• Title/Summary/Keyword: Lateral Resistance

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Analysis of Track-Bridge Interaction and Retrofit Design for Installation of CWR on Non-ballasted Railway Bridge (무도상 철도교 레일 장대화를 위한 궤도-교량 상호작용 해석 및 개량방안 분석)

  • Yoon, Jae Chan;Lee, Chang Jin;Jang, Seung Yup;Choi, Sang Hyun;Park, Sung Hyun;Jung, Hyuk Sang
    • Journal of The Korean Society For Urban Railway
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    • v.6 no.4
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    • pp.383-392
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    • 2018
  • This study investigated the change of additional axial stress of rail and reaction force at bridge bearings due to the track-bridge interaction when laying CWR on non-ballasted railway bridges including truss bridges with relatively long span. According to the results of the present study, additional axial stresses of rail and reaction forces at bridge bearings showed a large increase when CWR is installed on the non-ballasted railway bridge. The additional axial stress of rail can be acceptable if sufficient lateral resistance can be obtained. However, if the reaction force increases, there is a risk of damage of the bearing or pier, and therefore, it is necessary to take measures to mitigate the reaction force. It is found that additional axial stress of rail decreases when considering the frictional resistance of the bridge movable support, but its effect on the bearing reaction force is very small. On the other hand, when the longitudinal track restraint decreases, both additional axial stress of rail and bearing reaction force are reduced to a large extent. Also, when the ZLR fastening devices are applied to the region where the additional axial stress of rail is highest, bearing reaction force as well as additional axial stress of rail greatly decreased. Therefore, the application of ZLR fastening devices with the reduction of the longitudinal track restraints is very effective for installing CWR on non-ballasted railway bridges.

A FINITE ELEMENT AND STRAIN GAUGE ANALYSIS ON THE DISPLACEMENT OF CRANIOFACIAL COMPLEX WITH CERVICAL HEADGEAR (경부고정(頸部固定) headgear 사용시(使用時) 안면두개골(顔面頭蓋骨)의 변위(變位)에 관(關)한 장력계측법(張力計測法) 및 유한요소법적(有限要素法的) 연구(硏究))

  • Kim, Hyun-Soon;Nahm, Dong-Seok
    • The korean journal of orthodontics
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    • v.17 no.2
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    • pp.185-200
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    • 1987
  • This paper was undertaken to observe the displacement of craniofacial complex with cervical headgear and to compare narrowing or widening effect of palate by use of contraction or expansion face-bow, respectively. The 3-dimensional finite element method(FEM) was used for a mathematical model composed of 597 nodes and 790 elements and an electrical resistance strain gauge investigation was performed to validate the finite element model. The outer bow of cervical headgear was adjusted to be placed below the occlusal plane by $25^{\circ}$ and met the midsagittal plane by $40^{\circ}$, and was loaded 1kg on each right and left hook toward posterior direction. The results were as follows 1. Generally, the maxillary teeth and facial bone were displaced in posterior, medial and downward direction. 2. It was the maxillary 2nd bicuspid that moved bodily. 3. The craniofacial complex rotated in a clockwise direction around the rotating axis which lay from the most posterior and lowest point connecting nasal crest of maxillary bone and vomer, progressively toward a more posterior, lateral and upward direction, anterior and upper area of pterygomaxillary fissure, base of medial pterygoid plate and laterally to the contact area of zygomatic arch with squamous part of temporal bone. 4. No contraction effect was observed by contraction face-bow when compared to the standard face-bow. 5. In case of expansion face-bow, the areas of maxillary 2nd bicuspid, molars and palate were expanded remarkably.

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The Usefulness of Allogenous Costal Cartilage Graft for Correction of Short Nose and Tip Plasty (짧은 코 교정술과 비첨성형술에 있어서 동종늑연골 (Tutoplast®) 이식의 유용성)

  • Choi, Sung Won;Won, Dong Chul;Lim, Young Kook;Hong, Yong Taek;Kim, Hoon Nam
    • Archives of Craniofacial Surgery
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    • v.10 no.2
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    • pp.120-126
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    • 2009
  • Purpose: Autogenous cartilage is generally first choice in rhinoplasty because of its biocompatibility and resistance to infection. On the other hand, allogeneous cartilage graft might preferred over an autogenous graft to avoid additional donor site scars, morbidity and lengthened operating time. Allogenous costal cartilage ($Tutoplast^{(R)}$) not only have the advantage of averting donor site morbidity but also are resistant to infection, resembling autogenous cartilage graft. We report here a technique for rhinoplasty by using allogenous costal cartilage graft. Methods: Through open rhinoplastic approach, alar cartilage is released from upper lateral cartilage and relocated caudally. After relocation of alar cartilage, allogenous costal cartilage is immobilized by nonabsorbable suture material at caudal aspect of septal cartilage. Caudal end of allogenous costal cartilage is sutured between medial crura of alar cartilage. Tip projection is improved by using interdormal suture, transdormal suture and shield-shape cartilage graft which is harvested from concha Results: No significant resorption and infection was detected in any of patients. Aesthetic and functional results were satisfactory. Conclusion: The low incidence of major complication and versatility of allogeneous costal cartilage graft make safe and reliable source of cartilage graft in rhinoplasty.

