• Title/Summary/Keyword: Structural details

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Stress History Evaluation for Truss Bridge with Local Damages by Using Global-Local Model Combination (전체해석과 국부해석 조합법을 이용한 국부결함이 있는 트러스교 응력이력해석)

  • Kim, Hyo-Jin;Park, Sang-il;Bae, Gi-Hoon;Lee, Sang-Ho
    • Journal of Korean Society of societal Security
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    • v.3 no.1
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    • pp.33-42
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    • 2010
  • This study predicts the stress history for truss bridge with local damages by using global-local model combination method. For this end, the global structure is modeled by 3D frame elements and the selected local details are modeled by shell elements. Then superposition principle enable the global-local model to be combined interactively. Because the frame model cannot consider the rigidity of gusset plate and the interation of structural members due to the complexity of stress distribution in truss connection. The section modification factors are proposed to calibrate the stiffness of global frame element. The global-local model combination is verified by comparing the numerical results with experimental data obtained from the proof loading test to the operating truss bridge. Furthermore, stress histrories of the truss bridge are generated in the consideration of the rigidity of truss connection with local damage by using the combination method.

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Development of Vermiculite Board to Secure the Fire Resistance Performance of Light-Frame Wood Structural Wall (경골목구조 벽체의 내화성능확보를 위한 질석보드 개발)

  • Yoo, Seok Hyung;Cheong, Chang Heon
    • Fire Science and Engineering
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    • v.32 no.1
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    • pp.40-45
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    • 2018
  • It is considered that vermiculite as an inorganic material is highly effective when it is used as a building finishing material because it is eco-friendly. Vermiculite has excellent properties such as fire resistance, heat insulation, sound absorption as well as prevention of condensation, deodorization and aesthetics. In this study, we developed a finishing board with vermiculite as its main material and mixed with mineral loose wool (VB-L) or mineral powder (VB-P), and conducted fireproof test and insulation test. In addition, fire resistance tests were carried out by applying the two developed vermiculite boards as finishing materials for the standard wall details of light frame wood structures (KS F 1611-1). As a result of the fire resistance test, the VB-L specimen showed better fire resistance than the VB-P specimen. Both vermiculite boards showed sufficient fire resistance performance of 2 hours for a thickness of 30 mm.

A Study on the Exteriority of Interior in the Louis I. Kahn's Architecture - Focused on the Study of Character of Connecting Elements - (루이스 칸 건축의 외부화된 내부에 관한 연구 - 연결공간의 체험과 표현을 중심으로 -)

  • Woo, Young-Sun;Shin, Buhm-Shik
    • Journal of architectural history
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    • v.14 no.4 s.44
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    • pp.117-135
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    • 2005
  • This paper is a study of the possibility of experience and expression in the architecture of Louis I. Kahn by focusing on the characters of entrance, court and window/wall of his public buildings. In the course of composition, Kahn defined the entrance, court and window/wall as an connecting elements and elements of boundary. The characters revealed by these elements or rooms give the clue to insight Kahn's thought of relation of interior and exterior space or inner and outer space. Following are the characters of these elements. First, a entrance reveals the fact that inner space separates from outer space by connecting these two space and giving the value to inner space as the entity and totality like outer space. The entrance gives its ontological being to human subjects not by vision but experience and expression which is the essence of commonness, that is, Silence. Kahn made the possibility of activity amplify in this common and silent space. Second, this entrance is connected with wide and huge central space not individual spaces of interior space. This extreme procedure of entering makes human subject feel sublime of intoner space. And the central spaces becomes another exterior or another world in the inner world of architecture by the lights from above and by having the boundary wall which shows same pattern of exterior wall. Third, Kahn regarded a window as the giver of lights not as the medium of vision connecting inner space with outer. He tried to connect interior with exterior through the being and character of the light expressed in the interior. And in his buildings, interior space is connected with exterior by expressing the purpose of building, composition of inner space, structural truth and construction facts through the Form, a pattern of wall, details and ornamental joints. By practicing this thoughts in the real buildings, Kahn tried to gave aura to both the interior space and entity of architecture which is regarded as micro universe like flowers, rocks and human beings.

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Seismic Performance of Existing Welded Steel Moment Connections to Built-up Box Columns (기존 용접형 철골 박스기둥 접합부의 내진성능)

  • Kim, Tae-Jin;Stojadinovic, B.;Whittaker, A.S.
    • Journal of the Earthquake Engineering Society of Korea
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    • v.10 no.1 s.47
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    • pp.25-32
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    • 2006
  • In this study the seismic performance of welded steel moment connections to built-up box columns in the existing building built before 1994 Northridge earthquake was evaluated by cyclic tests. According to the test results, the pre-Northridge steel moment connections to the box columns also suffered from brittle fracture similar to that in the H-shaped column connections. However, the flange force transfer mechanism of the box column connections was substantially different from that of the H-shaped column connections, and the patterns of crack propagation may be changed due to the shape of the box column. Therefore, it is required to develop proper details for the box column connections instead of using the research results for H-shaped column connections in order to enhance the seismic performance the connections.

