• Title, Summary, Keyword: Slab joint

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SFRHPC interior beam-column-slab joints under reverse cyclic loading

  • Ganesan, N.;Nidhi, M.;Indira, P.V.
    • Advances in concrete construction
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    • v.3 no.3
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    • pp.237-250
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    • 2015
  • Beam-column joints are highly vulnerable locations which are to be designed for high ductility in order to take care of unexpected lateral forces such as wind and earthquake. Previous investigations reveal that the addition of steel fibres to concrete improves its ductility significantly. Also, due to presence of slab the strength and ductility of the beam increases considerably and ignoring the effect of slab can lead to underestimation of beam capacity and defiance of strong column weak beam concept. The influence of addition of steel fibres on the strength and behaviour of steel fibre reinforced high performance concrete (SFRHPC) interior beam-column-slab joints was investigated experimentally. The specimens were subjected to reverse cyclic loading. The variable considered was the volume fraction of crimped steel fibres i.e., 0%, 0.5% and 1.0%. The results show that the addition of steel fibres improves the first crack load, strength, ductility, energy absorption capacity and initial stiffness of the beam.

A Study on the Cause and Reduction of Cracks in the Wall Connecting the Underground Parking Lot and the Apartment (지하주차장과 아파트 연결 벽체의 균열 원인 분석 및 저감방안 연구)

  • Shim, Hak-Bo;Park, Soon-Jeon
    • Proceedings of the Korean Institute of Building Construction Conference
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    • pp.161-162
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    • 2020
  • Cracks are caused by drying shrinkage between the upper part of the underground parking lot and the apartment wall. As a result of the investigation, the distance between the apartment and the apartment is more than 45m, and the top slab of the underground parking lot is usually flat when there is not with steps. Therefore, the crack occurs more when the underground parking lot is a PC slab than a RC slab. In this study, the reduction of cracks was conducted by extending the slab, expanding the beam size, increasing the wall thickness, and installing a delay joint on slab. In each case, a finite element analysis was performed to examine the crack reduction method.

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An Experimental Study on Structural Capacity of Joint Between Composite PHC Wall Pile and Bottom Slab with CT Shear Connector (CT형강 전단연결재가 적용된 합성형 PHC벽체파일-하부슬래브 연결부 성능에 관한 실험적 연구)

  • Mha, Ho Seong;Won, Jeong Hun;Lee, Jong Ku
    • Journal of Korean Society of Steel Construction
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    • v.25 no.5
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    • pp.531-541
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    • 2013
  • This paper investigated the structural capacity of the CT shear connectors, which is a kind of the perfobond rib and functions as an anchor transferring the tension force in the joint between a composite PHC wall pile and a bottom slab. The direct pull-out test was performed for various specimens. From failure modes and load-displacement curves, it was found that transverse rebars should be placed to holes in a web to restrict pull-out failure of CT shear connectors. The results of additional tests for specimens with transverse rebars and various support lengths indicated that all specimens were failed by the tension failure of PHC pile before pull-out failure of CT shear connector and concrete pull-out failure. Thus, the CT shear connector could endure the tension force between the PHC wall pile and the bottom slab.

Comparative Analysis of Track-Bridge Interaction of Sliding Slab Track and Rail Expansion Joint for Long-Span Railway Bridge (장경간 철도 교량에 적용된 슬라이딩 궤도와 레일신축이음장치의 궤도-교량 상호작용 비교)

  • Lee, Kyoung Chan;Jang, Seung Yup;Lee, Jungwhee;Choi, Hyun Sung
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.29 no.2
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    • pp.169-177
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    • 2016
  • Sliding slab track system, which consists of low friction sliding layer between track slab and bridge deck, is recently devised to reduce track-bridge interaction effect of continuously welded rail(CWR) without applying special devices such as rail expansion joint(REJ). In this study, a series of track-bridge interaction analyses of a long-span bridge with sliding slab track and REJ are performed respectively and the results are compared. The bridge model includes PSC box girder bridge with 9 continuous spans, and steel-concrete composite girder bridge with 2 continuous spans. The total length of the bridge model is 1,205m, and the maximum spacing between the two fixed supports is 825m. Analyses results showed that the sliding slab track system is highly effective on interaction reduction since lower rail additional axial stress is resulted than REJ application. Additionally, horizontal reaction forces in fixed supports were also reduced compared to the results of REJ application. However, higher slab axial forces were developed in the sliding slab track due to the temperature load. Therefore, track slab section of the sliding slab track system should be carefully designed against slab axial forces.

