• Journal of the Korean Geotechnical Society
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• v.40 no.1
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• pp.55-63
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• 2024

In this study, a thermomechanical numerical model was developed to evaluate the stability of energy slabs. First, a wall-type energy slab was installed in a residential underground parking lot, and thermal performance tests were conducted. Based on the tests, a numerical thermohydraulics model of the energy slab was developed to accurately simulate the thermal behavior in thermal performance tests. Finally, utilizing the temperature data acquired using the developed model, a thermomechanical numerical model of the energy slab was established. The thermomechanical model was then used to simulate the thermal stresses induced by operating the energy slab. The results demonstrated a maximum thermal stress of 5,300 kPa, which highlights the need to utilize cement mortar with sufficient tensile strength to realize stable operation of the energy slab.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.4
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• pp.1-17
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• 2012

This study was carried out to propose the improved method by analyzing the change of green space arrangement and planting structure of apartment complexes in Seoul. 12 survey sites, which have obvious differences, were selected by reflecting the change of floor area ratio, underground parking place, and green space ratio. We divided the survey sites into four types that high green ratio(over 40%) apartment on natural ground, low green ratio(under 40%) apartment on natural ground, low green ratio(under 40%) apartment on artificial ground, and high green ratio(over 40%) apartment on artificial ground each period based on green space ratio and ground structure, plant crown volume, planting density, and planting pattern. The main factors of change of green space arrangement were green space ratio and ground structure. The Green space ratio was changed by the floor area ratio with constructing underground parking place and floor area ratio was adjusted by government policy and economic status. Average width of front green area has been changed from 10.0m in high green ratio apartment on natural ground for 3.5m, 2.7m, and 4.5m each period. The average width of the buffer green area has been changed from 15.0m in high green ratio apartment on natural ground of 7.7m, and 2.7m by extending parking place in the low green ratio apartment of artificial ground, so buffer green areas have been reduced and disconnected. So buffer green area in apartment complexes has been extended that the average width of the buffer green area was 3.8m caused by growing recognition of green since 2001. The ratio of native plant in canopy layer was increased from 45.1 % in the case of the high green ratio apartment of natural ground in 1980~1983 to 55.6%. Average plant crown volume increased from $1.27m^3/m^2$ in high green ratio apartment on natural ground for $3.47m^3/m^2$ in a low green ratio apartment on natural ground. But average plant crown volume is $0.27m^3/m^2$ in the high green ratio apartment of the artificial ground plant density of canopy layer was changed from 5 individuals per $100m^2$ to 14.5 individuals per $100m^2$. We should construct the buffer green area with natural ground and get the function of ecological and beautiful environment regarding to garden concept in case of front green area, width 4.5m. We should get the function of increasing green volume by multi-layer planting with shade woody species and flower woody species in case of back-side green area, width over 5.0m. We should get the function of covering the wall and increasing green landscape by planting with high woody species in case of side green area. We should apply the ecological planting technique to buffer green area and connect buffer green area to inner green area in apartment complexes.

• Journal of Environmental Impact Assessment
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• v.27 no.5
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• pp.405-416
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• 2018

In this research, the distribution of Platinum Group Elements (PGEs) at roadside dust in Daejeon, Korea was examined using an ICP-MS (Inductively Coupled Plasma-Mass Spectrometry) technique. For the quality assurance of the determination, method validation based on its accuracy and precision was conducted using SRM (Standard Reference Material). It was found that the relative errors of Pt, Pd, and Rh against each SRM value were -0.7%, -10.0%, and -20.4%, respectively, while relative standard deviations for three elements were less than 10%. The concentrations of Pt, Pd and Rh in roadside dust averaged as $17.4{\pm}9.2{\mu}g/kg$, $283.6{\pm}20.5{\mu}g/kg$, and $7.3{\pm}2.8{\mu}g/kg$, respectively. The concentrations of Pt and Rh have significantly higher distribution patterns in the dust at roadside and underground parking lot than those in soil of the background or other urban area. The correlation analysis between concentrations of PGEs in roadside dust indicates that the distribution of Pt and Rh concentration were strongly affected by automobile sources.

