• Earthquakes and Structures
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• v.8 no.1
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• pp.133-152
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• 2015

This paper investigates the soil effect on seismic behaviour of reinforced concrete (RC) buildings by using the spread plastic hinge model which includes material and geometric nonlinearity of the structural members. Therefore, typical reinforced concrete frame buildings are selected and nonlinear dynamic time history analyses and pushover analyses are performed. Three earthquake acceleration records are selected for nonlinear dynamic time history analyses. These records are adjusted to be compatible with the design spectrum defined in Turkish Seismic Code. Interstory drifts and damages of selected buildings are compared according to local soil classes. Also, capacity curves of these buildings are compared with maximum responses obtained from nonlinear dynamic time history analyses. The results show that, soil class influences the seismic behaviour of reinforced concrete buildings, significantly.

• Earthquakes and Structures
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• v.14 no.4
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• pp.285-295
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• 2018

In this study, the effect of local site conditions (site class and site amplifications) and structural variability are investigated on fragility functions of typical building structures. The study area is chosen as Eastern Turkey. The fragility functions are developed using site-specific uniform hazard spectrum (UHS). The site-specific UHS is obtained based on simulated ground motions. The implementation of ground motion simulation into seismic hazard assessment has the advantage of investigating detailed local site effects. The typical residential buildings in Erzincan are represented by equivalent single degree of freedom systems (ESDOFs). Predictive equations are accomplished for structural seismic demands of ESDOFs to derive fragility functions in a straightforward manner. To study the sensitivity of fragility curves to site class, two sites on soft and stiff soil are taken into account. Two alternative site amplification functions known as generic and theoretical site amplifications are examined for these two sites. The reinforced concrete frames located on soft soil display larger fragilities than those on stiff soil. Theoretical site amplification mostly leads to larger fragilities than generic site amplification more evidently for reinforced concrete buildings. Additionally, structural variability of ESDOFs is generally observed to increase the fragility especially for rigid structural models.

• Journal of Species Research
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• v.13 no.2
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• pp.142-146
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• 2024

The purpose of this study was to isolate and identify wild yeasts from soil collected in Daegu City and Cheongyang County, Republic of Korea. Among 11 strains isolated in this study, nine strains were previously reported and two strains were unreported in Republic of Korea. To identify wild yeast strains, pairwise sequence comparisons of the D1/D2 region of the 26S rRNA gene sequence were done using Basic Local Alignment Search Tool (BLAST). The cell morphologies were observed by phase contrast microscope and assimilation test are done using API 20C AUX kit. All strains were assigned to the phylum Basidiomycota. Of the two unrecorded yeast strains, CY-9-10C belongs to the genus Mrakia (family Mrakiaceae, order Cystofilobasidiales, class Tremellomycetes) and PG3-4-10C belongs to the genus Slooffia (family Chrysozymaceae, order Microbotryomycetes incertae sedis, class Microbotryomycetes). Both strains had oval-shaped and polar budding cells. This research described the morphological and biochemical properties of the two unreported yeast species that had not officially reported in Korea.

• Journal of Species Research
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• v.13 no.2
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• pp.136-141
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• 2024

The purpose of this study is to isolate and identify wild yeasts from the soil samples collected in Daegu and Daejeon City, Republic of Korea. Among 15 strains isolated in this study, 13 strains were previously reported and two strains had not been reported in Republic of Korea. To identify wild yeast strains, pairwise sequence comparisons of D1/D2 region of the 26S rRNA gene sequence were done using Basic Local Alignment Search Tool (BLAST). The cell morphologies were observed by phase contrast microscope and assimilation tests were done using API 20C AUX kit. All strains were assigned to the phylum Basidiomycota. The two unrecorded yeast strains, PG2-2-10C and DJ2-14-10C, belong to the genus Holtermanniella (family Holtermanniaceae, order Holtermanniales, class Tremellomycetes) and Goffeauzyma (family Filobasidiaceae, order Filobasidiales, class Tremellomycetes), respectively. The two unrecorded yeast strains had oval shape and polar budding cells. This research describers the morphological and biochemical properties of the two unreported yeast species that had not officially reported in Korea.

