• Title, Summary, Keyword: Longitudinal & lateral resistance force

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Development of Device to Resist Horizontal Displacement of Asphalt Concrete Track (아스팔트콘크리트 궤도용 궤도변위 저항 장치 개발)

  • Lee, Seonghyeok;Yoon, Wooyong;Bae, Younghoon
    • Journal of the Korean Society for Railway
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    • v.19 no.6
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    • pp.744-754
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    • 2016
  • Asphalt concrete track (ACT) is a track system connecting wide sleepers and concrete panels on top of an asphalt concrete layer; such a system requires adequate resistance force against various longitudinal and lateral external loads. In this study, a series of experiments were carried out to assess the longitudinal and lateral resistance force of a wide sleeper and concrete panel type ACT. The required shear resistance force of the horizontal displacement restraint device (HDRD) was evaluated. Furthermore, a concrete block type anchor and a steel pipe type anchor were developed as HDRDs. The shear resistance force was decided based on the experimental results of horizontal shear tests for each anchor system. In addition, proper numbers and arrangement design guidelines for the HDRDs were suggested considering the shear resisting capacity and economics for HDRDs applied to ACT.

Experimental studies of circular composite bridge piers for seismic loading

  • Chen, Sheng-Jin;Yang, Kuo-Chen;Lin, K.M.;Wang, C.C.
    • Steel and Composite Structures
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    • v.12 no.3
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    • pp.261-273
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    • 2012
  • This study proposes and examines a circular composite bridge pier for seismic resistance. The axial and flexural strengths of the proposed bridge pier are provided by the longitudinal reinforcing bars and the concrete, while the transverse reinforcements used in the conventional reinforced concrete pier are replaced by the steel tube. The shear strength of this composite pier relies on the steel tube and the concrete. This system is similar to the steel jacketing method which strengthens the existing reinforced concrete bridge piers. However, no transverse shear reinforcing bar is used in the proposed composite bridge pier. A series of experimental studies is conducted to investigate the seismic resistant characteristics of the proposed circular composite pier. The effects of the longitudinal reinforcing bars, the shear span-to-diameter ratio, and the thickness of the steel tube on the performance of strength, ductility, and energy dissipation of the proposed pier are discussed. The experimental results show that the strength of the proposed circular composite bridge pier can be predicted accurately by the similar method used in the reinforced concrete piers with minor modification. From these experimental studies, it is found that the proposed circular composite bridge pier not only simplifies the construction work greatly but also provides excellent ductility and energy dissipation capacity under seismic lateral force.

Study on the Machinability of Pinus densiflora at Chunyang District for Wood Patterns - Cutting Force, Surface Roughness and Suface Phenomenon by Face Milling - (목형용(木型用) 춘양목(春陽木)의 절삭가공(切削加工) 특성(特性)에 관(關)한 연구(硏究)(제2보(第2報)) - 정면(正面)밀링 절삭(切削)에 의한 절삭저항(切削抵抗), 표면조도(表面粗度) 및 가공표면상태(加工表面狀態) -)

  • Kim, Jeong-Du
    • Journal of the Korean Wood Science and Technology
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    • v.16 no.4
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    • pp.61-69
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    • 1988
  • Recently the automization of wood manufacturing and the development of CNC machine tools becomes the center of interest. Cutting mechanism, tool wear and the roughness of machined surface have been studied. In the studies about wood for special uses, concrete data of cutting is desired. While Pinus densiflora is characterized that heartwood develops as age increases, Chunyang District has the characteristic of strength, red color, relatively regular chap and high heartwood - percentage. But there is no data about cutting this wood, Chunyang District. In this study face milling by sintered carbide tool was excuted to Chunyang District. Cutting force, Surface roughness and states were investigated with regard to cutting speed. Example results were as follows; 1) Mean cutting resistance against lateral component force and longitudinal component force decreased rapidly up to cutting speed of 155 m/min, and remains constant above this speed. 2) The surface roughness of cutting surface lowered as cutting speed increased, regardless of fiber formation. Radial rougness of fiber is larger than lineal surface roughness. 3) Increase in Cutting speed made machining mark restrained. Down-milling showed larger marks than up-milling.

