a submerged breakwater is discussed in detail.

• Steel and Composite Structures
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• v.27 no.5
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• pp.599-611
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• 2018

In this article a four unknown quasi-3D shear deformation theory for the bending analysis of functionally graded (FG) plates is developed. The advantage of this theory is that, in addition to introducing the thickness stretching impact (${\varepsilon}_z{\neq}0$), the displacement field is modeled with only four variables, which is even less than the first order shear deformation theory (FSDT). The principle of virtual work is utilized to determine the governing equations. The obtained numerical results from the proposed theory are compared with the CPT, FSDT, and other quasi-3D HSDTs.