• Earthquakes and Structures
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• v.13 no.1
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• pp.67-77
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• 2017

Oil storage tanks are vital life-line structures, suffered significant damages during past earthquakes. In this study, a numerical model for an unanchored vertical vaulted-type tank was established by ANSYS software, including the tank-liquid coupling, nonlinear uplift and slip effect between the tank bottom and foundation. Four actual earthquakes recorded at different soil sites were selected as input to study the dynamic characteristics of the tank by nonlinear time-history dynamic analysis, including the elephant-foot buckling, the liquid sloshing, the uplift and slip at the bottom. The results demonstrate that, obvious elephant-foot deformation and buckling failure occurred near the bottom of the tank wall under the seismic input of Class-I and Class-IV sites. The local buckling failure appeared at the location close to the elephant-foot because the axial compressive stress exceeded the allowable critical stress. Under the seismic input of Class-IV site, significant nonlinear uplift and slip occurred at the tank bottom. Large amplitude vertical sloshing with a long period occurred on the free surface of the liquid under the seismic wave record at Class-III site. The seismic properties of the storage tank were affected by site class and should be considered in the seismic design of large tanks. Effective measures should be taken to reduce the seismic response of storage tanks, and ensure the safety of tanks.

• Journal of Korean Society for Geospatial Information Science
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• v.24 no.1
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• pp.17-24
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• 2016

At present, summer cloudburst and local torrential rainfalls have increased in this country, because of climatic change. Therefore, studies on prevention of soil loss have been actively proceeded, and Korea Forest Service has offered landslide hazard map. Landslide hazard map divides risks into 5 classes, by giving weight with 9 kinds of elements. In August 25 2014, soil loss occurred in the whole Oryun Tunnel, Geumjeong-gu, Busan, because of local torrential heavy rain. As a result of comparing with landslide hazard map, the area where soil loss occurred in reality is a safety zone on hazard map. Rainfall, soil map, geological map, forest type map, gradient, drainage network, watershed, basin shape, and efflux of the whole Oryun Tunnel where soil loss occurred were analyzed. As a result of an analysis, it is judged that soil, forest type, much efflux and peak discharge, degree of water network and basin shape of a place where landslide occurred are causes of soil loss. It is judged that efflux, peak discharge, and basin shape by the localized rainfall that is not considered in landslide hazard map of them are the biggest causes of soil loss. It is judged that efflux, peak discharge, degree of water network and basin shape by the rainfall are important through a study on a causual analysis on soil loss in the whole Oryun Tunnel where is one of occurrence area where a lot of propertywere lost by the record local torrential rainfalls. A localized torrential downpour should be prepared by considering these elements on judgement of a landslide hazard area.

• Journal of Species Research
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• v.10 no.4
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• pp.350-355
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• 2021

In 2020, 11 Basidiomycetous yeast strains were isolated from soil samples collected from the forests of Namhansanseong in Korea. Among them, seven species were reported, but four species were unreported in Korea. To identify wild yeasts, pairwise sequence comparisons of D1/D2 domain of the 26S rRNA were performed using Basic Local Alignment Search Tool (BLAST). The cell morphologies and assimilation test are observed by phase contrast microscope and API 20C AUX kit, respectively. The 11 strains were assigned to the genera Rhodotorula (4 strains) of the order Sporidiobolales of the class Microbotryomycetes; and Cryptococcus(2 strains), Goffeauzyma (1 strains), Naganishia (2 strains) of the order Filobasidiales and Saitozyma (2 strains) of the order Tremellales of the class Tremellomycetes in the phylum Basidiomycota. The unreported yeast strains Cryptococcus gastricus 20n5-2, Goffeauzyma gilvescens 20n2-7, Naganishia adeliensis 20n8-1, and Naganishia friedmannii 20n24-1 belong to the family Filobasidiaceae. All strains had oval shaped cells and cream-colored colonies cultured on on YM agar for 3 days. In this study, we focus on the description of four unreported yeast species in Korea.

