• Title/Summary/Keyword: steel reinforced concrete column

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Global seismic performance of a new precast CFST column to RC beam braced frame: Shake table test and numerical study

  • Xu, S.Y.;Li, Z.L.;Liu, H.J.
    • Steel and Composite Structures
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    • v.21 no.4
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    • pp.805-827
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    • 2016
  • A new type of precast CFST column to RC beam braced frame is proposed in this paper. A series of shake table tests were conducted to excite a one-third scale six-story model for investigating the global seismic performance of this type of structure against earthquake actions. Particular emphasis was given to its dynamic property, global seismic responses and failure path. Correspondingly, a numerical model built on the basis of fiber-beam-element model, multi-layer shell model and element-deactivation method was developed to simulate the seismic performance of the prototype structure. Numerical results were compared with the measured values from shake table tests to verify the validity and reliability of the numerical model. The results demonstrated that the proposed novel precast CFST column to RC beam braced frame performs excellently under strong earthquake excitations; the "strong CFST column-weak RC beam" and "strong connection-weak member" anti-seismic design principles can be easily achieved; the maximum deflections of precast CFSTC-RCB braced frame satisfied the deflection limitations proposed in national code; the numerical model can properly simulate the dynamic property and responses of the precast CFSTC-RCB braced frame that are highly concerned in engineering practice.

Compressive behavior of galvanized steel wire mesh (GSWM) strengthened RC short column of varying shapes

  • Marthong, Comingstarful
    • Structural Monitoring and Maintenance
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    • v.7 no.3
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    • pp.215-231
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    • 2020
  • In a reinforced concrete building different shapes of column are adopted depending on the structural orientation and the architectural aspect. When there is an increase in loading due to changes in usage or revision in the design codes these columns need to be strengthened for enhanced performance during their service life. Strengthening materials such as carbon fiber and glass fiber polymer has been successfully used however, due to high cost application other alternative materials need to be explore. Galvanized steel wire mesh (GSWM) is one of the suitable materials locally available. High tensile strength, low weight, corrosion resistance, easy installation, minimum change in dimensions of the sections and cost effectives are the advantages of GSWM. Therefore, in this paper, four different shapes of column such as circular, square, rectangular and L were wrapped with different layers GSWM and jacketed with mortar. All the specimens were tested under axial compression. The objective of the study is to investigate the effectiveness of GSWM as a confining material for strengthening of column having varying shape. Test results shows that the axial strength enhanced with wrapping of GSWM jacket and a circular column presented the highest load carrying capacity and ductility as compared to the others. From the study of 22 column specimens, it is found that axial load is increased upto 20% and 19% when circular and square column are strengthened with one wrap of GSWM respectively, while a rectangular and L column required a wraps of two and three layers respectively in order to achieved the same load capacity as that of a circular column. Based on the present study, it is concluded that GSWM can be effectively used for strengthening of different shapes of concrete columns economically.

Structural Design of High-Rise Concrete Condominium with Wall Dampers for Vibration Control

  • Tsushi, Takumi;Ogura, Fumitaka;Uekusa, Masahiro;Kake, Satoshi;Tsuchihashi, Toru;Yasuda, Masaharu;Furuta, Takuya
    • International Journal of High-Rise Buildings
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    • v.8 no.3
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    • pp.201-209
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    • 2019
  • This paper presents a structural design of the "(Tentative Name) Toranomon Hills Residential Tower" which is currently under construction in Tokyo. The building is a reinforced concrete high-rise residential complex building with 54 stories above ground, 4 basement levels, and a building height of about 220 m. It is a requirement to provide the highest grade of residence in Japan, and in terms of the structural design, it is required to provide wide and comfortable spaces with high seismic performance. These requirements are satisfied by providing a total of 774 vibration control walls of two types. Also, to further improve the structural performance, steel fibers at the rate of 1.0vol% are provided in the ultra-high strength concrete used in the column members.

Application of fiber element in the assessment of the cyclic loading behavior of RC columns

  • Sadjadi, R.;Kianoush, M.R.
    • Structural Engineering and Mechanics
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    • v.34 no.3
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    • pp.301-317
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    • 2010
  • This paper studies the reliability of an analytical tool for predicting the lateral load-deformation response of RC columns while subjected to lateral cyclic displacements and axial load. The analytical tool in this study is based on a fiber element model implemented into the program DRAIN-2DX (fiber element). The response of RC column under cyclic displacement is defined by the behavior of concrete, and reinforcing steel under general reversed-cyclic loading. A tri-linear stress-strain relationship for the cyclic behavior of steel is proposed and the improvement in the analytical results is studied. This study only considers the behavior of columns with flexural dominant mode of failure. It is concluded that with the implementation of appropriate constitutive material models, the described analytical tools can predict the response of the columns with reasonable accuracy when compared to experimental data.

Development of Foundation of Urban Overpass for Bimodal Tram System (바이모달 트램 운행을 위한 도심지 고가구조물 기초형식 개발)

  • Kang, Tae-Sik;Bae, Eul-Ho;Park, Young-Kon;Yoon, Hee-Taek
    • Proceedings of the KSR Conference
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    • 2008.06a
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    • pp.194-198
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    • 2008
  • The necessities of development of foundation having minimized occupying area and construction time are required for overpass in the downtown area by which bimodal tram will pass a crossway. We are studying a single column drilled pier foundation which is continuous from pier to pile foundation. Due to the increased resisting moment by reinforced steel which is ranged from the upper part of pile to lower part of column above ground, it can be possible to make a smaller pile-section and lessen the bar reinforcing. And for the excavation work is possible with smaller equipment, this foundation has a improved constructability and economical efficiency. This foundation needs smaller amount of concrete and has a small self-weight. It has an effect on improving resistance against earthquake due to improved ductility in addition to improved rigidity by interaction between concrete and steel.