Features of Critical Tensile Stresses in Jointed Concrete Pavements under Environmental and Vehicle Loads (환경하중과 차량하중에 의한 줄눈콘크리트포장의 극한인장응력 특성 분석)

  • Kim, Seong-Min
    • Journal of the Korea Concrete Institute
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    • v.19 no.4
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    • pp.449-456
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    • 2007
  • This research was conducted to analyze the features of the critical tensile stresses at the top and bottom of the concrete slab in the jointed concrete pavement (JCP) when subjected to both the environmental and vehicle loads. First, the stress distribution in JCP was analyzed when the system was subjected to only the environmental loads or the vehicle loads by using the finite element model of JCP. Then, the stresses were analyzed when the system was subjected to the environmental and vehicle loads at the same time. From this study, it was found that the critical tensile stresses at the slab bottom under the vehicle loads were almost constant regardless of the loading positions once the loads were applied at the positions having some distance from the transverse joint. The critical tensile stresses at the slab bottom could be obtained using the model consisting of normal springs for underlying layers by adding the critical stresses due to the environmental loads and the vehicle loads for the curled-down slab, and by subtracting the critical stress due to the environmental loads from that due to the vehicle loads for the curled-up slab. The critical tensile stresses at the top of the slab could be obtained using the model consisting of tensionless springs for underlying layers by adding the critical stress due to the environmental loads and the stress at the middle of the slab under the vehicle loads applied at the joint for the curled-up slab. An alternative to obtain the critical stresses at the top of the slab for the curled-up slab was to use the critical stresses under only the environmental loads obtained from the model having normal springs for underlying layers.

Slab Effect on Inelastic Behaviors of High Strength RC Beam-Column Joints (고강도 RC 보-기둥 접합부의 비탄성 거동에 대한 슬래브의 영향)

  • 장극관;김윤일;오영훈
    • Magazine of the Korea Concrete Institute
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    • v.9 no.2
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    • pp.167-177
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    • 1997
  • In thtx design of ductile moment -1csist1ng frnmcls (DMRFs) f'ollow~ng the. stlong columnweakbeam design philosophy, it is desirable that the joint and column remain essentiallyelastic in order to insure proper energy dissipation and lateral stability of the structure.Thv joint has been identifid as the "weak link: in DMRFs because any stiffness orstrength deterioration in this region can lead to substantial drifts and the possibility ofcollapse due to t'-delta effects. h3oreove1.. the tngintw is faced with the difficult task ofdetailing an element whose size is determined by theframing members, but \vhich mustresist a set of loads very different from those used in the design of the beams and columns.Four 3 -scale beam-column-slab joint assemblies were designed according to existing cod\ulcornerrequirements of' ACI 318-89. representing perimeter joints of DMRFs with reinforced highstrength concrete. The influence on aseismic behavior of beam-column joints due tomonolithic slab, has been investigated.lab, has been investigated.

Evaluation of Shear Load Carrying Capacity of Lateral Supporting Concrete Block for Sliding Slab Track Considering Construction Joint (타설 경계면을 고려한 슬라이딩 궤도 횡방향 지지 콘크리트 블록의 전단 내하력 평가)

  • Lee, Seong-Cheol;Jang, Seung Yup;Lee, Kyoung-Chan
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.30 no.1
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    • pp.55-61
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    • 2017
  • Recently several researches have been conducted to develop sliding track system in which friction between concrete track and bridge slab has been reduced. This paper investigated shear load carrying capacity of lateral supporting concrete block which should be implemented to resist lateral load due to train in sliding track system. In order to evaluate shear load carrying capacity of lateral supporting concrete block, analytical model has been developed considering concrete friction and rebar dowel action along construction joint. The proposed model predicted test results on the shear load carrying capacity from literature conservatively by 13~23% because effect of aggregate interlock along crack surface was neglected. Since construction joint status is ambiguous on construction site, it can be concluded that the proposed model can be used for reasonable design of lateral supporting concrete block. Based on the proposed model, design proposal for lateral supporting concrete block has been established.