• Journal of Korean Society for Geospatial Information Science
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• v.19 no.1
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• pp.21-28
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• 2011

Site conditions affect the magnitude of loss due to geologic hazards including, but not limited to, earthquakes, landslides and liquefaction. Reliable geologic loss estimation system requires site information which can be achieved by GIS-based method using geologic or topographic maps. Slope data derived from DEM can be an effective indicator for classifying the site conditions. We studied and discussed the effect of different DEM resolutions in the site classification. We limited the study area to the south-eastern Korea and used two different resolutions of DEMs to observe discrepancies in the site classification results. Largest discrepancy is observed in the areal coverage of site class C(very dense soil and soft rock) and E(soft soil). Comparison of results shows that more areas are classified as site class B(general rock) or E(soft soil) when we use higher resolution DEM. The comparison also shows that more areas are classified as site class C or D(stiff soil) using lower resolution DEM. The comparison of results using resampled DEMs with different resolutions shows that the areal coverage of site class B and E decreases with decreasing resolutions. On the contrary, areal coverage of site class C and D increase with decreasing resolutions. Loss estimation system can take advantage of higher-resolution DEMs in the area of rugged or populated to obtain precise local site information.

• Geomechanics and Engineering
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• v.22 no.3
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• pp.227-236
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• 2020

Expansive soils are renowned for their swelling-shrinkage property and these volumetric changes resultantly cause huge damage to civil infrastructures. Likewise, subgrades consisting of expansive soils instigate serviceability failures in pavements across various regions of Pakistan and worldwide. This study presents the use of polypropylene fibers to improve the engineering properties of a local swelling soil. The moisture-density relationship, unconfined compressive strength (UCS) and elastic modulus (E₅₀), California bearing ratio (CBR) and one-dimensional consolidation behavior of the soil treated with 0, 0.2, 0.4, 0.6 and 0.8% fibers have been investigated in this study. It is found that the maximum dry density of reinforced soil slightly decreased by 2.8% due to replacement of heavier soil particles by light-weight fibers and the optimum moisture content remained almost unaffected due to non-absorbent nature of the fibers. A significant improvement has been observed in UCS (an increase of 279%), E₅₀ (an increase of 113.6%) and CBR value (an increase of 94.4% under unsoaked and an increase of 55.6% under soaked conditions) of the soil reinforced with 0.4% fibers, thereby providing a better quality subgrade for the construction of pavements on such soils. Free swell and swell pressure of the soil also significantly reduced (94.4% and 87.9%, respectively) with the addition of 0.8% fibers and eventually converting the medium swelling soil to a low swelling class. Similarly, the compression and rebound indices also reduced by 69.9% and 88%, respectively with fiber inclusion of 0.8%. From the experimental evaluations, it emerges that polypropylene fiber has great potential as a low cost and sustainable stabilizing material for widespread swelling soils.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.1
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• pp.3-9
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• 1994

Characterstics, genesis and classification of soils derived from coarse grain granitic materials were discussed with four soil series, such as Samgag, Sangju. Sachon and Yecheon which were distributed over the area of Gangdae-Ri, Nengseo-Myeon, Yeoju-Gun, Gyunggi-Do. The results are as follows. 1. Samgag, Sangju, Sachon and Yecheon had a soil of excessively, well, imperfectly and poorly drained, thus they had a soil drainage sequence. 2. Soil textural class were from sandy loam to loam. Silt and clay content were increased with descending to the local bottom, while sand content was decreased. 3. Soils were very strongly to strongly acid and OM, CEC, exchangeable cation, and available $P_2O_5$ in soils seemed to be increased with ascending to the local boctom. 4. Kaolinite and Quartz were the dominant clay mineral and the other was Vermiculite and Illite. 5. Samgag was classified as Typic Dystrochrepts, Sangju as Dystric-Fluventic Eutrochrepts, Sachon as Aeric-Fluventic Halpaquepts, and Yecheon as Fluventic Haplaquepts.