Japanism in modern fashion - From 2001 S/S to 2011 S/S - (현대패션에 나타난 재패니즘(Japanism)에 관한 연구 - 2001S/S에서 2011S/S를 중심으로 -)

  • Kim, Sun Young
    • The Research Journal of the Costume Culture
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    • v.21 no.2
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    • pp.151-166
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    • 2013
  • This study aims to shed light on the diversity and complexity of design represented through modern fashion and to identify growth opportunities for globalizing and modernizing traditional clothing designs. To this end, formative trends and aesthetic characteristics of $21^{st}$ century fashion were analyzed, with an emphasis on Japanism reflected in the works of Western designers. The research methodology consisted of an analysis as well as a literature review. A total of 217 designs with Japanism characteristics were identified from the 2001 S/S collection to the 2011 S/S collection in Paris, Milano, New York, and London, and these were analyzed in terms of image, color details, pattern, and accessories. The research findings with regard to the characteristics of modern fashion designs that reflect Japanism were as follows. First, sensuality was projected by highlighting the erotic elements of Japanese clothing. Second, the underlying principles, styles, and elements of Japan's traditional clothing were embodied in a cross-cultural and eclectic manner that blurred the boundaries between styles by mix-and- matching the traditional and the contemporary, the East and the West, and different styles. Third, a variety of patterns, colors, accessories, and design techniques associated with Japanese traditional clothing played a critical role in creating flamboyant and decorative images in contemporary fashion. Fourth, the overlapping of the kimono style, the flat design that accentuates body curves, and the layered style has created a beautifully free-form fashion that demonstrates non-structural features.

Seismic performance evaluation of circular composite columns by shaking table test (진동대 실험을 통한 원형 합성 기둥의 내진 성능 평가)

  • Shim, Chang-Su;Chung, Young-Soo;Park, Ji-Ho;Park, Chang-Young
    • Journal of the Earthquake Engineering Society of Korea
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    • v.11 no.5
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    • pp.71-81
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    • 2007
  • For the design of composite bridge piers, detail requirements for the reinforcements is not clear to satisfy the required seismic performance. Composite bridge piers were suggested to reduce the sectional dimensions and to enhance the ductility of the columns under earthquake loadings. In this paper, five specimens of concrete encased composite columns of 400mm diameter with single core steel were fabricated to investigate the seismic performance of the composite columns. Shaking table tests and a Pseudo-Dynamic test were carried out and structural behavior of small-scaled models considering near-fault motions was evaluated. Test parameters were the pace of the transverse reinforcement, lap splice of longitudinal reinforcement and encased steel member sections. The displacement ductility from shaking table tests was lower than that from the pseudo-dynamic test. Limited ductile design and 50% lap splice of longitudinal reinforcement reduced the displacement ductility. Steel ratio showed significant effect on the ultimate strength. Lap splice and low transverse reinforcements reduced the displacement capacity. The energy dissipation capacity of composite columns did not show significant difference according to details.

Seismic Performance Evaluation of Non-Seismic Reinforced Concrete Buildings Strengthened by Perimeter Steel Moment Frame (철골 모멘트골조로 보강된 철근콘크리트 건물의 내진성능 평가)

  • Kim, Seonwoong
    • Journal of the Earthquake Engineering Society of Korea
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    • v.24 no.5
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    • pp.233-241
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    • 2020
  • This paper is to investigate the retrofitting effect for a non-seismic reinforced concrete frame strengthened by perimeter steel moment frames with indirect integrity, which ameliorates the problems of the direct integrity method. To achieve this, first, full-scale tests were conducted to address the structural behavior of a two-story non-seismic reinforced concrete frame and a strengthened frame. The non-seismic frame showed a maximum strength of 185 kN because the flexural-shear failure at the bottom end of columns on the first floor was governed, and shear cracks were concentrated at the beam-column joints on the second floor. The strengthened frame possessed a maximum strength of 338 kN, which is more than 1.8 times that of the non-seismic specimen. A considerable decrease in the quantity of cracks for the strengthened frame was observed compared with the non-seismic frame, while there was the obvious appearance of the failure pattern due to the shear crack. The lateral-resisting capacity for the non-seismic bare frame and the strengthened frame may be determined per the specified shear strength of the reinforced columns in accordance with the distance to a critical section. The effective depth of the column may be referred to as the longitudinal length from the border between the column and the foundation. The lateral-resisting capacity for the non-seismic bare frame and the strengthened frame may be reasonably determined per the specified shear strength of the reinforced columns in accordance with the distance to a critical section. The effective depth of the column may be referred to as the longitudinal length from the border between the column and the foundation. The proposed method had an error of about 2.2% for the non-seismic details and about 4.4% for the strengthened frame based on the closed results versus the experimental results.