Flexural Behavior of MRS Continuous Joints for the Prestressed Concrete One-way Joist Slab System (프리스트레스 콘크리트 일방향 장선구조로 구축한 MRS 연속단 접합부의 휨거동)

  • Oh, Young-Hun;Moon, Jeong-Ho;Im, Ju-Hyeuk;Choi, Dong-Sup;Lee, Kang-Chul
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.1
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    • pp.148-155
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    • 2010
  • The purpose of this study is to propose and evaluate the continuous joint constructed with MRS system which is utilized for floor system in the parking structures or commercial retail buildings. Four specimens were fabricated and tested to examine the structural performance of the continuous joint with different joint detailing. Structural test for the specimens was undertaken to simulate the actual stress condition of the negative moment resisting connection in the prestressed precast concrete parking structures with 8m span. Based on the experimental results, the MRS system could be designed as the ductile continuous joint governed by flexural behavior. Therefore the MRS system developed in this study would provide a superior joint behavior to conventional double-tee system when constructing monolithic joint composed of simply supported precast members.

Effects of Reinforcing Method Influnced to the Shear Strength of Vertical and Horizontal Joints in Precast Concrete Large Panel Structures -Focused on the Vertical Joints and Slab-Slab Type Horizontal Joints- (대형판조립식 구조 수직.수평접합부의 전단강도에 미치는 보강방법의 영향-수직접합부 및 슬래브-슬래브 수평접합부를 중심으로-)

  • Chung, Lan;Park, Hyun-Soo;Cho, Seung-Ho
    • Magazine of the Korea Concrete Institute
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    • v.8 no.4
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    • pp.171-179
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    • 1996
  • A proposal of the basic fbrm on the design of joint parts that can increase the shear strength by the useful joint shapes of each member is intended. The vertical joint parameters are the number of' shear key and a variety of' reinfbrcement details and the horizontal joint paramctcrs arc t,hc number of shear key and the direction of' shear f'orcc. 10 PC panel vortical joint arid 12 PC panel horizontal joint specimens were tested to investigate the effects of these parameters. Test results show that : 1. The ductility of the test specimen that has the horizontal reinforcing steels is larger than that does not have. 2. The maximum resisting force of round bar specimen is similar to that of strand wire specimen under the condition of fixed horizontal displacement.

Curling Behavior of Long-Span Concrete Pavement Slab under Environmental Loads (환경하중에 의한 장스팬 콘크리트 포장 슬래브의 컬링 거동 특성 분석)

  • Kim, Seong-Min;Shim, Jae-Soo;Park, Hee-Beom;Yun, Dong-Ju
    • International Journal of Highway Engineering
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    • v.11 no.3
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    • pp.151-161
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    • 2009
  • This study was conducted to investigate the characteristics of the curling behavior of long-span pavement slabs under environmental loads. By developing and using finite element models of the long-span pavement slabs, the stress distribution and the effects of slab length, slab thickness, stiffness of underlying layers, and the restraints of the slab ends on the curling behavior were analyzed. In addition, the field experiments were performed with the actual long-span pavement slab to obtain the curling behavior of the real structure under environmental loads. As a result of this study, it was found that the vertical displacements of the long-span pavement slab along the centerline due to the curling behavior were zero except for the areas near the slab ends, and the curling stresses were maximum and constant where the displacements were zero. The slab length and the stiffness of underlying layers did not affect the maximum curling stresses. The restraints at the slab ends made the curling stresses occur near the slab ends, but did not much affect the maximum curling stresses.

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