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A Structural Flexible Behavior T-type Joint for RCS Composite System (철근콘크리트기둥과 철골보 접합부의 휨성능(1))

  • Kim, Young-Soo;Kim, Young-Ho;Jeong, Jae-Hun;Kim, Jin-Mu;Won, Young-SuI;Joo, Kyung-Jai
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.5 no.4
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    • pp.139-146
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    • 2001
  • Res system, with Reinforced Concrete columns and Steel beams, is defined as system in which both steel and concrete materials are efficiently combined to maximize the structural and economic advantages of each material. Tested in this study were 4 exterior beam-to-column joint specimens with variables that influence joint rigidity of RCS structure. The purpose of this study is to compare and analyze the structural behavior of exterior joints through the existing studies and tests, and offer basic data for practical use of RCS structure by studying flexible behavior(semi-rigid effect) of joints according to joint details.

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Seismic Performance of Replaceable Steel Brace System Subjected to Combined Loadings (복합하중을 고려한 교체 가능한 강재 브레이스 시스템의 내진성능)

  • Ro Kyong Min;Kim Yoon Sung;Kim Min Sook;Lee Young Hak
    • Journal of Korean Association for Spatial Structures
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    • v.23 no.4
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    • pp.43-50
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    • 2023
  • This study aims to assess the seismic performance of retrofitted reinforced concrete columns using a Replaceable Steel Brace (RSB) system, subjected to combined axial, lateral, and torsional loadings. Through experimental testing, one non-retrofitted concrete column specimen and two retrofitted specimens with variable sliding slot lengths were subjected to eccentric lateral loads to simulate realistic seismic loading. The retrofitted specimens with RSBs exhibited enhanced resistance against shear cracking, effective torsional resistance, and demonstrated the feasibility of easy replacement. The RSB system substantially improved seismic performance, achieving approximately 1.7 times higher load capacity and 3.5 times greater energy dissipation compared to non-retrofitted column, thus validating its efficacy under combined loading conditions.

An Experimental Study on Shear Behavior of Internal Reinforced Concrete Beam-Column Assembly (철근콘크리트 보-기둥 내부 접합부의 전단 거동에 관한 실험적 연구)

  • Lee, Jung-Yoon;Kim, Jin-Young;Oh, Ki-Jong
    • Journal of the Korea Concrete Institute
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    • v.19 no.4
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    • pp.441-448
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    • 2007
  • The beam-column assembly in a ductile reinforced concrete (RC) frames subjected to seismic loading are generally controlled by shear and bond mechanisms, both of which exhibit poor hysteretic properties. Hence the response of joints is restricted essentially to the elastic domain. The usual earthquake resistant design philosophy of ductile frame buildings allows the beams to form plastic hinges adjacent to beam-column assembly. Increased strain in these plastic hinge regions affect on joint strain to be increased. Thus bond and shear joint strength are decreased. The research reported in this paper presents the test results of five RC beam-column assembly after developing plastic hinges in beams. Main parameter of the test Joints was the amount of the longitudinal tensile reinforcement of the beams. Test results indicted that the ductile capacity of joints increased as the longitudinal tensile reinforcement of the beams decreased. In addition, both the tensile strain of the longitudinal reinforcement bars in the joint and the ductile ratio of the beam-column assemblages increased due to the yielding of steel bars in the plastic hinge regions.

Experiments on the Composite Action of Steel Encased Composite Column (강재 매입형 합성기둥의 합성작용에 관한 실험)

  • Min Jin;Jung In-Keun;Shim Chang-Su;Chung Young-Soo
    • Journal of the Korea Concrete Institute
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    • v.17 no.3 s.87
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    • pp.393-400
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    • 2005
  • Steel encased composite columns have been used for buildings and piers of bridges. Since the column section for the pier is relatively larger than that of building columns, economical steel ratio needs to be investigated for the required performance. Composite action between concrete and embedded steel sections can be obtained by bond and friction. However, the behavior of the column depends on the load introduction mechanism. Compression can be applied to concrete section, steel section and composite section. In this paper, experiments on shear strength of the steel encased composite column were performed to study the effect of confinement by transverse reinforcements, mechanical interlock by holes, and shear connectors. Bond strength obtained from the tests showed considerably higher value than the design value. Confinement, mechanical interlock and stud connectors Increased the shear strength and these values can be used effectively to obtain composite action of Steel Reinforced Concrete(SRC) columns.

Material Resistance Factors for Reinforced Concrete Flexural and Compression Members (철근콘크리트 휨부재 및 압축부재의 재료조항계수 적용에 관한 연구)

  • 김재홍;이재훈
    • Journal of the Korea Concrete Institute
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    • v.12 no.2
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    • pp.21-30
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    • 2000
  • In the Ultimate Strength Design, the design strength of a member is determined by multiplying the strength reduction factor to the nominal strength. This concept may be a reasonable approach, however it can not consider failure modes appropriately. Moreover, column design strength diagram show an abrupt change at a low level of axial load, which does not seem to be reasonable. This research compares the design strength determined by the strength resistance factors. As the material resistance factors for flexure and compression, 0.65 and 0.90 are proposed for concrete and steel, respectively. The design strength calculation process by applying material resistance factors addresses failure modes more effectively than by applying member strength reduction factor, and provides more resnable design strength for reinforced concrete flexural and compression members.