Behavior of fully- connected and partially-connected multi-story steel plate shear wall structures

  • Azarafrooza, A.;Shekastehband, B.
    • Structural Engineering and Mechanics
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    • v.76 no.3
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    • pp.311-324
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    • 2020
  • Until now, a comparative study on fully and partially-connected steel shear walls leading to enhancing strength and stiffness reduction of partially-connected steel plate shear wall structures has not been reported. In this paper a number of 4-story and 8-story steel plate shear walls, are considered with three different connection details of infill plate to surrounding frame. The specimens are modeled using nonlinear finite element method verified excellently with the experimental results and analyzed under monotonic loading. A comparison between initial stiffness and shear strength of models as well as percentage of shear force by model boundary frame and infill plate are performed. Moreover, a comparison between energy dissipation, ductility factor and distribution of Von-Mises stresses of models are presented. According to the results, the initial stiffness, shear resistance, energy dissipation and ductility of the models with beam-only connected infill plates (SSW-BO) is found to be about 53%, 12%, 15% and 48% on average smaller than those of models with fully-connected infill plates (SPSW), respectively. However, performance characteristics of semi-supported steel shear walls (SSSW) containing secondary columns by simultaneously decreasing boundary frame strength and increasing thickness of infill plates are comparable to those of SPSWs. Results show that by using secondary columns as well as increasing thickness of infill plates, the stress demands on boundary frame decreases substantially by as much as 35%. A significant increase in infill plate share on shear capacity by as much as 95% and 72% progress for the 4-story SSW-BO and 8-story SSSW8, respectively, as compared with non-strengthened counterparts. A similar trend is achieved by strengthening secondary columns of 4-story SSSW leading to an increase of 50% in shear force contribution of infill plate.

In Vivo Characterization of Phosphotransferase-Encoding Genes istP and forP as Interchangeable Launchers of the C3',4'-Dideoxygenation Biosynthetic Pathway of 1,4-Diaminocyclitol Antibiotics

  • Nguyen, Lan Huong;Lee, Na Joon;Hwang, Hyun Ha;Son, Hye Bin;Kim, Hye Ji;Seo, Eun Gyo;Nguyen, Huu Hoang;Park, Je Won
    • Journal of Microbiology and Biotechnology
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    • v.29 no.3
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    • pp.367-372
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    • 2019
  • Deactivation of aminoglycosides by their modifying enzymes, including a number of aminoglycoside O-phosphotransferases, is the most ubiquitous resistance mechanism in aminoglycoside-resistant pathogens. Nonetheless, in a couple of biosynthetic pathways for gentamicins, fortimicins, and istamycins, phosphorylation of aminoglycosides seems to be a unique and initial step for the creation of a natural defensive structural feature such as a 3',4'-dideoxy scaffold. Our aim was to elucidate the biochemical details on the beginning of these C3',4'-dideoxygenation biosynthetic steps for aminoglycosides. The biosynthesis of istamycins must surely involve these 3',4'-didehydroxylation steps, but much less has been reported in terms of characterization of istamycin biosynthetic genes, especially about the phosphotransferase-encoding gene. In the disruption and complementation experiments pointing to a putative gene, istP, in the genome of wild-type Streptomyces tenjimariensis, the function of the istP gene was proved here to be a phosphotransferase. Next, an in-frame deletion of a known phosphotransferase-encoding gene forP from the genome of wild-type Micromonospora olivasterospora resulted in the appearance of a hitherto unidentified fortimicin shunt product, namely 3-O-methyl-FOR-KK1, whereas complementation of forP restored the natural fortimicin metabolite profiles. The bilateral complementation of an istP gene (or forP) in the ${\Delta}forP$ mutant (or ${\Delta}istP$ mutant strain) successfully restored the biosynthesis of 3',4'-dideoxy fortimicins and istamycins, thus clearly indicating that they are interchangeable launchers of the biosynthesis of 3',4'-dideoxy types of 1,4-diaminocyclitol antibiotics.

Evaluation of Three Support Shapes on Behavior of New Bolted Connection BBCC in Modularized Prefabricated Steel Structures

  • Naserabad, Alifazl Azizi;Ghasemi, Mohammad Reza;Shabakhty, Naser;Arab, Hammed Ghohani
    • International journal of steel structures
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    • v.18 no.5
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    • pp.1639-1653
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    • 2018
  • Bolted connections are suitable due to high quality prefabrication in the factory and erection in the workplace. Prefabrication and modularization cause high speed of erection and fabrication, high quality and quick return of investment. Their technical hitches transportation can be removed by prefabrication of joints and small fabrication of components. Box-columns are suitable members for bolted structures such as welded steel structures with moment frames in two directions etc., but their continual fabrication in multi-story buildings and performing the internal continuity plate in them will cause some practical dilemmas. The details of the proposal technique introduced here, is to remove such problems from the box columns. Besides, some other advantages include new prefabricated bolted beam-to-column connections referred to BBCC. This connection is a set of plates joined to columns, beams, support, and bolts. For a better understanding of its fabrication and erection techniques, two connection and one structural maquettes are made. The present work aims to study the cyclic behavior of connection numerically. To verify the accuracy of model, a similar tested connection was modelled. Its verification was then made through comparison with test results. The behavior of connection was evaluated for an exterior connection using three different support shapes. The effects of support shapes on rigidity, ductility, rotation capacity, maximum strength, four rad rotation strength were compared to those of the AISC seismic provision requirements. It was found that single beams support has all the AISC seismic provision requirements for special moment frames with and without a continuity plate, and box with continuity plate is the best support in the BBCC connection.