A Study on Products Analysis of the Domestic and Overseas Cycling Wears (시판 국내외 사이클 웨어의 제품 분석)

  • Park, Hyunjeong;Do, Wolhee
    • Fashion & Textile Research Journal
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    • v.22 no.3
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    • pp.368-377
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    • 2020
  • This study provided basic data to develop functional and fitness cycling wear for cyclists. We analyzed the domestic and overseas cycling wear brand patterns for tops and tights as well as compared pads attached to tights. The results were as follows. The tops of the cycling wear were designed with cutting lines in the lateral or yoke in the back to reflect cycling posture. It is necessary to study if there is a difference in the air resistance or fitness of the athlete. The sleeve hem band affected by arm movement during cycling, proper sewing and band pressure are also important. The tights have a brand that does not insert a band in front of the waist in consideration of the cyclist's breathing. It should take into account methods of constructing a proper garment pressure that does not interfere with cycling. Analyzing the cycling pad indicated that the three-dimensional shape and size of the pad show many differences for each brand, indicating a difference in cycling movement suitability. In addition, many of the cutting lines should account for the productive aspects because of the high consumption of the fabric in order to design a pattern considering the cycling posture.

Torsional effects in symmetrical steel buckling restrained braced frames: evaluation of seismic design provisions

  • Roy, Jonathan;Tremblay, Robert;Leger, Pierre
    • Earthquakes and Structures
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    • v.8 no.2
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    • pp.423-442
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    • 2015
  • The effects of accidental eccentricity on the seismic response of four-storey steel buildings laterally stabilized by buckling restrained braced frames are studied. The structures have a square, symmetrical footprint, without inherent eccentricity between the center of lateral resistance (CR) and the center of mass (CM). The position of the bracing bents in the buildings was varied to obtain three different levels of torsional sensitivity: low, intermediate and high. The structures were designed in accordance with the seismic design provisions of the 2010 National Building Code of Canada (NBCC). Three different analysis methods were used to account for accidental eccentricity in design: (1) Equivalent Static Procedure with static in-plane torsional moments assuming a mass eccentricity of 10% of the building dimension (ESP); (2) Response Spectrum Analysis with static torsional moments based on 10% of the building dimension (RSA-10); and (3) Response Spectrum Analysis with the CM being displaced by 5% of the building dimension (RSA-5). Time history analyses were performed under a set of eleven two-component historical records. The analyses showed that the ESP and RSA-10 methods can give appropriate results for all three levels of torsional sensitivity. When using the RSA-5 method, adequate performance was also achieved for the low and intermediate torsional sensitivity cases, but the method led to excessive displacements (5-10% storey drifts), near collapse state, for the highly torsionally sensitive structures. These results support the current provisions of NBCC 2010.

Maintenance and Dynamic Behavior of Advanced Spherical Bearings under Railway Open-Steel-Plate-Girder Bridges (판형교에서 개량된 스페리칼받침의 유지보수 및 동적 거동)

  • Choi, Eun-Soo;Lee, Hee-Up;Lee, Seung-Yong
    • Journal of the Korean Society for Railway
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    • v.11 no.2
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    • pp.165-175
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    • 2008
  • Line type rigid bearings for Open-Steel-Plate-Girder railway bridges have several problems in service, and they are unstable structurally. A series of lateral resistance tests were performed for a retrieved line type bearing. A spherical bearing with advanced maintenance-capability and a device to resist the up-lift was developed and replaced the existing ones. An experiment of maintenance for a new spherical bearing under real Open-Steel-Plate-Girder bridge was conducted and their good maintenance performance was proved. Also, a test against up-lift was performed for the bearing. The dynamic behavior of the bridge was measured and analyzed for the two cases of the existing and replaced bearings. Therefore, the suitability of the new spherical bearings on the railway bridge was improved.

