• The Journal of Engineering Geology
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• v.19 no.3
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• pp.287-294
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• 2009

To be design the slope, the area distributed the mica schist which was metamorphosed by shale or mudstone must carefully consider the stability. Mica schist is another unstable rock for slope by schistosity, cleavage, axial plane of a fold etc. In general mica schist contains the swelling clay minerals such as smectite, vermiculite and montmorillonite. These minerals make the slope unstable. At OO tunnel construction area for the rail way of the Kyungbu high speed train, the slope of mica schist is very unstable by the distribution phenomena of the discontinuous plane such as joints which are 1-5 cm spacing and thrust and strike-slip fault. By the drilling core of this area, most RQD have 0-20%.

• Applied Chemistry for Engineering
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• v.26 no.1
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• pp.40-46
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• 2015

Microcapsules containing the suspension of conducting materials such as carbon nanotube (CNT) or polyaniline (PANI) were prepared by in-situ polymerization of melamine and formaldehyde. Stable microcapsules were prepared and the mean diameter of the observed microcapsules was in the range of $10-20{\mu}m$. The surface morphology and chemical structure of microcapsules were investigated using optical microscope (OM), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FT-IR). The thermal properties of samples were investigated by thermogravimetric analysis (TGA). The conductivity of ruptured microcapsule containing the suspension of CNTs or PANIs in tetrachloroethylene and Isopar-G was measured. As the amount of CNTs and PANIs in the core of microcapsules increased, the measured current increased. Conductivity measurement results suggest that poly (melamine-formaldehyde) based core-shell microcapsules could be applied to self-healing electronic materials systems, where CNTs or PANIs bridge a broken circuit upon release.

• Land and Housing Review
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• v.4 no.3
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• pp.295-301
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• 2013

In this study, cases of domestic tall residential buildings were investigated for the structural types, numbers of stories, total heights, type of lateral load resisting systems, and zoning of concrete strength. Based on these investigation data, the structural planning pattern of tall residential building was analyzed. SRC structure is main structural types of tall residential building at the initial stage of domestic tall residential building, but RC structure is substituted for main structural types since 2005. Retaining wall system is positioned at the core part of structural plan as a lateral load resisting system. Concrete strength zoning of vertical members like columns are divided by vertical heights of lower parts, middle parts, and upper parts. Basic data of structural planning of 40stories and 60 stories residential buildings was proposed based on case investigation.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.7
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• pp.171-178
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• 2019

Auto Climbing Formwork System (ACS) for construction of high-rise building is a construction method for automatically lifting the formwork system supported by the anchor on the pre-constructed concrete wall. It has excellent construction speed and quality, but it has the possibility of structural failure depending on the quality of concrete and also has low economical efficiency due to the use of foreign technology. In order to overcome these problems, this study conducted an optimum design for the development of a new concept of Corner Supported Auto Climbing System (CS-ACS) in conjunction with the development of corner steel-reinforced concrete core wall system. For the design the formwork system, the basic module and structural member compositions were planned, and the structural analysis program was used to analyze the optimum member's cross section and spacing. As a result, the horizontal displacement and the stress of the horizontal members were influenced by the spacing more than the cross-section of the member. On the other hand, vertical members did not affect the displacement and stress of the formwork system. The form tie was very effective in controlling the displacement when adjusting the spacing of the horizontal members, but when the spacing of the form tie is more than 1,500mm, it is analyzed that form tie is yielding in basic module. When the span of the formwork system is more than 30m, it is analyzed that the basic module needs to be changed because of the increase of overall displacement.

• Journal of the Korea Concrete Institute
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• v.24 no.3
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• pp.275-283
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• 2012

Steel Plate for Rebar Connection was recently developed to splice rebars in delayed slab-wall joints in high-rise building, slurry wall-slab joints, temporary openings, etc. It consists of several couplers and a thin steel plate with shear key. Cyclic loading tests on slab-wall joints were conducted to verify structural behavior of the joints having Steel Plate for Rebar Connection. For comparison, joints with Rebend Connection and without splices were also tested. The joints with Steel Plate for Rebar Connection showed typical flexural behavior in the sequence of tension re-bar yielding, sufficient flexural deformation, crushing of compression concrete, and compression rebar buckling. However, the joints with Rebend Connection had more bond cracks in slabs faces and spalling in side cover-concrete, even though elastic behavior of the joints was similar to that of the joints with Steel Plate for Re-bar Connection. Consequently, the joints with Rebend Connection had less strengths and deformation capacities than the joints with Steel Plate for Re-bar Connection. In addition, stiffness of the joints with Rebend Connection degraded more rapidly than the other joints as cyclic loads were applied. This may be caused by low elastic modulus of re-straightened rebars and restraightening of kinked bar. For two types of diameters (13mm and 16mm) and two types of grades (SD300 and SD400) of rebars, the joints with Steel Plate for Rebar Connection had higher strength than nominal strength calculated from actual material properties. On the contrary, strengths of the joints with Rebend Connection decreased as bar diameter increased and as grade becames higher. Therefore, Rebend Connection should be used with caution in design and construction.

• Economic and Environmental Geology
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• v.49 no.6
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• pp.469-477
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• 2016

To evaluate the $CO_2$ storage capacity for the reservoir rock, the laboratory scale technique to measure the amount of $scCO_2$, replacing pore water of the reservior rock after the $CO_2$ injection was developed in this study. Laboratory experiments were performed to measure the $scCO_2$ displacement efficiency of the conglomerate and the sandstone in Janggi basin, which are classified as available $CO_2$ storage rocks in Korea. The high pressurized stainless steel cell containing two different walls was designed and undisturbed rock cores acquired from the deep drilling site around Janggi basin were used for the experiments. From the lab experiments, the average $scCO_2$ displacement efficiency of the conglomerate and the sandstone in Janggi basin was measured at 31.2% and 14.4%, respectively, which can be used to evaluate the feasibility of the Janggi basin as a $scCO_2$ storage site in Korea. Assuming that the effective radius of the $CO_2$ storage formations is 250 m and the average thickness of the conglomerate and the sandstone formation under 800 m in depth is 50 m each (from data of the drilling profile and the geophysical survey), the $scCO_2$ storage capacity of the reservoir rocks around the probable $scCO_2$ injection site in Janggi basin was calculated at 264,592 metric ton, demonstrating that the conglomerate and the sandstone formations in Janggi basin have a great potential for use as a pilot scale test site for the $CO_2$ storage in Korea.