• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.519-522
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• 2005

Ka-Hwa highway bridge, located in a corrosive marine environment, had been examined the current condition of reinforcement corrosion in concrete throughout half-cell potentials, electrical resistivity, chloride contamination of concrete, and visual observation. According to the test, the chloride corrosion reinforced concrete structure is not only the protecting film around the reinforcement is deteriorated but also corrosion activity develops, for example, delamination areas of concrete. The purpose of this paper is to report the effects of Ka-Hwa highway bridge damaged by chlodide attack and to present the results of repair of Ka-Hwa highway concrete bridge in domestic marine environment.

• International Journal of Concrete Structures and Materials
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• v.7 no.4
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• pp.273-285
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• 2013

An experimental investigation was conducted to compare the shear strength of full-scale beams constructed with chemically-based, self-consolidating concrete (SCC) with conventional concrete (CC). This experimental program consisted of 16 rectangular beams (12 without shear reinforcing and 4 with shear reinforcing in the form of stirrups), 8 beams for each mix design. Additionally, three different longitudinal reinforcement ratios were evaluated within the test matrix. The beam specimens were tested under a simply supported four-point condition. The experimental shear strengths of the beams were compared with both the shear provisions of selected standards (U.S., Australia, Canada, Europe, and Japan) and a shear database of CC specimens. This comparison indicates that chemically-based SCC beams possess comparable shear strength as CC beams.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.845-862
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• 2009

Recently, Tunnel in soil has been designed frequently because Mountain Tunnel has been increased rapidly due to straight of horizontal curve and residents' complaints, tunnel portal has been planned at closed to surface for minimization of environmental damage. To excavate tunnel in soil, where displacement and crushing occur in tunnel face and crown because of unstable ground condition, appropriate reinforcement method needed. On this paper, through design and construction of the soil tunnel, consider application of reinforcement method, economical efficiency and stability.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.126-127
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• 2018

Rebar work is important in terms of cost and process of reinforced concrete construction along with formwork and concrete construction, and the quality of reinforced concrete construction has a great influence on the safety and durability of the structure. Therefore it is important to thoroughly inspect the steel reinforcement after casting the concrete because it is difficult to confirm the actual condition of the reinforcement. The purpose of this study is to develop an augmented reality system to visualize the records of bar placing work, which is increasingly utilized in the construction field. In order to improve maintenance of reinforced concrete, this study suggests a plan to effectively manage the drawing information including the structural drawing, the placing drawing, and the photographed image at the construction and inspection stage, and develop a system that utilizes augmented reality technology that can display the state of the inside of a concrete structure by superimposing it on actual environment.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.11
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• pp.1068-1076
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• 2004

Technology on the proportional integral (PI) control have grown rapidly owing to the needs for the robust capacity of the controllers from industrial building sectors. However, PI controller requires tuning of gains for optimal control when the outside weather condition changes. The present study presents the possibility of reinforcement learning (RL) control algorithm with PI controller adapted in the HVAC system. The optimal design criteria of RL controller was proposed in the Environment Chamber experiment and a theoretical analysis was also conducted using TRNSYS program.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2001.11a
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• pp.1-7
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• 2001

To do performance evaluations about inorganic permanent form mixed in admixture(fly ash, silica fume) and after placed concrete, it is examined reinforcement materials in the permanent form from shear strength, bond strength and flexural strength tests. In this study, permanent form was inserted with reinforcement metal fitting is strength-tested in several method. The result of this study is belows. (1) In bond strength test, Most specimens are satisfied with criterion-6 kgf/$cm^2$. (2) Irrelative with the inserted metal fitting's shape, unevenness and aggregate, Permanent form and after placed concrete have good condition in the shear strength test. (3) In flexural test, there is no drop out of permanent form. Most cracks are located in nearby the strain point.

• Journal of the Korean Society of Safety
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• v.24 no.4
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• pp.82-89
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• 2009

Unlike concrete bridge, steel bridge resists external force by forming thin plate. Thus, because steel girder bridge has big slenderness ratio, buckling is a major design factor. Plate girder consists of flange and web plate. Because of economic views, web plate that resists shear forces is made by more thinner plate. Thus, web plate has much risk for buckling. The objective of this study is to analyze the buckling behaviors of plate girder and to present the proper reinforcement location of longitudinal stiffeners. Various parametric study according to the change of web height, transverse stiffeners and load condition are examined.

• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.3
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• pp.213-222
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• 1999

On condition that opening located at high shear strength position in H-shaped steel beams with web opening, beams are structurally to be frailed so necessity and efficiency of vertical reinforcement to add horizontal reinforcement already published ahead study. Up to the present study of web opening beams, limited one opening which located in comparatively small shear strength position. But frequently opening area is enlargement by necessity, so width of opening is larger by limit of depth or increasing number of opening. This study carry out experiment to make efficient reinforcing method about strength and deformation of steel beams with web openings. Parameters of this study are openings location, ratio of opening width within opening height and various reinforcing types.

• Journal of the Korea Institute of Building Construction
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• v.13 no.5
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• pp.482-490
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• 2013

Although the flat plate system is an efficient structural type due to the simplicity of its construction, the low story height, and the various plan design, the slab-column connections are vulnerable to punching shear failure from gravity load and eccentric shear failure from lateral load. To prevent the structure collapse, various construction methods of slab-column connection reinforcement are developed but none of these satisfies all of structural performance, economics, and constructability. This paper presents the reinforcement of slab-column connection with lattice bars. The structural performance is confirmed with the interior slab-column connection tests subjected to cyclic loading, and the economic feasibility is demonstrated from the structural design under the same condition with lattice bars, stud rails, and stirrups.

• Journal of the Korean Geosynthetics Society
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• v.17 no.2
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• pp.1-7
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• 2018

The number of construction of roads and railroads in soft ground such as coastal areas and wetlands is getting increased. For this reason cases that soft ground improvement is applied are increasing. In general, many ground improvement methods consider only the working conditions at the time or only economy. But if the working condition and economy are taken into consideration together, the number of applicable construction method gets limited. In such a case, a ground improvement method using both the surface layer portion and the deep layer portion is applied. But the basic research on this is still insufficient in practice. Therefore, in this study the reinforcement effect of geogrid was investigated by carrying out the model test realizing the case in which soft surface ground improvement and depth improvement are simultaneously applied. And it was intened to understand the effect of the thickness of surface layer, the diameter and length of the improvement body on the reinforcement effect of geogrid. The result showed that the effect of the surface layer thickness is greater than the effect of the deep layer diameter. Moreover, when the surface layer is reinforced with a geogrid, the strength of the surface layer part is enhanced and this effect of a geogrid reinforcement caused the reduction of surface settlement.