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Test and Analysis on the Longitudinal Gusset Plate Connection to Circular Hollow Section (CHS) of High Strength (고강도 원형강관의 길이방향 거셋플레이트 접합부 실험 및 해석)

  • Lee, Swoo-Heon;Shin, Kyung-Jae;Lee, Hee-Du;Kim, Woo-Bum
    • Journal of Korean Society of Steel Construction
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    • v.24 no.1
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    • pp.35-46
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    • 2012
  • With the increase in the demand for high-rise buildings, the use of high-strength steel has likewise increased. Thus, it has become more necessary to study the resistance force of the high-strength hollow structural section (HSS) joint of 600MPa. Additionally, the current design equation in Korea limits maximum yield stress at 360MPa in the case of HSS. In other words, since the current specification does not apply to HSS of 600MPa, this study aims to investigate the applicability of design equations as well as examine the behavior of the connection through the experiment and finite element analysis (FEA) of the plate-tube connection of 600MPa. In particular, this paper presents the behavior of joints with the gusset plates welded in the longitudinal direction of the circular hollow section (CHS) when the joints are subjected to lateral force. Comparing design equations with the results of FEA and the test, existing design equations are underestimated to be 56~79% in the case of high-strength materials.

Sensitivity of the ballast resistance and track irregularity on the track stability (궤도 안정성에 대한 도상저항력과 궤도틀림의 민감도)

  • Lim, Nam Hyoung;Choi, Sang Hyun;Lee, Chin Ok;Sung, Ik Hyun
    • Journal of Korean Society of Steel Construction
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    • v.17 no.5
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    • pp.519-526
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    • 2005
  • During summer, very high compressive force occurs on the continuous welded rail (CWR) track because of the increase of rail temperature (max. $60^{\circ}C$). This extreme temperature stress can cause the CWR track to buckle. Among many CWR parameters affecting the track buckling, the influence of the lateral and longitudinal ballast resistance was investigated on the stability of the CWR track in this study. Also, the sensitivity of the track irregularity such as the alignment defect and the gauge irregularity was investigated.

Structural Characteristics of Damaged Offshore Tubular Members

  • Cho, Sang-Rai;Kwon, Jong-Sig;Kwak, Dong-Il
    • Journal of Ocean Engineering and Technology
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    • v.24 no.4
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    • pp.1-7
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    • 2010
  • Over the past few decades various experimental and theoretical investigations have been performed on offshore tubular members with regard to damage resistance and residual strength. Analysis of damaged tubular members requires a three-dimensional shell analysis for accurate results. Even though various commercial packages are available for this purpose, a beam-column analysis is preferred for offshore structural designs. In this paper, empirical equations are provided for a more accurate beam-column analysis of damaged tubes including the relationships between the lateral denting load and the depth of the dent, the rate of dent deepening due to increasing curvature and the longitudinal variation in the dent depth of damaged tubes. A design equation to predict the ultimate bending capacities of damaged offshore tubular members is also presented.

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.

The Strain of Transverse Steel and Concrete Shear Resistance Degradation after Yielding of Reinforced Concrete Circular Pier (철근콘크리트 원형 교각의 횡방향철근 변형률과 항복이후 콘크리트 전단저항 저감)

  • Ko, Seong Hyun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.1
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    • pp.147-157
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    • 2018
  • The basis of capacity design has been explicitly or implicitly regulated in most bridge design specifications. It is to guarantee ductile failure of entire bridge system by preventing brittle failure of pier members and any other structural members until the columns provides fully enough plastic rotation capacity. Brittle shear is regarded as a mode of failure that should be avoided in reinforced concrete bridge pier design. To provide ductility behavior of column, the one of important factors is that flexural hinge of column must be detailed to ensure adequate and dependable shear strength and deformation capacity. Eight small scale circular reinforced concrete columns were tested under cyclic lateral load with 4.5 aspect ratio. The test variables are longitudinal steel ratio, transverse steel ratio, and axial load ratio. Eight flexurally dominated columns were tested. In all specimens, initial flexural-shear cracks occurred at 1.5% drift ratio. The multiple flexural-shear crack width and length gradually increased until the final stage. The angles of the major inclined cracks measured from the vertical column axis ranged between 42 and 48 degrees. In particular, this study focused on assessing transverse reinforcement contribution to the column shear strength. Transverse reinforcement contribution measured during test. Each three components of transverse reinforcement contribution, axial force contribution and concrete contribution were investigated and compared. It was assessed that the concrete stresses of all specimen were larger than stress limit of Korea Bridge Design Specifications.