Seismic Experiment of Precast Concrete Exterior Beam-Column Joint Using Bolt Type Connection and Prestressing Method (볼트 접합 및 프리스트레스를 적용한 프리캐스트 콘크리트 보-기둥 외부접합부의 내진실험)

  • Lee, Dong-Joo;Lee, Ju-Dong;Oh, Tae-Soo;Kang, Thomas H.K.
    • Journal of the Korea Concrete Institute
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    • v.26 no.2
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    • pp.125-133
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    • 2014
  • In this study, experimental research was carried out to investigate the seismic and structural performance of precast concrete exterior beam-column joints using bolt type connection and prestressing method. A total of five full-scale exterior beam-column joints were constructed and tested under reversed cyclic loading, controlled by displacement. Results of the test are as follows: Energy dissipation capacity and pinching phenomenon of PC beam-column joints showed disadvantageous behavior compared to RC beam-column joints. However, drift capacity of the PC joint was excellent. Also, yield mechanism concentrated on embedded nuts was suitable as an exterior beam-column joint of lateral load resistance frame. Additional application of prestressing method was also very effective to control excessive pinching and cracking in the joint region, and thus improved an overall seismic performance of the PC joint.

Settlement Reduction Effect of the Geogrid Reinforced Stone Column System (고강도 지오그리드로 보강된 Stone Column 공법의 침하감소효과)

  • Park, Sis-Am;Cho, Sung-Han;Yoo, Chung-Sik;Lee, Dae-Young
    • Journal of the Korean Geosynthetics Society
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    • v.5 no.1
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    • pp.15-23
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    • 2006
  • Sand Compaction Pile and Stone Column method have been used in widely during several decades as a technique to reinforce soft soils and increasing ultimate bearing capacity, accelerate consolidation settlement of the foundation ground. Stone column method, making a compaction pile using crushed stone, is a soft ground improvement method. However, stone column method is difficult to apply to the ground which is not mobilized enough lateral confine pressure because no bulging failure resistance. Hence, in present study, development the geogrid reinforced stone column system for settlement reduction and wide range of application of stone columns. To develop this system, triaxial compression tests were conducted for evaluation which is about behavior characteristics of stone column on replacement rate and confine pressure. Then, 3-dimensional numerical analysis were evaluated for application of the GRSC (geogrid reinforced stone column) system as evaluate behavior characteristics and settlement reduction effect of stone column reinforced by geogrid on types and reinforcing depth change of geogrid.

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Application of LRBs for Reduction of Wind-Induced Responses of Coupled Shear Wall Structures (전단벽 구조물의 풍응답 저감을 위한 LRB의 적용)

  • Park, Yong-Koo;Kim, Hyun-Su;Ko, Hyun;Kim, Min-Gyun;Lee, Dong-Guen
    • Journal of Korean Association for Spatial Structures
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    • v.11 no.1
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    • pp.47-56
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    • 2011
  • In general, shear walls are employed as lateral resistance system. Most of shear wall structures require openings in shear walls and thus shear walls are linked by floor slabs or coupling beams resulting in the coupled shear wall structures. In this study, an LRB (lead rubber bearing) was introduced in the middle of the coupling beam of the coupled shear wall structures and the wind-induced response reduction effect of this system was investigated. In order to evaluate the control performance of the proposed method, 20- and 30-story building structures were used as example structures and boundary nonlinear time history analyses have been performed using artificial wind excitation. Japanese vibration evaluation criteria was employed to evaluate whether the proposed system could improve the serviceability of the tall coupled shear wall structures under wind excitation. Based on analytical results, it has been shown that the proposed method that connects shear walls with LRBs can improve the wind-induced response control effect.

Evaluation of Seismic Performance for Various Types of Pile Head of Landing Pier (잔교식 안벽에서 말뚝 두부형식에 따른 내진성능 평가)

  • Jang In-Sung;Kwon O-Soon;Park Woo-Sun;Jeong Weon-Mu
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.17 no.2
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    • pp.70-79
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    • 2005
  • Most of landing piers in Korea employ the combination of vertical piles and batter piles, which shows good efficiency in static lateral resistance but poor seismic performance. Many attempts have continuously been made to increase the seismic performance of batter piles with various aseismatic systems. In this study, new types of aseismatic system were developed by use of rubber and ball bearing, and shaking table tests and 3 dim. numerical analyses were performed in order to compare the seismic performance for various types of pile head. The test and numerical analysis results show the high seismic performance of newly proposed systems and the applicability off dim. numerical analysis considering the non-linear behaviour of rubber and ball bearing systems.