• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05b
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• pp.89-90
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• 2011

External wall cleaning is a task that is currently being performed by human workers. The recent surge in the number of high-rise buildings has led to such problems as difficulties in cleaning the wall, high risk to the specialized workers, and increased maintenance expenses. As a fundamental measure to perform external wall cleaning work in a safer manner, automation/mechanization has been on the rise. This research aims to classify façade types and analyze the performance requirements of a wall-cleaning robot, as preliminary research to develop a wall-cleaning robot. The replacement of specialized workers with robots is expected to improve both safety for workers and quality of cleaning.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05b
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• pp.97-98
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• 2011

The number of high-rise buildings has increased year after year, with there currently being 5 projects in progress to construct buildings higher than 100 stories in Seoul alone. The construction cost for such high-rise buildings is significantly higher than the cost for a conventional low-rise building, while maintenance costs are expected to be two to three times higher. To reduce the maintenance cost of a high-rise building, there is the need for a guide rail to be used for maintenance, which is why there is the need for research on the guide rail system. For this reason, as preliminary research to develop a guide rail, this study aims to derive the factors increasing construction cost by taking the installation of a guide rail into account. This is expected to lay the groundwork for the design and construction of guide rails for high-rise building maintenance.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.05b
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• pp.77-79
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• 2011

As residents and building owners demand maintenance that is required to achieve sustainable building performance, efficient building management methods are required. Even though the demand for maintenance systems is increasing, current maintenance work for high-rise buildings mostly uses conventional ropes and gondolas that pose a high risk of accidents and exhibit poor performance and efficiency. Thus, there is an urgent need to develop an automation robot system that can reduce accidents and improve the maintenance efficiency of the conventional high-rise building façade maintenance system. As a preceding work for the development of an automation robot system, this study classified and analyzed the work processes of actual construction sites and proposed basic techniques for the work mechanisms of the robot system by investigating the motions of cleaning workers.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.1
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• pp.106-114
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• 2006

Uses of geosynthetics as a reinforcing material for earth structures have ever increased due to their excellent economy. fine external appearance. and easy construction. In the current practice of geosynthetics. however, the lacks of the standardized method of evaluating the soil/geosynthetics friction properties and the inconsistency of conventional design methods develop confusion to the civil engineers. The purpose of site monitoring of the retaining wall reinforced by geogrids was to evaluate the applicability of existing design methods to, and performance of. CHAMSTONE wall system. Full scale field performance during and after construction was monitored by incorporating instrumentation including strain gauges on the geogrid and soil pressure cells. The difference of the reinforcing effects of geosynthetics embedded in the soil will be also investigated by comparing of the line and curve types of retaining wall reinforced by geogrids with block type facings.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1371-1372
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• 2011

• Journal of architectural history
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• v.19 no.6
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• pp.121-135
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• 2010

This study was to analyze the architectural characteristics and facade construction of brick masonry auditorium through the Auditorium of Namsan Primary School in 1936. The results of this study were described separately as follows. 1. The auditorium is located away from the school buildings, and its plane is a chamber of rectangle type with an entrance installed on each of the four sides. 2. The external appearance is Renaissance eclectic style, laid red bricks on the lower wall of the window and having a mansard roof. The front and the rear are symmetric with respect to the projected wall at the center. 3. As to the structure of the building, a concrete lower wall was built on the concrete continuous footing, and the brick wall was constructed on the lower wall. The roof is queen post roof truss, and the wall girders were installed on the brick wall. 4. The auditorium has had a number of repairing and maintenance works, which changed the roof and windows outside and the floor, walls, ceiling, etc. inside. 5. The decorative elements of external appearance include lower wall, brick wall, entrances, windows, roof, and dormer windows. The brick wall gives verticality and solidity to the surface of the wall, and the lower wall and wall girders are connected like a cornice of the wall. The surface of the mansard roof and dormer windows express a stable vertically oriented shape.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2011.11a
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• pp.195-196
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• 2011

Recently, the number of high-rise buildings has been on the rise, which has meant that maintenance cost has increased by two and three times, along with the increase in the construction cost. It is suggested that the use of an auto-cleaning robot could increase the productivity and safety of cleaning work, which is mostly done outside of a building. In particular, the guide rail on a high-rise building could be useful in this capacity, as it has the advantage of not being significantly influenced by factors of the external environment, including wind pressure. For this reason, this research is preliminary research into a cleaning automation for a high-rise building, and aims to draw up a scenario for the vertically moving robot.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.1
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• pp.6-12
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• 2018

Recently, The use of the curtain wall method is increasing in construction. The curtain wall construction is widely applied to the exterior wall of the building for shortening construction period and economical efficiency. However, the replacement of deterioration of the weather resistance and structural behavior of the sealing material connecting the curtain wall method and the glass frame is necessary for introduction of the stable curtain wall method and quality improvement in accordance with KS F 4910 standard. In this study, the elastic restoring force test was performed in the external environment. In this study, the deterioration of the sealant was evaluated for structural sealants. In Korea, studies on the variable displacement behavior of structural sealants are lacked. In this study, the reproduced results in laboratory conditions are compared with the deteriorating conditions exposed to the external environment, and they are reflected in the design of sealing materials in the future. According to the results of the study, it was confirmed that the existing structure sealant meets the quality standard of KS F 4910, but in the conditions performed in this study, adhesion failure of the specimen and cracking of the surface occurred. Especially, in the weather resistance test, it is necessary to evaluate the long-term durability performance of the structural sealant used in the curtain wall method by checking the insoluble state of all the test pieces. Therefore, in order to apply a conventional structural sealant to the site, it is necessary to introduce another durability performance evaluation.

• Journal of the Korea Institute of Building Construction
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• v.12 no.2
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• pp.220-229
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• 2012

In recent years, the number of high-rise buildings has been on the rise. As buildings have become larger in scale, significantly different issues related to their construction and maintenance have emerged. In addition, the automation and mechanization of the cleaning work for the curtain wall, one of the most frequently-performed tasks in building maintenance, is required as a fundamental measure. For this reason, a guide-rail cleaning robot system is emerging as one of the measures in response to external factors, including gust. Therefore, this is a preliminary study for the automation and mechanization of the curtain wall cleaning of high-rise buildings, and aims to derive the basic units and prepare for the concept of the guide rail. It is expected to serve as precedent research for the development and operation of a curtain-wall cleaning robot, and to prepare the basis for an final design of optimal guide rail.

• KEPCO Journal on Electric Power and Energy
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• v.7 no.2
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• pp.285-293
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• 2021

The construction of underground structures such as power supply lines, communication lines, utility tunnels has significantly increased worldwide for improving urban aesthetics ensuring citizen safety, and efficient use of underground space. Those underground structures are usually constructed along with vertical cylindrical shafts to facilitate their construction and maintenance. When constructing a vertical shaft through the open-cut method, the walls are mostly designed to be flexible, allowing a certain level of displacement. The earth pressure applied to the flexible walls acts as an external force and its accurate estimation is essential for reasonable and economical structure design. The earth pressure applied to the flexible wall is closely interrelated to the displacement of the surrounding ground. This study simulated stepwise excavation for constructing a cylindrical vertical shaft through a centrifugal model experiment. One quadrant of the axisymmetric vertical shaft and the ground were modeled, and ground excavation was simulated by shrinking the vertical shaft. The deformation occurring on the entire ground during the excavation was continuously evaluated through digital image analysis. The digital image analysis evaluated complex ground deformation which varied with wall displacement, distance from the wall, and ground depth. When the ground deformation data accumulate through the method used in this study, they can be used for developing shaft wall models in future for analyzing the earth pressure acting on them.