• Journal of the Korea Concrete Institute
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• v.22 no.5
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• pp.695-702
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• 2010

This paper presents a reinforced concrete composite deck slab system newly developed using a high ductile ECC extrusion panel. In the construction practice, the cracking of reinforced concrete slab often becomes a problem especially in parking garages, underground structures, and buildings. The ECC panel manufactured by extrusion process as a precast product has not only a high-quality in control of cracking but also a merit in applying the construction of concrete slab because the use of ECC panel can realize a formless or half-precast construction with cast-in-place concrete. In the newly developed deck slab system, the ECC extrusion panel is located in the bottom of slab with the thickness of 10 mm, reinforcements are assembled and located on the ECC panel, and finally the topping concrete is placed in the field. In order to evaluate the newly developed slab system, experimental works by four point bending test are conducted to compare with the conventional reinforced concrete slab system. From experiment, the developed deck slab system using a ECC panel gives many improved performances both in control of bending cracking and in load-carrying capacities of slabs.

• Journal of The Korea Institute of Healthcare Architecture
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• v.27 no.3
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• pp.71-78
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• 2021

Purpose: It is important to plan the ward module at a time when the size of beds, the floor area, and the construction budget are all set prior to the hospital design. In this context this study aims (1) to derive various factors affecting the ward module, and (2) to analyze the appropriate room module according to the type. Methods: Design factors related to hospital modules are derived through precedential studies, and the types of ward elevation are classified by reviewing the drawings of 18 case hospitals. And the detailed dimensions and area of the derived elements are analyzed. Results: The X-axis modules of the ward are switched to long span structural columns of 9.9 m, 12.6 m and 13.2 m, but the ward modules still represent 6.6 m. The Y-axis module of the ward shows a dimension of 9 to 9.9m in the process of changing a multi-person room into a four-person room. Type A of curtain wall with columns located on the wall of the room and type B of curtain wall located in the center of the room are analyzed due to their variations. The square window type, which forms the elevation of the square window by exposing the columns to the elevation, and the outframe type, which protrudes from the structural columns and beams, have elevation designs limited. There are, however, no obstacles to the interior space of the hospital room, so the wall composition and furniture arrangement are expected to be free. The ward area of Curtain Wall Type A, which can secure an effective area of 5.9m*5.0m, are 52.1m². The Curtain Wall Type A, Square window type, and the outframe type are 49.8m². Implications: As part of the hospital standard module plan for economical and reasonable hospital building planning, a type was proposed in this study in conjunction with the external design. It is hoped that it be a base for standard module research linked together to the Central Treatment department, Outpatient department and underground parking lot.

• Korean Journal of Construction Engineering and Management
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• v.22 no.6
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• pp.55-63
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• 2021

Recently, as the problem of the traditional on-site labor-intensive construction production method has been raised due to changes in construction work labor and site conditions, the OSC method is gradually spreading as an alternative to this. Even in apartment houses, the application of the PC method is expanding centered on the underground parking lot, but the high cost structure is a problem compared to the conventional formwork method. In this study, factors affecting the calculation of construction cost in the economic evaluation, which are the core of determining the construction method for apartment buildings, are derived through domestic and foreign literature review and expert advice, the importance was analyzed through an opinion survey targeting industry experts. The measures to reduce construction cost were mainly derived from the improvement of the design and manufacturing process. It is expected that the factors affecting the construction cost and improvement measures of the PC method derived from this study will serve as a direction for technology development to spread the application of the PC method for apartment houses in the future.

• Journal of Environmental Health Sciences
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• v.48 no.5
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• pp.282-289
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• 2022

Background: Airborne fungi are ubiquitous in the air and exposure to an airborne fungus can be a significant risk factor. The composition of fungi has been potentially important for human health, especially for respiratory diseases like asthma and atopic dermatitis. Therefore, we attempted to ascertain what kind of airborne fungi affect human health at a nationwide level. Objectives: This study was carried out to provide information on indoor fungi distribution at multi-use facilities throughout South Korea. Methods: We classified our data by region and public facility after collection, cultivation, and identification via the sequencing of the ITS (internal transcribed spacer) region. We investigated whether or not the proliferation of HaCaT cells was affected by the identified airborne fungi. Results: In our data, the most isolated airborne fungi by region were Penicillium spp (Seoul, Daegu), Periconia sp (Gyeonggi-do), Iprex sp (Gangwon-do), Phanerochaete sp (Busan), Bjerkandera sp (Gwangju), and Aspergillus sp (Jeju-do). In the public facilities, the most detected fungi were Cladosporium sp (public transport), Penicillium sp (apartment house, retail market, financial institution, karaoke room), Bjerokandera sp (underground parking lot, public toilet, medical institution), Periconia sp (retail store), and Fusarium sp (general restaurant). Next, we selected twenty airborne fungi to examine their cytotoxicity and proliferation of human skin cells. In this experiment, the proliferation of the cells was influenced by most of the identified fungi. In case of the cytotoxicity test, most genera except for Rhodotorula sp and Moesziomyces sp showed cytotoxicity in HaCaT cells. Conclusions: The distribution of mold in the indoor air in multi-use facilities in South Korea differs from region to region, and this is an indicator that should be considered in future health impact studies. In addition, as a result of culturing about 20 types of bacteria dominant in indoor air, it was found that most (90%) inhibit the growth of skin cells, which can be harmful to health. An in-depth study of the health effects of floating fungi is needed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.1
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• pp.32-38
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• 2024

In the case of apartment building, it is difficult to conduct non-destructive testing due to the actual presence of people and the dust and noise generated during the core test, so inspections are performed each time in the common area and underground parking lot, and the tests are conducted on the finishing material rather than on the concrete surface due to low-cost orders. As the process progresses, poor inspection is inevitable. In addition, the proposed formulas for strength estimation have large fluctuations depending on the differences in test conditions and environments, and even if they show the same measured value, the deviation between each proposed formula is large, making it difficult to accurately estimate strength, making it difficult to use. Accordingly, we would like to select finishing materials mainly used in apartment complexes and compare and evaluate the compressive strength of concrete according to the type of finishing material by using non-destructive testing methods directly on the finishing materials without removing the finishing materials. The reliability evaluation results of the estimated compressive strength of concrete using the ultrasonic velocity method according to the type of finishing material are as follows. The error rate between the estimated compressive strength and compressive strength derived through the ultrasonic velocity method shows a wide range of variation, ranging from 21.83% to 58.89%. The effect of the presence or absence of finishing materials on the estimated compressive strength was found to be insignificant. Accordingly, it is necessary to select more types of finishing materials and study ultrasonic velocity methods according to the presence or absence of finishing materials, and to study estimation techniques that can increase reliability.

• Asian Journal of Atmospheric Environment
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• v.8 no.1
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• pp.35-47
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• 2014

The purpose of the study is to evaluate the pollution level (gaseous and particle phase) in the public facilities for the PAHs, non-regulated materials, forecast the risk level by the health risk assessment (HRA) and propose the guideline level. PAH assessments through sampling of particulate matter of diameter < 2.5 ${\mu}m$ ($PM_{2.5}$). The user and worker exposure scenario for the PAHs consists of 24-hour exposure scenario (WIES) assuming the worst case and the normal exposure scenario (MIES) based on the survey. This study investigated 20 PAH substances selected out of 32 substances known to be carcinogenic or potentially carcinogenic. The risk assessment applies major toxic equivalency factor (TEF) proposed from existing studies and estaimates individual Excess Cancer Risk (ECR). The study assesses the fine dusts ($PM_{2.5}$) and the exposure levels of the gaseous and particle PAH materials for 6 spots in each 8 facility, e.g. underground subway stations, child-care facilities, elderly care facilities, super market, indoor parking lot, terminal waiting room, internet caf$\acute{e}$ (PC-rooms), movie theater. For internet caf$\acute{e}$ (PC-rooms) in particular, that marks the highest $PM_{2.5}$ concentration and the average concentration of 10 spots (2 spots for each cafe) is 73.3 ${\mu}g/m^3$ (range: 6.8-185.2 ${\mu}g/m^3$). The high level of $PM_{2.5}$ seen in internet cafes was likely due to indoor smoking in most cases. For the gaseous PAHs, the detection frequency for 4-5 rings shows high and the elements with 6 rings shows low frequency. For the particle PAHs, the detection frequency for 2-3 rings shows low and the elements with 6 rings show high frequency. As a result, it is investigated that the most important PAHs are the naphthalene, acenaphthene and phenanthrene from the study of Kim et al. (2013) and this annual study. The health risk assessment demonstrates that each facility shows the level of $10^{-6}-10^{-4}$. Considering standards and local source of pollution levels, it is judged that the management standard of the benzo (a)pyrene, one of the PAHs, shall be managed with the range of 0.5-1.2 $ng/m^3$. Smoking and ventilation were considered as the most important PAHs exposure associated with public facility $PM_{2.5}$. This study only estimated for inhalation health risk of PAHs and focused on the associated cancer risk, while multiple measurements would be necessary for public health and policy.